Gender Differences in Defibrillator Practices in Out-of-Hospital Cardiac Arrest

Disparities remain in survival after out-of-hospital cardiac arrest (OHCA) for women compared to men. Our objective was to evaluate differences in automated external defibrillator (AED) use before Emergency Medical Services (EMS) arrival and time from arrival to initial EMS defibrillation by EMS-assessed gender (women or men).

This was a secondary analysis of adult non-traumatic, EMS-treated OHCA cases in the Portland Cardiac Arrest Epidemiologic Registry from 2018 to 2021. Emergency Medical Services-witnessed cardiac arrests were excluded and the primary outcomes were pre-EMS AED application and the time from EMS arrival to first defibrillation among patients in a shockable rhythm at first rhythm assessment without pre-EMS AED application. We examined pre-EMS AED application rates overall and separately for law enforcement, in cases where they were on-scene before EMS without a lay bystander AED applied, and lay responders, in cases where law enforcement had not applied an AED. We used multivariable logistic and linear regressions to adjust for potential confounders, including age, arrest location, witness status, bystander CPR, year, and time from dispatch to EMS arrival. We accounted for clustering by county of arrest using a mixed-effects approach.

Of the 3,135 adult, EMS-treated non-traumatic OHCAs that were not witnessed by EMS, 3,049 had all variables for analysis, of which 1,011 (33.2%) were women. The adjusted odds (adjusted odds ratio [95% CI]) for any pre-EMS placement of an AED was significantly higher for men compared to women (1.40 [1.05-1.86]). These odds favoring men remained when examining law enforcement AED application (1.89 [1.16-3.07]), but not lay bystander AED application (1.19 [0.83-1.71]). Among patients still in arrest on EMS arrival, with a shockable initial EMS rhythm, and without pre-EMS AED application, the time from EMS arrival on-scene to initial defibrillation was significantly longer for women compared to men (+0.81 min [0.22-1.41 min]).

Women with OHCA received lower rates of pre-EMS AED application and delays in initial EMS defibrillation compared to men.