Analysis of Prehospital Scene Time and Survival from Out-of-Hospital, Non-Traumatic, Cardiac Arrest

The purpose of this study was to determine whether shorter prehospital scene time (ST) is associated with an increased survival rate in non-traumatic, out-of-hospital, cardiac arrest (CA) in a medium-sized, metropolitan EMS system. Information was retrieved for all adult victims (age ≥18 years) of CA treated and transported by a metropolitan fire department over a 16-month period (6/87-9/88). Data were retrieved from the fire department's database, hospital records, and death certificates. Statistical analysis of continuous variables was performed using the two-tailed, Student's t-test and non-parametric evaluations were performed by chi-square analysis with p<0.05 considered significant. Two hundred ninety-eight cases were recorded of which 293 patients (98.3%) had documented ST (study group). Seventy-nine patients (27.0%) had ST <12 minutes, while 214 (73.0%) had ST≥12 minutes. Patients with ST <12 minutes were more likely to have return of spontaneous circulation in the field (26.6% vs. 15.9%, p<0.05) and also were more likely to survive than were patients with ST ≥12 minutes (13.9% vs. 6.5%, p<0.05). Mean ST for survivors was significantly less than for non-survivors (12.8 vs. 15.3 min., p<0.05). We conclude that, in our system, adult victims of CA with ST <12 minutes are more likely to survive than are patients with longer ST. In addition, the mean ST for survivors is shorter than for non-survivors. It remains unclear whether shorter ST actually has an impact on survival or is merely a reflection of a sub-group with rapid resuscitation and consequently a higher likelihood of survival. Future investigations are needed to determine whether shorter ST actually impacts the likelihood of survival from CA.