AIM: It is unclear whether prolonged resuscitation can result in successful outcome following out-of-hospital cardiac arrests (OHCA). We assessed associations between duration of pre-hospital resuscitation on survival and functional outcome following OHCA in patients achieving pre-hospital return of spontaneous circulation (ROSC).

METHODS: We included 1316 adult OHCA individuals with pre-hospital ROSC (2005-2011) handled by the largest nationwide ambulance provider in Denmark. Patients were stratified into 0-5, 6-10, 11-15, 16-20, 21-25 and >25min of cardiopulmonary resuscitation (CPR) by emergency medical services until ROSC was achieved. Nursing home admission and diagnosis of anoxic brain damage were measured as proxies of poor neurological/functional outcomes.

FINDINGS: Median time from CPR initiation to ROSC was 12min (IQR: 7-18) while 20.4% achieved ROSC after >25min. Overall, 37.5% (494) of the study population achieved 30-day survival. Thirty-day survival was inversely related to minutes of CPR to ROSC: ranging from 59.6% (127/213) for ≤5min to 13.8% (19/138) for >25min. If bystander initiated CPR before ambulance arrival, corresponding values ranged from 70.4% (107/152) to 21.8% (12/55). Of 30-day survivors, patients discharged to own home rather than nursing home ranged from 95.0% (124/127) to 84.7% (18/19), respectively. Of 30-day survivors, patients discharged without diagnosis of anoxic brain damage ranged from 98.4% (125/127) to 73.7% (14/19) for corresponding intervals.

CONCLUSION: Even those requiring prolonged resuscitation duration prior to ROSC had meaningful survival rates with the majority of survivors able to return to live in own homes. These data suggest that prolonged resuscitation is not futile.