The Cardiac Output and Oxygen Consumption of Nine Surgical Patients Before and After Operation 1

The effects of anesthesia and operation on the circulation and metabolic rate of man have not been accurately determined. A few studies of cardiac output and oxygen consumption have been reported in relation to surgical procedures, but the evidence is incomplete and inconclusive. Polano (1), using Broemser's method (2), has interpreted his data as indicating an increase in cardiac output in the immediate postoperative period. Rehn (3), with the same technic, has described a decrease in cardiac output postoperatively in those patients who show signs of shock and collapse. Broemser's method has been criticized on theoretical grounds (4). Altschule and Volk (5), using the ethyl iodide method, have described the changes in cardiac output and oxygen consumption which accompany total thyroidectomy, but they present no data for the immediate postoperative period. Blalock and his coworkers have found that trauma and hemorrhage (acute ex- periments) depress the cardiac output of dogs (6); that etherization produces an increase in cardiac output and a slight decrease in oxygen consumption; and that under very deep anesthesia the cardiac output returns to normal or is decreased (7).