Time of on-scene resuscitation in out of-hospital cardiac arrest patients transported without return of spontaneous circulation

Background: In out-of-hospital cardiac arrest (OHCA), return of spontaneous circulation (ROSC) on scene occurs only in a minority of patients. The optimal duration of resuscitation on scene before transport with ongoing cardiopulmonary resuscitation (CPR) is unknown. Purpose: To determine the time of resuscitation on scene ('time on scene') and survival in patients transported with ongoing CPR in the Netherlands. Methods: Data on OHCA patients (>18 years) without ROSC on scene, where resuscitation was started between January 1, 2012 and December 31, 2016 in the Amsterdam Resuscitation Study (ARREST) database were analyzed. Time on scene was related to 30-day survival. Results: Of the 5871 OHCA patients where resuscitation was started, 2437 did not achieve ROSC on scene. Of these, 655 patients were transported with ongoing CPR and 606 (93%) had complete rhythm data. At the moment of transport, 199 (33%) patients had a shockable rhythm, 299 (49%) pulseless electrical activity (PEA) and 108 (18%) asystole as rhythm. Twenty-nine patients (4%) were alive at 30 days. Patients who survived 30 days had a higher proportion of a shockable first monitored rhythm (89% vs. 52%, p < 0.001). Survivors had a significantly shorter time on scene (20 min vs. 26 min, p = 0.004), with the highest survival rate (8%) in patients transported within 20 min. In a multivariable model time on scene (OR 0.94; 95% CI 0.89-0.99) was independently associated with 30-day survival. Conclusion: In OHCA patients transported with ongoing CPR the survival rate significantly declines when time on scene increases.