Purpose: Korean national emergency care protocol for EMS providers recommends a minimum of 5 minutes of on-scene resuscitation before transport to hospital in cases of Out-of-Hospital Cardiac Arrest (OHCA). We compared survival outcome of OHCA patients according to scene time interval (STI)-protocol compliance of EMS.
Methods: EMS treated adult OHCAs with presumed cardiac etiology during a two-year period were analyzed. Non-compliance was defined as hospital transport with STI less than 6 minutes without return of spontaneous circulation (ROSC) on scene. Propensity score for compliance with protocol was calculated and based on the calculated propensity score, 1:1 matching was performed between compliance and non-compliance group. Univariate analysis as well as multivariable logistic model was used to evaluate the effect of compliance to survival outcome.
Results: Among a total of 28,100 OHCAs, EMS transported 7,026 (25.0%) cardiac arrests without ROSC on the scene with an STI less than 6 minutes. A total of 6,854 cases in each group were matched using propensity score matching. Overall survival to discharge rate did not differ in both groups (4.6% for compliance group vs. 4.5 for non-compliance group, p = 0.78). Adjusted odds ratio of compliance for survival to discharge were 1.12 (95% CI 0.92-1.36). More patients with favorable neurological outcome was shown in compliance group (2.5% vs. 1.7%, p < 0.01) and adjusted odds ratio was 1.91 (95% CI 1.42-2.59).
Conclusions: Although survival to discharge rate did not differ for patient with EMS non-compliance with STI protocol, lesser patients survived with favorable neurological outcomes when EMS did not stay for sufficient time on scene in OHCA before transport.
Keywords: EMS; cardiac arrest; epidemiology; outcome; scene time.