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

Abstract

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 experiments) 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).To determine more definitely the cardiac output and oxygen consumption of human subjects in relation to general surgical procedures, studies have been undertaken on hospital patients before operation, during recovery from anesthesia, and at suitable intervals thereafter. A. Ethyl iodide analysis in presence of ether vapor The effect of ether vapor on the analysis of ethyl iodide by Cool's method (10) was determined by the following experiments.A solution of ethyl iodide was prepared by breaking an ampule containing a known weight of redistilled ethyl iodide under the surface of the solute in a partly filled, calibrated liter flask. Fifty per cent ethyl alcohol was found to dissolve the ethyl iodide more rapidly than water and did not affect the results. This solution was pipetted directly into bromine water to compare the accuracy of this method for determining ethyl iodide with Cool's data. Differences between amounts of ethyl iodide expected and amounts obtained were 0.7, 0.1, and 0.1 per cent of the amount present. Double-ended glass sampling tubes, 500 cc. capacity, were charged with ether vapor, 6 to 8 volumes per cent. The solution of ethyl iodide was pipetted into these tubes which were subjected to Cool's procedure. The discrepancy between amounts expected and obtained was 0.6 and 0.4 per cent in two experiments. These differences are of the same order of magnitude as those described by Cool. Additional experiments conducted with titration bottles (see (9), Section II) and known concentrations of ethyl iodide vapor in the presence of ether gave similar results. Ether vapor was therefore considered to have no appreciable effect on the analysis of small amounts of ethyl iodide by the iodate method. (The presence of ether vapor causes a return of the blue color a few minutes after a titration has been completed, so that uniformity of procedur...

The Effects of the Patent Ductus Arteriosus on the Circulation 1

“…It is known that the output of the heart may be altered by various anesthetic agents. Regarding ether, Blalock (18) has studied the problem in dogs by one method and Snyder (19) in humans by another. It appears that at moderate levels of surgical anesthesia, there is an increase in the cardiac output while, at deeper levels an actual decrease may occur.…”