Value of Pre-hospital Videolaryngoscopy

Joseph E Pellegrini, PhD, CRNAVideolaryngoscopy: Should this be the Standard of Care for Emergency Intubations: What is the Evidence Conventional LaryngoscopyConventional laryngoscopy depends on achieving a line of sight from operator to glottic inlet with a recommendation to place patient in a traditional sniffing position.Sniffing position results in optimum alignment of the three axesOral ---Pharyngeal---laryngeal to achieve a line of site1-4% of all cases this is very difficult to achieve or impossibleOften you cannot predict these difficult or impossible casesMany of these intubations are effectively blind requiring increased neck extension, external laryngeal manipulation or the use of a gum elastic bougieConventional LarygoscopyConventional laryngoscopy requires flexing of the lower cervical spine and extending the atlanto-occipital jointLine of Site

Line of Site Traditional LaryngoscopyEasy to lose Line of SiteOften morbidity secondary to poor alignment or technique

VideolaryngoscopyVideolaryngoscopy consistently improves the view of the larynx even in conditions where direct laryngoscopy may lead to poor view (i.e. cervical spine cases)Videolaryngoscopy allows the camera to act an eye of the operator and is situated in the pharynx of the patientEnables projection of glottis on monitor without the need to anteriorly displace the lower jaw and reduce the cervical spine motionAllows the operator to see around the cornerLess sympathetic responseLess leverage requiredMore easily tolerated in an awake patient

Videolaryngoscopy Line of Sight

6PROS - RothfieldApproximately 25 million patients are intubated/year for surgical proceduresOverall safety of anesthesia markedly improved with advent of SaO2 and ETCO2 monitoringMorbidity with ETT placement alone ranges from 4-22%Reported decreased morbidity/adverse events with video versus traditional laryngoscopyMultiple studies have shown that using video to assist intubation is effective and reduces morbidityAllows you to look around the corner without hyperextending neck etc.

CONS - RussoSome studies dispute all positive videolaryngoscopy findings when intubation is performed by experienced anesthesia providersOnly effective when used by novices or outside ORsAnesthesia providers should only use as backup to CL?Report decreased effectiveness when video used in face of blood, emesis etc.Can be obscured by sunlight etc. Various publications show that direct view does not ensure placementToo angular versus too deep

Intubation outside the ORIntubation outside of OR associated with increased morbidity and mortalityData suggest that in-hospital first pass intubation success rates varies from 50-98%Most studies evaluated efficacy with anesthesia providersAchieved higher success ratesMany codes are done without anesthesia presenceLimited dataStudies indicate increased adverse events in hospital with direct tie-in to survival ratesIncreased morbidity outside anesthesia specialties

Video-laryngoscopyConventional Laryngoscopy fraught with problemsPoor illuminationLimited view angle (10-15 )Insufficient view is Number 1 reason for failure both in and out of the OREspecially apparent in NON- ANESTHESIA PROVIDERS

Intubations outside operating room often performed by NON ANESTHESIA PROVIDERS in many institutionsOB Anesthesia carried CODE BEEPERSometimes could not respond immediately to code and reliance on emergency room and ICU physicians to facilitate intubationRespiratory therapists presence consistent at all codesOften anesthesia paged emergently to intubate after multiple attemptsStudy ProposedGlidescope introducedTraining providedComparative study formulatedStudy efficacy, time to intubate, differences between providers, complications etc.

Complication rate: N=105 intubations3 traumatic bloody airways1 esophageal intubationNo dental trauma

Lessons LearnedGlidescope difficultiesFailure to intubate initiallyInability to place tube despite clear visualizationStylet need to use GS specific styletFlexible stylet Scope too deepPull back = successInadequate relaxationUse of succinylcholine versus midazolam versus nothingOver-eager residentsPlacing GS using conventional approach

Training parameters establishedSuccess rates approached 100% in final stages of studyGlidescopes purchased throughout hospital and findings presented at corporate levelFound to be easier to use than C-MAC and other devices by NON ANESTHESIA PERSONNEL

Intubation in the FieldParamedics have been able to intubate in the field since 2003Endotracheal intubations are essential components of paramedic trainingHigher survivability in areas where intubation is performed in the fieldSome problems arise once transported to hospital secondary to:Malpositioned tubesMultiple attemptsExperience of paramedic teamsRural versus metro

Pre-hospital IntubationOverall intubation success rate 85.3%Average paramedic experience 59.5 monthsAverage number of attempts per paramedic 1.3 (1-2.75)Mean intubation success rate per paramedic was 80.6 22.3

Maryland Data Pre-hospital IntubationsIntubations success rate in Baltimore City ranged from 78-98% successfulVariability among EMT providersDependent on trauma versus cardiac arrestHigher success rates noted in cardiac arrest casesEMTs well versed in use of airway adjuncts and alternative airwaysVaried results in other countiesArundel CountyIntubation success approximately 80%Carroll CountyIntubation success rates unknownPrince Georges CountyIntubation success rates unknown but suspected to be 70%Howard CountyIntubation success rates 64% with a first pass success rate of only 59%Cardiac arrestMultiple co-morbidities documentedAbility to study alternative techniques based on CMO for Howard CountyInterest by Howard County FD, EMT DivisionsMaryland Data Pre-hospital IntubationsStudy DesignImplementation of county-wide education for all EMTsPlacement of Ranger Glidescopes on all EMTData collection tool formulated to collect variables of interestIntubation attempts, Time to intubation, Number of EMTs , Rationale for intubation, Success ratesProspective study approved by State of Maryland IRBHoward County IRBSaint Agnes Hospital IRBGovernor OMalleys officeMaryland Data Pre-hospital IntubationsOther variables measuredAgeGenderMallampatiLaryngeal viewNumber of patients at sceneInitial saturation/Vital SignsFinal ETCO2Maryland Data Pre-hospital IntubationsGlidescope Ranger

344 cardiac arrest incidents evaluated152 intubations evaluated using Videolaryngoscopy192 intubation evaluated using Conventional laryngoscopy3 patients could not be intubatedCould not ventilate nor intubate5 patients used alternative techniques2 King LTD Airway3 Bag-valve mask

Maryland Data Pre-hospital Intubations

Videolaryngoscopy Success RatesSeaman K., Rothfield K, Pellegrini J. Video Laryngoscopy Improves Intubation Success in Cardiac Arrest and Enables Excellent CPR Quality

Interruption in CPRMean duration between VL and CL45.1 seconds (CI 37.1-53.0 seconds)Associated almost exclusively with CLCPR Fraction was 87.5% in VL group in patients where CPR analytics available CPR was uninterrupted in VL cases which equates to increased survivabilityPrimary reason for intubation58% cardiac arrest or airway protectionAirway protection secondary to drug overdose35% traumaAutomobile accidentGSWOther

Maryland Data Pre-hospital IntubationsOther variables measuredAge54.2 23.6 years Gender65% male35% femaleLaryngeal view85% Grade 1-2 view on first attempt10% Grade 4 views8 Patients required rescue methods with GS

Maryland Data Pre-hospital IntubationsInitial saturation/Vital Signs70% no recorded Oxygen saturation initial (on arrival to scene)Final Saturation levels (on arrival to ED)49% had no recorded saturation levels51% had recorded saturation levels ranging from 85% to 100%

Final ETCO2Median ETCO2 levels 25 mmHg60% of population had ETCO2 < 30 mmHg

Maryland Data Pre-hospital IntubationsTube properly placed on arrival to ED97% ratio of tube properly placed on arrival to ED37% increaseOther ComplicationsInappropriate tube size attempts6 ETT required placement using smaller tubeFogging of lensInability to adequately displace tongueCords clearly visible but unable to place tubeAspiration52% reported aspiration present on initial laryngoscopy22% blood23% gastric contents7 % foreign material

Maryland Data Pre-hospital IntubationsPlans for Future StudiesOther CountiesRefined educational toolsNew standards for troubleshootingNational implications

ExpansionAll first respondersSurvival DataDid not measure survival ratiosNew code mantraETCO2Intubation attemptsNo disruption of CPR reported when GS was usedMaryland Data Pre-hospital IntubationsStudySubjectsDesignResults (time to intubation)CommentsAnderson, Rovsing, & Olsen, 2011100 morbidly obese pts with BMI >35 (50 in glidescope group and 50 in DL group)RCT, providers had experience with at least 20 glidescope intubationsDL: 32 secVL: 48 secGlidescope intubation lasted slightly longer, but was of no clinical significance because there were no significant drops in SpO2 in either group. DL intubations were rated as more difficult than VL intubations, and DL intubations required significantly more lifting force. No difference in postoperative sore throat.Ndoko et al, 2008106 morbidly obese patients with BMI >35 (53 pts in each group)RCT, intubations performed by providers skilled in both techniquesDL: 56 secVL: 24 secBetter maintenance of SpO2 levels with VL compared to DL. Greater increase in MAP, heart rate, and bispectral index number was seen with the DL group. More intubations were rated as difficult in the DL group, and there was a higher incidence of postoperative sore throat in this group as well.Ranieri, Filho, Batista, & do Nascimento, 2012132 morbidly obese pts with BMI >35 (DL: 64pts, Airtraq VL: 68 pts)RCT, all intubations performed by anesthesiologists highly experienced in both VL and DLDL: 37 secVL: 14 secImproved vocal cord view and faster time to intubation with the VL as compared to Dl.Dhonneur et al 2009318 morbidly obese pts with BMI >35 (106 in each group of LMA CTrach, Airtraq Laryngoscope (VL), and Macintosh laryngoscope)RCT, intubations performed by senior anesthesiologists experienced in the use of VLDL: 69 secVL: 29 secThis study also compared the use of a videoscopic intubating LMA, but for our purposes we extrapolated data just from the other 2 groups. VL resulted in less shunting and better arterial O2 saturations as compared to DL. VL allowed for the fastest definitive airway, as compared to both other modalities. Arterial oxygenation was of better quality during use of VL compared to DL.Marrell, Blanc, Frascarolo, & Magnusson, 200780 morbidly obese pts (BMI >35)RCT, all intubations performed by same senior anesthesiologist. Laryngoscopy was performed with the same videolaryngoscope (MAC 3 blade Airtraq) but in the control group the screen was hidden.DL: 93 secVL: 59 secFound better view with VL vs DL and faster time to intubate, but no significant difference in lowest SpO2 during intubation

Videolaryngoscopy Bottom LineProsEasier to master than conventional laryngoscopeNovice masteryCan be used by wide variety of professionials & paraprofessionalsMore easily tolerated than CL in awake patientsLess sympathetic dischargeIntubation by committeeMore useful in patients with limited mobility or possess a difficult airwayPromotes faster time to intubation & less adverse events in morbidly obese patientsConsTechnology driven with all inherent problemsEnough saidDecreases skill in novicesCannot be used in all settings

Pellegrini@son.umaryland.edu