Background: The approach to managing out-of-hospital cardiac arrest (OOHCA) has generally involved either minimal on-scene resuscitation to reduce time to arrival at hospital or extended care at the scene to increase the chance of return of spontaneous circulation (ROSC) before transport. This study compared patient outcomes across EMS agencies with respect to the duration of on-scene time. We hypothesized that EMS agencies with greater average time on-scene would have more favorable outcomes.
Methods: The Cardiac Arrest Registry to Enhance Survival (CARES) was used to identify OOHCA cases, including characteristics and outcomes. EMS agencies were included if they submitted at least 80 OOHCAs from 2013 to 2017. To study outcomes based upon culture of OOHCA management, outcomes were studied by EMS agency rather than by individual patient cases. Agencies in the top and bottom quartiles of on-scene time duration were categorized as high (HOSTAs) and low on-scene time agencies (LOSTAs), respectively. Generalized estimating equation models compared HOSTAs and LOSTAs.
Results: We classified 89 agencies as HOSTAs (24,114 patients, average ≥25 minutes on scene) and 89 agencies as LOSTAs (37,297 patients, average <18.9 minutes on-scene). Among patients transported, HOSTAs were more likely to have a shockable rhythm (28.4% vs. 22.2%, OR = 1.4, 95%CI 1.2 to 1.5), a witnessed arrest (65.1% vs. 53.6%, OR = 1.7, 95% CI 1.5 to 1.9), and receive bystander CPR (41.9% vs. 37.0%, OR = 1.3, 95% CI 1.1 to 1.5) than LOSTAs, all p < 0.001. When controlling for these and other patient characteristics, including mechanical CPR device use, HOSTAs had a higher proportion of ROSC on emergency department arrival (66.7% vs. 31.1%, OR = 4.6, 95%CI 3.5 to 6.0, p < 0.001), survival to discharge for transported patients (22.3% vs. 11.2%, OR = 2.6, 95%CI 2.0 to 3.4, p < 0.001), and good neurologic outcome among survivors (84.9% vs. 78.6%, OR = 1.3, 95%CI = 1.0 to 1.7, p = 0.04) than LOSTAs.
Conclusions: This study suggests that HOSTAs have more favorable patient outcomes compared to LOSTAs. RESULTS indicate that spending more time on-scene performing resuscitation is associated with higher rates of ROSC, survival and survival with good neurologic function.