Racial and ethnic differences in time to shock delivery in out-of-hospital cardiac arrest

While prompt defibrillation is a key intervention in out-of-hospital cardiac arrest (OHCA), it remains unknown whether the time to first shock delivery by emergency medical services (EMS) clinicians varies across patients' races and ethnicities.

This retrospective cohort study included adults (≥18 years) with nontraumatic initially shockable OHCA in the Pragmatic Airway Resuscitation Trial, a cluster randomized control trial, comparing the effects of laryngeal tube and endotracheal intubation at 27 EMS agencies in the US from 2015 through 2017. We compared the differences in restricted mean survival time (RMST) of time from EMS arrival on the scene to the first shock delivery: the average time-to-event duration in survival analysis, across non-Hispanic White (hereafter, White), non-Hispanic Black (hereafter, Black), and Hispanic patients, with and without adjustment for patient demographics and cardiac arrest characteristics.

Four hundred thirty-four individuals (White: 303, Black: 103, Hispanic: 28) were included. The median interval between EMS arrival and shock delivery was 4.3 min (IQR 3.0-7.2) in White, 5.2 min (IQR 3.4-7.8) in Black, and 5.0 min (IQR 3.6-9.0) in Hispanic patients. The unadjusted RMST was 6.37 min (95% CI 5.78-6.97) for White, 7.47 min (95% CI 6.36-8.57) for Black, and 9.47 min (95% CI 6.62-12.33) for Hispanic patients. Compared to White patients, the unadjusted RMST differences were 1.10 min (95% CI -0.16 to 2.35) for Black and 3.10 min (95% CI 0.18-6.02) for Hispanic patients, and the adjusted RMST differences were 0.42 min (95% CI -0.88 to 1.72) for Black patients and 3.25 min (95% CI 0.43-6.07) for Hispanic patients.

In this cohort study, compared to White patients, Hispanic patients had longer time from EMS arrival to first shock delivery, whereas time to shock delivery in Black patients was not significantly different.