Abstract Body: Background: Emergency medical services clinicians commonly perform advanced airway management (AAM: i.e., supraglottic airway placement and endotracheal intubation) for out-of-hospital cardiac arrest (OHCA). Nevertheless, the heterogeneity of the treatment effect of prehospital AAM across age groups is still unclear.
Aim: To determine the association between prehospital AAM and survival after OHCA, compared with no AAM, across age groups.
Methods: This cohort study used the Resuscitation Outcomes Consortium Epidemiologic Registry database, a prospective OHCA registry at ten sites in the US and Canada from 2011 through 2015. Patients were stratified into ten sub-cohorts based on their first documented rhythm (shockable or non-shockable) and five age groups (0-9 years; 10-24; 25-44; 45-64; or ≥65) given the potential impact of rhythm and age on effect modification. To address resuscitation time bias, patients who received AAM during cardiopulmonary resuscitation (CPR) were sequentially matched with patients at risk of receiving AAM within the same minute based on time-dependent propensity scores. Matching was performed in each sub-cohort, and the matched sub-cohorts were integrated for the main analysis. The primary outcome was survival to hospital discharge.
Results: Of the 44,403 eligible patients, 39,157 (88.2%) received prehospital AAM during CPR. After time-dependent propensity score sequential matching, 29,973 who received AAM were matched with patients who had not yet received AAM at the same minute. AAM was associated with survival: 5.4% vs 4.8%, risk ratio (RR) 1.40 (95% CI 1.30-1.51). The associations were similar toward better survival in both the shockable (RR 1.27 [95% CI 1.17-1.38]) and non-shockable (RR 1.75 [95% CI 1.53-2.01]) cohorts. There was no apparent heterogeneity of the treatment effect of AAM on survival in all age groups: 0-9 years, RR 1.07 (95% CI 0.45-2.56); 10-24 years, 1.61 (1.07-2.45); 25-44 years, 1.68 (1.35-2.10); 45-64 years, 1.33 (1.19-1.48); 65 years or older, 1.40 (1.23-1.59).
Conclusions: In this study of the large multicenter OHCA registry in North America, prehospital AAM was associated with survival to hospital discharge regardless of the first documented rhythm. No apparent heterogeneity was found in the associations between AAM and survival among all age groups, suggesting that both pediatric and adult populations might benefit from prehospital AAM.