Mandated 30-minute Scene Time Interval Correlates With Improved Return of Spontaneous Circulation at Emergency Department Arrival: A Before and After Study

J Emerg Med. 2019 Oct;57(4):527-534. doi: 10.1016/j.jemermed.2019.06.021. Epub 2019 Aug 28.


Background: Conflicting ideas exist about whether or not Emergency Medical Service (EMS) personnel should treat a cardiac arrest on scene or transport immediately.

Objective: Our aim was to examine patient outcomes before and after an urban EMS system implemented a protocol change mandating a 30-min scene time interval (STI) for out-of-hospital cardiac arrest (OHCA).

Methods: This was a retrospective, single-center, observational study of OHCA patients before and after an EMS protocol change mandating resuscitation on scene. Data were retrieved from an EMS cardiac arrest database for all adults with non-traumatic OHCA between January 2015 and August 2016. Descriptive statistics were used to summarize the study population, and a regression model was used to determine the associations of the protocol with the return of spontaneous circulation (ROSC).

Results: A total of 633 patients were included in the study population, which was primarily male (61.3%) with a mean age of 65 years. After the 30-min STI was implemented, ROSC from OHCA increased to 40.1% of cases compared to 27.3% before the protocol change (p = 0.001; 95% confidence interval [CI] 0.053-0.203). The STI increased from 19 min 23 s to 29 min 40 s in the pre and post periods, respectively (p < 0.001). Regression indicated that the protocol change was independently associated with an improved chance of ROSC (OR 1.81; 95% CI 1.23-2.64).

Conclusions: A protocol change mandating a 30-min STI in OHCA correlated with increased STI and increased ROSC. While increased ROSC may not always equate with positive neurologic outcome, logistic regression indicated that the protocol change was independently associated with improved ROSC at emergency department arrival.

Keywords: out-of-hospital cardiac arrest; return of spontaneous circulation; scene time interval.

Publication types

  • Observational Study

MeSH terms

  • Aged
  • Aged, 80 and over
  • Arkansas / epidemiology
  • Emergency Service, Hospital / organization & administration
  • Emergency Service, Hospital / statistics & numerical data
  • Female
  • Hospital Mortality / trends
  • Humans
  • Logistic Models
  • Male
  • Middle Aged
  • Out-of-Hospital Cardiac Arrest / epidemiology
  • Out-of-Hospital Cardiac Arrest / mortality*
  • Out-of-Hospital Cardiac Arrest / therapy
  • Resuscitation / methods
  • Resuscitation / standards*
  • Resuscitation / statistics & numerical data
  • Retrospective Studies
  • Time Factors*
  • Treatment Outcome