Staffing Capacity and Ambulance Diversion inEmergency Departments United States 2003ndash04

by Catharine W Burt EdD and Linda F McCaig MPH Division of Health Care Statistics

Number 376 + September 27 2006

AbstractObjectivemdashThe increased demand for emergency department (ED) services

over the past decade has resulted in crowding This report presents estimates ofstructure and process characteristics of hospital EDs related to their capacity to treatmedical and surgical emergencies Estimates of EDs experiencing crowdedconditions are also presented

MethodsmdashSeveral facility supplements were added to the 2003ndash04 NationalHospital Ambulatory Medical Care Survey (NHAMCS) which were completed byhospital staff NHAMCS samples nonfederal short-stay and general hospitals in theUnited States Of all sample hospitals that operated 24-hour EDs 83 percentcompleted the supplemental questionnaires Data from 467 hospitals were weightedto produce national annual estimates of ED characteristics

ResultsmdashThere was an annual average of 4500 EDs operating in the UnitedStates during 2003 and 2004 Over one-half of EDs saw less than 20000 patientsannually but 1 out of 10 had an annual visit volume of more than 50000 patientsAlthough 161 percent of hospitals expanded their ED physical space within the last2 years approximately one-third of others planned to do so within the next 2 yearsMost EDs used outside contracts to provide physicians (647 percent) One-half ofEDs in metropolitan statistical areas (MSAs) had more than 5 percent of theirnursing positions vacant Of all on-call specialists the services of plastic and handsurgeons were most frequently reported as somewhat or very difficult to obtain(494 percent) Approximately one-third of US hospitals reported going onambulance diversion sometime in the previous year About 12 percent of hospitals inMSAs reported having spent between 5 and 19 percent of their operating time indiversion status Between 40 and 50 percent of US hospitals experienced crowdedconditions in the ED with almost two-thirds of metropolitan EDs experiencingcrowding

Keywords crowding c emergency department c NHAMCS

US DEPARTMENT OF HEALTH AND HUMAN SERVICESCenters for Disease Control and PreventionNational Center for Health Statistics

Acknowledgments

This report was prepared in the Division of Health Care Statistics Kimberly R Middleton in the Amdata Roberto H Valverde in the Technical Services Branch developed the analytical files This repInformation Services Information Design and Publishing Staff typeset by Annette F Holman CoCgraphics were produced by NOVA contractor Kyung Park of CoCHISNCHMDivision of Creative

IntroductionIn recent years growth in the use of

hospital emergency medical services(EMS) has coincided with a decline inthe number of EDs leading to concernsabout the capacity of EDs that continueto operate The annual number of EDvisits in the United States rose by 18between 1994 and 2004 (from 93million to 110 million) whereas thenumber of hospitals operating 24-hourEDs decreased by 12 during the sametime frame (1) Although most of theincrease in visits can be explained bygrowth in the US population overone-third is accounted for by the growthin per capita use during the last 11 years(2) Fewer EDs with increasing overallvolume led to average increases in thenumber of cases among operating EDs(up by 78 between 1995 and 2003)(Figure 1) (3)

A number of indicators have beenused to assess the capacity of EDs tohandle growth in demand including thetime patients wait to receive services(4) ED length of stay and treatmenttime (which decreases the availability of

bulatory Care Statistics Branch edited theort was edited by Klaudia M Cox Office ofHISNCHMDivision of Creative Services andServices

Figure 1 Volume of annual visits per operating emergency department United States1995ndash2003

Selected emergency department staffing capacity ambulance diversion andthroughput indexes at a glance

Index Total1 Metropolitan2Not

metropolitan3

Daily visit volume 676 934 258Standard treatment spaces 146 198 63Number of physicians with ED4 privileges 133 175 64Daily visits per treatment space 46 49 41Percent of nursing positions vacant 53 61 39Percent arriving by ambulance 130 138 118Average waiting time in minutes 371 458 228Average visit duration in minutes 1597 1816 1242Percent left before seen 14 18 07Percent transferred 30 21 45Percent admitted to hospital 125 134 111Inpatient staffed bed size 1365 1921 477Inpatient daily occupancy rate 603 664 506Annual hours on ambulance diversion 1460 2427 05

1Based on responses from 699 emergency departments2Emergency departments located in metropolitan statistical areas3Emergency departments located in micropolitan or rural areas4ED is emergency department

NOTE Means per emergency department in the United States 2003ndash04

2 Advance Data No 376 + September 27 2006

space for other patients) the extent towhich hospitals go on lsquolsquodiversionstatusrsquorsquo (periods of time whenambulances are diverted to otherhospitals) and the percentage of patientswho leave the ED without being seen(which may indicate patientsrsquo frustrationat long wait times or delays intreatment) These measures areimportant because they can be indicativeof systemic hospital inpatient problemssuch as a shortage of inpatient beds andnursing staff (5) As inpatient dischargesand days of care declined through the1980s and 1990s many hospitalsdecreased bed availability to cutoperating expenses and as a resultoccupancy rates increased therebydecreasing the hospitalsrsquo capacity tohandle an influx of patients from the ED(6) Until now there have been nonational estimates of occupancy ratesand their relationship with ambulancediversion practices

Understanding ED capacity isimportant because hospitals may beunable to accept incoming patients whenthe volume of ED visits increases to acertain level EDs experience pressurewhen patients are boarded to awaitadmission while additional cases areincoming The crowding problem isexacerbated by the fact that EDs arerequired by law to screen incomingpatients and if the patient needs

emergency treatment to treat or stabilizethe patient for transfer to anotherfacility The Emergency MedicalTreatment and Active Labor Act(EMTALA) places two requirements onhospitals first a hospital must providean appropriate medical screeningexamination to anyone who comes tothe ED and requests examination ortreatment for a medical condition or forwhom care is requested and second ifthe hospital determines that the person

has an emergency medical condition itmust provide appropriate stabilizationtreatment or transfer (and hospitalizationif it is deemed necessary) (7) Hospitalsare held liable for the cost of care ofpatients who are unable to pay theirbills Increased use of the ED bypersons unable to pay their bills notonly influences patient volume butleads to increased uncompensated careAlthough hospitals do not keep recordsof the amount of uncompensated carefor EMTALA-related care the AmericanHospital Association has calculated thatthe cost of uncompensated care was$269 billion for all communityhospitals in 2004 (8)

Besides increased waiting times andmore patients leaving without beingseen crowded EDs result in lengthenedEMS ambulance runs (9) ambulancediversion (610) greater risk for poorerpatient outcomes (11) and the lessenedability of hospitals to respond to publichealth emergencies including naturaldisasters and mass casualty incidents Inan effort to reduce crowding ambulancediversion practices resulted in thediversion of about 3 percent ofambulance patients to more distanthospitals (12) Among the many otherproblems faced by EDs are lack oftreatment space on-call specialists andlanguage translation services Much has

Advance Data No 376 + September 27 2006 3

been published on creative ways tohandle and measure ED crowding issues(13ndash18) including increasing theefficiency of and removing barriers topatient flow

Although the problem of EDcrowding has received national attention(19) there have been no previousnational surveys of how EDs operate insuch a challenging environment Thisreport is the first to describe theNationrsquos EDs in terms of their staffingand capacity (including staff relative totreatment space available) theavailability of specialized services (suchas translation services and access tospecialty physicians) the effect ofdemand and capacity on the ability toprovide services (in the form ofambulance diversions wait time andlength of stay) and variability amongEDs in areas that are metropolitan andnot metropolitan

See data highlights in the text boxon previous page

Methods

Sample and data collection

A series of special facilitysupplements were added to the 2003ndash04National Hospital Ambulatory MedicalCare Survey (NHAMCS) to assess thestructure and process characteristics ofhospitals related to their capacity to treatmedical and surgical emergenciesNHAMCS is a national probabilitysurvey conducted by the Centers forDisease Control and PreventionrsquosNational Center for Health Statistics(NCHS) The target of the NHAMCS isin-person visits made in the UnitedStates to outpatient departments (OPDs)and EDs of nonfederal short-stayhospitals (hospitals with an averagelength of stay of less than 30 days) orthose whose specialty is general(medical or surgical) or childrenrsquosgeneral The hospital sampling frameconsisted of hospitals listed in the 1991Verispan Hospital Database (VHD)updated using hospital data fromVerispan LLC specifically theirlsquolsquoHealthcare Market Index updated May15 2003rsquorsquo and their lsquolsquoHospital MarketProfiling Solution Second Quarter2003rsquorsquo These products were formerly

known as the SMG Hospital DatabaseUsing the 2003 data to update thesample allowed for the inclusion ofhospitals that had opened or changedtheir eligibility status since the previoussample was updated for 2001

The sample frame containsinformation about hospitals includinggeographic region metropolitanstatistical area status (metropolitan andnot metropolitan including rural areas)medical school affiliation ownershipand inpatient bed size Although theprimary purpose of NHAMCS is toestimate annual volume andcharacteristics of medical encountersoccurring in EDs and OPDs it alsoincludes facility-level information

A two-stage probability sampledesign is used to select EDs in theNHAMCS The design involves samplesof geographic primary sampling units(PSUs) such as counties or groups ofcounties representing the 50 states andthe District of Columbia and hospitalswithin PSUs Hospitals are randomlyassigned to 1 of 16 4-week rotatingpanels In any given year only 13panels are used Hospitals are eligiblefor ED facility questions if they reporthaving a 24-hour ED

A four-stage probability sample wasused to collect information on ED visitsThe sample involves 112 geographicPSUs hospitals that have EDs or OPDswithin PSUs emergency service areaswithin EDs and clinics within OPDsand patient visits within emergencyservice areas and clinics Hospital staffwere asked to complete Patient Recordforms for a systematic sample of 100visits that occur during a randomlyassigned 4-week reporting period The2003 NHAMCS was conducted fromDecember 30 2002 through December28 2003 and the 2004 NHAMCS wasconducted from December 29 2003through December 26 2004

To provide unbiased national annualestimates of EDs and theircharacteristics a facility weight wasconstructed for each responding ED thattakes into account the selection of thegeographic area and hospital as well assurvey nonresponse Detailedinformation on NHAMCS including itssample design and estimation strategiesis reported elsewhere (20) During 2003

and 2004 a total of 1060 hospitalswere approached to determine theireligibility An additional 66 hospitalsselected in 2003 were included withoutregard to sampled geographic areas toincrease the representation of rural andproprietary hospitals specifically formaking the facility-level estimates inthis report Of all sample hospitals thatoperated 24-hour EDs 83 percentcompleted the supplementalquestionnaires (n = 699 ED records (467unique hospitals of which 235responded in both 2003 and 2004)) andprovided the requisite amount ofencounter records (76842 visit records)See the lsquolsquoTechnical Notesrsquorsquo for samplesizes and weighted response rates byhospital characteristics

No personally identifyinginformation is collected in NHAMCSThe NHAMCS protocol was approvedby the NCHS Research Ethics ReviewBoard and an exception to patientauthorization for release of healthinformation for the survey was grantedfor compliance with the researchprovisions of the Health InformationPortability and Accountability ActPrivacy Rule The US Census Bureauwas responsible for data collection andprocessing of the supplements

Survey instruments

The supplements were self-reportinstruments which were left withhospital staff at the time of inductioninto NHAMCS The content of thesupplements included information onED staffing treatment and physicalspace language translation servicesinpatient occupancy and ambulancediversion Completed questionnaireswere collected after the hospitalrsquosassigned 4-week reporting period Therelevant content of the supplements isdescribed below

+ Staffing Capacity and AmbulanceDiversion (SCAD)mdashQuestions abouttreatment spaces expansion ofphysical space (2004 only)credentials of ED physicians contractstaffing nursing vacancies difficultyin providing on-call physiciancoverage for 19 specialties (2004only) availability of language

Sources for selected emergency department staffing capacity ambulance diversionand throughput indexes

Index Source

Daily visit volume Annual visit volume divided by 3655Standard treatment spaces Response from staffing capacity and ambulance

diversion (SCAD) questionNumber of physicians with ED1 privileges Response from SCAD questionDaily visits per treatment space Daily visit volume divided by number of standard

treatment spacesDaily visits per physician Daily visit volume divided by number of physicians with

ED1 privilegesPhysicians per space Number of physicians with ED1 privileges divided by

number of standard treatment spacesPercentage of nursing positions vacant Response from 2004 SCAD questionPercentage arriving by ambulance Percentage of sampled visits with ambulance as mode

of arrivalAverage waiting time in minutes Mean waiting time from sampled visitsAverage visit duration in minutes Mean length of stay from sampled visitsPercentage left before seen Percentage of sampled visits with left as a dispositionPercentage transferred Percentage of sampled visits with transfer as a

dispositionPercentage admitted to hospital Percentage of sampled visits with admit as a

dispositionInpatient staffed bed size Number of staffed beds from the sample frameInpatient daily occupancy rate Mean percentage of staffed beds occupied at midnight

during the 28-day reporting period from the HospitalCapacity Card

Annual hours on diversion Response from the bioterrorism question onambulance diversion hours

1ED is emergency department

4 Advance Data No 376 + September 27 2006

translation services and list oflanguages provided (2004 only) othernearby EDs and regulationsprohibiting ambulance diversion (seehttpwwwcdcgovnhamcsdataNHAMCS-903pdf for a copy of theform)

+ Ambulance Diversion LogmdashEntriesmade for each diversion periodexperienced during the 4-weekreporting period including start andend time reason for diversion andwho authorized the diversion status(see httpwwwcdcgovnhamcsdataNHAMCS-904pdf for a copy of thelog)

+ Hospital Capacity CardmdashNumbersand types of licensed and staffedinpatient beds daily entries ofinpatient census and number of openbeds as of midnight for each dayduring the reporting period (seehttpwwwcdcgovnhamcsdataNHAMCS-902pdf for a copy of thecard)

+ Bioterrorism and Mass CasualtyPreparedness (BT supplement)mdashTotalnumber of hours on ambulancediversion during the previous year(see httpwwwcdcgovnhamcsdataNHAMCS-905pdf for a copy of theform) For estimates from other itemsin this supplement see httpwwwcdcgovnchsdataadad364pdf

Capacity and diversion measureswere created for each ED from the datacollected on the above forms For eachresponding ED information from thediversion log was used to create anaverage length of a diversion (median)and summed to create total time ondiversion during the reporting periodThe number of diversion entries wasalso summed to provide a total numberof diversion periods in each EDPercentages of time on diversion werecalculated for each reason reported(multiple entries allowed per diversionperiod) The daily inpatient censusinformation for each of the 28 days andthe number of staffed beds reported onthe Hospital Capacity Card were used tocalculate an average daily occupancyrate (mean) for each ED Although thevariation among days in occupancy ratesand numbers of diversion periods is ofinterest these variables were

summarized to provide a single measureof each ED for analysis in this report

Analysis

For this report aggregated estimatesof each sampled hospitalrsquos EDutilization were created to describe howEDs vary with regard to importantfacility use characteristics Theseaggregated estimates come from thePatient Record form responses for eachED (see httpwwwcdcgovnchsdataahcdNHAMCS-100(ED)2004pdf for acopy of the form) and were merged toeach ED record that contained data onthe facility from the induction interviewsupplements and sample frame Tablesin this report have estimates for all EDsand separate estimates for EDs locatedin areas that are metropolitan and notmetropolitan Metropolitan status isbased on the US Census Bureau 2003definitions of MSAs Hospitals locatedin MSAs are considered metropolitanhospitals and the remaining areconsidered not metropolitan hospitalsand include those located inmicropolitan and rural areas Hospitalresponses were weighted to produce

national estimates averaged over 2003and 2004 There were a few supplementquestions that were asked only during2004 for which the 2004 estimate issupplied Because estimates are basedon a sample rather than the entireuniverse they are subject to samplingvariability Standard errors werecalculated using Taylor approximationsin SUDAAN which take into accountthe complex sample design ofNHAMCS (21) Estimates whosestandard error represents more than30 percent of the estimate have anasterisk () to indicate that they do notmeet the reliability standard set byNCHS Determination of statisticalsignificance was based at the 005 levelAdditional information regardingNHAMCS data collection sampling ornonsampling errors and estimation andtests of significance can be found inanother publication (22)

Indexes of staffing capacityambulance diversion and throughput foreach ED were created from the abovedata elements based on those suggestedin the Solberg et al article (18) Theyare shown in the text box below

Figure 1 Volume of annual visits per operating emergency department United States1995ndash2003

Selected emergency department staffing capacity ambulance diversion andthroughput indexes at a glance

Index Total1 Metropolitan2Not

metropolitan3

Daily visit volume 676 934 258Standard treatment spaces 146 198 63Number of physicians with ED4 privileges 133 175 64Daily visits per treatment space 46 49 41Percent of nursing positions vacant 53 61 39Percent arriving by ambulance 130 138 118Average waiting time in minutes 371 458 228Average visit duration in minutes 1597 1816 1242Percent left before seen 14 18 07Percent transferred 30 21 45Percent admitted to hospital 125 134 111Inpatient staffed bed size 1365 1921 477Inpatient daily occupancy rate 603 664 506Annual hours on ambulance diversion 1460 2427 05

1Based on responses from 699 emergency departments2Emergency departments located in metropolitan statistical areas3Emergency departments located in micropolitan or rural areas4ED is emergency department

NOTE Means per emergency department in the United States 2003ndash04

2 Advance Data No 376 + September 27 2006

space for other patients) the extent towhich hospitals go on lsquolsquodiversionstatusrsquorsquo (periods of time whenambulances are diverted to otherhospitals) and the percentage of patientswho leave the ED without being seen(which may indicate patientsrsquo frustrationat long wait times or delays intreatment) These measures areimportant because they can be indicativeof systemic hospital inpatient problemssuch as a shortage of inpatient beds andnursing staff (5) As inpatient dischargesand days of care declined through the1980s and 1990s many hospitalsdecreased bed availability to cutoperating expenses and as a resultoccupancy rates increased therebydecreasing the hospitalsrsquo capacity tohandle an influx of patients from the ED(6) Until now there have been nonational estimates of occupancy ratesand their relationship with ambulancediversion practices

Understanding ED capacity isimportant because hospitals may beunable to accept incoming patients whenthe volume of ED visits increases to acertain level EDs experience pressurewhen patients are boarded to awaitadmission while additional cases areincoming The crowding problem isexacerbated by the fact that EDs arerequired by law to screen incomingpatients and if the patient needs

emergency treatment to treat or stabilizethe patient for transfer to anotherfacility The Emergency MedicalTreatment and Active Labor Act(EMTALA) places two requirements onhospitals first a hospital must providean appropriate medical screeningexamination to anyone who comes tothe ED and requests examination ortreatment for a medical condition or forwhom care is requested and second ifthe hospital determines that the person

has an emergency medical condition itmust provide appropriate stabilizationtreatment or transfer (and hospitalizationif it is deemed necessary) (7) Hospitalsare held liable for the cost of care ofpatients who are unable to pay theirbills Increased use of the ED bypersons unable to pay their bills notonly influences patient volume butleads to increased uncompensated careAlthough hospitals do not keep recordsof the amount of uncompensated carefor EMTALA-related care the AmericanHospital Association has calculated thatthe cost of uncompensated care was$269 billion for all communityhospitals in 2004 (8)

Besides increased waiting times andmore patients leaving without beingseen crowded EDs result in lengthenedEMS ambulance runs (9) ambulancediversion (610) greater risk for poorerpatient outcomes (11) and the lessenedability of hospitals to respond to publichealth emergencies including naturaldisasters and mass casualty incidents Inan effort to reduce crowding ambulancediversion practices resulted in thediversion of about 3 percent ofambulance patients to more distanthospitals (12) Among the many otherproblems faced by EDs are lack oftreatment space on-call specialists andlanguage translation services Much has

Advance Data No 376 + September 27 2006 3

been published on creative ways tohandle and measure ED crowding issues(13ndash18) including increasing theefficiency of and removing barriers topatient flow

Although the problem of EDcrowding has received national attention(19) there have been no previousnational surveys of how EDs operate insuch a challenging environment Thisreport is the first to describe theNationrsquos EDs in terms of their staffingand capacity (including staff relative totreatment space available) theavailability of specialized services (suchas translation services and access tospecialty physicians) the effect ofdemand and capacity on the ability toprovide services (in the form ofambulance diversions wait time andlength of stay) and variability amongEDs in areas that are metropolitan andnot metropolitan

See data highlights in the text boxon previous page

Methods

Sample and data collection

A series of special facilitysupplements were added to the 2003ndash04National Hospital Ambulatory MedicalCare Survey (NHAMCS) to assess thestructure and process characteristics ofhospitals related to their capacity to treatmedical and surgical emergenciesNHAMCS is a national probabilitysurvey conducted by the Centers forDisease Control and PreventionrsquosNational Center for Health Statistics(NCHS) The target of the NHAMCS isin-person visits made in the UnitedStates to outpatient departments (OPDs)and EDs of nonfederal short-stayhospitals (hospitals with an averagelength of stay of less than 30 days) orthose whose specialty is general(medical or surgical) or childrenrsquosgeneral The hospital sampling frameconsisted of hospitals listed in the 1991Verispan Hospital Database (VHD)updated using hospital data fromVerispan LLC specifically theirlsquolsquoHealthcare Market Index updated May15 2003rsquorsquo and their lsquolsquoHospital MarketProfiling Solution Second Quarter2003rsquorsquo These products were formerly

known as the SMG Hospital DatabaseUsing the 2003 data to update thesample allowed for the inclusion ofhospitals that had opened or changedtheir eligibility status since the previoussample was updated for 2001

The sample frame containsinformation about hospitals includinggeographic region metropolitanstatistical area status (metropolitan andnot metropolitan including rural areas)medical school affiliation ownershipand inpatient bed size Although theprimary purpose of NHAMCS is toestimate annual volume andcharacteristics of medical encountersoccurring in EDs and OPDs it alsoincludes facility-level information

A two-stage probability sampledesign is used to select EDs in theNHAMCS The design involves samplesof geographic primary sampling units(PSUs) such as counties or groups ofcounties representing the 50 states andthe District of Columbia and hospitalswithin PSUs Hospitals are randomlyassigned to 1 of 16 4-week rotatingpanels In any given year only 13panels are used Hospitals are eligiblefor ED facility questions if they reporthaving a 24-hour ED

A four-stage probability sample wasused to collect information on ED visitsThe sample involves 112 geographicPSUs hospitals that have EDs or OPDswithin PSUs emergency service areaswithin EDs and clinics within OPDsand patient visits within emergencyservice areas and clinics Hospital staffwere asked to complete Patient Recordforms for a systematic sample of 100visits that occur during a randomlyassigned 4-week reporting period The2003 NHAMCS was conducted fromDecember 30 2002 through December28 2003 and the 2004 NHAMCS wasconducted from December 29 2003through December 26 2004

To provide unbiased national annualestimates of EDs and theircharacteristics a facility weight wasconstructed for each responding ED thattakes into account the selection of thegeographic area and hospital as well assurvey nonresponse Detailedinformation on NHAMCS including itssample design and estimation strategiesis reported elsewhere (20) During 2003

and 2004 a total of 1060 hospitalswere approached to determine theireligibility An additional 66 hospitalsselected in 2003 were included withoutregard to sampled geographic areas toincrease the representation of rural andproprietary hospitals specifically formaking the facility-level estimates inthis report Of all sample hospitals thatoperated 24-hour EDs 83 percentcompleted the supplementalquestionnaires (n = 699 ED records (467unique hospitals of which 235responded in both 2003 and 2004)) andprovided the requisite amount ofencounter records (76842 visit records)See the lsquolsquoTechnical Notesrsquorsquo for samplesizes and weighted response rates byhospital characteristics

No personally identifyinginformation is collected in NHAMCSThe NHAMCS protocol was approvedby the NCHS Research Ethics ReviewBoard and an exception to patientauthorization for release of healthinformation for the survey was grantedfor compliance with the researchprovisions of the Health InformationPortability and Accountability ActPrivacy Rule The US Census Bureauwas responsible for data collection andprocessing of the supplements

Survey instruments

The supplements were self-reportinstruments which were left withhospital staff at the time of inductioninto NHAMCS The content of thesupplements included information onED staffing treatment and physicalspace language translation servicesinpatient occupancy and ambulancediversion Completed questionnaireswere collected after the hospitalrsquosassigned 4-week reporting period Therelevant content of the supplements isdescribed below

+ Staffing Capacity and AmbulanceDiversion (SCAD)mdashQuestions abouttreatment spaces expansion ofphysical space (2004 only)credentials of ED physicians contractstaffing nursing vacancies difficultyin providing on-call physiciancoverage for 19 specialties (2004only) availability of language

Sources for selected emergency department staffing capacity ambulance diversionand throughput indexes

Index Source

Daily visit volume Annual visit volume divided by 3655Standard treatment spaces Response from staffing capacity and ambulance

diversion (SCAD) questionNumber of physicians with ED1 privileges Response from SCAD questionDaily visits per treatment space Daily visit volume divided by number of standard

treatment spacesDaily visits per physician Daily visit volume divided by number of physicians with

ED1 privilegesPhysicians per space Number of physicians with ED1 privileges divided by

number of standard treatment spacesPercentage of nursing positions vacant Response from 2004 SCAD questionPercentage arriving by ambulance Percentage of sampled visits with ambulance as mode

of arrivalAverage waiting time in minutes Mean waiting time from sampled visitsAverage visit duration in minutes Mean length of stay from sampled visitsPercentage left before seen Percentage of sampled visits with left as a dispositionPercentage transferred Percentage of sampled visits with transfer as a

dispositionPercentage admitted to hospital Percentage of sampled visits with admit as a

dispositionInpatient staffed bed size Number of staffed beds from the sample frameInpatient daily occupancy rate Mean percentage of staffed beds occupied at midnight

during the 28-day reporting period from the HospitalCapacity Card

Annual hours on diversion Response from the bioterrorism question onambulance diversion hours

1ED is emergency department

4 Advance Data No 376 + September 27 2006

translation services and list oflanguages provided (2004 only) othernearby EDs and regulationsprohibiting ambulance diversion (seehttpwwwcdcgovnhamcsdataNHAMCS-903pdf for a copy of theform)

+ Ambulance Diversion LogmdashEntriesmade for each diversion periodexperienced during the 4-weekreporting period including start andend time reason for diversion andwho authorized the diversion status(see httpwwwcdcgovnhamcsdataNHAMCS-904pdf for a copy of thelog)

+ Hospital Capacity CardmdashNumbersand types of licensed and staffedinpatient beds daily entries ofinpatient census and number of openbeds as of midnight for each dayduring the reporting period (seehttpwwwcdcgovnhamcsdataNHAMCS-902pdf for a copy of thecard)

+ Bioterrorism and Mass CasualtyPreparedness (BT supplement)mdashTotalnumber of hours on ambulancediversion during the previous year(see httpwwwcdcgovnhamcsdataNHAMCS-905pdf for a copy of theform) For estimates from other itemsin this supplement see httpwwwcdcgovnchsdataadad364pdf

Capacity and diversion measureswere created for each ED from the datacollected on the above forms For eachresponding ED information from thediversion log was used to create anaverage length of a diversion (median)and summed to create total time ondiversion during the reporting periodThe number of diversion entries wasalso summed to provide a total numberof diversion periods in each EDPercentages of time on diversion werecalculated for each reason reported(multiple entries allowed per diversionperiod) The daily inpatient censusinformation for each of the 28 days andthe number of staffed beds reported onthe Hospital Capacity Card were used tocalculate an average daily occupancyrate (mean) for each ED Although thevariation among days in occupancy ratesand numbers of diversion periods is ofinterest these variables were

summarized to provide a single measureof each ED for analysis in this report

Analysis

For this report aggregated estimatesof each sampled hospitalrsquos EDutilization were created to describe howEDs vary with regard to importantfacility use characteristics Theseaggregated estimates come from thePatient Record form responses for eachED (see httpwwwcdcgovnchsdataahcdNHAMCS-100(ED)2004pdf for acopy of the form) and were merged toeach ED record that contained data onthe facility from the induction interviewsupplements and sample frame Tablesin this report have estimates for all EDsand separate estimates for EDs locatedin areas that are metropolitan and notmetropolitan Metropolitan status isbased on the US Census Bureau 2003definitions of MSAs Hospitals locatedin MSAs are considered metropolitanhospitals and the remaining areconsidered not metropolitan hospitalsand include those located inmicropolitan and rural areas Hospitalresponses were weighted to produce

national estimates averaged over 2003and 2004 There were a few supplementquestions that were asked only during2004 for which the 2004 estimate issupplied Because estimates are basedon a sample rather than the entireuniverse they are subject to samplingvariability Standard errors werecalculated using Taylor approximationsin SUDAAN which take into accountthe complex sample design ofNHAMCS (21) Estimates whosestandard error represents more than30 percent of the estimate have anasterisk () to indicate that they do notmeet the reliability standard set byNCHS Determination of statisticalsignificance was based at the 005 levelAdditional information regardingNHAMCS data collection sampling ornonsampling errors and estimation andtests of significance can be found inanother publication (22)

Indexes of staffing capacityambulance diversion and throughput foreach ED were created from the abovedata elements based on those suggestedin the Solberg et al article (18) Theyare shown in the text box below

Advance Data No 376 + September 27 2006 3

been published on creative ways tohandle and measure ED crowding issues(13ndash18) including increasing theefficiency of and removing barriers topatient flow

Although the problem of EDcrowding has received national attention(19) there have been no previousnational surveys of how EDs operate insuch a challenging environment Thisreport is the first to describe theNationrsquos EDs in terms of their staffingand capacity (including staff relative totreatment space available) theavailability of specialized services (suchas translation services and access tospecialty physicians) the effect ofdemand and capacity on the ability toprovide services (in the form ofambulance diversions wait time andlength of stay) and variability amongEDs in areas that are metropolitan andnot metropolitan

See data highlights in the text boxon previous page

Methods

Sample and data collection

A series of special facilitysupplements were added to the 2003ndash04National Hospital Ambulatory MedicalCare Survey (NHAMCS) to assess thestructure and process characteristics ofhospitals related to their capacity to treatmedical and surgical emergenciesNHAMCS is a national probabilitysurvey conducted by the Centers forDisease Control and PreventionrsquosNational Center for Health Statistics(NCHS) The target of the NHAMCS isin-person visits made in the UnitedStates to outpatient departments (OPDs)and EDs of nonfederal short-stayhospitals (hospitals with an averagelength of stay of less than 30 days) orthose whose specialty is general(medical or surgical) or childrenrsquosgeneral The hospital sampling frameconsisted of hospitals listed in the 1991Verispan Hospital Database (VHD)updated using hospital data fromVerispan LLC specifically theirlsquolsquoHealthcare Market Index updated May15 2003rsquorsquo and their lsquolsquoHospital MarketProfiling Solution Second Quarter2003rsquorsquo These products were formerly

known as the SMG Hospital DatabaseUsing the 2003 data to update thesample allowed for the inclusion ofhospitals that had opened or changedtheir eligibility status since the previoussample was updated for 2001

The sample frame containsinformation about hospitals includinggeographic region metropolitanstatistical area status (metropolitan andnot metropolitan including rural areas)medical school affiliation ownershipand inpatient bed size Although theprimary purpose of NHAMCS is toestimate annual volume andcharacteristics of medical encountersoccurring in EDs and OPDs it alsoincludes facility-level information

A two-stage probability sampledesign is used to select EDs in theNHAMCS The design involves samplesof geographic primary sampling units(PSUs) such as counties or groups ofcounties representing the 50 states andthe District of Columbia and hospitalswithin PSUs Hospitals are randomlyassigned to 1 of 16 4-week rotatingpanels In any given year only 13panels are used Hospitals are eligiblefor ED facility questions if they reporthaving a 24-hour ED

A four-stage probability sample wasused to collect information on ED visitsThe sample involves 112 geographicPSUs hospitals that have EDs or OPDswithin PSUs emergency service areaswithin EDs and clinics within OPDsand patient visits within emergencyservice areas and clinics Hospital staffwere asked to complete Patient Recordforms for a systematic sample of 100visits that occur during a randomlyassigned 4-week reporting period The2003 NHAMCS was conducted fromDecember 30 2002 through December28 2003 and the 2004 NHAMCS wasconducted from December 29 2003through December 26 2004

To provide unbiased national annualestimates of EDs and theircharacteristics a facility weight wasconstructed for each responding ED thattakes into account the selection of thegeographic area and hospital as well assurvey nonresponse Detailedinformation on NHAMCS including itssample design and estimation strategiesis reported elsewhere (20) During 2003

and 2004 a total of 1060 hospitalswere approached to determine theireligibility An additional 66 hospitalsselected in 2003 were included withoutregard to sampled geographic areas toincrease the representation of rural andproprietary hospitals specifically formaking the facility-level estimates inthis report Of all sample hospitals thatoperated 24-hour EDs 83 percentcompleted the supplementalquestionnaires (n = 699 ED records (467unique hospitals of which 235responded in both 2003 and 2004)) andprovided the requisite amount ofencounter records (76842 visit records)See the lsquolsquoTechnical Notesrsquorsquo for samplesizes and weighted response rates byhospital characteristics

No personally identifyinginformation is collected in NHAMCSThe NHAMCS protocol was approvedby the NCHS Research Ethics ReviewBoard and an exception to patientauthorization for release of healthinformation for the survey was grantedfor compliance with the researchprovisions of the Health InformationPortability and Accountability ActPrivacy Rule The US Census Bureauwas responsible for data collection andprocessing of the supplements

Survey instruments

The supplements were self-reportinstruments which were left withhospital staff at the time of inductioninto NHAMCS The content of thesupplements included information onED staffing treatment and physicalspace language translation servicesinpatient occupancy and ambulancediversion Completed questionnaireswere collected after the hospitalrsquosassigned 4-week reporting period Therelevant content of the supplements isdescribed below

+ Staffing Capacity and AmbulanceDiversion (SCAD)mdashQuestions abouttreatment spaces expansion ofphysical space (2004 only)credentials of ED physicians contractstaffing nursing vacancies difficultyin providing on-call physiciancoverage for 19 specialties (2004only) availability of language

Sources for selected emergency department staffing capacity ambulance diversionand throughput indexes

Index Source

Daily visit volume Annual visit volume divided by 3655Standard treatment spaces Response from staffing capacity and ambulance

diversion (SCAD) questionNumber of physicians with ED1 privileges Response from SCAD questionDaily visits per treatment space Daily visit volume divided by number of standard

treatment spacesDaily visits per physician Daily visit volume divided by number of physicians with

ED1 privilegesPhysicians per space Number of physicians with ED1 privileges divided by

number of standard treatment spacesPercentage of nursing positions vacant Response from 2004 SCAD questionPercentage arriving by ambulance Percentage of sampled visits with ambulance as mode

of arrivalAverage waiting time in minutes Mean waiting time from sampled visitsAverage visit duration in minutes Mean length of stay from sampled visitsPercentage left before seen Percentage of sampled visits with left as a dispositionPercentage transferred Percentage of sampled visits with transfer as a

dispositionPercentage admitted to hospital Percentage of sampled visits with admit as a

dispositionInpatient staffed bed size Number of staffed beds from the sample frameInpatient daily occupancy rate Mean percentage of staffed beds occupied at midnight

during the 28-day reporting period from the HospitalCapacity Card

Annual hours on diversion Response from the bioterrorism question onambulance diversion hours

1ED is emergency department

4 Advance Data No 376 + September 27 2006

translation services and list oflanguages provided (2004 only) othernearby EDs and regulationsprohibiting ambulance diversion (seehttpwwwcdcgovnhamcsdataNHAMCS-903pdf for a copy of theform)

+ Ambulance Diversion LogmdashEntriesmade for each diversion periodexperienced during the 4-weekreporting period including start andend time reason for diversion andwho authorized the diversion status(see httpwwwcdcgovnhamcsdataNHAMCS-904pdf for a copy of thelog)

+ Hospital Capacity CardmdashNumbersand types of licensed and staffedinpatient beds daily entries ofinpatient census and number of openbeds as of midnight for each dayduring the reporting period (seehttpwwwcdcgovnhamcsdataNHAMCS-902pdf for a copy of thecard)

+ Bioterrorism and Mass CasualtyPreparedness (BT supplement)mdashTotalnumber of hours on ambulancediversion during the previous year(see httpwwwcdcgovnhamcsdataNHAMCS-905pdf for a copy of theform) For estimates from other itemsin this supplement see httpwwwcdcgovnchsdataadad364pdf

Capacity and diversion measureswere created for each ED from the datacollected on the above forms For eachresponding ED information from thediversion log was used to create anaverage length of a diversion (median)and summed to create total time ondiversion during the reporting periodThe number of diversion entries wasalso summed to provide a total numberof diversion periods in each EDPercentages of time on diversion werecalculated for each reason reported(multiple entries allowed per diversionperiod) The daily inpatient censusinformation for each of the 28 days andthe number of staffed beds reported onthe Hospital Capacity Card were used tocalculate an average daily occupancyrate (mean) for each ED Although thevariation among days in occupancy ratesand numbers of diversion periods is ofinterest these variables were

summarized to provide a single measureof each ED for analysis in this report

Analysis

For this report aggregated estimatesof each sampled hospitalrsquos EDutilization were created to describe howEDs vary with regard to importantfacility use characteristics Theseaggregated estimates come from thePatient Record form responses for eachED (see httpwwwcdcgovnchsdataahcdNHAMCS-100(ED)2004pdf for acopy of the form) and were merged toeach ED record that contained data onthe facility from the induction interviewsupplements and sample frame Tablesin this report have estimates for all EDsand separate estimates for EDs locatedin areas that are metropolitan and notmetropolitan Metropolitan status isbased on the US Census Bureau 2003definitions of MSAs Hospitals locatedin MSAs are considered metropolitanhospitals and the remaining areconsidered not metropolitan hospitalsand include those located inmicropolitan and rural areas Hospitalresponses were weighted to produce

national estimates averaged over 2003and 2004 There were a few supplementquestions that were asked only during2004 for which the 2004 estimate issupplied Because estimates are basedon a sample rather than the entireuniverse they are subject to samplingvariability Standard errors werecalculated using Taylor approximationsin SUDAAN which take into accountthe complex sample design ofNHAMCS (21) Estimates whosestandard error represents more than30 percent of the estimate have anasterisk () to indicate that they do notmeet the reliability standard set byNCHS Determination of statisticalsignificance was based at the 005 levelAdditional information regardingNHAMCS data collection sampling ornonsampling errors and estimation andtests of significance can be found inanother publication (22)

Indexes of staffing capacityambulance diversion and throughput foreach ED were created from the abovedata elements based on those suggestedin the Solberg et al article (18) Theyare shown in the text box below

Sources for selected emergency department staffing capacity ambulance diversionand throughput indexes

Index Source

Daily visit volume Annual visit volume divided by 3655Standard treatment spaces Response from staffing capacity and ambulance

diversion (SCAD) questionNumber of physicians with ED1 privileges Response from SCAD questionDaily visits per treatment space Daily visit volume divided by number of standard

treatment spacesDaily visits per physician Daily visit volume divided by number of physicians with

ED1 privilegesPhysicians per space Number of physicians with ED1 privileges divided by

number of standard treatment spacesPercentage of nursing positions vacant Response from 2004 SCAD questionPercentage arriving by ambulance Percentage of sampled visits with ambulance as mode

of arrivalAverage waiting time in minutes Mean waiting time from sampled visitsAverage visit duration in minutes Mean length of stay from sampled visitsPercentage left before seen Percentage of sampled visits with left as a dispositionPercentage transferred Percentage of sampled visits with transfer as a

dispositionPercentage admitted to hospital Percentage of sampled visits with admit as a

dispositionInpatient staffed bed size Number of staffed beds from the sample frameInpatient daily occupancy rate Mean percentage of staffed beds occupied at midnight

during the 28-day reporting period from the HospitalCapacity Card

Annual hours on diversion Response from the bioterrorism question onambulance diversion hours

1ED is emergency department

4 Advance Data No 376 + September 27 2006

translation services and list oflanguages provided (2004 only) othernearby EDs and regulationsprohibiting ambulance diversion (seehttpwwwcdcgovnhamcsdataNHAMCS-903pdf for a copy of theform)

+ Ambulance Diversion LogmdashEntriesmade for each diversion periodexperienced during the 4-weekreporting period including start andend time reason for diversion andwho authorized the diversion status(see httpwwwcdcgovnhamcsdataNHAMCS-904pdf for a copy of thelog)

+ Hospital Capacity CardmdashNumbersand types of licensed and staffedinpatient beds daily entries ofinpatient census and number of openbeds as of midnight for each dayduring the reporting period (seehttpwwwcdcgovnhamcsdataNHAMCS-902pdf for a copy of thecard)

+ Bioterrorism and Mass CasualtyPreparedness (BT supplement)mdashTotalnumber of hours on ambulancediversion during the previous year(see httpwwwcdcgovnhamcsdataNHAMCS-905pdf for a copy of theform) For estimates from other itemsin this supplement see httpwwwcdcgovnchsdataadad364pdf

Capacity and diversion measureswere created for each ED from the datacollected on the above forms For eachresponding ED information from thediversion log was used to create anaverage length of a diversion (median)and summed to create total time ondiversion during the reporting periodThe number of diversion entries wasalso summed to provide a total numberof diversion periods in each EDPercentages of time on diversion werecalculated for each reason reported(multiple entries allowed per diversionperiod) The daily inpatient censusinformation for each of the 28 days andthe number of staffed beds reported onthe Hospital Capacity Card were used tocalculate an average daily occupancyrate (mean) for each ED Although thevariation among days in occupancy ratesand numbers of diversion periods is ofinterest these variables were

summarized to provide a single measureof each ED for analysis in this report

Analysis

For this report aggregated estimatesof each sampled hospitalrsquos EDutilization were created to describe howEDs vary with regard to importantfacility use characteristics Theseaggregated estimates come from thePatient Record form responses for eachED (see httpwwwcdcgovnchsdataahcdNHAMCS-100(ED)2004pdf for acopy of the form) and were merged toeach ED record that contained data onthe facility from the induction interviewsupplements and sample frame Tablesin this report have estimates for all EDsand separate estimates for EDs locatedin areas that are metropolitan and notmetropolitan Metropolitan status isbased on the US Census Bureau 2003definitions of MSAs Hospitals locatedin MSAs are considered metropolitanhospitals and the remaining areconsidered not metropolitan hospitalsand include those located inmicropolitan and rural areas Hospitalresponses were weighted to produce

national estimates averaged over 2003and 2004 There were a few supplementquestions that were asked only during2004 for which the 2004 estimate issupplied Because estimates are basedon a sample rather than the entireuniverse they are subject to samplingvariability Standard errors werecalculated using Taylor approximationsin SUDAAN which take into accountthe complex sample design ofNHAMCS (21) Estimates whosestandard error represents more than30 percent of the estimate have anasterisk () to indicate that they do notmeet the reliability standard set byNCHS Determination of statisticalsignificance was based at the 005 levelAdditional information regardingNHAMCS data collection sampling ornonsampling errors and estimation andtests of significance can be found inanother publication (22)

Indexes of staffing capacityambulance diversion and throughput foreach ED were created from the abovedata elements based on those suggestedin the Solberg et al article (18) Theyare shown in the text box below

Figure 2 Percentage of emergency departments that have recently expanded or plan toexpand physical space by selected characteristics United States 2004

Advance Data No 376 + September 27 2006 5

Crowding in the ED is a result ofdemand exceeding capacity Althoughcrowding is often measured as anopinion of ED staff or recentlymeasured as full waiting rooms (23 24)NHAMCS did not collect these dataelements To estimate the number ofhospitals experiencing ED crowdingresponses to the SCAD and BTsupplements and estimates of throughputfrom the NHAMCS visit data for eachhospital were used Therefore in thisreport the measure of whether the EDexperienced crowded conditions wasobtained using the following criteriahaving any ambulance diversion hoursreported having a mean waiting timefor urgent cases greater than 60 minutesor having the percentage of cases leftwithout being seen greater than or equalto 3 percent In a raw sample 428 EDrecords met the criteria for crowdingand 149 did not A national estimate ofthe percentage of hospitals experiencingcrowding is presented as well as thoseindexes with significant differences(p lt 05) between EDs experiencingcrowded conditions and those that didnot

ResultsThere was an average of 4500 EDs

operating in the United States during2003 and 2004 Two-thirds were locatedin states within the Midwest and South4 out of 10 were located in areas thatare not metropolitan (Table 1) MostEDs were operated by voluntarynonprofit hospitals (652 percent) andmany were located in hospitals withfewer than 100 beds (572 percent)Public hospitals accounted for one-quarter of all EDs Over one-half ofEDs saw fewer than 20000 casesannually but 1 out of 10 EDs had anannual visit volume of more than 50000cases EDs in metropolitan areas tendedto have a much larger visit volume thantheir counterparts in areas that are notmetropolitan The average dailyinpatient occupancy rate in metropolitanhospitals was also larger than inhospitals in areas that were notmetropolitan One-half of hospitals notin metropolitan areas reportedoccupancy rates under 50 percent

compared with 171 percent ofmetropolitan hospitals

Treatment spaces

EDs in metropolitan areas reportedmore standard and auxiliary treatmentspaces than those not in metropolitanareas (Table 2) Auxiliary treatmentspaces may include chairs or hallwaystretchers Due to the higher volumefound in metropolitan areasmetropolitan EDs were more likely tohave increased both the number oftreatment spaces and their physicalspace within the last 2 years Although161 percent of all hospitals expandedtheir ED physical space within the last 2years approximately one-third of othersplan to do so within the next 2 yearsAbout 432 percent of all EDs recentlyexpanded or plan to do so butexpansion varied by most EDcharacteristics (Figure 2) EDs morelikely to choose expansion includedthose with higher volume thoseclassified as proprietary voluntary ornonprofit those affiliated with medicalschools and those with any ambulance

diversion hours reported and largeraverage visit durations

Staffing

Most EDs employed physiciansusing outside contracts (647 percent)Presence of emergency medicinespecialists (either through boardcertification or emergency medicineresidency programs) varied greatlyacross hospitals (Table 3) In many EDs(387 percent) some or all EDphysicians had responsibilities elsewherein the hospital such as providinginpatient care or administrativefunctions Physicians in hospitals inareas that were not metropolitan weremore apt to have non-EDresponsibilities than those inmetropolitan hospitals EDs inmetropolitan areas were more likely tohave nursing vacancies Although347 percent of metropolitan EDs had5 or more of their nursing positionsvacant only 183 percent of EDs inareas that were not metropolitan had 5or more vacant nursing positions(calculated from Table 3) About

Figure 3 Percentage of emergency departments indicating difficulty in providing on-callphysicians by physician specialty United States 2004

Figure 4 Mean percentage of diversion hours by reasons for diversion United States2003ndash04

6 Advance Data No 376 + September 27 2006

three-quarters of EDs that were not inmetropolitan areas reported that lessthan 5 of nursing positions werevacant compared with one-half ofmetropolitan EDs Difficulties inobtaining services of on-call specialistswere reported in many EDs with plasticsurgeons and hand surgeons morefrequently being reported as somewhat

or very difficult to obtain (Figure 3)The services of radiologists andanesthesiologists were fairly easy toobtain

Ambulance diversion

Approximately one-third of UShospitals (344 percent) reported going

on ambulance diversion status sometimein the previous year whereas514 percent reported no diversion hoursInformation on the number of hours ondiversion was missing for 142 percentof EDs Metropolitan hospitals weremore likely to have diversion hoursreported (501 percent) compared withhospitals not in metropolitan areas(92 percent) About 12 percent ofmetropolitan hospitals reported havingspent 5ndash19 of their operating time indiversion status with about 27 percentspending 20 or more of their time ondiversion (Table 4) Although theduration of ambulance diversion periodsvaries widely the most frequentlyreported duration ranged between 3 and4 hours Lack of inpatient beds and EDcrowding were frequent reasons forgoing on diversion Staffing shortagesand equipment failure were cited lessfrequently (Figure 4) Diversion periodswere most frequently ordered by nursingstaff or the hospital administrator(Figure 5) Percentage of time ondiversion is positively related tooccupancy rates and bed sizes ofhospitals Figure 6 plots the centroid forEDs on occupancy and bed size bypercentage of time on diversion (none1ndash4 5ndash9 10ndash19 and 20 ormore) For example EDs with nodiversion hours reported had thesmallest mean bed size (138) andsmallest mean occupancy rate (60)and EDs reporting 20 or more of theirtime on diversion had the largest meanbed size (311) and largest meanoccupancy rate (81)

Triage levels

EDs often use nursing triage toidentify the most urgent patients(Table 5) Most hospitals used a 3- or4-level triage system (636 percent) andabout one-quarter used a 5-level system

Language translation services

EDs reported providing a widerange of translation services AlthoughSpanish was the most frequent languageprovided (775 percent of EDs) RussianFrench Chinese and Vietnamese wereeach reported as available in 10ndash14percent of metropolitan EDs

Figure 5 Mean percentage of diversion hours by who ordered the diversionUnited States 2003ndash04

Figure 6 Percentage of time on ambulance diversion as a function of hospital bed sizeand occupancy rate in metropolitan emergency departments United States 2003ndash04

Advance Data No 376 + September 27 2006 7

Emergency departmentutilization

EDs varied widely in terms of theirprofile of patient and paymentcharacteristics diagnostic and treatmentservices and case disposition (Table 6)Two-thirds of EDs not in metropolitanareas saw fewer than 30 cases each dayIn contrast two-thirds of metropolitanEDs cared for 50ndash200 cases each dayChildren represented 10ndash30 of the EDcaseload and seniors represented 5ndash25of the caseload One in 10 EDs reportedthat 50 or more of their cases hadMedicaid and 186 percent of EDs

reported that 25 or more of their caseswere uninsured (Table 6) Figure 7shows the distribution of EDs on therelative caseloads for expected paymentsources For example private insuranceaccounts for about 33 of all ED visitsand uninsured cases make up about 15of all ED visits These percentagesvaried considerably among EDs

ED caseloads also varied by patientacuity as measured by cases arriving byambulance and cases triaged asemergent or urgent About one-third ofhospitals had less than 10 of theirpatients arriving via ambulance and138 percent had 30 or more of their

patients arriving via ambulance One infive EDs had less than 20 triaged asemergent or urgent whereas381 percent of EDs had 65 or moreof their cases so triaged ED caseloadacuity did not vary by metropolitanstatus However the provision ofdiagnostic or therapeutic services didvary with metropolitan EDs providinggreater numbers of services per 100cases (Table 6) For example only194 percent of metropolitan EDsprovided an average of less than 40therapeutic services (eg intravenousfluids wound care) per 100 visitscompared with 415 percent of EDs notin metropolitan areas About286 percent of metropolitan EDsprovided an average of 70 or moretherapeutic services per 100 visitscompared with 129 percent of EDs notin metropolitan areas About one-half ofEDs employed the services of physicianassistants and nurse practitioners with185 percent using their services in 20or more of their cases

On average 2 percent of cases weretransferred to another facility However185 percent of EDs transferred anaverage of 10 or more of their casesto other hospitals Overall only17 percent of cases left without beingseen although 72 percent of EDs had5 or more of their patients leavewithout seeing a physician

Waiting times in metropolitan areaswere longer than in areas that were notmetropolitan One-fifth of patients inmetropolitan EDs waited over an hourto see a physician whereas 317 percentof patients in areas that were notmetropolitan were seen within 15minutes About 128 percent ofmetropolitan EDs had average waitingtimes greater than 60 minutes for theirurgent cases which are defined duringtriage as cases that should be seenbetween 15 and 60 minutes after arrival(Table 6) Overall treatment timestended to be longer in metropolitanareas than in areas that were notmetropolitan For example aboutone-half of patients in areas that werenot metropolitan spent less than 90minutes in the treatment area whereasin metropolitan areas only one in fivepatients had treatments that lasted less

Figure 7 Box plots of emergency departments on caseload percentages for expectedsources of payment United States 2003ndash04

Figure 8 Average total visit duration parsed by waiting and treatment times inmetropolitan areas by emergency department characteristics United States 2003ndash04

8 Advance Data No 376 + September 27 2006

than 90 minutes The total ED visitduration is the sum of the waiting timeand the treatment time Figure 8 displays

the total visit duration parsed by waitingand treatment times according toselected ED characteristics Both waiting

and treatment times contributed to totalvisit duration being longest in EDs thatgo on diversion 20 or more of thetime Metropolitan visits lasted 2ndash3times longer than nonmetropolitan visitson average

Indexes of staffing capacityand throughput

Table 7 presents selected indexes ofED functioning using measures fromNHAMCS The indexes are meanestimates for all EDs combined andseparately for those in metropolitanareas and areas that were notmetropolitan The 25th 50th and 75thpercentiles are also presented to showthe variation across EDs Significantdifferences between urban and ruralareas were found for all indexes withthe exception of visits per space visitsper physician physicians per spacepercentage arriving by ambulance andpercentage admitted to hospital For EDsthat had any diversion the averagenumber of hours on diversion for theyear was 3639 among metropolitanEDs the average number of hours ondiversion was 4039 (Table 7) Formetropolitan EDs 25 percent reportedbeing on diversion for more than 5244hours during the previous year

Estimates of ED crowding

Ambulance diversion cannot beused as the sole criteria for EDcrowding because about 8 percent ofhospitals reported that there were lawsprohibiting that practice in theirlocation Using the criteria of anyambulance diversion hours averagewaiting time greater or equal to 60minutes for urgent cases or percentageof visits where the patient left beforebeing seen greater than or equal to3 percent approximately 449 percent(95 confidence interval 398 to 500)of EDs experienced crowding some timeduring 2003 and 2004 Approximately637 percent of metropolitan EDsexperienced crowding compared with144 percent of EDs that were notmetropolitan Because EDs experiencingcrowding tend to be larger in annual EDvisit volume this corresponds to626 percent of all emergency visitsbeing made to hospitals that experienced

Figure 9 Percentage of emergency departments that experienced crowding by selectedhospital characteristics United States 2003ndash04

Figure 10 Ratio of indexes with significant differences between crowded and uncrowdedemergency departments in metropolitan areas

Advance Data No 376 + September 27 2006 9

ED crowding Additionally crowdingwas more common among EDs withlarger inpatient bed sizes and thoseassociated with medical schools(Figure 9)

When examining differences in thestaffing capacity and throughputindexes for EDs located in metropolitanareas EDs experiencing crowding weresignificantly higher than those notexperiencing crowding for aboutone-half of those measures (Figure 10)The percentage of cases left beforebeing seen in crowded EDs (21) wasfour times as high as the percentage inuncrowded EDs (04) The percentageof nursing positions vacant in crowdedEDs (77) was twice that ofuncrowded EDs (39) Average waitingtime was 50 longer in crowded EDs(518 minutes) compared withuncrowded EDs (354 minutes)

DiscussionThis report shows how US

nonfederal general and short-stayhospitals vary with respect to structureprocess and patient attributes inproviding emergency medical careNational estimates of the steps hospitalstake to provide such care are describedseparately for hospitals located inmetropolitan areas and in areas thatwere not metropolitan The fundamentaldifferences in the size of metropolitanhospitals both in terms of bed size andED visit volume affect many of theobserved differences in staffing patternsED crowding and duration of visits Ineffect the problems facing urban EDsare very different than those facing ruralEDs In areas that were notmetropolitan most EDs are the only oneavailable for patients residing in thecatchment area There are no lsquolsquonearbyrsquorsquochoices for an emergency visit whereasmost metropolitan EDs have severalother EDs available within a 20-minuteambulance ride or a 5-mile radius EDpatient profiles also vary bymetropolitan status EDs that are not inmetropolitan areas were more likely tohave a higher proportion of Medicarepatients and to transfer patients

One area of distinction betweenhospitals that are in metropolitan or not

10 Advance Data No 376 + September 27 2006

metropolitan areas is the issue ofcrowding NHAMCS data provideinformation on key measures of EDcrowding Some of the indexesdeveloped by an expert panel (18)covering several domains of EDfunctioning (eg patient demand EDcapacity patient complexity and EDefficiency) were used to describe EDsexperiencing crowding Using thedefinition of crowding in this report 40to 50 percent of US EDs experiencedcrowding at some point in 2003 and2004 Among EDs located inmetropolitan areas the percentageincreased to 64 percent Indexes of EDfunctioning related to demand capacityand throughput found that one-half ofthose studied were related to crowdedconditions in metropolitan EDsSurprisingly indexes of staffing werenot related to crowding with theexception of the percentage of nursingpositions vacant

This report showed that periods ofambulance diversion occurred inone-half of EDs located in metropolitanareas Ambulance diversion is an effectof ED crowding and some of itsconsequences are increased transit timesand the potential for poor clinicaloutcomes (5) In addition a studyconducted in Los Angeles found thatdiversion hours at one ED wereinterrelated with the diversion hours ofthe nearest ED so that when one EDwent on diversion others nearby soonfollowed In addition to crowding in theED a leading reason for ambulancediversion is insufficient appropriateinpatient beds to place critically ill orinjured patients As with the 2002Government Accountability Office studyof metropolitan EDs (6) NHAMCSfound that diversion was positivelyrelated to hospital inpatient occupancyrates The average occupancy rate formetropolitan hospitals with nodiversions was 60 whereas it was81 for hospitals that spent as much as20 of their time on diversion

Increasing demand on EDs that arestill open has caused almost one-half ofall EDs to expand their physical spaceA California study found that althoughthe number of beds per populationremained stable during the 1990s thebeds were being occupied by more

labor-intensive patients resulting indecreased capacity (25) The NHAMCSresults showed that metropolitan statuswas not related to expanding physicalspace

This report shows that ED treatmentspaces and staffing levels vary acrossmetropolitan and not metropolitan areasMost EDs that are not in metropolitanareas have fewer than 10 standardtreatment spaces where metropolitanEDs typically have 10 to 50 spacesProviding nursing staff to cover all thespaces in metropolitan areas is anothermatter NHAMCS found that one-quarterof metropolitan EDs had 5ndash19 percent oftheir nursing positions vacant Inaddition to nursing shortages in the EDthere is the problem of high turnoverleading to a high proportion of newinexperienced emergency nursesSometimes nurses unfamiliar with theED are sent to work from other areas ofthe hospital which can contribute toreduced efficiency in the delivery ofcare (7)

On-call physician specialists providespecialized care for patients beyond theexpertise of the emergency physicianand usually have no guarantee ofpayment for the services they provideFrom a specialistrsquos business perspectivebeing on-call may result in time spentwith little generation of income (26)NHAMCS data showed that on-callservices provided by plastic and handsurgeons were the most difficult toobtain compared with other specialtiesA California survey of emergencymedicine physicians found that five ofthe seven specialities in which thegreatest proportion of EDs reportedtrouble with specialty response weresurgical (27)

Triage systems are known to varyfrom hospital to hospital However theyall share the same goal of prioritizingpatients for treatment This prioritizationis relevant to patient safety especiallywhen ED crowding delays evaluationAlthough research found that thereliability and validity of the EmergencySeverity Index a 5-level triage systemwere better than in a 3-level system(2829) NHAMCS findings showed thatabout one-quarter of US EDs used theformer and those that used the 5-level

system were predominantly inmetropolitan areas

This survey found that multiplelanguage services were available morefrequently in metropolitan EDs Medicalerrors may result from patient-providercommunication problems due tolanguage barriers Limited Englishproficiency can lead to increased use ofmedical resources in children (30) andserious medical events during pediatrichospitalizations (31) NHAMCS datashowed that over 90 percent of EDsreported providing language translationservices with one-third offering 30 ormore different languages

Visit and patient profile patternsdiffered among hospitals indicating widevariation in reimbursement andtreatment practices Over one-quarter ofhospitals had 30 or more of theirvisits made by Medicaid recipients andabout one-fifth had 25 or more oftheir visits made by uninsured personsSuch hospitals treat a larger proportionof cases from safety-net populations andare at risk of higher rates ofuncompensated care Most of these highsafety-net hospitals do not receivesufficient Medicaid DisproportionateShare Program funds to offset theirfinancial losses (32) Collected chargesfor self-pay patients are as low as 1for the hospital to under 20 for thephysician (3334) Office-basedphysicians are also at risk for underpayment when they provide EMTALA-related care in hospitals In 2003ndash04228 percent of office-based physiciansreported that they spent an average of106 hours providing EMTALA-relatedcare during their last full week of work(35)

Hospitals also vary with respect tonumbers of pediatric cases seen in theED A separate study usingsupplemental data from the 2002ndash03NHAMCS found that hospitals with fewpediatric ED cases are least prepared forhandling the stabilization of severepediatric emergencies with regard tosmall-sized equipment such as needlesendotracheal tubes and access toemergency medicine specialistsespecially those specializing in pediatricemergencies (36) The NHAMCS datain this report found that one-fifth ofEDs transferred as much as 10 or

Advance Data No 376 + September 27 2006 11

more of their cases including pediatriccases implying that these hospitals werenot best equipped to handle a sizablevolume of their cases

This report also showed variationamong hospitals with respect to EDthroughput measures In metropolitanhospitals one-fifth of EDs had patientswaiting on average an hour or morebefore receiving treatment and one innine EDs had 5 or more of theirpatients leaving before being seen Astudy conducted in a California publichospital of patients who left beforebeing seen found that about one-halfwere judged to require immediate careand 11 percent were hospitalized withina week (37) NHAMCS data found thaton average the percentage of patientsleaving before being seen was positivelyassociated with increased waiting timesin metropolitan EDs

Although a previous study foundthat 91 percent of ED directorsnationwide reported overcrowding (38)this advance data report is the first topresent objective findings of EDcrowding in the United States The datapresented support the Institute ofMedicinersquos (I0M) recent report on thecrisis in US emergency medical care(39) The IOM found that capacity andexpertise were lacking for normaloperations and that the system lackedstability and the capacity to respond tolarge disasters and epidemics Thisadvance data report shows that themajority of urban hospitals experiencecrowding and commonly turn awayseverely ill or injured patients Thiscould affect the capacity of largerhospitals to treat patients who areinjured due to a mass casualty event orbecome ill as a result of an infectiousdisease outbreak

LimitationsUtilization estimates for EDs were

based on visits sampled during the4-week reporting period rather than thefull year To the extent that visitcharacteristics vary in a hospital acrossmonths then the variation around thedistribution of EDs on visitcharacteristics may be understated Alsothe sample size for hospitals that are notmetropolitan (n = 122) was not always

large enough to produce reliableestimates for some variables associatedwith large volume EDs because suchEDs are rarely found in rural areas Thepercentage of EDs experiencingcrowded conditions is most likely anunderestimate because informationconcerning diversion hours was notreported for 14 percent of the EDsConsistency between 2003 and 2004data collection among hospitals thatparticipated both years shows thatamong those EDs missing ambulancediversion hours in 2004 most providedan answer for 2003 of which aboutone-half had reported diversion hours(data not shown)

ConclusionsThis report provides many basic

statistics necessary for reviewing thestructure process and patient profilecharacteristics associated with thedelivery of emergency medical care inthis country It also provides nationalbenchmarks for potential measures ofworkflow necessary for understandingmonitoring and managing ED crowdingOther reports will examine therelationship that these variables mayhave on the quality of emergencymedical care Further information aboutNHAMCS and its supplements may befound at wwwcdcgovnchsnhamcshtm

References1 American Hospital Association

(personal communication with ScottBates) 2006

2 McCaig LF Nawar EW NationalHospital Ambulatory Medical CareSurvey 2004 emergency departmentsummary Advance data from vitaland health statistics no 372Hyattsville MD National Center forHealth Statistics 2006

3 ACEP Statistics Fact Sheet Availablefrom httpwwwaceporgwebportalNewsroomTemplatesDefault_PrimaryaspxNRMODE=PublishedampNRORIGINALURL=2fwebportal2fNewsroom2fNewsMediaResources2fStatisticsData2fdefault2ehtmampNRNODEGUID=7b0AA2DBFD-5FA5-4E21-9C66-F69C8AFCC35B7dampNRCACHEHINT=NoModifyGuestwait

4 McCaig LF Ly N National HospitalAmbulatory Medical Care Survey2000 emergency departmentsummary Advance data from vitaland health statistics no 326Hyattsville MD National Center forHealth Statistics 2002

5 Derlet RW Richards JROvercrowding in the nationrsquosemergency departments Complexcauses and disturbing effects AnnEmerg Med 3563ndash8 2000

6 General Accounting Office Hospitalemergency departments Crowdedconditions vary among hospitals andcommunities Washington GeneralAccounting Office 2003

7 Emergency Medical Treatment andActive Labor Act (EMTALA)codified as amended at 42 USC1395dd 1990 Health Care FinancingAdministration EMTALARegulations 42 CFR Parts 488489 1003 1994

8 American Hospital AssociationUncompensated hospital care costfact sheet American HospitalAssociation 2005 Available fromhttpwwwahaorgahacontent2005pdf0511UncompensatedCareFactSheetpdf

9 Silka PA Geiderman JM Kim JYDiversion of ALS ambulancesCharacteristics causes and effects ina large urban system Prehosp EmergCare 523ndash28 2001

10 Sun BC Mohanty SA Weiss R etal Effects of hospital closures andhospital characteristics on emergencydepartment ambulance diversion LosAngeles County 1998 to 2004 AnnEmerg Med 47309ndash16 2006

11 Schull MH Vermeulen M SlaughterG Morrison L Daly P Emergencydepartment crowding andthrombolysis delays in acutemyocardial infarction Ann EmergMed 44577ndash85 2004

12 Burt CW McCaig LF Valverde RHAnalysis of ambulance transports anddiversions among US emergencydepartments Ann Emerg Med47317ndash26 2006

13 Brewster LR Felland LE Emergencydepartment diversions Hospital andcommunity strategies alleviate thecrisis Issue Brief No78 Center forStudying Health System ChangeWashington 2003

14 McConnell KJ Richards CF DayaM et al Effect of ICU capacity onemergency department length of stay

Figure 3 Percentage of emergency departments indicating difficulty in providing on-callphysicians by physician specialty United States 2004

Figure 4 Mean percentage of diversion hours by reasons for diversion United States2003ndash04

6 Advance Data No 376 + September 27 2006

three-quarters of EDs that were not inmetropolitan areas reported that lessthan 5 of nursing positions werevacant compared with one-half ofmetropolitan EDs Difficulties inobtaining services of on-call specialistswere reported in many EDs with plasticsurgeons and hand surgeons morefrequently being reported as somewhat

or very difficult to obtain (Figure 3)The services of radiologists andanesthesiologists were fairly easy toobtain

Ambulance diversion

Approximately one-third of UShospitals (344 percent) reported going

on ambulance diversion status sometimein the previous year whereas514 percent reported no diversion hoursInformation on the number of hours ondiversion was missing for 142 percentof EDs Metropolitan hospitals weremore likely to have diversion hoursreported (501 percent) compared withhospitals not in metropolitan areas(92 percent) About 12 percent ofmetropolitan hospitals reported havingspent 5ndash19 of their operating time indiversion status with about 27 percentspending 20 or more of their time ondiversion (Table 4) Although theduration of ambulance diversion periodsvaries widely the most frequentlyreported duration ranged between 3 and4 hours Lack of inpatient beds and EDcrowding were frequent reasons forgoing on diversion Staffing shortagesand equipment failure were cited lessfrequently (Figure 4) Diversion periodswere most frequently ordered by nursingstaff or the hospital administrator(Figure 5) Percentage of time ondiversion is positively related tooccupancy rates and bed sizes ofhospitals Figure 6 plots the centroid forEDs on occupancy and bed size bypercentage of time on diversion (none1ndash4 5ndash9 10ndash19 and 20 ormore) For example EDs with nodiversion hours reported had thesmallest mean bed size (138) andsmallest mean occupancy rate (60)and EDs reporting 20 or more of theirtime on diversion had the largest meanbed size (311) and largest meanoccupancy rate (81)

Triage levels

EDs often use nursing triage toidentify the most urgent patients(Table 5) Most hospitals used a 3- or4-level triage system (636 percent) andabout one-quarter used a 5-level system

Language translation services

EDs reported providing a widerange of translation services AlthoughSpanish was the most frequent languageprovided (775 percent of EDs) RussianFrench Chinese and Vietnamese wereeach reported as available in 10ndash14percent of metropolitan EDs

Figure 5 Mean percentage of diversion hours by who ordered the diversionUnited States 2003ndash04

Figure 6 Percentage of time on ambulance diversion as a function of hospital bed sizeand occupancy rate in metropolitan emergency departments United States 2003ndash04

Advance Data No 376 + September 27 2006 7

Emergency departmentutilization

EDs varied widely in terms of theirprofile of patient and paymentcharacteristics diagnostic and treatmentservices and case disposition (Table 6)Two-thirds of EDs not in metropolitanareas saw fewer than 30 cases each dayIn contrast two-thirds of metropolitanEDs cared for 50ndash200 cases each dayChildren represented 10ndash30 of the EDcaseload and seniors represented 5ndash25of the caseload One in 10 EDs reportedthat 50 or more of their cases hadMedicaid and 186 percent of EDs

reported that 25 or more of their caseswere uninsured (Table 6) Figure 7shows the distribution of EDs on therelative caseloads for expected paymentsources For example private insuranceaccounts for about 33 of all ED visitsand uninsured cases make up about 15of all ED visits These percentagesvaried considerably among EDs

ED caseloads also varied by patientacuity as measured by cases arriving byambulance and cases triaged asemergent or urgent About one-third ofhospitals had less than 10 of theirpatients arriving via ambulance and138 percent had 30 or more of their

patients arriving via ambulance One infive EDs had less than 20 triaged asemergent or urgent whereas381 percent of EDs had 65 or moreof their cases so triaged ED caseloadacuity did not vary by metropolitanstatus However the provision ofdiagnostic or therapeutic services didvary with metropolitan EDs providinggreater numbers of services per 100cases (Table 6) For example only194 percent of metropolitan EDsprovided an average of less than 40therapeutic services (eg intravenousfluids wound care) per 100 visitscompared with 415 percent of EDs notin metropolitan areas About286 percent of metropolitan EDsprovided an average of 70 or moretherapeutic services per 100 visitscompared with 129 percent of EDs notin metropolitan areas About one-half ofEDs employed the services of physicianassistants and nurse practitioners with185 percent using their services in 20or more of their cases

On average 2 percent of cases weretransferred to another facility However185 percent of EDs transferred anaverage of 10 or more of their casesto other hospitals Overall only17 percent of cases left without beingseen although 72 percent of EDs had5 or more of their patients leavewithout seeing a physician

Waiting times in metropolitan areaswere longer than in areas that were notmetropolitan One-fifth of patients inmetropolitan EDs waited over an hourto see a physician whereas 317 percentof patients in areas that were notmetropolitan were seen within 15minutes About 128 percent ofmetropolitan EDs had average waitingtimes greater than 60 minutes for theirurgent cases which are defined duringtriage as cases that should be seenbetween 15 and 60 minutes after arrival(Table 6) Overall treatment timestended to be longer in metropolitanareas than in areas that were notmetropolitan For example aboutone-half of patients in areas that werenot metropolitan spent less than 90minutes in the treatment area whereasin metropolitan areas only one in fivepatients had treatments that lasted less

Figure 7 Box plots of emergency departments on caseload percentages for expectedsources of payment United States 2003ndash04

Figure 8 Average total visit duration parsed by waiting and treatment times inmetropolitan areas by emergency department characteristics United States 2003ndash04

8 Advance Data No 376 + September 27 2006

than 90 minutes The total ED visitduration is the sum of the waiting timeand the treatment time Figure 8 displays

the total visit duration parsed by waitingand treatment times according toselected ED characteristics Both waiting

and treatment times contributed to totalvisit duration being longest in EDs thatgo on diversion 20 or more of thetime Metropolitan visits lasted 2ndash3times longer than nonmetropolitan visitson average

Indexes of staffing capacityand throughput

Table 7 presents selected indexes ofED functioning using measures fromNHAMCS The indexes are meanestimates for all EDs combined andseparately for those in metropolitanareas and areas that were notmetropolitan The 25th 50th and 75thpercentiles are also presented to showthe variation across EDs Significantdifferences between urban and ruralareas were found for all indexes withthe exception of visits per space visitsper physician physicians per spacepercentage arriving by ambulance andpercentage admitted to hospital For EDsthat had any diversion the averagenumber of hours on diversion for theyear was 3639 among metropolitanEDs the average number of hours ondiversion was 4039 (Table 7) Formetropolitan EDs 25 percent reportedbeing on diversion for more than 5244hours during the previous year

Estimates of ED crowding

Ambulance diversion cannot beused as the sole criteria for EDcrowding because about 8 percent ofhospitals reported that there were lawsprohibiting that practice in theirlocation Using the criteria of anyambulance diversion hours averagewaiting time greater or equal to 60minutes for urgent cases or percentageof visits where the patient left beforebeing seen greater than or equal to3 percent approximately 449 percent(95 confidence interval 398 to 500)of EDs experienced crowding some timeduring 2003 and 2004 Approximately637 percent of metropolitan EDsexperienced crowding compared with144 percent of EDs that were notmetropolitan Because EDs experiencingcrowding tend to be larger in annual EDvisit volume this corresponds to626 percent of all emergency visitsbeing made to hospitals that experienced

Figure 9 Percentage of emergency departments that experienced crowding by selectedhospital characteristics United States 2003ndash04

Figure 10 Ratio of indexes with significant differences between crowded and uncrowdedemergency departments in metropolitan areas

Advance Data No 376 + September 27 2006 9

ED crowding Additionally crowdingwas more common among EDs withlarger inpatient bed sizes and thoseassociated with medical schools(Figure 9)

When examining differences in thestaffing capacity and throughputindexes for EDs located in metropolitanareas EDs experiencing crowding weresignificantly higher than those notexperiencing crowding for aboutone-half of those measures (Figure 10)The percentage of cases left beforebeing seen in crowded EDs (21) wasfour times as high as the percentage inuncrowded EDs (04) The percentageof nursing positions vacant in crowdedEDs (77) was twice that ofuncrowded EDs (39) Average waitingtime was 50 longer in crowded EDs(518 minutes) compared withuncrowded EDs (354 minutes)

DiscussionThis report shows how US

nonfederal general and short-stayhospitals vary with respect to structureprocess and patient attributes inproviding emergency medical careNational estimates of the steps hospitalstake to provide such care are describedseparately for hospitals located inmetropolitan areas and in areas thatwere not metropolitan The fundamentaldifferences in the size of metropolitanhospitals both in terms of bed size andED visit volume affect many of theobserved differences in staffing patternsED crowding and duration of visits Ineffect the problems facing urban EDsare very different than those facing ruralEDs In areas that were notmetropolitan most EDs are the only oneavailable for patients residing in thecatchment area There are no lsquolsquonearbyrsquorsquochoices for an emergency visit whereasmost metropolitan EDs have severalother EDs available within a 20-minuteambulance ride or a 5-mile radius EDpatient profiles also vary bymetropolitan status EDs that are not inmetropolitan areas were more likely tohave a higher proportion of Medicarepatients and to transfer patients

One area of distinction betweenhospitals that are in metropolitan or not

10 Advance Data No 376 + September 27 2006

metropolitan areas is the issue ofcrowding NHAMCS data provideinformation on key measures of EDcrowding Some of the indexesdeveloped by an expert panel (18)covering several domains of EDfunctioning (eg patient demand EDcapacity patient complexity and EDefficiency) were used to describe EDsexperiencing crowding Using thedefinition of crowding in this report 40to 50 percent of US EDs experiencedcrowding at some point in 2003 and2004 Among EDs located inmetropolitan areas the percentageincreased to 64 percent Indexes of EDfunctioning related to demand capacityand throughput found that one-half ofthose studied were related to crowdedconditions in metropolitan EDsSurprisingly indexes of staffing werenot related to crowding with theexception of the percentage of nursingpositions vacant

This report showed that periods ofambulance diversion occurred inone-half of EDs located in metropolitanareas Ambulance diversion is an effectof ED crowding and some of itsconsequences are increased transit timesand the potential for poor clinicaloutcomes (5) In addition a studyconducted in Los Angeles found thatdiversion hours at one ED wereinterrelated with the diversion hours ofthe nearest ED so that when one EDwent on diversion others nearby soonfollowed In addition to crowding in theED a leading reason for ambulancediversion is insufficient appropriateinpatient beds to place critically ill orinjured patients As with the 2002Government Accountability Office studyof metropolitan EDs (6) NHAMCSfound that diversion was positivelyrelated to hospital inpatient occupancyrates The average occupancy rate formetropolitan hospitals with nodiversions was 60 whereas it was81 for hospitals that spent as much as20 of their time on diversion

Increasing demand on EDs that arestill open has caused almost one-half ofall EDs to expand their physical spaceA California study found that althoughthe number of beds per populationremained stable during the 1990s thebeds were being occupied by more

labor-intensive patients resulting indecreased capacity (25) The NHAMCSresults showed that metropolitan statuswas not related to expanding physicalspace

This report shows that ED treatmentspaces and staffing levels vary acrossmetropolitan and not metropolitan areasMost EDs that are not in metropolitanareas have fewer than 10 standardtreatment spaces where metropolitanEDs typically have 10 to 50 spacesProviding nursing staff to cover all thespaces in metropolitan areas is anothermatter NHAMCS found that one-quarterof metropolitan EDs had 5ndash19 percent oftheir nursing positions vacant Inaddition to nursing shortages in the EDthere is the problem of high turnoverleading to a high proportion of newinexperienced emergency nursesSometimes nurses unfamiliar with theED are sent to work from other areas ofthe hospital which can contribute toreduced efficiency in the delivery ofcare (7)

On-call physician specialists providespecialized care for patients beyond theexpertise of the emergency physicianand usually have no guarantee ofpayment for the services they provideFrom a specialistrsquos business perspectivebeing on-call may result in time spentwith little generation of income (26)NHAMCS data showed that on-callservices provided by plastic and handsurgeons were the most difficult toobtain compared with other specialtiesA California survey of emergencymedicine physicians found that five ofthe seven specialities in which thegreatest proportion of EDs reportedtrouble with specialty response weresurgical (27)

Triage systems are known to varyfrom hospital to hospital However theyall share the same goal of prioritizingpatients for treatment This prioritizationis relevant to patient safety especiallywhen ED crowding delays evaluationAlthough research found that thereliability and validity of the EmergencySeverity Index a 5-level triage systemwere better than in a 3-level system(2829) NHAMCS findings showed thatabout one-quarter of US EDs used theformer and those that used the 5-level

system were predominantly inmetropolitan areas

This survey found that multiplelanguage services were available morefrequently in metropolitan EDs Medicalerrors may result from patient-providercommunication problems due tolanguage barriers Limited Englishproficiency can lead to increased use ofmedical resources in children (30) andserious medical events during pediatrichospitalizations (31) NHAMCS datashowed that over 90 percent of EDsreported providing language translationservices with one-third offering 30 ormore different languages

Visit and patient profile patternsdiffered among hospitals indicating widevariation in reimbursement andtreatment practices Over one-quarter ofhospitals had 30 or more of theirvisits made by Medicaid recipients andabout one-fifth had 25 or more oftheir visits made by uninsured personsSuch hospitals treat a larger proportionof cases from safety-net populations andare at risk of higher rates ofuncompensated care Most of these highsafety-net hospitals do not receivesufficient Medicaid DisproportionateShare Program funds to offset theirfinancial losses (32) Collected chargesfor self-pay patients are as low as 1for the hospital to under 20 for thephysician (3334) Office-basedphysicians are also at risk for underpayment when they provide EMTALA-related care in hospitals In 2003ndash04228 percent of office-based physiciansreported that they spent an average of106 hours providing EMTALA-relatedcare during their last full week of work(35)

Hospitals also vary with respect tonumbers of pediatric cases seen in theED A separate study usingsupplemental data from the 2002ndash03NHAMCS found that hospitals with fewpediatric ED cases are least prepared forhandling the stabilization of severepediatric emergencies with regard tosmall-sized equipment such as needlesendotracheal tubes and access toemergency medicine specialistsespecially those specializing in pediatricemergencies (36) The NHAMCS datain this report found that one-fifth ofEDs transferred as much as 10 or

Advance Data No 376 + September 27 2006 11

more of their cases including pediatriccases implying that these hospitals werenot best equipped to handle a sizablevolume of their cases

This report also showed variationamong hospitals with respect to EDthroughput measures In metropolitanhospitals one-fifth of EDs had patientswaiting on average an hour or morebefore receiving treatment and one innine EDs had 5 or more of theirpatients leaving before being seen Astudy conducted in a California publichospital of patients who left beforebeing seen found that about one-halfwere judged to require immediate careand 11 percent were hospitalized withina week (37) NHAMCS data found thaton average the percentage of patientsleaving before being seen was positivelyassociated with increased waiting timesin metropolitan EDs

Although a previous study foundthat 91 percent of ED directorsnationwide reported overcrowding (38)this advance data report is the first topresent objective findings of EDcrowding in the United States The datapresented support the Institute ofMedicinersquos (I0M) recent report on thecrisis in US emergency medical care(39) The IOM found that capacity andexpertise were lacking for normaloperations and that the system lackedstability and the capacity to respond tolarge disasters and epidemics Thisadvance data report shows that themajority of urban hospitals experiencecrowding and commonly turn awayseverely ill or injured patients Thiscould affect the capacity of largerhospitals to treat patients who areinjured due to a mass casualty event orbecome ill as a result of an infectiousdisease outbreak

LimitationsUtilization estimates for EDs were

based on visits sampled during the4-week reporting period rather than thefull year To the extent that visitcharacteristics vary in a hospital acrossmonths then the variation around thedistribution of EDs on visitcharacteristics may be understated Alsothe sample size for hospitals that are notmetropolitan (n = 122) was not always

large enough to produce reliableestimates for some variables associatedwith large volume EDs because suchEDs are rarely found in rural areas Thepercentage of EDs experiencingcrowded conditions is most likely anunderestimate because informationconcerning diversion hours was notreported for 14 percent of the EDsConsistency between 2003 and 2004data collection among hospitals thatparticipated both years shows thatamong those EDs missing ambulancediversion hours in 2004 most providedan answer for 2003 of which aboutone-half had reported diversion hours(data not shown)

ConclusionsThis report provides many basic

statistics necessary for reviewing thestructure process and patient profilecharacteristics associated with thedelivery of emergency medical care inthis country It also provides nationalbenchmarks for potential measures ofworkflow necessary for understandingmonitoring and managing ED crowdingOther reports will examine therelationship that these variables mayhave on the quality of emergencymedical care Further information aboutNHAMCS and its supplements may befound at wwwcdcgovnchsnhamcshtm

References1 American Hospital Association

(personal communication with ScottBates) 2006

2 McCaig LF Nawar EW NationalHospital Ambulatory Medical CareSurvey 2004 emergency departmentsummary Advance data from vitaland health statistics no 372Hyattsville MD National Center forHealth Statistics 2006

3 ACEP Statistics Fact Sheet Availablefrom httpwwwaceporgwebportalNewsroomTemplatesDefault_PrimaryaspxNRMODE=PublishedampNRORIGINALURL=2fwebportal2fNewsroom2fNewsMediaResources2fStatisticsData2fdefault2ehtmampNRNODEGUID=7b0AA2DBFD-5FA5-4E21-9C66-F69C8AFCC35B7dampNRCACHEHINT=NoModifyGuestwait

4 McCaig LF Ly N National HospitalAmbulatory Medical Care Survey2000 emergency departmentsummary Advance data from vitaland health statistics no 326Hyattsville MD National Center forHealth Statistics 2002

5 Derlet RW Richards JROvercrowding in the nationrsquosemergency departments Complexcauses and disturbing effects AnnEmerg Med 3563ndash8 2000

6 General Accounting Office Hospitalemergency departments Crowdedconditions vary among hospitals andcommunities Washington GeneralAccounting Office 2003

7 Emergency Medical Treatment andActive Labor Act (EMTALA)codified as amended at 42 USC1395dd 1990 Health Care FinancingAdministration EMTALARegulations 42 CFR Parts 488489 1003 1994

8 American Hospital AssociationUncompensated hospital care costfact sheet American HospitalAssociation 2005 Available fromhttpwwwahaorgahacontent2005pdf0511UncompensatedCareFactSheetpdf

9 Silka PA Geiderman JM Kim JYDiversion of ALS ambulancesCharacteristics causes and effects ina large urban system Prehosp EmergCare 523ndash28 2001

10 Sun BC Mohanty SA Weiss R etal Effects of hospital closures andhospital characteristics on emergencydepartment ambulance diversion LosAngeles County 1998 to 2004 AnnEmerg Med 47309ndash16 2006

11 Schull MH Vermeulen M SlaughterG Morrison L Daly P Emergencydepartment crowding andthrombolysis delays in acutemyocardial infarction Ann EmergMed 44577ndash85 2004

12 Burt CW McCaig LF Valverde RHAnalysis of ambulance transports anddiversions among US emergencydepartments Ann Emerg Med47317ndash26 2006

13 Brewster LR Felland LE Emergencydepartment diversions Hospital andcommunity strategies alleviate thecrisis Issue Brief No78 Center forStudying Health System ChangeWashington 2003

14 McConnell KJ Richards CF DayaM et al Effect of ICU capacity onemergency department length of stay

Figure 5 Mean percentage of diversion hours by who ordered the diversionUnited States 2003ndash04

Figure 6 Percentage of time on ambulance diversion as a function of hospital bed sizeand occupancy rate in metropolitan emergency departments United States 2003ndash04

Advance Data No 376 + September 27 2006 7

Emergency departmentutilization

EDs varied widely in terms of theirprofile of patient and paymentcharacteristics diagnostic and treatmentservices and case disposition (Table 6)Two-thirds of EDs not in metropolitanareas saw fewer than 30 cases each dayIn contrast two-thirds of metropolitanEDs cared for 50ndash200 cases each dayChildren represented 10ndash30 of the EDcaseload and seniors represented 5ndash25of the caseload One in 10 EDs reportedthat 50 or more of their cases hadMedicaid and 186 percent of EDs

reported that 25 or more of their caseswere uninsured (Table 6) Figure 7shows the distribution of EDs on therelative caseloads for expected paymentsources For example private insuranceaccounts for about 33 of all ED visitsand uninsured cases make up about 15of all ED visits These percentagesvaried considerably among EDs

ED caseloads also varied by patientacuity as measured by cases arriving byambulance and cases triaged asemergent or urgent About one-third ofhospitals had less than 10 of theirpatients arriving via ambulance and138 percent had 30 or more of their

patients arriving via ambulance One infive EDs had less than 20 triaged asemergent or urgent whereas381 percent of EDs had 65 or moreof their cases so triaged ED caseloadacuity did not vary by metropolitanstatus However the provision ofdiagnostic or therapeutic services didvary with metropolitan EDs providinggreater numbers of services per 100cases (Table 6) For example only194 percent of metropolitan EDsprovided an average of less than 40therapeutic services (eg intravenousfluids wound care) per 100 visitscompared with 415 percent of EDs notin metropolitan areas About286 percent of metropolitan EDsprovided an average of 70 or moretherapeutic services per 100 visitscompared with 129 percent of EDs notin metropolitan areas About one-half ofEDs employed the services of physicianassistants and nurse practitioners with185 percent using their services in 20or more of their cases

On average 2 percent of cases weretransferred to another facility However185 percent of EDs transferred anaverage of 10 or more of their casesto other hospitals Overall only17 percent of cases left without beingseen although 72 percent of EDs had5 or more of their patients leavewithout seeing a physician

Waiting times in metropolitan areaswere longer than in areas that were notmetropolitan One-fifth of patients inmetropolitan EDs waited over an hourto see a physician whereas 317 percentof patients in areas that were notmetropolitan were seen within 15minutes About 128 percent ofmetropolitan EDs had average waitingtimes greater than 60 minutes for theirurgent cases which are defined duringtriage as cases that should be seenbetween 15 and 60 minutes after arrival(Table 6) Overall treatment timestended to be longer in metropolitanareas than in areas that were notmetropolitan For example aboutone-half of patients in areas that werenot metropolitan spent less than 90minutes in the treatment area whereasin metropolitan areas only one in fivepatients had treatments that lasted less

Figure 7 Box plots of emergency departments on caseload percentages for expectedsources of payment United States 2003ndash04

Figure 8 Average total visit duration parsed by waiting and treatment times inmetropolitan areas by emergency department characteristics United States 2003ndash04

8 Advance Data No 376 + September 27 2006

than 90 minutes The total ED visitduration is the sum of the waiting timeand the treatment time Figure 8 displays

the total visit duration parsed by waitingand treatment times according toselected ED characteristics Both waiting

and treatment times contributed to totalvisit duration being longest in EDs thatgo on diversion 20 or more of thetime Metropolitan visits lasted 2ndash3times longer than nonmetropolitan visitson average

Indexes of staffing capacityand throughput

Table 7 presents selected indexes ofED functioning using measures fromNHAMCS The indexes are meanestimates for all EDs combined andseparately for those in metropolitanareas and areas that were notmetropolitan The 25th 50th and 75thpercentiles are also presented to showthe variation across EDs Significantdifferences between urban and ruralareas were found for all indexes withthe exception of visits per space visitsper physician physicians per spacepercentage arriving by ambulance andpercentage admitted to hospital For EDsthat had any diversion the averagenumber of hours on diversion for theyear was 3639 among metropolitanEDs the average number of hours ondiversion was 4039 (Table 7) Formetropolitan EDs 25 percent reportedbeing on diversion for more than 5244hours during the previous year

Estimates of ED crowding

Ambulance diversion cannot beused as the sole criteria for EDcrowding because about 8 percent ofhospitals reported that there were lawsprohibiting that practice in theirlocation Using the criteria of anyambulance diversion hours averagewaiting time greater or equal to 60minutes for urgent cases or percentageof visits where the patient left beforebeing seen greater than or equal to3 percent approximately 449 percent(95 confidence interval 398 to 500)of EDs experienced crowding some timeduring 2003 and 2004 Approximately637 percent of metropolitan EDsexperienced crowding compared with144 percent of EDs that were notmetropolitan Because EDs experiencingcrowding tend to be larger in annual EDvisit volume this corresponds to626 percent of all emergency visitsbeing made to hospitals that experienced

Figure 9 Percentage of emergency departments that experienced crowding by selectedhospital characteristics United States 2003ndash04

Figure 10 Ratio of indexes with significant differences between crowded and uncrowdedemergency departments in metropolitan areas

Advance Data No 376 + September 27 2006 9

ED crowding Additionally crowdingwas more common among EDs withlarger inpatient bed sizes and thoseassociated with medical schools(Figure 9)

When examining differences in thestaffing capacity and throughputindexes for EDs located in metropolitanareas EDs experiencing crowding weresignificantly higher than those notexperiencing crowding for aboutone-half of those measures (Figure 10)The percentage of cases left beforebeing seen in crowded EDs (21) wasfour times as high as the percentage inuncrowded EDs (04) The percentageof nursing positions vacant in crowdedEDs (77) was twice that ofuncrowded EDs (39) Average waitingtime was 50 longer in crowded EDs(518 minutes) compared withuncrowded EDs (354 minutes)

DiscussionThis report shows how US

nonfederal general and short-stayhospitals vary with respect to structureprocess and patient attributes inproviding emergency medical careNational estimates of the steps hospitalstake to provide such care are describedseparately for hospitals located inmetropolitan areas and in areas thatwere not metropolitan The fundamentaldifferences in the size of metropolitanhospitals both in terms of bed size andED visit volume affect many of theobserved differences in staffing patternsED crowding and duration of visits Ineffect the problems facing urban EDsare very different than those facing ruralEDs In areas that were notmetropolitan most EDs are the only oneavailable for patients residing in thecatchment area There are no lsquolsquonearbyrsquorsquochoices for an emergency visit whereasmost metropolitan EDs have severalother EDs available within a 20-minuteambulance ride or a 5-mile radius EDpatient profiles also vary bymetropolitan status EDs that are not inmetropolitan areas were more likely tohave a higher proportion of Medicarepatients and to transfer patients

One area of distinction betweenhospitals that are in metropolitan or not

10 Advance Data No 376 + September 27 2006

metropolitan areas is the issue ofcrowding NHAMCS data provideinformation on key measures of EDcrowding Some of the indexesdeveloped by an expert panel (18)covering several domains of EDfunctioning (eg patient demand EDcapacity patient complexity and EDefficiency) were used to describe EDsexperiencing crowding Using thedefinition of crowding in this report 40to 50 percent of US EDs experiencedcrowding at some point in 2003 and2004 Among EDs located inmetropolitan areas the percentageincreased to 64 percent Indexes of EDfunctioning related to demand capacityand throughput found that one-half ofthose studied were related to crowdedconditions in metropolitan EDsSurprisingly indexes of staffing werenot related to crowding with theexception of the percentage of nursingpositions vacant

This report showed that periods ofambulance diversion occurred inone-half of EDs located in metropolitanareas Ambulance diversion is an effectof ED crowding and some of itsconsequences are increased transit timesand the potential for poor clinicaloutcomes (5) In addition a studyconducted in Los Angeles found thatdiversion hours at one ED wereinterrelated with the diversion hours ofthe nearest ED so that when one EDwent on diversion others nearby soonfollowed In addition to crowding in theED a leading reason for ambulancediversion is insufficient appropriateinpatient beds to place critically ill orinjured patients As with the 2002Government Accountability Office studyof metropolitan EDs (6) NHAMCSfound that diversion was positivelyrelated to hospital inpatient occupancyrates The average occupancy rate formetropolitan hospitals with nodiversions was 60 whereas it was81 for hospitals that spent as much as20 of their time on diversion

Increasing demand on EDs that arestill open has caused almost one-half ofall EDs to expand their physical spaceA California study found that althoughthe number of beds per populationremained stable during the 1990s thebeds were being occupied by more

labor-intensive patients resulting indecreased capacity (25) The NHAMCSresults showed that metropolitan statuswas not related to expanding physicalspace

This report shows that ED treatmentspaces and staffing levels vary acrossmetropolitan and not metropolitan areasMost EDs that are not in metropolitanareas have fewer than 10 standardtreatment spaces where metropolitanEDs typically have 10 to 50 spacesProviding nursing staff to cover all thespaces in metropolitan areas is anothermatter NHAMCS found that one-quarterof metropolitan EDs had 5ndash19 percent oftheir nursing positions vacant Inaddition to nursing shortages in the EDthere is the problem of high turnoverleading to a high proportion of newinexperienced emergency nursesSometimes nurses unfamiliar with theED are sent to work from other areas ofthe hospital which can contribute toreduced efficiency in the delivery ofcare (7)

On-call physician specialists providespecialized care for patients beyond theexpertise of the emergency physicianand usually have no guarantee ofpayment for the services they provideFrom a specialistrsquos business perspectivebeing on-call may result in time spentwith little generation of income (26)NHAMCS data showed that on-callservices provided by plastic and handsurgeons were the most difficult toobtain compared with other specialtiesA California survey of emergencymedicine physicians found that five ofthe seven specialities in which thegreatest proportion of EDs reportedtrouble with specialty response weresurgical (27)

Triage systems are known to varyfrom hospital to hospital However theyall share the same goal of prioritizingpatients for treatment This prioritizationis relevant to patient safety especiallywhen ED crowding delays evaluationAlthough research found that thereliability and validity of the EmergencySeverity Index a 5-level triage systemwere better than in a 3-level system(2829) NHAMCS findings showed thatabout one-quarter of US EDs used theformer and those that used the 5-level

system were predominantly inmetropolitan areas

This survey found that multiplelanguage services were available morefrequently in metropolitan EDs Medicalerrors may result from patient-providercommunication problems due tolanguage barriers Limited Englishproficiency can lead to increased use ofmedical resources in children (30) andserious medical events during pediatrichospitalizations (31) NHAMCS datashowed that over 90 percent of EDsreported providing language translationservices with one-third offering 30 ormore different languages

Visit and patient profile patternsdiffered among hospitals indicating widevariation in reimbursement andtreatment practices Over one-quarter ofhospitals had 30 or more of theirvisits made by Medicaid recipients andabout one-fifth had 25 or more oftheir visits made by uninsured personsSuch hospitals treat a larger proportionof cases from safety-net populations andare at risk of higher rates ofuncompensated care Most of these highsafety-net hospitals do not receivesufficient Medicaid DisproportionateShare Program funds to offset theirfinancial losses (32) Collected chargesfor self-pay patients are as low as 1for the hospital to under 20 for thephysician (3334) Office-basedphysicians are also at risk for underpayment when they provide EMTALA-related care in hospitals In 2003ndash04228 percent of office-based physiciansreported that they spent an average of106 hours providing EMTALA-relatedcare during their last full week of work(35)

Hospitals also vary with respect tonumbers of pediatric cases seen in theED A separate study usingsupplemental data from the 2002ndash03NHAMCS found that hospitals with fewpediatric ED cases are least prepared forhandling the stabilization of severepediatric emergencies with regard tosmall-sized equipment such as needlesendotracheal tubes and access toemergency medicine specialistsespecially those specializing in pediatricemergencies (36) The NHAMCS datain this report found that one-fifth ofEDs transferred as much as 10 or

Advance Data No 376 + September 27 2006 11

more of their cases including pediatriccases implying that these hospitals werenot best equipped to handle a sizablevolume of their cases

This report also showed variationamong hospitals with respect to EDthroughput measures In metropolitanhospitals one-fifth of EDs had patientswaiting on average an hour or morebefore receiving treatment and one innine EDs had 5 or more of theirpatients leaving before being seen Astudy conducted in a California publichospital of patients who left beforebeing seen found that about one-halfwere judged to require immediate careand 11 percent were hospitalized withina week (37) NHAMCS data found thaton average the percentage of patientsleaving before being seen was positivelyassociated with increased waiting timesin metropolitan EDs

Although a previous study foundthat 91 percent of ED directorsnationwide reported overcrowding (38)this advance data report is the first topresent objective findings of EDcrowding in the United States The datapresented support the Institute ofMedicinersquos (I0M) recent report on thecrisis in US emergency medical care(39) The IOM found that capacity andexpertise were lacking for normaloperations and that the system lackedstability and the capacity to respond tolarge disasters and epidemics Thisadvance data report shows that themajority of urban hospitals experiencecrowding and commonly turn awayseverely ill or injured patients Thiscould affect the capacity of largerhospitals to treat patients who areinjured due to a mass casualty event orbecome ill as a result of an infectiousdisease outbreak

LimitationsUtilization estimates for EDs were

based on visits sampled during the4-week reporting period rather than thefull year To the extent that visitcharacteristics vary in a hospital acrossmonths then the variation around thedistribution of EDs on visitcharacteristics may be understated Alsothe sample size for hospitals that are notmetropolitan (n = 122) was not always

large enough to produce reliableestimates for some variables associatedwith large volume EDs because suchEDs are rarely found in rural areas Thepercentage of EDs experiencingcrowded conditions is most likely anunderestimate because informationconcerning diversion hours was notreported for 14 percent of the EDsConsistency between 2003 and 2004data collection among hospitals thatparticipated both years shows thatamong those EDs missing ambulancediversion hours in 2004 most providedan answer for 2003 of which aboutone-half had reported diversion hours(data not shown)

ConclusionsThis report provides many basic

statistics necessary for reviewing thestructure process and patient profilecharacteristics associated with thedelivery of emergency medical care inthis country It also provides nationalbenchmarks for potential measures ofworkflow necessary for understandingmonitoring and managing ED crowdingOther reports will examine therelationship that these variables mayhave on the quality of emergencymedical care Further information aboutNHAMCS and its supplements may befound at wwwcdcgovnchsnhamcshtm

References1 American Hospital Association

(personal communication with ScottBates) 2006

2 McCaig LF Nawar EW NationalHospital Ambulatory Medical CareSurvey 2004 emergency departmentsummary Advance data from vitaland health statistics no 372Hyattsville MD National Center forHealth Statistics 2006

3 ACEP Statistics Fact Sheet Availablefrom httpwwwaceporgwebportalNewsroomTemplatesDefault_PrimaryaspxNRMODE=PublishedampNRORIGINALURL=2fwebportal2fNewsroom2fNewsMediaResources2fStatisticsData2fdefault2ehtmampNRNODEGUID=7b0AA2DBFD-5FA5-4E21-9C66-F69C8AFCC35B7dampNRCACHEHINT=NoModifyGuestwait

4 McCaig LF Ly N National HospitalAmbulatory Medical Care Survey2000 emergency departmentsummary Advance data from vitaland health statistics no 326Hyattsville MD National Center forHealth Statistics 2002

5 Derlet RW Richards JROvercrowding in the nationrsquosemergency departments Complexcauses and disturbing effects AnnEmerg Med 3563ndash8 2000

6 General Accounting Office Hospitalemergency departments Crowdedconditions vary among hospitals andcommunities Washington GeneralAccounting Office 2003

7 Emergency Medical Treatment andActive Labor Act (EMTALA)codified as amended at 42 USC1395dd 1990 Health Care FinancingAdministration EMTALARegulations 42 CFR Parts 488489 1003 1994

8 American Hospital AssociationUncompensated hospital care costfact sheet American HospitalAssociation 2005 Available fromhttpwwwahaorgahacontent2005pdf0511UncompensatedCareFactSheetpdf

9 Silka PA Geiderman JM Kim JYDiversion of ALS ambulancesCharacteristics causes and effects ina large urban system Prehosp EmergCare 523ndash28 2001

10 Sun BC Mohanty SA Weiss R etal Effects of hospital closures andhospital characteristics on emergencydepartment ambulance diversion LosAngeles County 1998 to 2004 AnnEmerg Med 47309ndash16 2006

11 Schull MH Vermeulen M SlaughterG Morrison L Daly P Emergencydepartment crowding andthrombolysis delays in acutemyocardial infarction Ann EmergMed 44577ndash85 2004

12 Burt CW McCaig LF Valverde RHAnalysis of ambulance transports anddiversions among US emergencydepartments Ann Emerg Med47317ndash26 2006

13 Brewster LR Felland LE Emergencydepartment diversions Hospital andcommunity strategies alleviate thecrisis Issue Brief No78 Center forStudying Health System ChangeWashington 2003

14 McConnell KJ Richards CF DayaM et al Effect of ICU capacity onemergency department length of stay

Figure 7 Box plots of emergency departments on caseload percentages for expectedsources of payment United States 2003ndash04

Figure 8 Average total visit duration parsed by waiting and treatment times inmetropolitan areas by emergency department characteristics United States 2003ndash04

8 Advance Data No 376 + September 27 2006

than 90 minutes The total ED visitduration is the sum of the waiting timeand the treatment time Figure 8 displays

the total visit duration parsed by waitingand treatment times according toselected ED characteristics Both waiting

and treatment times contributed to totalvisit duration being longest in EDs thatgo on diversion 20 or more of thetime Metropolitan visits lasted 2ndash3times longer than nonmetropolitan visitson average

Indexes of staffing capacityand throughput

Table 7 presents selected indexes ofED functioning using measures fromNHAMCS The indexes are meanestimates for all EDs combined andseparately for those in metropolitanareas and areas that were notmetropolitan The 25th 50th and 75thpercentiles are also presented to showthe variation across EDs Significantdifferences between urban and ruralareas were found for all indexes withthe exception of visits per space visitsper physician physicians per spacepercentage arriving by ambulance andpercentage admitted to hospital For EDsthat had any diversion the averagenumber of hours on diversion for theyear was 3639 among metropolitanEDs the average number of hours ondiversion was 4039 (Table 7) Formetropolitan EDs 25 percent reportedbeing on diversion for more than 5244hours during the previous year

Estimates of ED crowding

Ambulance diversion cannot beused as the sole criteria for EDcrowding because about 8 percent ofhospitals reported that there were lawsprohibiting that practice in theirlocation Using the criteria of anyambulance diversion hours averagewaiting time greater or equal to 60minutes for urgent cases or percentageof visits where the patient left beforebeing seen greater than or equal to3 percent approximately 449 percent(95 confidence interval 398 to 500)of EDs experienced crowding some timeduring 2003 and 2004 Approximately637 percent of metropolitan EDsexperienced crowding compared with144 percent of EDs that were notmetropolitan Because EDs experiencingcrowding tend to be larger in annual EDvisit volume this corresponds to626 percent of all emergency visitsbeing made to hospitals that experienced

Figure 9 Percentage of emergency departments that experienced crowding by selectedhospital characteristics United States 2003ndash04

Figure 10 Ratio of indexes with significant differences between crowded and uncrowdedemergency departments in metropolitan areas

Advance Data No 376 + September 27 2006 9

ED crowding Additionally crowdingwas more common among EDs withlarger inpatient bed sizes and thoseassociated with medical schools(Figure 9)

When examining differences in thestaffing capacity and throughputindexes for EDs located in metropolitanareas EDs experiencing crowding weresignificantly higher than those notexperiencing crowding for aboutone-half of those measures (Figure 10)The percentage of cases left beforebeing seen in crowded EDs (21) wasfour times as high as the percentage inuncrowded EDs (04) The percentageof nursing positions vacant in crowdedEDs (77) was twice that ofuncrowded EDs (39) Average waitingtime was 50 longer in crowded EDs(518 minutes) compared withuncrowded EDs (354 minutes)

DiscussionThis report shows how US

nonfederal general and short-stayhospitals vary with respect to structureprocess and patient attributes inproviding emergency medical careNational estimates of the steps hospitalstake to provide such care are describedseparately for hospitals located inmetropolitan areas and in areas thatwere not metropolitan The fundamentaldifferences in the size of metropolitanhospitals both in terms of bed size andED visit volume affect many of theobserved differences in staffing patternsED crowding and duration of visits Ineffect the problems facing urban EDsare very different than those facing ruralEDs In areas that were notmetropolitan most EDs are the only oneavailable for patients residing in thecatchment area There are no lsquolsquonearbyrsquorsquochoices for an emergency visit whereasmost metropolitan EDs have severalother EDs available within a 20-minuteambulance ride or a 5-mile radius EDpatient profiles also vary bymetropolitan status EDs that are not inmetropolitan areas were more likely tohave a higher proportion of Medicarepatients and to transfer patients

One area of distinction betweenhospitals that are in metropolitan or not

10 Advance Data No 376 + September 27 2006

metropolitan areas is the issue ofcrowding NHAMCS data provideinformation on key measures of EDcrowding Some of the indexesdeveloped by an expert panel (18)covering several domains of EDfunctioning (eg patient demand EDcapacity patient complexity and EDefficiency) were used to describe EDsexperiencing crowding Using thedefinition of crowding in this report 40to 50 percent of US EDs experiencedcrowding at some point in 2003 and2004 Among EDs located inmetropolitan areas the percentageincreased to 64 percent Indexes of EDfunctioning related to demand capacityand throughput found that one-half ofthose studied were related to crowdedconditions in metropolitan EDsSurprisingly indexes of staffing werenot related to crowding with theexception of the percentage of nursingpositions vacant

This report showed that periods ofambulance diversion occurred inone-half of EDs located in metropolitanareas Ambulance diversion is an effectof ED crowding and some of itsconsequences are increased transit timesand the potential for poor clinicaloutcomes (5) In addition a studyconducted in Los Angeles found thatdiversion hours at one ED wereinterrelated with the diversion hours ofthe nearest ED so that when one EDwent on diversion others nearby soonfollowed In addition to crowding in theED a leading reason for ambulancediversion is insufficient appropriateinpatient beds to place critically ill orinjured patients As with the 2002Government Accountability Office studyof metropolitan EDs (6) NHAMCSfound that diversion was positivelyrelated to hospital inpatient occupancyrates The average occupancy rate formetropolitan hospitals with nodiversions was 60 whereas it was81 for hospitals that spent as much as20 of their time on diversion

Increasing demand on EDs that arestill open has caused almost one-half ofall EDs to expand their physical spaceA California study found that althoughthe number of beds per populationremained stable during the 1990s thebeds were being occupied by more

labor-intensive patients resulting indecreased capacity (25) The NHAMCSresults showed that metropolitan statuswas not related to expanding physicalspace

This report shows that ED treatmentspaces and staffing levels vary acrossmetropolitan and not metropolitan areasMost EDs that are not in metropolitanareas have fewer than 10 standardtreatment spaces where metropolitanEDs typically have 10 to 50 spacesProviding nursing staff to cover all thespaces in metropolitan areas is anothermatter NHAMCS found that one-quarterof metropolitan EDs had 5ndash19 percent oftheir nursing positions vacant Inaddition to nursing shortages in the EDthere is the problem of high turnoverleading to a high proportion of newinexperienced emergency nursesSometimes nurses unfamiliar with theED are sent to work from other areas ofthe hospital which can contribute toreduced efficiency in the delivery ofcare (7)

On-call physician specialists providespecialized care for patients beyond theexpertise of the emergency physicianand usually have no guarantee ofpayment for the services they provideFrom a specialistrsquos business perspectivebeing on-call may result in time spentwith little generation of income (26)NHAMCS data showed that on-callservices provided by plastic and handsurgeons were the most difficult toobtain compared with other specialtiesA California survey of emergencymedicine physicians found that five ofthe seven specialities in which thegreatest proportion of EDs reportedtrouble with specialty response weresurgical (27)

Triage systems are known to varyfrom hospital to hospital However theyall share the same goal of prioritizingpatients for treatment This prioritizationis relevant to patient safety especiallywhen ED crowding delays evaluationAlthough research found that thereliability and validity of the EmergencySeverity Index a 5-level triage systemwere better than in a 3-level system(2829) NHAMCS findings showed thatabout one-quarter of US EDs used theformer and those that used the 5-level

system were predominantly inmetropolitan areas

This survey found that multiplelanguage services were available morefrequently in metropolitan EDs Medicalerrors may result from patient-providercommunication problems due tolanguage barriers Limited Englishproficiency can lead to increased use ofmedical resources in children (30) andserious medical events during pediatrichospitalizations (31) NHAMCS datashowed that over 90 percent of EDsreported providing language translationservices with one-third offering 30 ormore different languages

Visit and patient profile patternsdiffered among hospitals indicating widevariation in reimbursement andtreatment practices Over one-quarter ofhospitals had 30 or more of theirvisits made by Medicaid recipients andabout one-fifth had 25 or more oftheir visits made by uninsured personsSuch hospitals treat a larger proportionof cases from safety-net populations andare at risk of higher rates ofuncompensated care Most of these highsafety-net hospitals do not receivesufficient Medicaid DisproportionateShare Program funds to offset theirfinancial losses (32) Collected chargesfor self-pay patients are as low as 1for the hospital to under 20 for thephysician (3334) Office-basedphysicians are also at risk for underpayment when they provide EMTALA-related care in hospitals In 2003ndash04228 percent of office-based physiciansreported that they spent an average of106 hours providing EMTALA-relatedcare during their last full week of work(35)

Hospitals also vary with respect tonumbers of pediatric cases seen in theED A separate study usingsupplemental data from the 2002ndash03NHAMCS found that hospitals with fewpediatric ED cases are least prepared forhandling the stabilization of severepediatric emergencies with regard tosmall-sized equipment such as needlesendotracheal tubes and access toemergency medicine specialistsespecially those specializing in pediatricemergencies (36) The NHAMCS datain this report found that one-fifth ofEDs transferred as much as 10 or

Advance Data No 376 + September 27 2006 11

more of their cases including pediatriccases implying that these hospitals werenot best equipped to handle a sizablevolume of their cases

This report also showed variationamong hospitals with respect to EDthroughput measures In metropolitanhospitals one-fifth of EDs had patientswaiting on average an hour or morebefore receiving treatment and one innine EDs had 5 or more of theirpatients leaving before being seen Astudy conducted in a California publichospital of patients who left beforebeing seen found that about one-halfwere judged to require immediate careand 11 percent were hospitalized withina week (37) NHAMCS data found thaton average the percentage of patientsleaving before being seen was positivelyassociated with increased waiting timesin metropolitan EDs

Although a previous study foundthat 91 percent of ED directorsnationwide reported overcrowding (38)this advance data report is the first topresent objective findings of EDcrowding in the United States The datapresented support the Institute ofMedicinersquos (I0M) recent report on thecrisis in US emergency medical care(39) The IOM found that capacity andexpertise were lacking for normaloperations and that the system lackedstability and the capacity to respond tolarge disasters and epidemics Thisadvance data report shows that themajority of urban hospitals experiencecrowding and commonly turn awayseverely ill or injured patients Thiscould affect the capacity of largerhospitals to treat patients who areinjured due to a mass casualty event orbecome ill as a result of an infectiousdisease outbreak

LimitationsUtilization estimates for EDs were

based on visits sampled during the4-week reporting period rather than thefull year To the extent that visitcharacteristics vary in a hospital acrossmonths then the variation around thedistribution of EDs on visitcharacteristics may be understated Alsothe sample size for hospitals that are notmetropolitan (n = 122) was not always

large enough to produce reliableestimates for some variables associatedwith large volume EDs because suchEDs are rarely found in rural areas Thepercentage of EDs experiencingcrowded conditions is most likely anunderestimate because informationconcerning diversion hours was notreported for 14 percent of the EDsConsistency between 2003 and 2004data collection among hospitals thatparticipated both years shows thatamong those EDs missing ambulancediversion hours in 2004 most providedan answer for 2003 of which aboutone-half had reported diversion hours(data not shown)

ConclusionsThis report provides many basic

statistics necessary for reviewing thestructure process and patient profilecharacteristics associated with thedelivery of emergency medical care inthis country It also provides nationalbenchmarks for potential measures ofworkflow necessary for understandingmonitoring and managing ED crowdingOther reports will examine therelationship that these variables mayhave on the quality of emergencymedical care Further information aboutNHAMCS and its supplements may befound at wwwcdcgovnchsnhamcshtm

References1 American Hospital Association

(personal communication with ScottBates) 2006

2 McCaig LF Nawar EW NationalHospital Ambulatory Medical CareSurvey 2004 emergency departmentsummary Advance data from vitaland health statistics no 372Hyattsville MD National Center forHealth Statistics 2006

3 ACEP Statistics Fact Sheet Availablefrom httpwwwaceporgwebportalNewsroomTemplatesDefault_PrimaryaspxNRMODE=PublishedampNRORIGINALURL=2fwebportal2fNewsroom2fNewsMediaResources2fStatisticsData2fdefault2ehtmampNRNODEGUID=7b0AA2DBFD-5FA5-4E21-9C66-F69C8AFCC35B7dampNRCACHEHINT=NoModifyGuestwait

4 McCaig LF Ly N National HospitalAmbulatory Medical Care Survey2000 emergency departmentsummary Advance data from vitaland health statistics no 326Hyattsville MD National Center forHealth Statistics 2002

5 Derlet RW Richards JROvercrowding in the nationrsquosemergency departments Complexcauses and disturbing effects AnnEmerg Med 3563ndash8 2000

6 General Accounting Office Hospitalemergency departments Crowdedconditions vary among hospitals andcommunities Washington GeneralAccounting Office 2003

7 Emergency Medical Treatment andActive Labor Act (EMTALA)codified as amended at 42 USC1395dd 1990 Health Care FinancingAdministration EMTALARegulations 42 CFR Parts 488489 1003 1994

8 American Hospital AssociationUncompensated hospital care costfact sheet American HospitalAssociation 2005 Available fromhttpwwwahaorgahacontent2005pdf0511UncompensatedCareFactSheetpdf

9 Silka PA Geiderman JM Kim JYDiversion of ALS ambulancesCharacteristics causes and effects ina large urban system Prehosp EmergCare 523ndash28 2001

10 Sun BC Mohanty SA Weiss R etal Effects of hospital closures andhospital characteristics on emergencydepartment ambulance diversion LosAngeles County 1998 to 2004 AnnEmerg Med 47309ndash16 2006

11 Schull MH Vermeulen M SlaughterG Morrison L Daly P Emergencydepartment crowding andthrombolysis delays in acutemyocardial infarction Ann EmergMed 44577ndash85 2004

12 Burt CW McCaig LF Valverde RHAnalysis of ambulance transports anddiversions among US emergencydepartments Ann Emerg Med47317ndash26 2006

13 Brewster LR Felland LE Emergencydepartment diversions Hospital andcommunity strategies alleviate thecrisis Issue Brief No78 Center forStudying Health System ChangeWashington 2003

14 McConnell KJ Richards CF DayaM et al Effect of ICU capacity onemergency department length of stay

Figure 9 Percentage of emergency departments that experienced crowding by selectedhospital characteristics United States 2003ndash04

Figure 10 Ratio of indexes with significant differences between crowded and uncrowdedemergency departments in metropolitan areas

Advance Data No 376 + September 27 2006 9

ED crowding Additionally crowdingwas more common among EDs withlarger inpatient bed sizes and thoseassociated with medical schools(Figure 9)

When examining differences in thestaffing capacity and throughputindexes for EDs located in metropolitanareas EDs experiencing crowding weresignificantly higher than those notexperiencing crowding for aboutone-half of those measures (Figure 10)The percentage of cases left beforebeing seen in crowded EDs (21) wasfour times as high as the percentage inuncrowded EDs (04) The percentageof nursing positions vacant in crowdedEDs (77) was twice that ofuncrowded EDs (39) Average waitingtime was 50 longer in crowded EDs(518 minutes) compared withuncrowded EDs (354 minutes)

DiscussionThis report shows how US

nonfederal general and short-stayhospitals vary with respect to structureprocess and patient attributes inproviding emergency medical careNational estimates of the steps hospitalstake to provide such care are describedseparately for hospitals located inmetropolitan areas and in areas thatwere not metropolitan The fundamentaldifferences in the size of metropolitanhospitals both in terms of bed size andED visit volume affect many of theobserved differences in staffing patternsED crowding and duration of visits Ineffect the problems facing urban EDsare very different than those facing ruralEDs In areas that were notmetropolitan most EDs are the only oneavailable for patients residing in thecatchment area There are no lsquolsquonearbyrsquorsquochoices for an emergency visit whereasmost metropolitan EDs have severalother EDs available within a 20-minuteambulance ride or a 5-mile radius EDpatient profiles also vary bymetropolitan status EDs that are not inmetropolitan areas were more likely tohave a higher proportion of Medicarepatients and to transfer patients

One area of distinction betweenhospitals that are in metropolitan or not

10 Advance Data No 376 + September 27 2006

metropolitan areas is the issue ofcrowding NHAMCS data provideinformation on key measures of EDcrowding Some of the indexesdeveloped by an expert panel (18)covering several domains of EDfunctioning (eg patient demand EDcapacity patient complexity and EDefficiency) were used to describe EDsexperiencing crowding Using thedefinition of crowding in this report 40to 50 percent of US EDs experiencedcrowding at some point in 2003 and2004 Among EDs located inmetropolitan areas the percentageincreased to 64 percent Indexes of EDfunctioning related to demand capacityand throughput found that one-half ofthose studied were related to crowdedconditions in metropolitan EDsSurprisingly indexes of staffing werenot related to crowding with theexception of the percentage of nursingpositions vacant

This report showed that periods ofambulance diversion occurred inone-half of EDs located in metropolitanareas Ambulance diversion is an effectof ED crowding and some of itsconsequences are increased transit timesand the potential for poor clinicaloutcomes (5) In addition a studyconducted in Los Angeles found thatdiversion hours at one ED wereinterrelated with the diversion hours ofthe nearest ED so that when one EDwent on diversion others nearby soonfollowed In addition to crowding in theED a leading reason for ambulancediversion is insufficient appropriateinpatient beds to place critically ill orinjured patients As with the 2002Government Accountability Office studyof metropolitan EDs (6) NHAMCSfound that diversion was positivelyrelated to hospital inpatient occupancyrates The average occupancy rate formetropolitan hospitals with nodiversions was 60 whereas it was81 for hospitals that spent as much as20 of their time on diversion

Increasing demand on EDs that arestill open has caused almost one-half ofall EDs to expand their physical spaceA California study found that althoughthe number of beds per populationremained stable during the 1990s thebeds were being occupied by more

labor-intensive patients resulting indecreased capacity (25) The NHAMCSresults showed that metropolitan statuswas not related to expanding physicalspace

This report shows that ED treatmentspaces and staffing levels vary acrossmetropolitan and not metropolitan areasMost EDs that are not in metropolitanareas have fewer than 10 standardtreatment spaces where metropolitanEDs typically have 10 to 50 spacesProviding nursing staff to cover all thespaces in metropolitan areas is anothermatter NHAMCS found that one-quarterof metropolitan EDs had 5ndash19 percent oftheir nursing positions vacant Inaddition to nursing shortages in the EDthere is the problem of high turnoverleading to a high proportion of newinexperienced emergency nursesSometimes nurses unfamiliar with theED are sent to work from other areas ofthe hospital which can contribute toreduced efficiency in the delivery ofcare (7)

On-call physician specialists providespecialized care for patients beyond theexpertise of the emergency physicianand usually have no guarantee ofpayment for the services they provideFrom a specialistrsquos business perspectivebeing on-call may result in time spentwith little generation of income (26)NHAMCS data showed that on-callservices provided by plastic and handsurgeons were the most difficult toobtain compared with other specialtiesA California survey of emergencymedicine physicians found that five ofthe seven specialities in which thegreatest proportion of EDs reportedtrouble with specialty response weresurgical (27)

Triage systems are known to varyfrom hospital to hospital However theyall share the same goal of prioritizingpatients for treatment This prioritizationis relevant to patient safety especiallywhen ED crowding delays evaluationAlthough research found that thereliability and validity of the EmergencySeverity Index a 5-level triage systemwere better than in a 3-level system(2829) NHAMCS findings showed thatabout one-quarter of US EDs used theformer and those that used the 5-level

system were predominantly inmetropolitan areas

This survey found that multiplelanguage services were available morefrequently in metropolitan EDs Medicalerrors may result from patient-providercommunication problems due tolanguage barriers Limited Englishproficiency can lead to increased use ofmedical resources in children (30) andserious medical events during pediatrichospitalizations (31) NHAMCS datashowed that over 90 percent of EDsreported providing language translationservices with one-third offering 30 ormore different languages

Visit and patient profile patternsdiffered among hospitals indicating widevariation in reimbursement andtreatment practices Over one-quarter ofhospitals had 30 or more of theirvisits made by Medicaid recipients andabout one-fifth had 25 or more oftheir visits made by uninsured personsSuch hospitals treat a larger proportionof cases from safety-net populations andare at risk of higher rates ofuncompensated care Most of these highsafety-net hospitals do not receivesufficient Medicaid DisproportionateShare Program funds to offset theirfinancial losses (32) Collected chargesfor self-pay patients are as low as 1for the hospital to under 20 for thephysician (3334) Office-basedphysicians are also at risk for underpayment when they provide EMTALA-related care in hospitals In 2003ndash04228 percent of office-based physiciansreported that they spent an average of106 hours providing EMTALA-relatedcare during their last full week of work(35)

Hospitals also vary with respect tonumbers of pediatric cases seen in theED A separate study usingsupplemental data from the 2002ndash03NHAMCS found that hospitals with fewpediatric ED cases are least prepared forhandling the stabilization of severepediatric emergencies with regard tosmall-sized equipment such as needlesendotracheal tubes and access toemergency medicine specialistsespecially those specializing in pediatricemergencies (36) The NHAMCS datain this report found that one-fifth ofEDs transferred as much as 10 or

Advance Data No 376 + September 27 2006 11

more of their cases including pediatriccases implying that these hospitals werenot best equipped to handle a sizablevolume of their cases

This report also showed variationamong hospitals with respect to EDthroughput measures In metropolitanhospitals one-fifth of EDs had patientswaiting on average an hour or morebefore receiving treatment and one innine EDs had 5 or more of theirpatients leaving before being seen Astudy conducted in a California publichospital of patients who left beforebeing seen found that about one-halfwere judged to require immediate careand 11 percent were hospitalized withina week (37) NHAMCS data found thaton average the percentage of patientsleaving before being seen was positivelyassociated with increased waiting timesin metropolitan EDs

Although a previous study foundthat 91 percent of ED directorsnationwide reported overcrowding (38)this advance data report is the first topresent objective findings of EDcrowding in the United States The datapresented support the Institute ofMedicinersquos (I0M) recent report on thecrisis in US emergency medical care(39) The IOM found that capacity andexpertise were lacking for normaloperations and that the system lackedstability and the capacity to respond tolarge disasters and epidemics Thisadvance data report shows that themajority of urban hospitals experiencecrowding and commonly turn awayseverely ill or injured patients Thiscould affect the capacity of largerhospitals to treat patients who areinjured due to a mass casualty event orbecome ill as a result of an infectiousdisease outbreak

LimitationsUtilization estimates for EDs were

based on visits sampled during the4-week reporting period rather than thefull year To the extent that visitcharacteristics vary in a hospital acrossmonths then the variation around thedistribution of EDs on visitcharacteristics may be understated Alsothe sample size for hospitals that are notmetropolitan (n = 122) was not always

large enough to produce reliableestimates for some variables associatedwith large volume EDs because suchEDs are rarely found in rural areas Thepercentage of EDs experiencingcrowded conditions is most likely anunderestimate because informationconcerning diversion hours was notreported for 14 percent of the EDsConsistency between 2003 and 2004data collection among hospitals thatparticipated both years shows thatamong those EDs missing ambulancediversion hours in 2004 most providedan answer for 2003 of which aboutone-half had reported diversion hours(data not shown)

ConclusionsThis report provides many basic

statistics necessary for reviewing thestructure process and patient profilecharacteristics associated with thedelivery of emergency medical care inthis country It also provides nationalbenchmarks for potential measures ofworkflow necessary for understandingmonitoring and managing ED crowdingOther reports will examine therelationship that these variables mayhave on the quality of emergencymedical care Further information aboutNHAMCS and its supplements may befound at wwwcdcgovnchsnhamcshtm

References1 American Hospital Association

(personal communication with ScottBates) 2006

2 McCaig LF Nawar EW NationalHospital Ambulatory Medical CareSurvey 2004 emergency departmentsummary Advance data from vitaland health statistics no 372Hyattsville MD National Center forHealth Statistics 2006

3 ACEP Statistics Fact Sheet Availablefrom httpwwwaceporgwebportalNewsroomTemplatesDefault_PrimaryaspxNRMODE=PublishedampNRORIGINALURL=2fwebportal2fNewsroom2fNewsMediaResources2fStatisticsData2fdefault2ehtmampNRNODEGUID=7b0AA2DBFD-5FA5-4E21-9C66-F69C8AFCC35B7dampNRCACHEHINT=NoModifyGuestwait

4 McCaig LF Ly N National HospitalAmbulatory Medical Care Survey2000 emergency departmentsummary Advance data from vitaland health statistics no 326Hyattsville MD National Center forHealth Statistics 2002

5 Derlet RW Richards JROvercrowding in the nationrsquosemergency departments Complexcauses and disturbing effects AnnEmerg Med 3563ndash8 2000

6 General Accounting Office Hospitalemergency departments Crowdedconditions vary among hospitals andcommunities Washington GeneralAccounting Office 2003

7 Emergency Medical Treatment andActive Labor Act (EMTALA)codified as amended at 42 USC1395dd 1990 Health Care FinancingAdministration EMTALARegulations 42 CFR Parts 488489 1003 1994

8 American Hospital AssociationUncompensated hospital care costfact sheet American HospitalAssociation 2005 Available fromhttpwwwahaorgahacontent2005pdf0511UncompensatedCareFactSheetpdf

9 Silka PA Geiderman JM Kim JYDiversion of ALS ambulancesCharacteristics causes and effects ina large urban system Prehosp EmergCare 523ndash28 2001

10 Sun BC Mohanty SA Weiss R etal Effects of hospital closures andhospital characteristics on emergencydepartment ambulance diversion LosAngeles County 1998 to 2004 AnnEmerg Med 47309ndash16 2006

11 Schull MH Vermeulen M SlaughterG Morrison L Daly P Emergencydepartment crowding andthrombolysis delays in acutemyocardial infarction Ann EmergMed 44577ndash85 2004

12 Burt CW McCaig LF Valverde RHAnalysis of ambulance transports anddiversions among US emergencydepartments Ann Emerg Med47317ndash26 2006

13 Brewster LR Felland LE Emergencydepartment diversions Hospital andcommunity strategies alleviate thecrisis Issue Brief No78 Center forStudying Health System ChangeWashington 2003

14 McConnell KJ Richards CF DayaM et al Effect of ICU capacity onemergency department length of stay

10 Advance Data No 376 + September 27 2006

metropolitan areas is the issue ofcrowding NHAMCS data provideinformation on key measures of EDcrowding Some of the indexesdeveloped by an expert panel (18)covering several domains of EDfunctioning (eg patient demand EDcapacity patient complexity and EDefficiency) were used to describe EDsexperiencing crowding Using thedefinition of crowding in this report 40to 50 percent of US EDs experiencedcrowding at some point in 2003 and2004 Among EDs located inmetropolitan areas the percentageincreased to 64 percent Indexes of EDfunctioning related to demand capacityand throughput found that one-half ofthose studied were related to crowdedconditions in metropolitan EDsSurprisingly indexes of staffing werenot related to crowding with theexception of the percentage of nursingpositions vacant

This report showed that periods ofambulance diversion occurred inone-half of EDs located in metropolitanareas Ambulance diversion is an effectof ED crowding and some of itsconsequences are increased transit timesand the potential for poor clinicaloutcomes (5) In addition a studyconducted in Los Angeles found thatdiversion hours at one ED wereinterrelated with the diversion hours ofthe nearest ED so that when one EDwent on diversion others nearby soonfollowed In addition to crowding in theED a leading reason for ambulancediversion is insufficient appropriateinpatient beds to place critically ill orinjured patients As with the 2002Government Accountability Office studyof metropolitan EDs (6) NHAMCSfound that diversion was positivelyrelated to hospital inpatient occupancyrates The average occupancy rate formetropolitan hospitals with nodiversions was 60 whereas it was81 for hospitals that spent as much as20 of their time on diversion

Increasing demand on EDs that arestill open has caused almost one-half ofall EDs to expand their physical spaceA California study found that althoughthe number of beds per populationremained stable during the 1990s thebeds were being occupied by more

labor-intensive patients resulting indecreased capacity (25) The NHAMCSresults showed that metropolitan statuswas not related to expanding physicalspace

This report shows that ED treatmentspaces and staffing levels vary acrossmetropolitan and not metropolitan areasMost EDs that are not in metropolitanareas have fewer than 10 standardtreatment spaces where metropolitanEDs typically have 10 to 50 spacesProviding nursing staff to cover all thespaces in metropolitan areas is anothermatter NHAMCS found that one-quarterof metropolitan EDs had 5ndash19 percent oftheir nursing positions vacant Inaddition to nursing shortages in the EDthere is the problem of high turnoverleading to a high proportion of newinexperienced emergency nursesSometimes nurses unfamiliar with theED are sent to work from other areas ofthe hospital which can contribute toreduced efficiency in the delivery ofcare (7)

On-call physician specialists providespecialized care for patients beyond theexpertise of the emergency physicianand usually have no guarantee ofpayment for the services they provideFrom a specialistrsquos business perspectivebeing on-call may result in time spentwith little generation of income (26)NHAMCS data showed that on-callservices provided by plastic and handsurgeons were the most difficult toobtain compared with other specialtiesA California survey of emergencymedicine physicians found that five ofthe seven specialities in which thegreatest proportion of EDs reportedtrouble with specialty response weresurgical (27)

Triage systems are known to varyfrom hospital to hospital However theyall share the same goal of prioritizingpatients for treatment This prioritizationis relevant to patient safety especiallywhen ED crowding delays evaluationAlthough research found that thereliability and validity of the EmergencySeverity Index a 5-level triage systemwere better than in a 3-level system(2829) NHAMCS findings showed thatabout one-quarter of US EDs used theformer and those that used the 5-level

system were predominantly inmetropolitan areas

This survey found that multiplelanguage services were available morefrequently in metropolitan EDs Medicalerrors may result from patient-providercommunication problems due tolanguage barriers Limited Englishproficiency can lead to increased use ofmedical resources in children (30) andserious medical events during pediatrichospitalizations (31) NHAMCS datashowed that over 90 percent of EDsreported providing language translationservices with one-third offering 30 ormore different languages

Visit and patient profile patternsdiffered among hospitals indicating widevariation in reimbursement andtreatment practices Over one-quarter ofhospitals had 30 or more of theirvisits made by Medicaid recipients andabout one-fifth had 25 or more oftheir visits made by uninsured personsSuch hospitals treat a larger proportionof cases from safety-net populations andare at risk of higher rates ofuncompensated care Most of these highsafety-net hospitals do not receivesufficient Medicaid DisproportionateShare Program funds to offset theirfinancial losses (32) Collected chargesfor self-pay patients are as low as 1for the hospital to under 20 for thephysician (3334) Office-basedphysicians are also at risk for underpayment when they provide EMTALA-related care in hospitals In 2003ndash04228 percent of office-based physiciansreported that they spent an average of106 hours providing EMTALA-relatedcare during their last full week of work(35)

Hospitals also vary with respect tonumbers of pediatric cases seen in theED A separate study usingsupplemental data from the 2002ndash03NHAMCS found that hospitals with fewpediatric ED cases are least prepared forhandling the stabilization of severepediatric emergencies with regard tosmall-sized equipment such as needlesendotracheal tubes and access toemergency medicine specialistsespecially those specializing in pediatricemergencies (36) The NHAMCS datain this report found that one-fifth ofEDs transferred as much as 10 or

Advance Data No 376 + September 27 2006 11

more of their cases including pediatriccases implying that these hospitals werenot best equipped to handle a sizablevolume of their cases

This report also showed variationamong hospitals with respect to EDthroughput measures In metropolitanhospitals one-fifth of EDs had patientswaiting on average an hour or morebefore receiving treatment and one innine EDs had 5 or more of theirpatients leaving before being seen Astudy conducted in a California publichospital of patients who left beforebeing seen found that about one-halfwere judged to require immediate careand 11 percent were hospitalized withina week (37) NHAMCS data found thaton average the percentage of patientsleaving before being seen was positivelyassociated with increased waiting timesin metropolitan EDs

Although a previous study foundthat 91 percent of ED directorsnationwide reported overcrowding (38)this advance data report is the first topresent objective findings of EDcrowding in the United States The datapresented support the Institute ofMedicinersquos (I0M) recent report on thecrisis in US emergency medical care(39) The IOM found that capacity andexpertise were lacking for normaloperations and that the system lackedstability and the capacity to respond tolarge disasters and epidemics Thisadvance data report shows that themajority of urban hospitals experiencecrowding and commonly turn awayseverely ill or injured patients Thiscould affect the capacity of largerhospitals to treat patients who areinjured due to a mass casualty event orbecome ill as a result of an infectiousdisease outbreak

LimitationsUtilization estimates for EDs were

based on visits sampled during the4-week reporting period rather than thefull year To the extent that visitcharacteristics vary in a hospital acrossmonths then the variation around thedistribution of EDs on visitcharacteristics may be understated Alsothe sample size for hospitals that are notmetropolitan (n = 122) was not always

large enough to produce reliableestimates for some variables associatedwith large volume EDs because suchEDs are rarely found in rural areas Thepercentage of EDs experiencingcrowded conditions is most likely anunderestimate because informationconcerning diversion hours was notreported for 14 percent of the EDsConsistency between 2003 and 2004data collection among hospitals thatparticipated both years shows thatamong those EDs missing ambulancediversion hours in 2004 most providedan answer for 2003 of which aboutone-half had reported diversion hours(data not shown)

ConclusionsThis report provides many basic

statistics necessary for reviewing thestructure process and patient profilecharacteristics associated with thedelivery of emergency medical care inthis country It also provides nationalbenchmarks for potential measures ofworkflow necessary for understandingmonitoring and managing ED crowdingOther reports will examine therelationship that these variables mayhave on the quality of emergencymedical care Further information aboutNHAMCS and its supplements may befound at wwwcdcgovnchsnhamcshtm

References1 American Hospital Association

(personal communication with ScottBates) 2006

2 McCaig LF Nawar EW NationalHospital Ambulatory Medical CareSurvey 2004 emergency departmentsummary Advance data from vitaland health statistics no 372Hyattsville MD National Center forHealth Statistics 2006

3 ACEP Statistics Fact Sheet Availablefrom httpwwwaceporgwebportalNewsroomTemplatesDefault_PrimaryaspxNRMODE=PublishedampNRORIGINALURL=2fwebportal2fNewsroom2fNewsMediaResources2fStatisticsData2fdefault2ehtmampNRNODEGUID=7b0AA2DBFD-5FA5-4E21-9C66-F69C8AFCC35B7dampNRCACHEHINT=NoModifyGuestwait

4 McCaig LF Ly N National HospitalAmbulatory Medical Care Survey2000 emergency departmentsummary Advance data from vitaland health statistics no 326Hyattsville MD National Center forHealth Statistics 2002

5 Derlet RW Richards JROvercrowding in the nationrsquosemergency departments Complexcauses and disturbing effects AnnEmerg Med 3563ndash8 2000

6 General Accounting Office Hospitalemergency departments Crowdedconditions vary among hospitals andcommunities Washington GeneralAccounting Office 2003

7 Emergency Medical Treatment andActive Labor Act (EMTALA)codified as amended at 42 USC1395dd 1990 Health Care FinancingAdministration EMTALARegulations 42 CFR Parts 488489 1003 1994

8 American Hospital AssociationUncompensated hospital care costfact sheet American HospitalAssociation 2005 Available fromhttpwwwahaorgahacontent2005pdf0511UncompensatedCareFactSheetpdf

9 Silka PA Geiderman JM Kim JYDiversion of ALS ambulancesCharacteristics causes and effects ina large urban system Prehosp EmergCare 523ndash28 2001

10 Sun BC Mohanty SA Weiss R etal Effects of hospital closures andhospital characteristics on emergencydepartment ambulance diversion LosAngeles County 1998 to 2004 AnnEmerg Med 47309ndash16 2006

11 Schull MH Vermeulen M SlaughterG Morrison L Daly P Emergencydepartment crowding andthrombolysis delays in acutemyocardial infarction Ann EmergMed 44577ndash85 2004

12 Burt CW McCaig LF Valverde RHAnalysis of ambulance transports anddiversions among US emergencydepartments Ann Emerg Med47317ndash26 2006

13 Brewster LR Felland LE Emergencydepartment diversions Hospital andcommunity strategies alleviate thecrisis Issue Brief No78 Center forStudying Health System ChangeWashington 2003

14 McConnell KJ Richards CF DayaM et al Effect of ICU capacity onemergency department length of stay

Advance Data No 376 + September 27 2006 11

more of their cases including pediatriccases implying that these hospitals werenot best equipped to handle a sizablevolume of their cases

This report also showed variationamong hospitals with respect to EDthroughput measures In metropolitanhospitals one-fifth of EDs had patientswaiting on average an hour or morebefore receiving treatment and one innine EDs had 5 or more of theirpatients leaving before being seen Astudy conducted in a California publichospital of patients who left beforebeing seen found that about one-halfwere judged to require immediate careand 11 percent were hospitalized withina week (37) NHAMCS data found thaton average the percentage of patientsleaving before being seen was positivelyassociated with increased waiting timesin metropolitan EDs

Although a previous study foundthat 91 percent of ED directorsnationwide reported overcrowding (38)this advance data report is the first topresent objective findings of EDcrowding in the United States The datapresented support the Institute ofMedicinersquos (I0M) recent report on thecrisis in US emergency medical care(39) The IOM found that capacity andexpertise were lacking for normaloperations and that the system lackedstability and the capacity to respond tolarge disasters and epidemics Thisadvance data report shows that themajority of urban hospitals experiencecrowding and commonly turn awayseverely ill or injured patients Thiscould affect the capacity of largerhospitals to treat patients who areinjured due to a mass casualty event orbecome ill as a result of an infectiousdisease outbreak

LimitationsUtilization estimates for EDs were

based on visits sampled during the4-week reporting period rather than thefull year To the extent that visitcharacteristics vary in a hospital acrossmonths then the variation around thedistribution of EDs on visitcharacteristics may be understated Alsothe sample size for hospitals that are notmetropolitan (n = 122) was not always

large enough to produce reliableestimates for some variables associatedwith large volume EDs because suchEDs are rarely found in rural areas Thepercentage of EDs experiencingcrowded conditions is most likely anunderestimate because informationconcerning diversion hours was notreported for 14 percent of the EDsConsistency between 2003 and 2004data collection among hospitals thatparticipated both years shows thatamong those EDs missing ambulancediversion hours in 2004 most providedan answer for 2003 of which aboutone-half had reported diversion hours(data not shown)

ConclusionsThis report provides many basic

statistics necessary for reviewing thestructure process and patient profilecharacteristics associated with thedelivery of emergency medical care inthis country It also provides nationalbenchmarks for potential measures ofworkflow necessary for understandingmonitoring and managing ED crowdingOther reports will examine therelationship that these variables mayhave on the quality of emergencymedical care Further information aboutNHAMCS and its supplements may befound at wwwcdcgovnchsnhamcshtm

References1 American Hospital Association

(personal communication with ScottBates) 2006

2 McCaig LF Nawar EW NationalHospital Ambulatory Medical CareSurvey 2004 emergency departmentsummary Advance data from vitaland health statistics no 372Hyattsville MD National Center forHealth Statistics 2006

3 ACEP Statistics Fact Sheet Availablefrom httpwwwaceporgwebportalNewsroomTemplatesDefault_PrimaryaspxNRMODE=PublishedampNRORIGINALURL=2fwebportal2fNewsroom2fNewsMediaResources2fStatisticsData2fdefault2ehtmampNRNODEGUID=7b0AA2DBFD-5FA5-4E21-9C66-F69C8AFCC35B7dampNRCACHEHINT=NoModifyGuestwait

4 McCaig LF Ly N National HospitalAmbulatory Medical Care Survey2000 emergency departmentsummary Advance data from vitaland health statistics no 326Hyattsville MD National Center forHealth Statistics 2002

5 Derlet RW Richards JROvercrowding in the nationrsquosemergency departments Complexcauses and disturbing effects AnnEmerg Med 3563ndash8 2000

6 General Accounting Office Hospitalemergency departments Crowdedconditions vary among hospitals andcommunities Washington GeneralAccounting Office 2003

7 Emergency Medical Treatment andActive Labor Act (EMTALA)codified as amended at 42 USC1395dd 1990 Health Care FinancingAdministration EMTALARegulations 42 CFR Parts 488489 1003 1994

8 American Hospital AssociationUncompensated hospital care costfact sheet American HospitalAssociation 2005 Available fromhttpwwwahaorgahacontent2005pdf0511UncompensatedCareFactSheetpdf

9 Silka PA Geiderman JM Kim JYDiversion of ALS ambulancesCharacteristics causes and effects ina large urban system Prehosp EmergCare 523ndash28 2001

10 Sun BC Mohanty SA Weiss R etal Effects of hospital closures andhospital characteristics on emergencydepartment ambulance diversion LosAngeles County 1998 to 2004 AnnEmerg Med 47309ndash16 2006

11 Schull MH Vermeulen M SlaughterG Morrison L Daly P Emergencydepartment crowding andthrombolysis delays in acutemyocardial infarction Ann EmergMed 44577ndash85 2004

12 Burt CW McCaig LF Valverde RHAnalysis of ambulance transports anddiversions among US emergencydepartments Ann Emerg Med47317ndash26 2006

13 Brewster LR Felland LE Emergencydepartment diversions Hospital andcommunity strategies alleviate thecrisis Issue Brief No78 Center forStudying Health System ChangeWashington 2003

14 McConnell KJ Richards CF DayaM et al Effect of ICU capacity onemergency department length of stay

series Uncorrected proofs June 142006

12 Advance Data No 376 + September 27 2006

and ambulance diversion Ann EmergMed 45471ndash8 2005

15 Kelen GD Scheulen PA Hill PMEffect of an emergency department(ED) managed acute care unit on EDovercrowding and emergencymedical services diversion AcadEmerg Med 81095ndash1100 2001

16 Spaite DW Bartholomeaux F GuistoJ et al Rapid process redesign in auniversity-based emergencydepartment Decreasing waiting timeintervals and improving patientsatisfaction Ann Emerg Med39168ndash77 2002

17 Taylor J Donrsquot bring me your tiredyour poor The crowded state ofAmericarsquos emergency departmentsNational Health Policy Forum IssueBrief no 811 2006 Available fromhttpwwwnhpforgpdfs_ibIB811_EDCrowding_07-07-06pdf

18 Solberg LI Asplin BR Weinick RMMagid DJ Emergency departmentcrowding Consensus development ofpotential measures Ann Emerg Med42824ndash34 2003

19 US News and World Report Codeblue crisis in the ER 2001 Availablefrom httpwwwusnewscomusnewshealtharticles010910archive_003670_4htm

20 McCaig LF McLemore T Plan andoperation of the National HospitalAmbulatory Medical Care SurveyNational Center for Health StatisticsVital Health Stat 1(34) 1994

21 Research Triangle InstituteSUDAAN (Release 901) [ComputerSoftware] Research Triangle ParkNC Research Triangle Institute2005

22 McCaig LF Burt CW NationalHospital Ambulatory Medical CareSurvey 2003 emergency departmentsummary Advance data from vitaland health statistics no 358Hyattsville MD National Center forHealth Statistics 2005

23 Epstein SK Tian L Development ofan emergency department work scoreto predict ambulance diversion AcadEmerg Med13421ndash6 2006

24 Asplin B Measuring crowding Timefor a paradigm shift Acad EmergMed13459ndash61 2006

25 Lambe S Washington DL Fink A etal Trends in the use and capacity ofCaliforniarsquos emergency departments1990ndash1999 Ann Emerg Med39389ndash96 2002

26 Taylor TB Threats to the health caresafety net Acad Emerg Med81080ndash7 2001

27 Rudkin SE Oman J Langdorf MI etal The state of ED on-call coveragein California Am J Emerg Med22575ndash81 2004

28 Travers D Waller A Bowling J etal Five-level triage system moreeffective than three-level system intertiary emergency department JEmerg Nurs 28395ndash400 2002

29 Fernandes C Wuerz R Clark S etal How reliable is emergencydepartment triage Ann Emerg Med34141ndash7 1999

30 Hampers LC McNulty JEProfessional interpreters and bilingualphysicians in a pediatric emergencydepartment Arch Pediatr AdolescMed 1561108ndash13 2002

31 Cohen AL Rivara F Marcuse EK etal Are language barriers associatedwith serious medical events inhospitalized pediatric patientsPediatrics 116575ndash9 1999

32 Burt CW Arispe IE Characteristicsof emergency departments servinghigh volumes of safety-net patientsUnited States 2000 National Centerfor Health Statistics Vital Health Stat13(155) 2004

33 Beck CM Paul RI Payment ofemergency department bills byMedicaid patients Ann Emerg Med5(4) 330ndash3 1998

34 Irvin C Fox J Pothoven KFinancial impact on emergencyphysicians for nonreimbursed carefor the uninsured Ann Emerg Med42(4)571ndash6 2003

35 Hing E Burt CW Characteristics ofoffice-based physicians and theirpractices United States 2003ndash04National Center for Health StatisticsVital Health Stat 13(164) To bepublished

36 Middleton KR Burt CW Availabilityof pediatric services and equipmentin emergency departments UnitedStates 2002ndash03 Advance data fromvital and health statistics no 367Hyattsville MD National Center forHealth Statistics 2006

37 Baker DW Stevens CD Brook RHPatients who leave a public hospitalemergency department without beingseen by a physician Causes andconsequences JAMA 2661085ndash901991

38 Derlet RW Richards JR Kravitz RLFrequent overcrowding in US

emergency departments Acad EmergMed 8151-55 2001

39 Institute of Medicine Hospital-basedemergency care At the breakingpoint Future of emergency care

Table 1 Percent distribution of emergency departments and corresponding standard errors by hospital characteristics according tometropolitan status United States 2003ndash04

Characteristic

Total Metropolitan area Not metropolitan area

Percentdistribution

Standarderror

Percentdistribution

Standarderror

Percentdistribution

Standarderror

All emergency departments 1000 1000 1000

Geographic region

Northeast 153 11 182 20 104 20Midwest 304 26 236 22 414 57South 371 21 354 31 399 50West 172 13 228 23 83 25

Ownership

Voluntary nonprofit 652 39 699 34 576 81Government 252 39 187 30 356 85Proprietary 96 15 114 19 68 22

Annual emergency department visit volume

Less than 20000 554 28 330 39 918 2720000ndash50000 325 25 476 33 61 2650000 or more 121 12 195 21 01 01

Staffed bed size

Less than 100 572 27 351 35 931 23100ndash199 200 21 280 28 70 23200ndash299 109 14 176 23 00 300 or more 119 11 193 19 00

Inpatient daily occupancy rate1

Less than 50 292 28 171 28 488 6150ndash59 127 22 114 25 149 4460ndash69 105 13 139 20 49 1070ndash79 138 17 177 21 75 2980ndash89 132 20 176 23 61 4390ndash99 83 14 95 16 64 26Missing 123 17 129 19 114 34

Medical school affiliation

Yes 281 24 384 29 113 45No 706 24 595 30 887 45Missing 13 05 21 08

Metropolitan status

Metropolitan area 618 32 Not metropolitan area 382 32

Category not applicable Figure does not meet standard of reliability or precision00 Quantity more than zero but less than 0051Defined as beds filled as of midnight divided by staffed beds

Advance Data No 376 + September 27 2006 13

Table 2 Percent distribution of emergency departments and corresponding standard errors by treatment space characteristicsaccording to metropolitan status United States 2003ndash04

Characteristic

Total Metropolitan area Not metropolitan area

Percentdistribution

Standarderror

Percentdistribution

Standarderror

Percentdistribution

Standarderror

All emergency departments 1000 1000 1000

Number of standard treatment spaces

Less than 5 143 38 14 07 352 845ndash9 317 31 200 32 505 7510ndash19 269 27 361 32 121 3920ndash49 232 17 368 28 12 0850 or more 26 06 42 09 00 Missing 14 05 15 06 11 08

Number of other treatment spaces1

Less than 5 644 27 499 34 879 365ndash9 167 21 231 29 62 2010ndash19 100 13 148 20 21 1220 or more 60 10 89 15 12 08Missing 30 08 32 08 26 17

Increased number of standard treatmentspaces in last 2 years2

Yes 227 25 270 31 149 61No 761 27 711 33 851 61Missing 12 07 19 11 00

Expanded physical space in last 2 years2

Yes 161 25 160 25 163 53No 827 26 821 28 837 53Missing 12 07 19 11 00

Physical space expansion planned within next 2 years23

Yes 323 41 387 45 206 89No 457 42 423 41 518 92Missing 220 40 190 28 276 98

Category not applicable Figure does not meet standard of reliability or precision00 Quantity more than zero but less than 0051Other treatment spaces includes chairs or stretchers in hallways2Data available only for 20043Excludes emergency departments that expanded space within the last 2 years

14 Advance Data No 376 + September 27 2006

Table 3 Percent distribution of emergency departments and corresponding standard errors by staffing characteristics according tometropolitan status United States 2003ndash04

Characteristic

Total Metropolitan area Not metropolitan area

Percentdistribution

Standarderror

Percentdistribution

Standarderror

Percentdistribution

Standarderror

All emergency departments 1000 1000 1000

Employment status of emergency department physicians

Hospital 214 22 235 27 179 34Outside contract 647 31 686 29 585 60Both 116 24 56 14 214 50Other 22 06 22 05 22 14Missing 01 00 01 01 00

Number of emergency department physicians

Less than 5 225 38 141 24 362 825ndash9 238 24 221 29 267 4610ndash19 225 23 275 26 143 4120 or more 137 17 199 24 36 18Missing 175 22 165 21 192 48

Percent of emergency department physicianswith emergency medicine residency

Under 5 178 25 94 23 315 495ndash24 52 13 49 15 56 2325ndash49 71 15 92 18 38 2550ndash74 105 17 115 18 90 3375ndash89 67 12 107 18 03 0390 or more 202 21 252 24 122 36Missing 324 27 293 27 375 56

Percent of emergency department physicianswith emergency medicine board certification

Less than 5 432 28 403 26 479 575ndash24 23 07 21 06 27 1525ndash49 52 14 50 15 55 2750ndash74 44 11 49 09 36 2475ndash89 34 07 54 12 00 90 or more 100 13 131 17 49 21Missing 316 25 293 25 355 55

Percent of emergency departments where physicianshave responsibilities elsewhere in the hospital

Yes some physicians 257 25 237 26 288 49Yes all physicians 130 29 90 19 195 67No 600 34 658 31 506 69Missing 13 04 15 05 11 08

Percent of nursing positions currently vacant1

Less than 5 571 37 485 45 738 805ndash9 99 18 139 26 12 1610ndash19 113 19 123 26 94 3320 or more 83 24 85 26 77 48Missing 134 23 167 31 72 35

Category not applicable Figure does not meet standard of reliability or precision00 Quantity more than zero but less than 0051Data available only for 2004

Advance Data No 376 + September 27 2006 15

Table 4 Percent distribution of emergency departments and corresponding standard errors by ambulance diversion characteristicsaccording to metropolitan status United States 2003ndash04

Characteristic

Total Metropolitan area Not metropolitan area

Percentdistribution

Standarderror

Percentdistribution

Standarderror

Percentdistribution

Standarderror

All emergency departments 1000 1000 1000

Number of nearby emergency departments

0 346 30 198 23 585 741ndash2 365 35 347 31 393 753ndash4 157 19 244 28 16 095ndash7 89 13 140 20 06 058 or more 28 05 46 08 00 Missing 16 04 25 07 00

State or local lawregulation prohibiting diversion

Yes 80 17 75 18 89 32No 912 17 913 19 911 32Missing 08 03 12 05 00

Percent of operating time in diversionstatus during previous year

0 514 25 333 34 808 351ndash4 256 23 359 29 91 345ndash9 38 08 62 14 00 10ndash19 33 06 54 09 00 20 or more 17 03 27 05 00 Missing 142 18 166 21 101 33

Average length of ambulance diversion12

Less than 2 hours 170 35 177 36 2 hours 141 23 147 29 3ndash4 hours 325 42 337 42 5ndash9 hours 241 41 227 41 10 or more hours 123 31 112 30

Category not applicable Figure does not meet standard of reliability or precision00 Quantity more than zero but less than 0051Based on approximately 930 emergency departments reporting ambulance diversions2Distribution of ambulance diversions

16 Advance Data No 376 + September 27 2006

Table 2 Percent distribution of emergency departments and corresponding standard errors by treatment space characteristicsaccording to metropolitan status United States 2003ndash04

Characteristic

Total Metropolitan area Not metropolitan area

Percentdistribution

Standarderror

Percentdistribution

Standarderror

Percentdistribution

Standarderror

All emergency departments 1000 1000 1000

Number of standard treatment spaces

Less than 5 143 38 14 07 352 845ndash9 317 31 200 32 505 7510ndash19 269 27 361 32 121 3920ndash49 232 17 368 28 12 0850 or more 26 06 42 09 00 Missing 14 05 15 06 11 08

Number of other treatment spaces1

Less than 5 644 27 499 34 879 365ndash9 167 21 231 29 62 2010ndash19 100 13 148 20 21 1220 or more 60 10 89 15 12 08Missing 30 08 32 08 26 17

Increased number of standard treatmentspaces in last 2 years2

Yes 227 25 270 31 149 61No 761 27 711 33 851 61Missing 12 07 19 11 00

Expanded physical space in last 2 years2

Yes 161 25 160 25 163 53No 827 26 821 28 837 53Missing 12 07 19 11 00

Physical space expansion planned within next 2 years23

Yes 323 41 387 45 206 89No 457 42 423 41 518 92Missing 220 40 190 28 276 98

Category not applicable Figure does not meet standard of reliability or precision00 Quantity more than zero but less than 0051Other treatment spaces includes chairs or stretchers in hallways2Data available only for 20043Excludes emergency departments that expanded space within the last 2 years

14 Advance Data No 376 + September 27 2006

Table 3 Percent distribution of emergency departments and corresponding standard errors by staffing characteristics according tometropolitan status United States 2003ndash04

Characteristic

Total Metropolitan area Not metropolitan area

Percentdistribution

Standarderror

Percentdistribution

Standarderror

Percentdistribution

Standarderror

All emergency departments 1000 1000 1000

Employment status of emergency department physicians

Hospital 214 22 235 27 179 34Outside contract 647 31 686 29 585 60Both 116 24 56 14 214 50Other 22 06 22 05 22 14Missing 01 00 01 01 00

Number of emergency department physicians

Less than 5 225 38 141 24 362 825ndash9 238 24 221 29 267 4610ndash19 225 23 275 26 143 4120 or more 137 17 199 24 36 18Missing 175 22 165 21 192 48

Percent of emergency department physicianswith emergency medicine residency

Under 5 178 25 94 23 315 495ndash24 52 13 49 15 56 2325ndash49 71 15 92 18 38 2550ndash74 105 17 115 18 90 3375ndash89 67 12 107 18 03 0390 or more 202 21 252 24 122 36Missing 324 27 293 27 375 56

Percent of emergency department physicianswith emergency medicine board certification

Less than 5 432 28 403 26 479 575ndash24 23 07 21 06 27 1525ndash49 52 14 50 15 55 2750ndash74 44 11 49 09 36 2475ndash89 34 07 54 12 00 90 or more 100 13 131 17 49 21Missing 316 25 293 25 355 55

Percent of emergency departments where physicianshave responsibilities elsewhere in the hospital

Yes some physicians 257 25 237 26 288 49Yes all physicians 130 29 90 19 195 67No 600 34 658 31 506 69Missing 13 04 15 05 11 08

Percent of nursing positions currently vacant1

Less than 5 571 37 485 45 738 805ndash9 99 18 139 26 12 1610ndash19 113 19 123 26 94 3320 or more 83 24 85 26 77 48Missing 134 23 167 31 72 35

Category not applicable Figure does not meet standard of reliability or precision00 Quantity more than zero but less than 0051Data available only for 2004

Advance Data No 376 + September 27 2006 15

Table 4 Percent distribution of emergency departments and corresponding standard errors by ambulance diversion characteristicsaccording to metropolitan status United States 2003ndash04

Characteristic

Total Metropolitan area Not metropolitan area

Percentdistribution

Standarderror

Percentdistribution

Standarderror

Percentdistribution

Standarderror

All emergency departments 1000 1000 1000

Number of nearby emergency departments

0 346 30 198 23 585 741ndash2 365 35 347 31 393 753ndash4 157 19 244 28 16 095ndash7 89 13 140 20 06 058 or more 28 05 46 08 00 Missing 16 04 25 07 00

State or local lawregulation prohibiting diversion

Yes 80 17 75 18 89 32No 912 17 913 19 911 32Missing 08 03 12 05 00

Percent of operating time in diversionstatus during previous year

0 514 25 333 34 808 351ndash4 256 23 359 29 91 345ndash9 38 08 62 14 00 10ndash19 33 06 54 09 00 20 or more 17 03 27 05 00 Missing 142 18 166 21 101 33

Average length of ambulance diversion12

Less than 2 hours 170 35 177 36 2 hours 141 23 147 29 3ndash4 hours 325 42 337 42 5ndash9 hours 241 41 227 41 10 or more hours 123 31 112 30

Category not applicable Figure does not meet standard of reliability or precision00 Quantity more than zero but less than 0051Based on approximately 930 emergency departments reporting ambulance diversions2Distribution of ambulance diversions

16 Advance Data No 376 + September 27 2006

Table 3 Percent distribution of emergency departments and corresponding standard errors by staffing characteristics according tometropolitan status United States 2003ndash04

Characteristic

Total Metropolitan area Not metropolitan area

Percentdistribution

Standarderror

Percentdistribution

Standarderror

Percentdistribution

Standarderror

All emergency departments 1000 1000 1000

Employment status of emergency department physicians

Hospital 214 22 235 27 179 34Outside contract 647 31 686 29 585 60Both 116 24 56 14 214 50Other 22 06 22 05 22 14Missing 01 00 01 01 00

Number of emergency department physicians

Less than 5 225 38 141 24 362 825ndash9 238 24 221 29 267 4610ndash19 225 23 275 26 143 4120 or more 137 17 199 24 36 18Missing 175 22 165 21 192 48

Percent of emergency department physicianswith emergency medicine residency

Under 5 178 25 94 23 315 495ndash24 52 13 49 15 56 2325ndash49 71 15 92 18 38 2550ndash74 105 17 115 18 90 3375ndash89 67 12 107 18 03 0390 or more 202 21 252 24 122 36Missing 324 27 293 27 375 56

Percent of emergency department physicianswith emergency medicine board certification

Less than 5 432 28 403 26 479 575ndash24 23 07 21 06 27 1525ndash49 52 14 50 15 55 2750ndash74 44 11 49 09 36 2475ndash89 34 07 54 12 00 90 or more 100 13 131 17 49 21Missing 316 25 293 25 355 55

Percent of emergency departments where physicianshave responsibilities elsewhere in the hospital

Yes some physicians 257 25 237 26 288 49Yes all physicians 130 29 90 19 195 67No 600 34 658 31 506 69Missing 13 04 15 05 11 08

Percent of nursing positions currently vacant1

Less than 5 571 37 485 45 738 805ndash9 99 18 139 26 12 1610ndash19 113 19 123 26 94 3320 or more 83 24 85 26 77 48Missing 134 23 167 31 72 35

Category not applicable Figure does not meet standard of reliability or precision00 Quantity more than zero but less than 0051Data available only for 2004

Advance Data No 376 + September 27 2006 15

Table 4 Percent distribution of emergency departments and corresponding standard errors by ambulance diversion characteristicsaccording to metropolitan status United States 2003ndash04

Characteristic

Total Metropolitan area Not metropolitan area

Percentdistribution

Standarderror

Percentdistribution

Standarderror

Percentdistribution

Standarderror

All emergency departments 1000 1000 1000

Number of nearby emergency departments

0 346 30 198 23 585 741ndash2 365 35 347 31 393 753ndash4 157 19 244 28 16 095ndash7 89 13 140 20 06 058 or more 28 05 46 08 00 Missing 16 04 25 07 00

State or local lawregulation prohibiting diversion

Yes 80 17 75 18 89 32No 912 17 913 19 911 32Missing 08 03 12 05 00

Percent of operating time in diversionstatus during previous year

0 514 25 333 34 808 351ndash4 256 23 359 29 91 345ndash9 38 08 62 14 00 10ndash19 33 06 54 09 00 20 or more 17 03 27 05 00 Missing 142 18 166 21 101 33

Average length of ambulance diversion12

Less than 2 hours 170 35 177 36 2 hours 141 23 147 29 3ndash4 hours 325 42 337 42 5ndash9 hours 241 41 227 41 10 or more hours 123 31 112 30

Category not applicable Figure does not meet standard of reliability or precision00 Quantity more than zero but less than 0051Based on approximately 930 emergency departments reporting ambulance diversions2Distribution of ambulance diversions

16 Advance Data No 376 + September 27 2006

Table 4 Percent distribution of emergency departments and corresponding standard errors by ambulance diversion characteristicsaccording to metropolitan status United States 2003ndash04

Characteristic

Total Metropolitan area Not metropolitan area

Percentdistribution

Standarderror

Percentdistribution

Standarderror

Percentdistribution

Standarderror

All emergency departments 1000 1000 1000

Number of nearby emergency departments

0 346 30 198 23 585 741ndash2 365 35 347 31 393 753ndash4 157 19 244 28 16 095ndash7 89 13 140 20 06 058 or more 28 05 46 08 00 Missing 16 04 25 07 00

State or local lawregulation prohibiting diversion

Yes 80 17 75 18 89 32No 912 17 913 19 911 32Missing 08 03 12 05 00

Percent of operating time in diversionstatus during previous year

0 514 25 333 34 808 351ndash4 256 23 359 29 91 345ndash9 38 08 62 14 00 10ndash19 33 06 54 09 00 20 or more 17 03 27 05 00 Missing 142 18 166 21 101 33

Average length of ambulance diversion12

Less than 2 hours 170 35 177 36 2 hours 141 23 147 29 3ndash4 hours 325 42 337 42 5ndash9 hours 241 41 227 41 10 or more hours 123 31 112 30

Category not applicable Figure does not meet standard of reliability or precision00 Quantity more than zero but less than 0051Based on approximately 930 emergency departments reporting ambulance diversions2Distribution of ambulance diversions

16 Advance Data No 376 + September 27 2006

Table 5 Percent distribution of emergency departments and corresponding standard errors by triage and language translationcharacteristics according to metropolitan status United States 2003ndash04

Characteristic

Total Metropolitan area Not metropolitan area

Percentdistribution

Standarderror

Percentdistribution

Standarderror

Percentdistribution

Standarderror

All emergency departments 1000 1000 1000

Number of levels in nursing triage system3 472 27 438 30 527 594 164 24 175 25 148 515 233 25 282 27 153 47Other 43 11 50 13 33 20No triage system 72 19 30 19 130 38Missing 17 06 20 08 10 10

Number of different languages in translation service1

1 214 30 154 34 325 672ndash9 200 30 214 31 173 5910ndash29 98 28 114 35 68 4430 or more 343 43 395 43 248 88No language translation service 86 30 55 24 144 72Missing 59 19 67 23 42 30

Percent ofemergency

departmentsStandard

error

Percent ofemergency

departmentsStandard

error

Percent ofemergency

departmentsStandard

error

Leading languages offered1

Spanish 775 32 794 35 740 62Russian 90 17 140 24 00 00French 86 27 119 38 24 24Chinese 72 13 111 21 00 00Vietnamese 67 15 104 23 00 00Korean 39 10 61 16 00 00

Category not applicable Figure does not meet standard of reliability or precision00 Quantity more than zero but less than 0051Data available only for 2004

Advance Data No 376 + September 27 2006 17

Table 6 Percent distribution of emergency departments and corresponding standard errors by utilization estimates according tometropolitan status United States 2003ndash04

Characteristic

Total Metropolitan area Not metropolitan area

Percentdistribution

Standarderror

Percentdistribution

Standarderror

Percentdistribution

Standarderror

All emergency departments 1000 1000 1000

Daily visit volumeLess than 30 322 33 110 31 669 6430ndash49 180 26 155 29 221 5650ndash99 246 22 335 29 103 28100ndash199 195 16 311 26 07 06200 or more 55 09 89 14 00

Patient characteristics

Percent under 18 yearsLess than 10 63 08 98 12 05 0510ndash19 215 22 256 27 148 3920ndash29 453 28 355 25 612 5130ndash49 181 24 184 29 176 4050 or more 89 15 107 19 59 27

Percent 65 years and overLess than 5 62 12 100 18 00 5ndash14 338 25 419 27 206 3815ndash24 354 29 311 28 424 5225ndash34 138 21 103 17 196 4735 or more 108 18 68 15 175 39

Percent MedicareLess than 5 48 11 77 17 00 5ndash14 280 26 354 29 159 4115ndash24 364 25 404 27 300 4825ndash34 176 27 69 14 348 5835 or more 133 17 96 14 193 37

Percent MedicaidLess than 10 161 20 192 21 111 3610ndash19 285 28 308 32 246 5420ndash29 277 26 224 22 363 5530ndash49 173 22 177 24 165 4250 or more 105 15 98 17 116 31

Percent private insuranceLess than 10 48 10 40 07 61 2510ndash19 57 11 66 12 42 1920ndash29 215 22 180 22 272 4730ndash49 452 25 436 25 479 5250 or more 228 20 278 26 146 35

Percent uninsuredLess than 5 160 24 145 20 185 545ndash14 384 30 324 25 481 6415ndash24 271 27 308 30 211 5125ndash34 104 16 115 17 87 3535 or more 82 13 110 16 37 21

Patient acuity

Percent arriving by ambulanceUnder 10 376 28 365 31 395 5610ndash14 457 31 430 29 500 6015ndash29 29 06 44 09 04 0330 or more 138 21 161 22 102 39

Percent emergent and urgentUnder 20 218 26 224 28 208 4720ndash34 129 19 140 19 110 3735ndash49 142 17 153 23 123 2650ndash64 130 18 124 18 141 3965 or more 381 29 358 32 419 58

See footnotes at end of table

18 Advance Data No 376 + September 27 2006

Table 6 Percent distribution of emergency departments and corresponding standard errors by utilization estimates according tometropolitan status United States 2003ndash04mdashCon

Characteristic

Total Metropolitan area Not metropolitan area

Percentdistribution

Standarderror

Percentdistribution

Standarderror

Percentdistribution

Standarderror

Services provided

Average number of diagnostic services per 100 visitsLess than 200 187 25 148 22 252 56200ndash299 249 22 240 24 264 40300ndash399 274 25 230 22 344 55400 or more 290 27 382 31 141 45

Average number of therapeutic services per 100 visitsLess than 40 278 25 194 27 415 5040ndash59 342 30 330 26 361 6760ndash69 154 22 190 24 96 4170 or more 226 21 286 25 129 31

Percent using physician assistants or nurse practitioners0 573 35 516 29 665 771ndash9 152 20 180 24 105 3210ndash19 90 14 117 16 47 2420 or more 185 31 187 21 183 74

Percent not seeing a physician0 180 24 144 21 238 521ndash2 184 22 182 21 187 463ndash19 379 27 444 27 273 5220 or more 258 33 230 23 302 75

Disposition

Percent admittedLess than 5 240 26 232 30 254 525ndash9 113 19 115 20 111 3810ndash14 189 24 174 20 213 5215ndash19 193 24 172 22 226 5220 or more 255 20 308 24 195 41

Percent transferredLess than 1 289 25 384 29 134 411ndash2 198 20 207 21 183 413ndash9 329 30 238 25 476 6010 or more 185 18 170 21 208 35

Percent left before being seenLess than 1 579 28 504 35 700 511ndash2 259 23 276 29 232 393ndash4 90 16 110 19 59 345 or more 72 13 110 20 09 07

Throughput measures

Average waiting timeLess than 15 minutes 176 22 90 20 317 4615ndash29 minutes 298 31 192 27 469 5430ndash44 minutes 247 24 293 28 173 4245ndash59 minutes 149 19 222 27 30 1760 minutes or more 130 14 203 21 12 08

Average treatment time in minutesLess than 60 minutes 82 27 48 18 137 6360ndash89 minutes 219 21 154 22 326 4690ndash119 minutes 291 31 274 27 318 68120ndash179 minutes 292 26 356 29 190 46180 minutes or more 116 13 169 20 30 07

Average total visit durationLess than 2 hours 318 35 175 34 549 682 hours 398 30 412 28 375 683 hours 182 18 260 25 57 284 hours or more 102 12 153 19 19 12

See footnotes at end of table

Advance Data No 376 + September 27 2006 19

Table 6 Percent distribution of emergency departments and corresponding standard errors by utilization estimates according tometropolitan status United States 2003ndash04mdashCon

Characteristic

Total Metropolitan area Not metropolitan area

Percentdistribution

Standarderror

Percentdistribution

Standarderror

Percentdistribution

Standarderror

Throughput measuresmdashCon

Average waiting time for urgent cases1Less than 15 minutes 273 29 165 30 446 5415ndash29 minutes 251 28 200 24 333 5930ndash44 minutes 273 24 318 27 201 3945ndash59 minutes 125 15 189 23 20 1160 minutes or more 79 10 128 16 01 00

Category not applicable Figure does not meet standard of reliability or precision00 Quantity more than zero but less than 0051Urgent cases are defined as those that must be seen within 15ndash60 minutes

20 Advance Data No 376 + September 27 2006

Table 7 Means and quartiles for selected indexes of staffing capacity ambulance diversion and throughput in emergency departmentsUnited States 2003ndash04

Index MeanStandard

error25th

percentile Median75th

percentile

Daily visit volume

Total 676 30 231 478 940Metropolitan area 934 41 460 819 1259Not metropolitan area 258 26 133 218 323

Standard treatment spaces

Total 146 06 57 100 194Metropolitan area 198 08 99 164 250Not metropolitan area 63 06 27 54 76

Number of physicians with ED1 privileges

Total 133 28 37 76 143Metropolitan area 175 44 57 106 188Not metropolitan area 64 08 23 43 83

Visits per space

Total 46 01 34 44 54Metropolitan area 49 01 37 46 55Not metropolitan area 41 03 28 38 53

Visits per physician

Total 75 05 28 58 100Metropolitan area 84 05 42 69 104Not metropolitan area 61 09 17 31 81

Physicians per space

Total 13 03 05 07 13Metropolitan area 13 04 05 07 10Not metropolitan area 14 02 05 10 19

Percent nursing positions vacant2

Total 53 07 00 07 77Metropolitan area 61 09 00 19 90Not metropolitan area 39 14 00 00 18

Percent arriving by ambulance

Total 130 04 74 121 174Metropolitan area 138 05 73 128 187Not metropolitan area 118 06 74 114 152

Average waiting time3

Total 371 12 190 331 486Metropolitan area 458 14 295 415 567Not metropolitan area 228 14 138 193 290

Average treatment time3

Total 1260 34 869 1110 1512Metropolitan area 1396 39 1002 1250 1591Not metropolitan area 1036 52 738 961 1117

Average visit duration3

Total 1597 38 1127 1452 1872Metropolitan area 1816 47 1329 1661 2121Not metropolitan area 1242 51 929 1178 1367

Percent left before being seen

Total 14 01 00 00 19Metropolitan area 18 02 00 10 26Not metropolitan area 07 02 00 00 11

Percent transferred

Total 30 02 09 20 42Metropolitan area 21 02 00 13 30Not metropolitan area 45 05 17 34 60

See footnotes at end of table

Advance Data No 376 + September 27 2006 21

Table 7 Means and quartiles for selected indexes of staffing capacity ambulance diversion and throughput in emergency departmentsUnited States 2003ndash04mdashCon

Index MeanStandard

error25th

percentile Median75th

percentile

Percent admitted to hospital

Total 125 04 59 126 181Metropolitan area 134 06 61 132 194Not metropolitan area 111 07 57 105 168

Inpatient staffed bed size

Total 1365 61 384 850 1758Metropolitan area 1921 87 794 1432 2713Not metropolitan area 477 43 232 378 612

Inpatient daily occupancy rate4

Total 603 15 425 617 799Metropolitan area 664 16 542 712 826Not metropolitan area 506 34 348 474 652

Annual hours on ambulance diversion

Total 1460 166 00 00 77Metropolitan area 2427 290 00 16 1088Not metropolitan area 05 02 00 00 00

Annual hours on ambulance diversion for EDsthat reported any diversions15

Total 3639 414 18 249 4534Metropolitan area 4039 448 19 448 5244Not metropolitan area

Figure does not meet standard of reliability or precision00 Quantity is zero or more than zero but less than 0051ED is emergency department2Data available only for 20043Time in minutes4Defined as beds filled as of midnight divided by staffed beds5Ambulance diversion hours were reported by 344 percent of all emergency departments and 501 percent of those in metropolitan areas Too few emergency departments reported any diversionhours in nonmetropolitan areas to provide a reliable estimate of mean numbers of hours

22 Advance Data No 376 + September 27 2006

Technical Notes

Number of hospital emergency departments and survey responses by selected hospital characteristics United States 2003ndash04

Hospital characteristic

Numberof sampled

in-scope EDs1

Number ofresponding

EDs12

Number ofnonresponding

EDs1

Unweightedresponse

rate2

Weightedresponse

rate23

All 24-hour EDs1 839 699 140 833 847

Geographic region

Northeast 197 154 43 782 852Midwest 195 161 34 826 846South 284 240 44 845 865West 163 144 19 883 795

Metropolitan status

Metropolitan area 685 577 108 842 865Not metropolitan area 154 122 32 792 830

Ownership

Voluntary 586 495 91 845 830Government 160 132 28 825 887Proprietary 91 71 20 780 822

ED annual visit volume1

Less than 20000 225 188 37 836 85020000 to 50000 368 311 57 845 853Over 50000 246 200 46 813 815

Medical school affiliation

Yes 391 324 67 829 852No 448 375 73 837 845

1ED is emergency department2Responding to both the Staffing Capacity and Ambulance Diversion Supplement and the annual request for visit data3Weighted by the first two stages of sample selection (primary sampling unit and hospital)

Advance Data No 376 + September 27 2006 23

Suggested citation

Burt CW McCaig LF Staffing capacity andambulance diversion in emergencydepartments United States 2003ndash04Advance data from vital and health statisticsno 376 Hyattsville MD National Center forHealth Statistics 2006

Copyright information

All material appearing in this report is in thepublic domain and may be reproduced orcopied without permission citation as tosource however is appreciated

National Center for Health Statistics

DirectorEdward J Sondik PhD

Acting Co-Deputy DirectorsJennifer H Madans PhD

Michael H Sadagursky

US DEPARTMENT OFHEALTH amp HUMAN SERVICES

Centers for Disease Control and PreventionNational Center for Health Statistics3311 Toledo RoadHyattsville MD 20782

OFFICIAL BUSINESSPENALTY FOR PRIVATE USE $300

To receive this publication regularly contactthe National Center for Health Statistics bycalling 1-866-441-NCHS (6247)E-mail nchsquerycdcgovInternet wwwcdcgovnchs

06-0139 (906)CS105940T26541DHHS Publication No (PHS) 2006-1250

24 Advance Data No 376 + September 27 2006

FIRST CLASSPOSTAGE amp FEES PAID

CDCNCHSPERMIT NO G-284

Table 6 Percent distribution of emergency departments and corresponding standard errors by utilization estimates according tometropolitan status United States 2003ndash04mdashCon

Characteristic

Total Metropolitan area Not metropolitan area

Percentdistribution

Standarderror

Percentdistribution

Standarderror

Percentdistribution

Standarderror

Services provided

Average number of diagnostic services per 100 visitsLess than 200 187 25 148 22 252 56200ndash299 249 22 240 24 264 40300ndash399 274 25 230 22 344 55400 or more 290 27 382 31 141 45

Average number of therapeutic services per 100 visitsLess than 40 278 25 194 27 415 5040ndash59 342 30 330 26 361 6760ndash69 154 22 190 24 96 4170 or more 226 21 286 25 129 31

Percent using physician assistants or nurse practitioners0 573 35 516 29 665 771ndash9 152 20 180 24 105 3210ndash19 90 14 117 16 47 2420 or more 185 31 187 21 183 74

Percent not seeing a physician0 180 24 144 21 238 521ndash2 184 22 182 21 187 463ndash19 379 27 444 27 273 5220 or more 258 33 230 23 302 75

Disposition

Percent admittedLess than 5 240 26 232 30 254 525ndash9 113 19 115 20 111 3810ndash14 189 24 174 20 213 5215ndash19 193 24 172 22 226 5220 or more 255 20 308 24 195 41

Percent transferredLess than 1 289 25 384 29 134 411ndash2 198 20 207 21 183 413ndash9 329 30 238 25 476 6010 or more 185 18 170 21 208 35

Percent left before being seenLess than 1 579 28 504 35 700 511ndash2 259 23 276 29 232 393ndash4 90 16 110 19 59 345 or more 72 13 110 20 09 07

Throughput measures

Average waiting timeLess than 15 minutes 176 22 90 20 317 4615ndash29 minutes 298 31 192 27 469 5430ndash44 minutes 247 24 293 28 173 4245ndash59 minutes 149 19 222 27 30 1760 minutes or more 130 14 203 21 12 08

Average treatment time in minutesLess than 60 minutes 82 27 48 18 137 6360ndash89 minutes 219 21 154 22 326 4690ndash119 minutes 291 31 274 27 318 68120ndash179 minutes 292 26 356 29 190 46180 minutes or more 116 13 169 20 30 07

Average total visit durationLess than 2 hours 318 35 175 34 549 682 hours 398 30 412 28 375 683 hours 182 18 260 25 57 284 hours or more 102 12 153 19 19 12

See footnotes at end of table

Advance Data No 376 + September 27 2006 19

Table 6 Percent distribution of emergency departments and corresponding standard errors by utilization estimates according tometropolitan status United States 2003ndash04mdashCon

Characteristic

Total Metropolitan area Not metropolitan area

Percentdistribution

Standarderror

Percentdistribution

Standarderror

Percentdistribution

Standarderror

Throughput measuresmdashCon

Average waiting time for urgent cases1Less than 15 minutes 273 29 165 30 446 5415ndash29 minutes 251 28 200 24 333 5930ndash44 minutes 273 24 318 27 201 3945ndash59 minutes 125 15 189 23 20 1160 minutes or more 79 10 128 16 01 00

Category not applicable Figure does not meet standard of reliability or precision00 Quantity more than zero but less than 0051Urgent cases are defined as those that must be seen within 15ndash60 minutes

20 Advance Data No 376 + September 27 2006

Table 7 Means and quartiles for selected indexes of staffing capacity ambulance diversion and throughput in emergency departmentsUnited States 2003ndash04

Index MeanStandard

error25th

percentile Median75th

percentile

Daily visit volume

Total 676 30 231 478 940Metropolitan area 934 41 460 819 1259Not metropolitan area 258 26 133 218 323

Standard treatment spaces

Total 146 06 57 100 194Metropolitan area 198 08 99 164 250Not metropolitan area 63 06 27 54 76

Number of physicians with ED1 privileges

Total 133 28 37 76 143Metropolitan area 175 44 57 106 188Not metropolitan area 64 08 23 43 83

Visits per space

Total 46 01 34 44 54Metropolitan area 49 01 37 46 55Not metropolitan area 41 03 28 38 53

Visits per physician

Total 75 05 28 58 100Metropolitan area 84 05 42 69 104Not metropolitan area 61 09 17 31 81

Physicians per space

Total 13 03 05 07 13Metropolitan area 13 04 05 07 10Not metropolitan area 14 02 05 10 19

Percent nursing positions vacant2

Total 53 07 00 07 77Metropolitan area 61 09 00 19 90Not metropolitan area 39 14 00 00 18

Percent arriving by ambulance

Total 130 04 74 121 174Metropolitan area 138 05 73 128 187Not metropolitan area 118 06 74 114 152

Average waiting time3

Total 371 12 190 331 486Metropolitan area 458 14 295 415 567Not metropolitan area 228 14 138 193 290

Average treatment time3

Total 1260 34 869 1110 1512Metropolitan area 1396 39 1002 1250 1591Not metropolitan area 1036 52 738 961 1117

Average visit duration3

Total 1597 38 1127 1452 1872Metropolitan area 1816 47 1329 1661 2121Not metropolitan area 1242 51 929 1178 1367

Percent left before being seen

Total 14 01 00 00 19Metropolitan area 18 02 00 10 26Not metropolitan area 07 02 00 00 11

Percent transferred

Total 30 02 09 20 42Metropolitan area 21 02 00 13 30Not metropolitan area 45 05 17 34 60

See footnotes at end of table

Advance Data No 376 + September 27 2006 21

Table 7 Means and quartiles for selected indexes of staffing capacity ambulance diversion and throughput in emergency departmentsUnited States 2003ndash04mdashCon

Index MeanStandard

error25th

percentile Median75th

percentile

Percent admitted to hospital

Total 125 04 59 126 181Metropolitan area 134 06 61 132 194Not metropolitan area 111 07 57 105 168

Inpatient staffed bed size

Total 1365 61 384 850 1758Metropolitan area 1921 87 794 1432 2713Not metropolitan area 477 43 232 378 612

Inpatient daily occupancy rate4

Total 603 15 425 617 799Metropolitan area 664 16 542 712 826Not metropolitan area 506 34 348 474 652

Annual hours on ambulance diversion

Total 1460 166 00 00 77Metropolitan area 2427 290 00 16 1088Not metropolitan area 05 02 00 00 00

Annual hours on ambulance diversion for EDsthat reported any diversions15

Total 3639 414 18 249 4534Metropolitan area 4039 448 19 448 5244Not metropolitan area

Figure does not meet standard of reliability or precision00 Quantity is zero or more than zero but less than 0051ED is emergency department2Data available only for 20043Time in minutes4Defined as beds filled as of midnight divided by staffed beds5Ambulance diversion hours were reported by 344 percent of all emergency departments and 501 percent of those in metropolitan areas Too few emergency departments reported any diversionhours in nonmetropolitan areas to provide a reliable estimate of mean numbers of hours

22 Advance Data No 376 + September 27 2006

Technical Notes

Number of hospital emergency departments and survey responses by selected hospital characteristics United States 2003ndash04

Hospital characteristic

Numberof sampled

in-scope EDs1

Number ofresponding

EDs12

Number ofnonresponding

EDs1

Unweightedresponse

rate2

Weightedresponse

rate23

All 24-hour EDs1 839 699 140 833 847

Geographic region

Northeast 197 154 43 782 852Midwest 195 161 34 826 846South 284 240 44 845 865West 163 144 19 883 795

Metropolitan status

Metropolitan area 685 577 108 842 865Not metropolitan area 154 122 32 792 830

Ownership

Voluntary 586 495 91 845 830Government 160 132 28 825 887Proprietary 91 71 20 780 822

ED annual visit volume1

Less than 20000 225 188 37 836 85020000 to 50000 368 311 57 845 853Over 50000 246 200 46 813 815

Medical school affiliation

Yes 391 324 67 829 852No 448 375 73 837 845

1ED is emergency department2Responding to both the Staffing Capacity and Ambulance Diversion Supplement and the annual request for visit data3Weighted by the first two stages of sample selection (primary sampling unit and hospital)

Advance Data No 376 + September 27 2006 23

Suggested citation

Burt CW McCaig LF Staffing capacity andambulance diversion in emergencydepartments United States 2003ndash04Advance data from vital and health statisticsno 376 Hyattsville MD National Center forHealth Statistics 2006

Copyright information

All material appearing in this report is in thepublic domain and may be reproduced orcopied without permission citation as tosource however is appreciated

National Center for Health Statistics

DirectorEdward J Sondik PhD

Acting Co-Deputy DirectorsJennifer H Madans PhD

Michael H Sadagursky

US DEPARTMENT OFHEALTH amp HUMAN SERVICES

Centers for Disease Control and PreventionNational Center for Health Statistics3311 Toledo RoadHyattsville MD 20782

OFFICIAL BUSINESSPENALTY FOR PRIVATE USE $300

To receive this publication regularly contactthe National Center for Health Statistics bycalling 1-866-441-NCHS (6247)E-mail nchsquerycdcgovInternet wwwcdcgovnchs

06-0139 (906)CS105940T26541DHHS Publication No (PHS) 2006-1250

24 Advance Data No 376 + September 27 2006

FIRST CLASSPOSTAGE amp FEES PAID

CDCNCHSPERMIT NO G-284

Table 6 Percent distribution of emergency departments and corresponding standard errors by utilization estimates according tometropolitan status United States 2003ndash04mdashCon

Characteristic

Total Metropolitan area Not metropolitan area

Percentdistribution

Standarderror

Percentdistribution

Standarderror

Percentdistribution

Standarderror

Throughput measuresmdashCon

Average waiting time for urgent cases1Less than 15 minutes 273 29 165 30 446 5415ndash29 minutes 251 28 200 24 333 5930ndash44 minutes 273 24 318 27 201 3945ndash59 minutes 125 15 189 23 20 1160 minutes or more 79 10 128 16 01 00

Category not applicable Figure does not meet standard of reliability or precision00 Quantity more than zero but less than 0051Urgent cases are defined as those that must be seen within 15ndash60 minutes

20 Advance Data No 376 + September 27 2006

Table 7 Means and quartiles for selected indexes of staffing capacity ambulance diversion and throughput in emergency departmentsUnited States 2003ndash04

Index MeanStandard

error25th

percentile Median75th

percentile

Daily visit volume

Total 676 30 231 478 940Metropolitan area 934 41 460 819 1259Not metropolitan area 258 26 133 218 323

Standard treatment spaces

Total 146 06 57 100 194Metropolitan area 198 08 99 164 250Not metropolitan area 63 06 27 54 76

Number of physicians with ED1 privileges

Total 133 28 37 76 143Metropolitan area 175 44 57 106 188Not metropolitan area 64 08 23 43 83

Visits per space

Total 46 01 34 44 54Metropolitan area 49 01 37 46 55Not metropolitan area 41 03 28 38 53

Visits per physician

Total 75 05 28 58 100Metropolitan area 84 05 42 69 104Not metropolitan area 61 09 17 31 81

Physicians per space

Total 13 03 05 07 13Metropolitan area 13 04 05 07 10Not metropolitan area 14 02 05 10 19

Percent nursing positions vacant2

Total 53 07 00 07 77Metropolitan area 61 09 00 19 90Not metropolitan area 39 14 00 00 18

Percent arriving by ambulance

Total 130 04 74 121 174Metropolitan area 138 05 73 128 187Not metropolitan area 118 06 74 114 152

Average waiting time3

Total 371 12 190 331 486Metropolitan area 458 14 295 415 567Not metropolitan area 228 14 138 193 290

Average treatment time3

Total 1260 34 869 1110 1512Metropolitan area 1396 39 1002 1250 1591Not metropolitan area 1036 52 738 961 1117

Average visit duration3

Total 1597 38 1127 1452 1872Metropolitan area 1816 47 1329 1661 2121Not metropolitan area 1242 51 929 1178 1367

Percent left before being seen

Total 14 01 00 00 19Metropolitan area 18 02 00 10 26Not metropolitan area 07 02 00 00 11

Percent transferred

Total 30 02 09 20 42Metropolitan area 21 02 00 13 30Not metropolitan area 45 05 17 34 60

See footnotes at end of table

Advance Data No 376 + September 27 2006 21

Table 7 Means and quartiles for selected indexes of staffing capacity ambulance diversion and throughput in emergency departmentsUnited States 2003ndash04mdashCon

Index MeanStandard

error25th

percentile Median75th

percentile

Percent admitted to hospital

Total 125 04 59 126 181Metropolitan area 134 06 61 132 194Not metropolitan area 111 07 57 105 168

Inpatient staffed bed size

Total 1365 61 384 850 1758Metropolitan area 1921 87 794 1432 2713Not metropolitan area 477 43 232 378 612

Inpatient daily occupancy rate4

Total 603 15 425 617 799Metropolitan area 664 16 542 712 826Not metropolitan area 506 34 348 474 652

Annual hours on ambulance diversion

Total 1460 166 00 00 77Metropolitan area 2427 290 00 16 1088Not metropolitan area 05 02 00 00 00

Annual hours on ambulance diversion for EDsthat reported any diversions15

Total 3639 414 18 249 4534Metropolitan area 4039 448 19 448 5244Not metropolitan area

Figure does not meet standard of reliability or precision00 Quantity is zero or more than zero but less than 0051ED is emergency department2Data available only for 20043Time in minutes4Defined as beds filled as of midnight divided by staffed beds5Ambulance diversion hours were reported by 344 percent of all emergency departments and 501 percent of those in metropolitan areas Too few emergency departments reported any diversionhours in nonmetropolitan areas to provide a reliable estimate of mean numbers of hours

22 Advance Data No 376 + September 27 2006

Technical Notes

Number of hospital emergency departments and survey responses by selected hospital characteristics United States 2003ndash04

Hospital characteristic

Numberof sampled

in-scope EDs1

Number ofresponding

EDs12

Number ofnonresponding

EDs1

Unweightedresponse

rate2

Weightedresponse

rate23

All 24-hour EDs1 839 699 140 833 847

Geographic region

Northeast 197 154 43 782 852Midwest 195 161 34 826 846South 284 240 44 845 865West 163 144 19 883 795

Metropolitan status

Metropolitan area 685 577 108 842 865Not metropolitan area 154 122 32 792 830

Ownership

Voluntary 586 495 91 845 830Government 160 132 28 825 887Proprietary 91 71 20 780 822

ED annual visit volume1

Less than 20000 225 188 37 836 85020000 to 50000 368 311 57 845 853Over 50000 246 200 46 813 815

Medical school affiliation

Yes 391 324 67 829 852No 448 375 73 837 845

1ED is emergency department2Responding to both the Staffing Capacity and Ambulance Diversion Supplement and the annual request for visit data3Weighted by the first two stages of sample selection (primary sampling unit and hospital)

Advance Data No 376 + September 27 2006 23

Suggested citation

Burt CW McCaig LF Staffing capacity andambulance diversion in emergencydepartments United States 2003ndash04Advance data from vital and health statisticsno 376 Hyattsville MD National Center forHealth Statistics 2006

Copyright information

All material appearing in this report is in thepublic domain and may be reproduced orcopied without permission citation as tosource however is appreciated

National Center for Health Statistics

DirectorEdward J Sondik PhD

Acting Co-Deputy DirectorsJennifer H Madans PhD

Michael H Sadagursky

US DEPARTMENT OFHEALTH amp HUMAN SERVICES

Centers for Disease Control and PreventionNational Center for Health Statistics3311 Toledo RoadHyattsville MD 20782

OFFICIAL BUSINESSPENALTY FOR PRIVATE USE $300

To receive this publication regularly contactthe National Center for Health Statistics bycalling 1-866-441-NCHS (6247)E-mail nchsquerycdcgovInternet wwwcdcgovnchs

06-0139 (906)CS105940T26541DHHS Publication No (PHS) 2006-1250

24 Advance Data No 376 + September 27 2006

FIRST CLASSPOSTAGE amp FEES PAID

CDCNCHSPERMIT NO G-284

Table 7 Means and quartiles for selected indexes of staffing capacity ambulance diversion and throughput in emergency departmentsUnited States 2003ndash04

Index MeanStandard

error25th

percentile Median75th

percentile

Daily visit volume

Total 676 30 231 478 940Metropolitan area 934 41 460 819 1259Not metropolitan area 258 26 133 218 323

Standard treatment spaces

Total 146 06 57 100 194Metropolitan area 198 08 99 164 250Not metropolitan area 63 06 27 54 76

Number of physicians with ED1 privileges

Total 133 28 37 76 143Metropolitan area 175 44 57 106 188Not metropolitan area 64 08 23 43 83

Visits per space

Total 46 01 34 44 54Metropolitan area 49 01 37 46 55Not metropolitan area 41 03 28 38 53

Visits per physician

Total 75 05 28 58 100Metropolitan area 84 05 42 69 104Not metropolitan area 61 09 17 31 81

Physicians per space

Total 13 03 05 07 13Metropolitan area 13 04 05 07 10Not metropolitan area 14 02 05 10 19

Percent nursing positions vacant2

Total 53 07 00 07 77Metropolitan area 61 09 00 19 90Not metropolitan area 39 14 00 00 18

Percent arriving by ambulance

Total 130 04 74 121 174Metropolitan area 138 05 73 128 187Not metropolitan area 118 06 74 114 152

Average waiting time3

Total 371 12 190 331 486Metropolitan area 458 14 295 415 567Not metropolitan area 228 14 138 193 290

Average treatment time3

Total 1260 34 869 1110 1512Metropolitan area 1396 39 1002 1250 1591Not metropolitan area 1036 52 738 961 1117

Average visit duration3

Total 1597 38 1127 1452 1872Metropolitan area 1816 47 1329 1661 2121Not metropolitan area 1242 51 929 1178 1367

Percent left before being seen

Total 14 01 00 00 19Metropolitan area 18 02 00 10 26Not metropolitan area 07 02 00 00 11

Percent transferred

Total 30 02 09 20 42Metropolitan area 21 02 00 13 30Not metropolitan area 45 05 17 34 60

See footnotes at end of table

Advance Data No 376 + September 27 2006 21

Table 7 Means and quartiles for selected indexes of staffing capacity ambulance diversion and throughput in emergency departmentsUnited States 2003ndash04mdashCon

Index MeanStandard

error25th

percentile Median75th

percentile

Percent admitted to hospital

Total 125 04 59 126 181Metropolitan area 134 06 61 132 194Not metropolitan area 111 07 57 105 168

Inpatient staffed bed size

Total 1365 61 384 850 1758Metropolitan area 1921 87 794 1432 2713Not metropolitan area 477 43 232 378 612

Inpatient daily occupancy rate4

Total 603 15 425 617 799Metropolitan area 664 16 542 712 826Not metropolitan area 506 34 348 474 652

Annual hours on ambulance diversion

Total 1460 166 00 00 77Metropolitan area 2427 290 00 16 1088Not metropolitan area 05 02 00 00 00

Annual hours on ambulance diversion for EDsthat reported any diversions15

Total 3639 414 18 249 4534Metropolitan area 4039 448 19 448 5244Not metropolitan area

Figure does not meet standard of reliability or precision00 Quantity is zero or more than zero but less than 0051ED is emergency department2Data available only for 20043Time in minutes4Defined as beds filled as of midnight divided by staffed beds5Ambulance diversion hours were reported by 344 percent of all emergency departments and 501 percent of those in metropolitan areas Too few emergency departments reported any diversionhours in nonmetropolitan areas to provide a reliable estimate of mean numbers of hours

22 Advance Data No 376 + September 27 2006

Technical Notes

Number of hospital emergency departments and survey responses by selected hospital characteristics United States 2003ndash04

Hospital characteristic

Numberof sampled

in-scope EDs1

Number ofresponding

EDs12

Number ofnonresponding

EDs1

Unweightedresponse

rate2

Weightedresponse

rate23

All 24-hour EDs1 839 699 140 833 847

Geographic region

Northeast 197 154 43 782 852Midwest 195 161 34 826 846South 284 240 44 845 865West 163 144 19 883 795

Metropolitan status

Metropolitan area 685 577 108 842 865Not metropolitan area 154 122 32 792 830

Ownership

Voluntary 586 495 91 845 830Government 160 132 28 825 887Proprietary 91 71 20 780 822

ED annual visit volume1

Less than 20000 225 188 37 836 85020000 to 50000 368 311 57 845 853Over 50000 246 200 46 813 815

Medical school affiliation

Yes 391 324 67 829 852No 448 375 73 837 845

1ED is emergency department2Responding to both the Staffing Capacity and Ambulance Diversion Supplement and the annual request for visit data3Weighted by the first two stages of sample selection (primary sampling unit and hospital)

Advance Data No 376 + September 27 2006 23

Suggested citation

Burt CW McCaig LF Staffing capacity andambulance diversion in emergencydepartments United States 2003ndash04Advance data from vital and health statisticsno 376 Hyattsville MD National Center forHealth Statistics 2006

Copyright information

All material appearing in this report is in thepublic domain and may be reproduced orcopied without permission citation as tosource however is appreciated

National Center for Health Statistics

DirectorEdward J Sondik PhD

Acting Co-Deputy DirectorsJennifer H Madans PhD

Michael H Sadagursky

US DEPARTMENT OFHEALTH amp HUMAN SERVICES

Centers for Disease Control and PreventionNational Center for Health Statistics3311 Toledo RoadHyattsville MD 20782

OFFICIAL BUSINESSPENALTY FOR PRIVATE USE $300

To receive this publication regularly contactthe National Center for Health Statistics bycalling 1-866-441-NCHS (6247)E-mail nchsquerycdcgovInternet wwwcdcgovnchs

06-0139 (906)CS105940T26541DHHS Publication No (PHS) 2006-1250

24 Advance Data No 376 + September 27 2006

FIRST CLASSPOSTAGE amp FEES PAID

CDCNCHSPERMIT NO G-284

Table 7 Means and quartiles for selected indexes of staffing capacity ambulance diversion and throughput in emergency departmentsUnited States 2003ndash04mdashCon

Index MeanStandard

error25th

percentile Median75th

percentile

Percent admitted to hospital

Total 125 04 59 126 181Metropolitan area 134 06 61 132 194Not metropolitan area 111 07 57 105 168

Inpatient staffed bed size

Total 1365 61 384 850 1758Metropolitan area 1921 87 794 1432 2713Not metropolitan area 477 43 232 378 612

Inpatient daily occupancy rate4

Total 603 15 425 617 799Metropolitan area 664 16 542 712 826Not metropolitan area 506 34 348 474 652

Annual hours on ambulance diversion

Total 1460 166 00 00 77Metropolitan area 2427 290 00 16 1088Not metropolitan area 05 02 00 00 00

Annual hours on ambulance diversion for EDsthat reported any diversions15

Total 3639 414 18 249 4534Metropolitan area 4039 448 19 448 5244Not metropolitan area

Figure does not meet standard of reliability or precision00 Quantity is zero or more than zero but less than 0051ED is emergency department2Data available only for 20043Time in minutes4Defined as beds filled as of midnight divided by staffed beds5Ambulance diversion hours were reported by 344 percent of all emergency departments and 501 percent of those in metropolitan areas Too few emergency departments reported any diversionhours in nonmetropolitan areas to provide a reliable estimate of mean numbers of hours

22 Advance Data No 376 + September 27 2006

Technical Notes

Number of hospital emergency departments and survey responses by selected hospital characteristics United States 2003ndash04

Hospital characteristic

Numberof sampled

in-scope EDs1

Number ofresponding

EDs12

Number ofnonresponding

EDs1

Unweightedresponse

rate2

Weightedresponse

rate23

All 24-hour EDs1 839 699 140 833 847

Geographic region

Northeast 197 154 43 782 852Midwest 195 161 34 826 846South 284 240 44 845 865West 163 144 19 883 795

Metropolitan status

Metropolitan area 685 577 108 842 865Not metropolitan area 154 122 32 792 830

Ownership

Voluntary 586 495 91 845 830Government 160 132 28 825 887Proprietary 91 71 20 780 822

ED annual visit volume1

Less than 20000 225 188 37 836 85020000 to 50000 368 311 57 845 853Over 50000 246 200 46 813 815

Medical school affiliation

Yes 391 324 67 829 852No 448 375 73 837 845

1ED is emergency department2Responding to both the Staffing Capacity and Ambulance Diversion Supplement and the annual request for visit data3Weighted by the first two stages of sample selection (primary sampling unit and hospital)

Advance Data No 376 + September 27 2006 23

Suggested citation

Burt CW McCaig LF Staffing capacity andambulance diversion in emergencydepartments United States 2003ndash04Advance data from vital and health statisticsno 376 Hyattsville MD National Center forHealth Statistics 2006

Copyright information

All material appearing in this report is in thepublic domain and may be reproduced orcopied without permission citation as tosource however is appreciated

National Center for Health Statistics

DirectorEdward J Sondik PhD

Acting Co-Deputy DirectorsJennifer H Madans PhD

Michael H Sadagursky

US DEPARTMENT OFHEALTH amp HUMAN SERVICES

Centers for Disease Control and PreventionNational Center for Health Statistics3311 Toledo RoadHyattsville MD 20782

OFFICIAL BUSINESSPENALTY FOR PRIVATE USE $300

To receive this publication regularly contactthe National Center for Health Statistics bycalling 1-866-441-NCHS (6247)E-mail nchsquerycdcgovInternet wwwcdcgovnchs

06-0139 (906)CS105940T26541DHHS Publication No (PHS) 2006-1250

24 Advance Data No 376 + September 27 2006

FIRST CLASSPOSTAGE amp FEES PAID

CDCNCHSPERMIT NO G-284

Technical Notes

Number of hospital emergency departments and survey responses by selected hospital characteristics United States 2003ndash04

Hospital characteristic

Numberof sampled

in-scope EDs1

Number ofresponding

EDs12

Number ofnonresponding

EDs1

Unweightedresponse

rate2

Weightedresponse

rate23

All 24-hour EDs1 839 699 140 833 847

Geographic region

Northeast 197 154 43 782 852Midwest 195 161 34 826 846South 284 240 44 845 865West 163 144 19 883 795

Metropolitan status

Metropolitan area 685 577 108 842 865Not metropolitan area 154 122 32 792 830

Ownership

Voluntary 586 495 91 845 830Government 160 132 28 825 887Proprietary 91 71 20 780 822

ED annual visit volume1

Less than 20000 225 188 37 836 85020000 to 50000 368 311 57 845 853Over 50000 246 200 46 813 815

Medical school affiliation

Yes 391 324 67 829 852No 448 375 73 837 845

1ED is emergency department2Responding to both the Staffing Capacity and Ambulance Diversion Supplement and the annual request for visit data3Weighted by the first two stages of sample selection (primary sampling unit and hospital)

Advance Data No 376 + September 27 2006 23

Suggested citation

Burt CW McCaig LF Staffing capacity andambulance diversion in emergencydepartments United States 2003ndash04Advance data from vital and health statisticsno 376 Hyattsville MD National Center forHealth Statistics 2006

Copyright information

All material appearing in this report is in thepublic domain and may be reproduced orcopied without permission citation as tosource however is appreciated

National Center for Health Statistics

DirectorEdward J Sondik PhD

Acting Co-Deputy DirectorsJennifer H Madans PhD

Michael H Sadagursky

US DEPARTMENT OFHEALTH amp HUMAN SERVICES

Centers for Disease Control and PreventionNational Center for Health Statistics3311 Toledo RoadHyattsville MD 20782

OFFICIAL BUSINESSPENALTY FOR PRIVATE USE $300

To receive this publication regularly contactthe National Center for Health Statistics bycalling 1-866-441-NCHS (6247)E-mail nchsquerycdcgovInternet wwwcdcgovnchs

06-0139 (906)CS105940T26541DHHS Publication No (PHS) 2006-1250

24 Advance Data No 376 + September 27 2006

FIRST CLASSPOSTAGE amp FEES PAID

CDCNCHSPERMIT NO G-284

Suggested citation

Burt CW McCaig LF Staffing capacity andambulance diversion in emergencydepartments United States 2003ndash04Advance data from vital and health statisticsno 376 Hyattsville MD National Center forHealth Statistics 2006

Copyright information

All material appearing in this report is in thepublic domain and may be reproduced orcopied without permission citation as tosource however is appreciated

National Center for Health Statistics

DirectorEdward J Sondik PhD

Acting Co-Deputy DirectorsJennifer H Madans PhD

Michael H Sadagursky

US DEPARTMENT OFHEALTH amp HUMAN SERVICES

Centers for Disease Control and PreventionNational Center for Health Statistics3311 Toledo RoadHyattsville MD 20782

OFFICIAL BUSINESSPENALTY FOR PRIVATE USE $300

To receive this publication regularly contactthe National Center for Health Statistics bycalling 1-866-441-NCHS (6247)E-mail nchsquerycdcgovInternet wwwcdcgovnchs

06-0139 (906)CS105940T26541DHHS Publication No (PHS) 2006-1250

24 Advance Data No 376 + September 27 2006

FIRST CLASSPOSTAGE amp FEES PAID

CDCNCHSPERMIT NO G-284