We included 9 studies with a total of 13,150 patients. Three studies included only patients with an out-of-hospital cardiac arrest. There was marked between-study heterogeneity with respect to blood pressure definition (MAP vs. systolic), exposure duration and modelling (dichotomous vs. continuous). All studies examined either mortality or neurological status as an outcome. Seven of nine studies demonstrated that higher blood pressure was associated with improved outcomes either by an association between higher MAP and good neurologic outcome or the presence of hypotension and increased odds of mortality