Acidosis has been observed to develop in both animals and humans while undergoing total cardiopulmonary by-pass.1-4 The present study was designed to elucidate the etiology and type of acidosis encountered.
Data were obtained during total body perfusions of 76 healthy, adult, mongrel dogs of average weight 18.9 kg. (range, 11.9-35.7). The animals were used without special preoperative preparation. Thiamylal (Surital, Parke-Davis) sodium, 12.5 mg. per kilogram of body weight, intravenously, was used to anesthetize both experimental and blood donor dogs. Ventilation was accomplished mechanically with intermittent positivepressure air and endotracheal intubation.The right hemothorax was entered through the periosteal bed of the previously resected fifth rib. The superior vena cava was cannulated via the azygos vein and the inferior vena cava via the right atrial appendage with No. 22 polyvinyl catheters. The cavae were encircled with umbilical cord tape tourniquets. The superficial femoral artery was cannulated in