CRD Summary: This review assessed the efficacy of vasopressin compared with epinephrine for the treatment of sudden cardiac arrest. The author concluded that vasopressin conferred no survival benefit, but should be considered a safe and appropriate alternative treatment. However, the reporting of the review process was poor and no validity assessment was conducted, so the reliability of the conclusion is unclear.

CRD Commentary: The review assessed a clear question and had clearly defined inclusion criteria. The author searched some relevant databases, but his decision to limit the review to peer-reviewed studies might have increased the possibility that some relevant studies were not included in the review, particularly as he did not report assessing publication bias. The author did not report using methods designed to reduce bias and error when selecting studies for the review or extracting the data, nor did he report a formal assessment of validity. In addition, only limited characteristics of the included studies were reported. The decision to use meta-analysis appears appropriate given the clinical homogeneity of the included studies, but the statistical methods used were poorly reported and there was no apparent assessment of statistical heterogeneity. The author's conclusion and recommendations appear appropriate given the evidence presented but, given the lack of a validity assessment and the poor reporting of review methodology, their reliability cannot be established