Delayed return of spontaneous circulation (the Lazarus phenomenon) after cessation of out-of-hospital cardiopulmonary resuscitation

Introduction: The delayed return of spontaneous circulation (ROSC) after cessation of cardiopulmonary resuscitation (CPR), also known as the Lazarus phenomenon, is a rare event described in several case reports. This study aims to determine the incidence and the time of occurrence of the Lazarus phenomenon after cessation of out-of-hospital CPR.

Methods: This prospective observational cohort study was conducted in the Helsinki Emergency Medical Service in Finland from 1 January 2011 through 31 December 2016. All out-of-hospital CPR attempts were carefully monitored for 10min after the cessation of CPR in order to detect delayed ROSC.

Results: Altogether, 2102 out-of-hospital cardiac arrests occurred during the six-year study period. CPR was attempted in 1376 (65.5%) cases. In 840 cases (61.0% of all attempts) CPR attempts were terminated on site. The Lazarus phenomenon occurred five times, with an incidence of 5.95/1000 (95% CI 2.10-14.30) in field-terminated CPR attempts. Time to delayed ROSC from the cessation of CPR varied from 3 to 8min. Three of the five patients with delayed ROSC died at the scene within 2-15min while two died later in hospital within 1.5 and 26h, respectively.

Conclusions: We observed that the Lazarus phenomenon is a real albeit rare event and can occur a few minutes after the cessation of out-of-hospital CPR. We suggest a 10-min monitoring period before diagnosing death. CPR guidelines should be updated to include information of the Lazarus phenomenon and appropriate monitoring for it.