SODIUM-BICARBONATE MAY IMPROVE OUTCOME IN DOGS WITH BRIEF OR PROLONGED CARDIAC-ARREST

Objective: Despite the absence of outcome evaluation, the use of sodiu m bicarbonate in cardiac arrest has declined based on advanced cardiac life-support guidelines, The effects of bicarbonate therapy on outcom e in a canine model of ventricular fibrillation cardiac arrest of brie f (5-min) and prolonged (15-min) duration were examined. Design: Prosp ective, randomized, controlled trial. Setting: Experimental animal lab oratory in a university medical center. Subjects: Thirty-two adult dog s, weighing 10 to 17 kg. Interventions: The animals were prepared with ketamine, nitrous oxide/oxygen, halothane, and pancuronium, Ventricul ar fibrillation was then electrically induced and maintained in arrest for 5 mins (n = 12) or 15 mins (n = 20), Canine advanced cardiac life -support protocols were instituted, including defibrillation, cardiopu lmonary resuscitation (CPR), and the administration of epinephrine (0. 1 mg/kg), atropine, and lidocaine, The bicarbonate group received 1 mm ol/kg of sodium bicarbonate initially, and base deficit was corrected to -5 mmol/L with additional bicarbonate, whereas acidemia was untreat ed in the control group, Cardiopulmonary values were recorded at inter vals between 5 mins and 24 hrs, and the neurologic deficit score was d etermined at 24 hrs after CPR. Measurements and Main Results: The trea tment group received an additional 2 to 3 mmol/kg of bicarbonate in th e early postresuscitation phase, Compared with controls, the bicarbona te group demonstrated equivalent (with brief arrest) or improved (with prolonged arrest) return of spontaneous circulation and survival to 2 4 hrs, with lessened neurologic deficit, The acidosis of arrest was de creased in the prolonged arrest group without hypercarbia, Improved co ronary and systemic perfusion pressures were noted in the bicarbonate group with prolonged arrest, and the epinephrine requirement for retur n of spontaneous circulation was decreased. Conclusions: The empirical administration of bicarbonate improves the survival rate and neurolog ic outcome in a canine model of cardiac arrest.