Bystander cardiopulmonary resuscitation differences by sex – the role of arrest recognition

Purpose To assess whether bystander cardiopulmonary resuscitation (CPR) differed by patient sex among bystander-witnessed out-of-hospital cardiac arrests (OHCA). Methods This study is a retrospective analysis of paramedic-attended OHCA in New South Wales (NSW) between January 2017 to December 2019 (restricted to bystander-witnessed cases). Exclusions included OHCA in aged care, medical facilities, with advance care directives, from non-medical causes. Multivariate logistic regression examined the association of patient sex with bystander CPR. Secondary outcomes were OHCA recognition, bystander AED application, initial shockable rhythm, and survival outcomes. Results Of 4,491cases, females were less likely to receive bystander CPR in private residential (Adjusted Odds ratio [AOR]: 0.82, 95%CI: 0.70-0.95) and public locations (AOR: 0.58, 95%CI:0.39-0.88). OHCA recognition during the emergency call was lower for females arresting in public locations (84.6% vs 91.6%-males, p=0.002) and it partially explained the association of sex with bystander CPR (∼44%). This difference was not observed in private residential locations (p=0.2). Bystander AED use was lower for females (4.8% vs 9.6%, p<0.001) however, after adjustment for location and other covariates, this relationship was no longer significant (AOR: 0.83, 95%CI: 0.60-1.12). Females were less likely to record an initial shockable rhythm (AOR: 0.52, 95%CI: 0.44-0.61) but more likely to survive the event (AOR: 1.34, 95%CI: 1.15 – 1.56). There was no sex difference in survival to hospital discharge (AOR: 0.96, 95%CI: 0.77-1.19). Conclusion OHCA recognition and bystander CPR differ by patient sex in NSW. Research is needed to understand why this difference occurs and to raise public awareness of this issue.