Do oxygen consumption and carbon dioxide production affect cardiac output after cardiopulmonary bypass?
This study examines the oxygen consumption (VO2) and carbon dioxide production (VCO2) occurring before, during, and after cardiopulmonary bypass (CPB) and whether they correlate with changes in cardiac output. Twenty-three patients undergoing open heart surgery were studied. Group 1 (N = 11) received fentanyl citrate, 50 micrograms/kg, intravenously during the induction of anesthesia. Group 2 (N = 12) received 100 micrograms/kg of fentanyl citrate intravenously. We measured VO2, VCO2, as well as hemodynamic and biochemical factors. Initial statistical analyses failed to show any differences in the VO2, VCO2, hemodynamic, or biochemical factors between groups 1 and 2. Therefore, the data from both groups were combined. In comparing the average (for all data) of the post-CPB with the pre-CPB periods in both groups for the metabolic factors, there were 9.0%, 11.5%, and 2.4% increases in the VO2, VCO2, and respiratory quotient, respectively. There was an 80% increase in total serum lactate
