Bystander cardiopulmonary resuscitation and survival in out-of-hospital cardiac arrest of non-cardiac origin

Abstract Background Knowledge about the effect of bystander cardiopulmonary resuscitation (CPR) in out-of-hospital cardiac arrest (OHCA) of non-cardiac origin is lacking. We aimed to investigate the association between bystander CPR and survival in OHCA of presumed non-cardiac origin. Methods From the Danish Cardiac Arrest Registry and through linkage with national Danish healthcare registries we identified all adult patients with OHCA of presumed non-cardiac origin in Denmark (2001–2014). These were categorized further into OHCA of medical and non-medical cause. We analyzed temporal trends in bystander CPR and 30-day survival during the study period. Multiple logistic regression was used to examine the association between bystander CPR and 30-day survival and reported as standardized 30-day survival chances with versus without bystander CPR standardized to the prehospital OHCA-factors and patient characteristics of all patients in the study population. Results We identified 10,761 OHCAs of presumed non-cardiac origin. Bystander CPR was associated with an increased 30-day survival chance of 3.4% (95% confidence interval [CI]: 2.9–3.9) versus 1.8% (95% CI: 1.4–2.2) with no bystander CPR, corresponding to a significant difference of 1.6% (95% CI: 0.9–2.3). During the study period, the overall bystander CPR rates increased from 13.6% (95% CI: 11.2–16.5) to 62.7% (95% CI: 60.2–65.2). 30-day survival increased overall from 1.3% (95% CI: 0.7–2.6) to 4.0% (95% CI: 3.1–5.2). Similar findings were observed in subgroups of medical and non-medical OHCA. Table 1. Patient and arrest characteristics according to cause of out-of-hospital cardiac arrest Overall Medical OHCA Non-medical OHCA Patient characteristics Total patients 10761 7625 3136 Median age,y 67 70 50 Male, n (%) 6357 (59.1) 4154 (54.5) 2204 (70.4) OHCA factors Witnessed arrest, n (%) 4306 (40.0) 3574 (46.9) 732 (23.3) Public location, n (%) 6979 (64.9) 5494 (72.1) 1485 (47.4) OHCA, out-of-hospital cardiac arrest; CPR, cardiopulmonary resuscitation. Figure 1. Temporal trends Conclusion Bystander CPR was associated with a higher chance of 30-day survival among OHCA of presumed non-cardiac origin regardless of the underlying cause (medical/non-medical). Rates of bystander CPR and 30-day survival improved during the study period.