Mechanical CPR Device Use and Cardiac Arrest Survival in EMS Agencies

BACKGROUND: Cardiopulmonary resuscitation (CPR) by health care responders is often suboptimal during out-of-hospital cardiac arrest (OHCA). Mechanical CPR devices have been promoted as a strategy to improve CPR quality. Whether their use in routine care is associated with improved OHCA survival at emergency medical service (EMS) agencies is unclear. METHODS: Within the Cardiac Arrest Registry to Enhance Survival, we assessed agency-level rates of OHCA survival at EMS agencies with ≥2 years of OHCA data before and after their first documented use of a mechanical CPR device from 2013 to 2019 using an observational cohort study design. Temporal trends in favorable neurological survival (without severe neurological disability) and survival to discharge were first assessed in EMS agencies that did not initiate mechanical CPR device use (control agencies) using multivariable hierarchical logistic regression. Then an interrupted time series analysis evaluated whether introduction of mechanical CPR devices at EMS agencies was associated with higher OHCA survival. RESULTS: Among 51 994 patients with OHCA at 73 control agencies, there were no temporal trends in risk-adjusted rates of favorable neurological survival (annual rates ranged between 9.6% and 10.6%; P trend =0.23) or survival to discharge (annual rates ranged between 11.1% and 12.0%; P trend =0.31). At 49 EMS agencies that introduced mechanical CPR devices (14 110 OHCAs before and 17 804 OHCAs after), the mean EMS agency risk-adjusted rate of favorable neurological survival was 8.9%±2.2% before mechanical CPR device introduction and 8.3%±1.3% after, with no change in model intercept (adjusted odds ratio, 0.94 [95% CI, 0.80–1.11]; P =0.48) or slope after introduction of mechanical CPR devices (adjusted odds ratio per year, 1.03 [95% CI, 0.96–1.12]; P =0.41). Similarly, the mean EMS agency risk-adjusted rate of survival to discharge was 11.0%±2.2% before and 10.0%±1.0% after device introduction, with no significant change in model intercept or slope after device introduction. CONCLUSIONS: In a large US registry of OHCA, EMS agency rates of favorable neurological survival and survival to discharge were not higher after the initiation of mechanical CPR device use.