Intra-cardiac arrest transport and survival from out-of-hospital cardiac arrest: A nationwide observational study

Aim: To assess whether intra-cardiac arrest transport as compared to continued on-scene resuscitation was associated with improved clinical outcomes among out-of-hospital cardiac arrest patients in Denmark.

Methods: This was an observational study using data from population-based registries in Denmark. Adults (aged ≥ 18 to ≤ 65 years) with an out-of-hospital cardiac arrest attended by Emergency Medical Services (EMS) between 2016 and 2018 were included. The primary outcome was survival to 30 days. Time-dependent propensity score matching was used to match patients transported to the hospital within 20 minutes of EMS arrival to patients with assumed on-scene resuscitation (with or without subsequent intra-cardiac arrest transport) at risk of being transported within the same minute.

Results: The full cohort included 2,873 cardiac arrests. The median age was 56 (quartiles: 48 to 62) years, 1987 (69%) were male, and 104 (4%) were transported within 20 minutes. A total of 87 transported patients were matched to 87 patients at risk of being transported based on the propensity score. Although not reaching statistical significance, in comparison with on-scene resuscitation, intra-cardiac arrest transport was associated with increased survival to 30 days (risk ratio, 1.55; 95%CI, 0.99-2.44; P = 0.06). Similar associations were observed for return of spontaneous circulation and survival to one year.

Conclusions: Among patients aged 18-65 years, intra-cardiac arrest transport was associated with a non-significant increase in survival within 20 minutes of EMS on-scene arrival. However, the results did not eliminate the potential for bias and the results should be interpreted carefully.