Survival with full neurologic recovery and no cerebral pathology after prolonged cardiopulmonary resuscitation with vasopressin in pigs.

OBJECTIVES: We sought to determine the effects of vasopressin and saline placebo in comparison with epinephrine on neurologic recovery and possible cerebral pathology in an established porcine model of prolonged cardiopulmonary resuscitation (CPR).
BACKGROUND: It is unknown whether increased cerebral blood flow during CPR with vasopressin is beneficial with regard to neurologic recovery or detrimental owing to complications such as cerebral edema after return of spontaneous circulation.
METHODS: After 4 min of cardiac arrest, followed by 3 min of basic life support CPR, 17 animals were randomly assigned to receive every 5 min either vasopressin (0.4, 0.4 and 0.8 U/kg; n = 6), epinephrine (45, 45 and 200 microg/kg; n = 6) or saline placebo (n = 5). The mean value +/- SEM of aortic diastolic pressure was significantly (p < 0.05) higher 90 s after each of three vasopressin versus epinephrine versus saline placebo injections (60 +/- 3 vs. 45 +/- 3 vs. 29 +/- 2 mm Hg; 49 +/- 5 vs. 27 +/- 3 vs. 23 +/- 1 mm Hg; and 50 +/- 6 vs. 21 +/- 3 vs. 16 +/- 3 mm Hg, respectively). After 22 min of cardiac arrest, including 18 min of CPR, defibrillation was attempted to achieve return of spontaneous circulation.
RESULTS: All the pigs that received epinephrine and saline placebo died, whereas all pigs on vasopressin survived (p < 0.05). Neurologic evaluation 24 h after successful resuscitation revealed only an unsteady gait in all vasopressin-treated animals; after 96 h, magnetic resonance imaging revealed no cerebral pathology.
CONCLUSIONS: During prolonged CPR, repeated vasopressin administration, but not epinephrine or saline placebo, ensured long-term survival with full neurologic recovery and no cerebral pathology in this porcine CPR model.