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Three Part Question

In [adult patients with out of hospital cardiac arrest], what is the [association between advanced airway management] with [neurologic outcome]?

Clinical Scenario

A 65 year old male has an out of hospital cardiac arrest that is witnessed by bystanders. EMS arrives and the patient needs an advanced airway. The airway kit has endotracheal tubes as well as supraglottic airways. The EMS responder must decide which airway will provide the best outcome for the patient.

Search Strategy

Medline 1946-06/13 using OVID interface, Cochrane Library (2013), PubMed clinical queries


[(exp out-of-hospital cardiac arrest) AND (exp airway management)]. Limit to prospective studies

Search Outcome

32 papers were identified; of which three answered the clinical question.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Kajino, K. et al. 2011 Japan	5377 adult witnessed, non-traumatic, out of hospital cardiac arrests that received advanced airway placement by EMS. 1,679 endotracheal intubations (ETI) and 3,698 supraglottic airways (SGA).	Prospective population based cohort study	Primary outcome was neurologically favorable one-month survival. Secondary outcomes were ROSC, admission to hospital, and overall one-month survival.	Neurologic outcome was similar. Time from collapse to ETI was longer than that for SGA. Greater training among EMS resulted in more favorable outcomes.	This study was not a randomized study. CPR and airway management quality was not assessed, for example, no mention of length of CPR interruptions for airway placement. Bias exists in regards to why EMTs chose ETI over SGA as protocol was not always followed. The study shows the quicker either airway is placed, the better the outcome yet the study states no difference between ETI and SGA even though ETI took 1.4 minutes longer. This is suggestive that ETI is better but because it takes longer to place, the results wash out in the end.
Wang, H. et al. May 2012 United States, Canada	10,455 adult, out of hospital cardiac arrest patients that needed and received advanced airways. 8,847 received endotracheal intubation (ETI) and 1,968 received supraglottic airways (SGA).	Secondary analysis of prospectively collected data from ROC PRIMED study.	Primary outcome was survival to hospital discharge with satisfactory functional status. Secondary outcomes were 24 hour survival and ROSC.	Successful ETI when compared to successful SGA had better outcomes. 4.7% compared to 3.9% respectively had satisfactory functional status at time of discharge from hospital.	This study may not be applicable to all EMS groups as the groups involved were highly trained in ETI. Quality of airway management was not assessed, for example, duration of pauses in CPR, number of attempts at airway placement, ventilation rates, etc. Time to airway placement was not reported which could easily skew the data.
Hasegawa, K. et al. Jan 2013 Japan	649,359 adult patients with out of hospital cardiac arrest who underwent resuscitation and were subsequently transported to hospitals. 367,837 patients had bag-valve mask ventilation (BVM), 239,550 had suprglottic airways (SGA), and 41,972 had endotracheal intubation (ETI).	Prospective, population based study	Primary outcome was favorable neurologic outcome at one month after cardiac arrest.	BVM had a more favorable outcome when compared to all advanced airways, 2.9% and 1.1% respectively. Both ETI and SGA were similarly associated with less favorable outcomes with odds ratios of 0.41 and 0.38 respectively when compared to BVM.	This is an observational study rather than a randomized control trial. Those patients who had ROSC before airway management would automatically fall under BVM assignment, skewing the data in favor of BVM. This study was in Japan, a country that has only permitted ETI since 2004.

Comment(s)

Often it is assumed that aggressive airway intervention is associated with more favorable neurologic outcomes in patients presenting with out of hospital cardiac arrest. These studies put this assumption to the test in an effort to shed light on the best form of pre-hospital airway management.

Clinical Bottom Line

Endotracheal intubation (ETI) as a form of advanced airway management in adult, out of hospital cardiac arrests, appears to have a more favorable neurologic outcome when compared to supraglottic airways (SGA). However, when both ETI and SGA are compared to bag-valve mask ventilation (BVM) alone, the BVM ventilation had the best neurologic outcome. Overall, the more training EMS responders have, the better the neurologic outcome despite the method of airway management used.

References

1. Kajino, K. et al. Comparison of supraglottic airway versus endotracheal intubation for the pre-hospital treatment of out-of-hospital cardiac arrest. Critical Care 2011. 15(5) R236
2. Wang, H. et al. Endotracheal intubation versus supraglottic airway insertion in out-of-hospital cardiac arrest. Resuscitation 2012, 83(9):1061-6.
3. Hasegawa, K. et al. Association of Prehospital Advanced Airway Management With Neurologic Outcome and Survival in Patients With Out-of-Hospital Cardiac Arrest JAMA 2013;309(3):257-266.