Randomized, blinded comparison of epinephrine and vasopressin for treatment of naturally occurring cardiopulmonary arrest in dogs.

Background: Administration of epinephrine during CPR is recommended for treatment of cardiopulmonary arrest (CPA) in dogs. Administration of epinephrine during CPR might be associated with deleterious adverse effects. Vasopressin has been studied for use in CPR as an alternative.
Hypothesis: That administration of vasopressin instead of epinephrine with standard CPR techniques will result in improved outcome.
Animals: Seventy-seven client-owned dogs identified in the ER/ICU with CPA were eligible for inclusion.
Methods: Randomized, prospective clinical study. Dogs were randomized to receive epinephrine (0.01-0.02 mg/kg) or vasopressin (0.5-1 U/kg) in a blinded fashion. Attending veterinarians were asked to adhere to standardized CPR protocol for the 1st 6 minutes of CPR, during which time doses of the study drug were administered at 3-minute intervals.
Results: A total of 60 dogs completed this study with 31 receiving epinephrine and 29 receiving vasopressin. Overall rate of return of spontaneous circulation (ROSC) was 60% (36/60), 32% (19/60) of dogs survived to 20 minutes, 18% (11/60) survived to 1 hour. No difference was seen in rates of ROSC between the 2 groups (P = .20). Dogs receiving epinephrine were more likely to survive to 1 hour (odds ratio 5.86; 95% CI: 1.19-28.95) than those receiving vasopressin (P = .027).
Conclusions and Clinical Importance: ROSC was similar in dogs receiving epinephrine or vasopressin. In this study, a survival advantage at 1 hour was seen in those animals receiving epinephrine. No advantage of routine use of vasopressin over epinephrine was detected. Further studies are required to examine subgroups of dogs that might benefit from specific interventions.
(Copyright © 2011 by the American College of Veterinary Internal Medicine.)