Time to Return of Spontaneous Circulation and Survival: When to Transport in out-of-Hospital Cardiac Arrest?

In out-of-hospital cardiac arrest (OHCA), 10-50% of patients have return of spontaneous circulation (ROSC) before hospital arrival. It is important to investigate the relation between time-to-ROSC and survival to determine the optimal timing of transport to the hospital in patients without ROSC. We analyzed data of OHCA patients with a presumed cardiac cause (excluding traumatic and other obvious non-cardiac causes) and ROSC before hospital arrival from the Amsterdam Resuscitation Study (ARREST) database. ROSC included those patients whose ROSC was persistent or transient before or during transport, lasting ≥1 min. Of these data, we analyzed the association between the time of emergency medical services (EMS) arrival until ROSC (time-to-ROSC) and 30-day survival. Of 3632 OHCA patients with attempted resuscitation, 810 patients with prehospital ROSC were included. Of these, 332 (41%) survived 30 days. Survivors had a significant shorter time-to-ROSC compared to non-survivors of median 5 min (IQR 2,10) vs. median 12 min (IQR 9,17) (p < 0.001). Of the survivors, 90% achieved ROSC within 15 min compared to 22 min of non-survivors. In a multivariable model adjusted for known system determinants time-to-ROSC per minute was significantly associated with 30-day survival (OR 0.89; 95%CI 0.86-0.91). A ROC curve showed 8 min as the time-to-ROSC with the best test performance (sensitivity of 0.72 and specificity of 0.77). In OHCA patients with prehospital ROSC survival significantly decreases with increasing time-to-ROSC. Of all patients, 90% of survivors had achieved ROSC within the first 15 min of EMS resuscitation. The optimal time for the decision to transport is between 8 and 15 min after EMS arrival.