One-lung anesthesia--a comparison of pulmonary gas exchange during anesthesia with ketamine or enflurane

Twenty-four men undergoing elective pulmonary resection with a period of one-lung ventilation were studied to compare the effects of ketamine-O2 and enflurane-O2 anesthesia on arterial oxygen tension (PaO2) and intrapulmonary shunting (Qs/Qt). No statistically significant differences were demonstrated between ketamine and enflurane in mean peak Qs/Qt, 43% and 42%, respectively, or minimum PaO2 values, 169 torr and 127 torr, respectively. Stroke volume index, left ventricular stroke work index, and cardiac index were, however, significantly greater with ketamine. No emergence hallucinations were observed in either group. These findings suggest that ketamine affords no advantage over enflurane anesthesia in terms of Qs/Qt, and arterial oxygen desaturation during endobronchial anesthesia.