Written by Sam Parnell
For adults with out-of-hospital cardiac arrest (OHCA), initial laryngeal tube (LT) insertion by EMS providers was associated with improved 72-hour survival, return of spontaneous circulation (ROSC), hospital survival, favorable neurologic outcome, and airway success compared to initial endotracheal tube (ETT) insertion.
Why does this matter?
Endotracheal intubation (ETI) has been a cornerstone of EMS care for OHCA. However, there are multiple challenges with paramedic ETI including insertion failure, need for several attempts, and significant interruptions in compressions. In addition, this is a relatively rare EMS procedure, with many U.S. paramedics only performing one procedure annually. We also know bag-mask ventilation was as good as ETI. Supraglottic airway (SGA) devices, such as the LT, are an appealing alternative to ETI during OHCA, as insertion is quick, simple, and require less training. Today’s study called PART – Pragmatic Airway Resuscitation Trial – focuses on the LT; tomorrow’s study, AIRWAYS-2, will cover use of the i-gel SGA for OHCA.
Should we put the tube in the trachea or larynx?
This was a multi-center, pragmatic, cluster-crossover, randomized trial of 3004 adults with OHCA comparing initial airway management by paramedics of LT insertion vs ETI by 27 different EMS agencies in the U.S. from December 1, 2015 to November 4, 2017. The primary outcome was 72-hour survival, which was 18.3% for the LT group and 15.4% in the ETI group (P = 0.04; RR 1.19). Secondary outcomes also favored the LT group vs ETI group including ROSC (27.9% vs 24.3%; P = 0.03), hospital survival (10.8% vs 8.1%; P = 0.01), and favorable neurological status at discharge (7.1% vs 5.0%; P = 0.02). In addition, ETI had increased risk of adverse events compared to LT insertion, such as multiple (≥3) insertion attempts (1.4% vs 0.4%; P = 0.01) and unsuccessful initial insertion (44.1% vs 11.8%; P < .001). Furthermore, 33.1% of patients in the ETI group were reintubated after arrival to the Emergency Department. The study had several limitations, including the pragmatic and unblinded design, practice setting, and ETI performance characteristics.
This raises the question of whether ETI should be the standard for airway management. The results from this trial suggest that a strategy of initial LT insertion improved clinical outcomes and perhaps should be the preferred initial airway management strategy in OHCA. We will cover AIRWAYS-2 tomorrow, which showed no difference in outcomes using a different SGA, the i-gel.
FOAMfrat has interviews with the lead authors of PART and AIRWAYS-2.
EMLoN has a quick, incisive analysis of both the PART and AIRWAYS-2 studies.
Journal of EMS weighs in on this study.
JWatch concluded, Maybe Paramedics Should Not Perform ETI (subscription required)
Effect of a Strategy of Initial Laryngeal Tube Insertion vs Endotracheal Intubation on 72-Hour Survival in Adults With Out-of-Hospital Cardiac Arrest: A Randomized Clinical Trial. JAMA. 2018 Aug 28;320(8):769-778. doi: 10.1001/jama.2018.7044.
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Reviewed by Clay Smith
3 thoughts on “EMS ETT or LT for OHCA? Answers in PART”
As a current paramedic who is also a scientist/clinical researcher I wanted to throw my two cents out on this. For what it’s worth, my next move is medical school so I am not one of those die-hard medics who defends ETI simply because I don’t want to lose the ability to perform the skill. As a clinical researcher I am a proponent of evidence-based medicine, and I think there are some very compelling findings in many of these studies on ETI for OHCA. If it isn’t the best choice for airway management in these patients then we should let it got the way of the dinosaurs and move on to an alternative that is better for our patients. However, I think that these discussions often extrapolate the data on studies of prehospital ETI for OHCA to make an argument against prehospital ETI in all cases. As noted in the last sentence of the comment box on the NEJM article ("Maybe paramedics should not perform ETI”), "These results cannot be generalized to presentations other than cardiac arrest and are not informative regarding anything paramedics do during cardiac arrest resuscitations other than airway management." The title of the NEJM article is misleadingly broad and exemplifies this issue.
Paramedics are confronted with many other situations where the ability to quickly and definitively secure the airway can mean the difference between a live patient and a dead one – airway burns, treatment refractory angioedema, trauma, crashing hypoxic COPD or respiratory patients who fighting to tear off CPAP or too exhausted to maintain adequate respirations, etc. They are performing intubations in conditions far less controlled than the emergency department, and many paramedics are operating in rural areas where transport time ranges from 20 minutes to more than an hour. In all of these cases, RSI intubation is a critical skill in the paramedic toolbox. I do think that there are paramedics who should not be intubating because they lack the skill and clinical judgement required to do this effectively, and I believe that it is a skill that should require bi-annual visits to the OR to maintain proficiency in medics who are allowed to intubate but do not reach a minimum number in the field during that time. Some of the things done by the medics during studies of prehospital ETI for OHCA are clearly harmful – we should not be stopping CPR to intubate a patient as the priority should be to maintain high quality CPR and defibrillate as soon as possible (if possible), and we should not be trying 3 times to get a tube in the field. Even standardizing use of a bougie would go a long way in improving first pass success rates, and your first attempt should always be your best. When I am considering intubation on any patient, the first thing I think about is whether there is anything I can do other than intubation that will help this patient, and the second thing I consider is what the odds are that this patient will ever be able to be weaned off the tube in the ICU if I make the decision to intubate them in the field. I recognize that this procedure carries significant risks of harm to the patient if performed incorrectly, so I take care to use it only when absolutely necessary. I have found RSI intubation to be an invaluable tool in cases where I had to employ it in the field, and other studies such as the 2017 meta-analysis on prehospital ETI have also found high rates of success >90% in non-physicians intubating with RSI (Crewdson K, Lockey DJ, Røislien J, Lossius HM, Rehn M. The success of pre-hospital tracheal intubation by different pre-hospital providers: a systematic literature review and meta-analysis. Critical Care. 2017;21:31. doi:10.1186/s13054-017-1603-7.).
To wrap this up, my main point is that paramedicine needs to embrace evidence based medicine and make adjustments to long-held tradition when it is clearly best for the patient to do so. However, it is equally important that paramedics have the knowledge, skills, abilities and authorization to perform RSI intubations in the field on patients when it is necessary to do so. It would be devastating to lose a patient in the field who could have been saved with RSI-assisted intubation, and in my experience these patients are encountered with enough frequency to warrant the inclusion of RSI ETI in the skillset for paramedics who demonstrate the training, competency, critical thinking and commitment required to effectively employ it. Stepping off the soapbox now….
JB, great comments. Agree, it appears an ETT may not be best for OHCA. But it is a fair point that the NEJM Journal Watch post may be throwing the baby out with the bathwater. ETI is an important skill but tough to maintain.
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