The impact of first responder turnout and curb-to-care intervals on survival from out-of-hospital cardiac arrest

Abstract

Purpose: Patients with out-of-hospital cardiac arrest (OHCA) more likely survive when emergency medical services (EMS) arrive quickly. We studied time response elements in OHCA with attention to EMS intervals before wheels roll and after wheels stop to understand their contribution to total time response and clinical outcome.

Methods: We analyzed EMS responses to OHCA from 2009-2014 in an urban, fire department based system. The Call-to-Care Interval, from call receipt to hands-on EMS care, was comprised of four time intervals: 1) call received to EMS notification (Activation), 2) EMS notification to vehicle wheels rolling (Turnout), 3) wheels rolling to arrival at scene (Travel), and 4) arrival at scene to hands-on EMS care (Curb-to-Care). We created a new time interval (On-Feet) comprised of the turnout and curb-to-care intervals. Using logistic regression, we evaluated whether the total EMS response interval and discrete time intervals were related to survival to discharge.

Results: Of 1,831 cases, 1,806 (98.6%) had complete information. The mean lengths for the intervals were 7.2±3.6min. (call-to-care), 58±39s (activation), 63±29s (turnout), 2.5±1.3min (travel), 2.4±1.6min (curb-to-care), and 3.5±1.7min (on-feet). After adjustment, "On Feet" interval was associated with OHCA survival (OR=0.91 [95% CI=0.83-1.00] for each additional minute).

Conclusions: Turnout and curb-to-care intervals were half of the total response interval in our EMS system. Measurement should incorporate these two intervals to accurately characterize and possibly reduce the professional response interval.

Keywords: Call-to-care interval; Curb-to-care interval; EMS; OHCA; Response intervals; Turnout interval.