Objective: No evidence supports vasopressin over epinephrine in cardiac arrest; however animal and some clinical studies support their concurrent use. This systematic review compares the efficacy of vasopressin and epinephrine used together versus repeated doses of epinephrine alone in cardiac arrest.
Methods: We searched MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials. We included randomized controlled trials (RCTs) where vasopressin and epinephrine were administered concurrently to cardiac arrest patients within the half-life of vasopressin. Two reviewers assessed studies for eligibility, data extraction and quality. Appropriateness of studies for meta-analysis was assessed. The primary outcome was survival to hospital discharge and the secondary outcome was return of spontaneous circulation (ROSC).
Results: From 235 titles identified, we reviewed 29 abstracts. Three cardiac arrest studies were included (N=1226). Study 1 randomized vasopressin versus epinephrine then subsequent epinephrine. Study 2 randomized two doses of vasopressin versus epinephrine. Study 3 randomized vasopressin versus placebo, administered following initial epinephrine. All studies favored combination treatment for ROSC, but only study 2 was statistically significant (RR 1.42, 95% CI 1.14-1.77). Studies 1 and 2 reported survival to discharge, only study 2 was significant (RR 3.69, 95% CI 1.52-8.95). The methods for the three studies were too dissimilar to allow pooling of results.
Conclusion: This systematic review of the combination of vasopressin and epinephrine found trends towards better ROSC but equivocal effects on survival. At the present time, there is inadequate evidence to advocate the sequential use of vasopressin and epinephrine for cardiac arrest.