Abstract: | The relationship between changes in wholebody O2 consumption (VO2) and cardiovascular dynamics during changing levels of N2O-fentanyl and N2O-thiopental anesthesia was determined in 24 dogs. Dose-dependent reductions in VO2, mean blood pressure, and cardiac output occurred with infusion of fentanyl and thiopental. Painful stimuli increased VO2 during light anesthesia but not during deeper levels of anesthesia. Deep levels of N2O-fentanyl and N2O-thiopental anesthesia may protect the patient with limited cardiac reserve by reducing VO2 and preventing increases in VO2 caused by painful stimuli. |