A systematic review of autoresuscitation after cardiac arrest.

OBJECTIVE: There is a lack of consensus on how long circulation must cease for death to be determined after cardiac arrest. The lack of scientific evidence concerning autoresuscitation influences the practice of organ donation after cardiac death. We conducted a systematic review to summarize the evidence on the timing of autoresuscitation. DATA SOURCES: Electronic databases were searched from date of first issue of each journal until July 2008. STUDY SELECTION: Any original study reporting autoresuscitation, as defined by the unassisted return of spontaneous circulation after cardiac arrest, was considered eligible. Reports of electrocardiogram activity without signs of return of circulation were excluded. DATA EXTRACTION: For each study case, we extracted patient characteristics, duration of cardiopulmonary resuscitation, terminal heart rhythms, time to unassisted return of spontaneous circulation, monitoring, and outcomes. DATA SYNTHESIS: A total of 1265 citations were identified and, of these, 27 articles describing 32 cases of autoresuscitation were included (n = 32; age, 27-94 yrs). The studies came from 16 different countries and were considered of very-low quality (case reports or letters to the editor). All 32 cases reported autoresuscitation after failed cardiopulmonary resuscitation, with times ranging from a few seconds to 33 mins; however, continuity of observation and methods of monitoring were highly inconsistent. For the eight studies reporting continuous electrocardiogram monitoring and exact times, autoresuscitation did not occur beyond 7 mins after failed cardiopulmonary resuscitation. No cases of autoresuscitation in the absence of cardiopulmonary resuscitation were reported.
CONCLUSIONS: These findings suggest that the provision of cardiopulmonary resuscitation may influence autoresuscitation. In the absence of cardiopulmonary resuscitation, as may apply to controlled organ donation after cardiac death after withdrawal of life-sustaining therapies, autoresuscitation has not been reported. The provision of cardiopulmonary resuscitation, as may apply to uncontrolled organ donation after cardiac death, may influence observation time. However, existing evidence is limited and is consequently insufficient to support or refute the recommended waiting period to determine death after a cardiac arrest, strongly supporting the need for prospective studies in dying patients.