Abstract
PURPOSE: Current practice in organ donation after death determination by circulatory criteria (DCD) advises a five-minute observation period following circulatory arrest, monitoring for unassisted resumption of spontaneous circulation (i.e., autoresuscitation). In light of newer data, the objective of this updated systematic review was to determine whether a five-minute observation time was still adequate for death determination by circulatory criteria. SOURCE: We searched four electronic databases from inception to 28 August 2021, for studies evaluating or describing autoresuscitation events after circulatory arrest. Citation screening and data abstraction were conducted independently and in duplicate. We assessed certainty in evidence using the GRADE framework. PRINCIPAL FINDINGS: Eighteen new studies on autoresuscitation were identified, consisting of 14 case reports and four observational studies. Most studies evaluated adults (n = 15, 83%) and patients with unsuccessful resuscitation following cardiac arrest (n = 11, 61%). Overall, autoresuscitation was reported to occur between one and 20 min after circulatory arrest. Among all eligible studies identified by our reviews (n = 73), seven observational studies were identified. In observational studies of controlled withdrawal of life-sustaining measures with or without DCD (n = 6), 19 autoresuscitation events were reported in 1,049 patients (incidence 1.8%; 95% confidence interval, 1.1 to 2.8). All resumptions occurred within five minutes of circulatory arrest and all patients with autoresuscitation died. CONCLUSION: A five-minute observation time is sufficient for controlled DCD (moderate certainty). An observation time greater than five minutes may be needed for uncontrolled DCD (low certainty). The findings of this systematic review will be incorporated into a Canadian guideline on death determination. STUDY REGISTRATION: PROSPERO (CRD42021257827); registered 9 July 2021.