ED Ultrasound

Rob Hall MDOral Presentation

PGY4 Emergency Medicine

October 30th, 2003

ED echo (“Eddie”)ED ultrasound

WHY SHOULD WE?

Ultrasound imaging enhances the physician's ability to evaluate, diagnose, and treat emergency department (ED) patients. Because ultrasound imaging is often time-dependent in the acutely ill or injured patient, the emergency physician is in an ideal position to use this technology. Focused ultrasound examinations provide immediate information and can answer specific questions about the patient's physical condition. Such bedside ultrasound imaging is within the scope of practice of emergency physicians.

CAEP Position Statement:Feb 1999

Ultrasound should be available 24 hours per day for emergency patients, particularly for those being evaluated for cardac tamponade, abdominal aortic aneurysm, abdominal trauma, and ectopic pregnancy. A focused or limited bedside Emergency Department ultrasound should be available, performed by technicians, radiologists, or appropriately trained, qualified and experienced Emergency Physicians.

Who is doing ED ultrasound in the USA?

Counselman. Acad Emerg Med 2000 Mail out survery 80% response rate 95% of emergency medicine training programs

teaching and using ultrasound Accounting for response bias --------- 75% of

programs Conclusion: ED ultrasound is mainstay in US

emerg programs

What do all these places have in common?

Winnipeg Lethbridge Kelowna Lillooet Abbotsford Vancouver Victoria Nanaimo

Fredericton Sacre’ Coeur Granby St-Paul Monmagny Montreal Ottawa Torondo Windsor Brampton Sarnia Kingston Parry Sound Huntsvile Sault Sainte

Marie

What do all of these specialists have in common?

Main objective: literature review of ED ultrasound

4 Primary Indications

AAA

Cardiac FAST

Pregnancy

Main objective: literature review of ED ultrasound

4 Primary Indications

AAA

Cardiac FAST

Pregnancy

AAA: objectives

Is there literature supporting ED ultrasound to detect AAAs?

How much training is required be accurate?

AAA: general information

Ultrasound done by radiology is nearly 100% sensitive for the detection of AAA

Ultrasound measurements correlate with CT and laparotomy measurements w/I 2-3mm

Physical examination is unreliable: Lederle JAMA 1999 3.0-3.9cm 29% sensitivity 4.0-4.9cm 50% sensitivity > 5.0cm 75% sensitivity

AAA: 6 prospective studies Study Size Training Sens. %

(C.I.s)

Spec.%

(C.I.s)

Accurracy

(C.I.s)

Jones

2003

N=66 8hrs 98

(86-100)

100

(87-100)

99

(90-100)

Rowland 2001

N=33 3 days 100

(74-100)

100

(85-100)

100

(90-100)

Kuhn

2000

N=68 3 days 100

(87-100)

100

(91-100)

100

Mandavia 2000

N=44 16hrs 50

(15-70)

95

(79-98)

93

Lanoix

2000

N=20 4hrs 100

(40-100)

100

(76-100)

100

Schlager 95 N=11 16hrs 100 100 100

AAA: 6 prospective studies Study Size Training Sens. %

(C.I.s)

Spec.%

(C.I.s)

Accurracy

(C.I.s)

Jones

2003

N=66 8hrs 98

(86-100)

100

(87-100)

99

(90-100)

Rowland 2001

N=33 3 days 100

(74-100)

100

(85-100)

100

(90-100)

Kuhn

2000

N=68 3 days 100

(87-100)

100

(91-100)

100

Mandavia 2000

N=44 16hrs 50

(15-70)

95

(79-98)

93

Lanoix

2000

N=20 4hrs 100

(40-100)

100

(76-100)

100

Schlager 95 N=11 16hrs 100 100 100

AAA

Jones. Emergency Medicine 2003. Prospective N=66 scans for AAA Initial training was an 8 hour course covering four

primary indications Gold standard = CT or laparotomy Results

Sensitivity 98% (86-100) Specificity 100% (87-100) Accuracy 99% (90-100)

AAA

Khun. Ann Emerg Med 2000 Prospective, N=68 Training was 3 days (2hrs for AAA) Gold standard = radiologist review of video Results

Sensitivity 100% (87-100) Specificity 100% (91-100) Accuracy 100% (no CI)

AAA: conclusions

Emergency Physicians can achieve accuracy in detection of AAAs with limited training

Our scans should aim to be 95% accurate

Main objective: literature review of ED ultrasound

4 Primary Indications

AAA

Cardiac FAST

Pregnancy

Cardiac: objectives

Can ED ultrasound be used to predict survival post cardiac arrest?

Is there literature supporting ED ultrasound for the detection of pericardial effusions? LV function?

Cardiac arrest and ED ultrasound

Blaivas Acad Emerg Med 2001 Prospective, N=166 Cardiac standstill

0/136 survival Cardiac activity 20/33

survival

Salen Acad Emerg Med 2001 Prospective, N=102 Standstill: 2/61

survival Cardiac activity: 11/41

survival ETC02 production was

a better predictor

Cardiac: conclusions

There is insufficient evidence to prove that cardiac standstill is a reliable indicator of cardiac arrest survival

Cardiac standstill should be considered in the decision to terminate resuscitation but should not be the sole criterion

Cardiac: LV function

Moore. Acad Emerg Med 2002 Looked at atraumatic

hypotensive patients Prospective, N=51,

cardiology as gold standard

Ratings: normal (1), mod depressed (2), severely depressed (3)

Kappa 0.61 (0.39-0.83)

EP ratings

Cardiologist ratings

1 2 3

1 17 5 0

2 7 9 2

3 0 2 8

Cardiac: pericardial effusions

Study Method Training Sens Spec Accuracy

Mandavia

2001

N=515 16hrs 96

(90-99)

98

(96-99)

97.5

(95-99)

Mandavia

2000

N = 28 16hrs 100

(50-100)

100

(60-100)

100

Lanoix 2000

N=67 4hrs 88

(47-99)

98

(90-99)

97

Ma 1995 N=245 10hrs + 20 exams

100 99 99

Cardiac: pericardial effusions

Study Method Training Sens Spec Accuracy

Mandavia

2001

N=515 16hrs 96

(90-99)

98

(96-99)

97.5

(95-99)

Mandavia

2000

N = 28 16hrs 100

(50-100)

100

(60-100)

100

Lanoix 2000

N=67 4hrs 88

(47-99)

98

(90-99)

97

Ma 1995 N=245 10hrs + 20 exams

100 99 99

Cardiac: pericardial effusions

Mandavia. Ann Emerg Med 2001 Prospective study, N=515 Training = 16hrs, 5hrs dedicated to echo Gold standard = blinded cardiologist interpretation All scans were clinically indicated Results:

Technically adequate in 93% Sensitivity 96% (90-99) Specificity 98% (96-99) Accuracy 97.5% (95-99)

Cardiac: conclusions

Emergency Physicians can achieve accuracy in detection of pericardial effusion with limited training

Our scans should aim to be 95% accurate

Determination of LV function requires further study

Main objective: literature review of ED ultrasound

4 Primary Indications

AAA

Cardiac FAST

Pregnancy

Pregnancy: objectives

How does ED ultrasound affect patient satisfaction? How does

ED ultrasound affect ED flow?

Is there literature supporting the accuracy of ED ultrasound in pregnancy?

Pregnancy: patient satisfaction

Krubel. Am J Emerg Med . 1998 Prospective; ½ got ED ultrasound Survey of 96 ED visits Showed

Improved overall satisfaction with ED care Improved satisfaction with tests performed Reduced desire for a second opinion Reduced anxiety after the ED visit

Pregnancy: ED flow

Useful Not Useful

Remember the chart review we did last year: pregnancy related u/s Document IUP was

found in 72% of initial ultrasounds

ED ultrasound would likely be useful in 72% of patients

Pregnancy: ED flow

Rogerson. Acad Emerg Med ED RUQ ultrasound is associated with a

reduced time to diagnosis and treatment of rupture ectopic pregnancies

Retrospective review Time ED u/s Radiology u/s

To Dx 58 min (28-87) 197 (162-232) To OR 111 min (69-153) 322 (270-364)

Pregnancy: ED flow

Blaivas. Acad Emerg Med 2000 Do emergency physicians save time when

locating a live IUP with bedside ultrasound? Retrospective review of 1419 charts Length of stays

ED ultrasound 3hr 40min Rad ultrasound 4hr 39min Absolute diff 59 min, p=0.0001

Pregnancy: ED flow

Burgher. Acad Emerg Med 1998 Before and after ED u/s introduction study Mean L.O.S. before: 234 min Mean L.O.S. after: 164 min Difference 70 min, p=0.0003

Shih. Ann Emerg Med Prospective; L.O.S. decreased when ultrasound

showed an IUP ED ultrasound: mean L.O.S. 45 min Radiology ultrasound: mean L.O.S. 177min

Pregnancy: conclusions

ED ultrasound can improve ED flow ED ultrasound can improve patient

satisfaction

Pregnancy: detecting an IUP

How accurate can ER docs be after minimal training?

Is it safe?

Pregnancy: detecting and IUP

Studies look at sensitivity and specificity of detecting an IUP not an ectopic

Specificity is therefore more important!

IUP

present

IUP absent

U/S shows IUP

True

Positive

False Positive (BAD!!!!!!)

U/S doesn’t show IUP

False Negative

True Negative

Pregnancy: 6 prospective studies Study Size Training Sens. %

(C.I.s)

Spec.%

(C.I.s)

Accurracy

(C.I.s)

Mandavia 2000

N=101 16 hrs 76

(61-99)

92

(76-96)

83%

Lanoix

2000

N=33 4hrs 100

(82-100)

90

(54-99.5)

97%

Shih

1997

N=125 24hrs +10exams

94%

(82-98%)

100

(83-100)

96%

Durham

1997

N=136 24hrs + 10 exams

97%

(91-97)

Mateer

1995

N=152 12hrs + 12 exams

99

(97-100)

93

(80-100)

Jehle 1989 N=40 ?? 97.5

Pregnancy: 6 prospective studies Study Size Training Sens. %

(C.I.s)

Spec.%

(C.I.s)

Accurracy

(C.I.s)

Mandavia 2000

N=101 16 hrs 76

(61-99)

92

(76-96)

83%

Lanoix

2000

N=33 4hrs 100

(82-100)

90

(54-99.5)

97%

Shih

1997

N=125 24hrs +10exams

94%

(82-98%)

100

(83-100)

96%

Durham

1997

N=136 24hrs + 10 exams

97%

(91-97)

Mateer

1995

N=152 12hrs + 12 exams

99

(97-100)

93

(80-100)

Jehle 1989 N=40 ?? 97.5

Pregnancy: detecting an IUP

Shih. Ann Emerg Med 1997 Prospective, N=125 Training: 24hrs + 10 proctored exams Gold standard was formal ultrasound Some were transvag some transabd Results

Sensitivity for IUP: 94% (C.I. 82-98%) Specificity for IUP: 100% (C.I. 83-100)

Pregnancy: detecting an IUP

Durham. Ann Emerg Med 1997 Prospective, N=136 Training: 24hrs + 20 proctored exams (variable) Gold standard: formal ultrasound Pre-defined possible ultrasound results and

correlated ER interpretation vs formal ultrasound result

Results showed overall 97% accurracy (91-97% C.I.)

Pregnancy: detecting an IUP:Durham. Ann Emerg Med 1997

Diagnosis Correct Incorrect Accuracy (95%C.I.)

IUP with fetal pole

87 0 100% (97-100)

IUP <6wks 9 3 75% (59-93)

Indeterminate 15 0 100% (82-100)

Ectopic 7 1 88% (60-95)

Bl. Ovum 2 0

Molar 1 0

Totals 121 4 97% (91-97)

Pregnancy: detecting an IUP

Mateer. Acad Emerg Med Prospective, N=152 Training: 12hrs + 12 proctored exams Gold standard: interpretation by gyne Also looked at results compared to final outcome ER interpretation versus gyne interpretation

Correct 94% Incorrect 4.7% Inadequate 1.4%

Pregnancy: conclusions

Emergency physicians can accurately detect Intra-uterine pregnancy

Our scans should aim to be 95% accurate Specificity for IUP needs to be 100%

If you’re not sure it’s an IUP, call it a “NO definitive IUP” and get a formal ultrasound

Main objective: literature review of ED ultrasound

4 Primary Indications

AAA

Cardiac FAST

Pregnancy

FAST: objectives

What is the learning curve for FAST?

Can surgeons use FAST accurately?

Can emergency physicians use FAST accurately?

FAST: general comments

Sensitivity is very dependant on the gold standard

FAST done by RADIOLOGISTS Laparotomy as gold standard

Sensitivties 93-97% Specificities 99-100%

CT as gold standard Sensitivity 89% Specificity 99%

FAST: variable sensitivity

Melanson. Emerg Med Clinics 1998 Reviewed 30+ studies Summarized studies with > 250 scans Sensitivities ranged from 70-99% Specificities ranged from 95-99%

FAST: variable sensitivity

Branney. J. Trauma. 1995 Used CAPD patients and looked at sensitivity

with various volumes of dialysate FAST sensitivity clearly varies with volume of

intraperitoneal fluid

FAST: learning curves

Gracias. American Surgeon: showed correlation of sensitivity with experience Minimal (<30exams): sensitivity 59% Moderate (30-100): sensitivity 88% Extensive (>100): sensitivity 100%

Shackford. J Trauma. 1999 Prospective, N=241 Surgeons with 8hr training and 10 supervised exams Gold standard problems

FAST learning curves: Shackford 1999Error rates

0

2

4

6

8

10

12

14

16

18

Exams 1-5 Exams 6-10 Exams11-15 Exams 16-20 Exams 20-25

FAST: surgeons

Rozycki. J Trauma Prospective, N=476 32hour training (some had more) Gold standard problems: CT, lap, DPL, or

serial exams!!!! Sensitivity 79%, Specificity 96%, Accuracy

92% Compared to radiology review of still images

Accuracy 90%, 5% technically inadequate

FAST: 6 prospective studies Study Size Training Sens. %

(C.I.s)

Spec.%

(C.I.s)

Accurracy

(C.I.s)

Mandavia 2000

N=198 16 hrs 86

(61-93)

100

(94-100)

97

Lanoix

2000

N=44 4hrs 94

(68-97)

93

(75-99)

93

Jones

2003

N=122 unclear

?8hrs

72

(53-86)

97

(91-99)

90

(83-95)

Rowland

2001

N=66 3 days 64

(31-89)

85

(73-94)

82

(70-90)

Ma

1995

N=245 10hr +20 exams

86 99 98

Vassiliadis

2003

N=140 variable 70 (58-97) 98 (95-100) 91 (86-96)

FAST: 6 prospective studies Study Size Training Sens. %

(C.I.s)

Spec.%

(C.I.s)

Accurracy

(C.I.s)

Mandavia 2000

N=198 16 hrs 86

(61-93)

100

(94-100)

97

Lanoix

2000

N=44 4hrs 94

(68-97)

93

(75-99)

93

Jones

2003

N=122 unclear

?8hrs

72

(53-86)

97

(91-99)

90

(83-95)

Rowland

2001

N=66 3 days 64

(31-89)

85

(73-94)

82

(70-90)

Ma

1995

N=245 10hr +20 exams

86 99 98

Vassiliadis

2003

N=140 variable 70 (58-97) 98 (95-100) 91 (86-96)

FAST: emergency physicians

Mandavia. Acad Emerg Med 2000 Prospective, total N=1138, FAST N=198 Training = 16 hr session Gold standard = over-read by ED physician

with “extensive” ultrasound training Results

Sensitivity 86% (61-93) Specificity 100% (94-100) Accuracy 97%

FAST: emergency physicians

Ma. J Trauma. 1995 Prospective, N=245 Training = 10 hrs + 20 exams Gold standard problems: CT, DPL, lap, clinical

observation Also had “surgical sonographer” overread Results: sensitivity 86%, specificity 99%, accuracy

98% (NO confidence intervals) Compared to “surgical sonographer”: agreement with

ER interpretation in 95%

FAST: conclusions

FAST likely takes longer to learn Emergency physicians can achieve high specificity FAST done by Radiology is approximately 90% sensitive Emergency physicians have been shown to be accurate

when interpretation is compared to experienced ultrasonographer

Emergency physicians have NOT been shown to achieve high sensitivity INTERPRET A NEGATIVE SCAN WITH CAUTION!!

Final Recomendations

SAEM/CAEP guidelines Training of an introductory course + 50 proctored

exams is reasonably supported by the literature FAST may be the one exception: we should consider

further training in FAST Targets for our scans

Accurracy 95% Technically limited scans < 5-10%

High specificity four all four primary indications ----------------> be aware of this …….

Final Recommendations

Pregnany Definitive IUP ---------- r/o ectopic No definitive IUP --------- get a formal u/s

No AAA --------- scan if still suspicious No effusion ------ echo if still suspicious No free fluid ------- CT scan when stable

Questions?

Comments?