Timing of advanced airway management by emergency medical services personnel following out-of-hospital cardiac arrest: A population-based cohort study

Background: Early prehospital advanced airway management (AAM) by emergency medical services (EMS) personnel has been intended to improve patient outcomes from out-of-hospital cardiac arrest (OHCA). However, few studies examine the effectiveness of early prehospital AAM. We investigated whether early prehospital AAM was associated with functionally favourable survival after adult OHCA. Methods: We conducted a population-based cohort study of OHCA in Osaka, Japan, between 2005 and 2012. We included all consecutive, non-traumatic adult OHCA in which EMS personnel performed cardiopulmonary resuscitation (CPR) and AAM. Main exposure was time from CPR to AAM. Primary outcome was functionally favourable survival at one-month. As the primary analysis, we estimated adjusted odds ratio (OR) of time from CPR to AAM using multivariable logistic regression in the original cohort. In the secondary analysis, we divided the time from CPR to AAM into early (0-4 min) and late (5-29 min). We calculated propensity scores (PS) for early AAM and performed PS-matching. Results: We included 27,471 patients who received prehospital AAM by EMS personnel. In this original cohort, time from CPR to AAM was inversely associated with functionally favourable survival (adjusted OR 0.90 for oneincrement of minute, 95% confidence interval [CI] 0.87-0.94). In the PS-matched cohort of 17,022 patients, early AAM, compared to late AAM, was associated with functionally favourable survival: 2.2% vs 1.4%; adjusted OR 1.58 (95% CI 1.24-2.02). Conclusions: Earlier prehospital AAM by EMS personnel was associated with functionally better survival among adult patients who received AAM.