Euthanasia of small animals with nitrogen; comparison with intravenous pentobarbital

Intravenous pentobarbital (with or without addition of saturated potassium chloride) was compared with nitrogen gas exposure for euthanasia of small animals (dogs, cats, and rabbits) in a humane society environment. Initially, electrocardiographic) and electroencephalographic monitoring were used to establish the time of death in presedated animals given either pentobarbital or exposed to nitrogen; later, nitrogen euthanasia alone was studied. Sedation with acepromazine delayed the effects of nitrogen exposure. Addition of intravenous potassium chloride dramatically enhanced the effects of pentobarbital. When sedation was omitted, nitrogen was quantitatively as effective as pentobarbital alone. An adequate flow of nitrogen is essential and the concentration of oxygen in the euthanasia chamber must be monitored.