Comparison of the effects of sevoflurane and isoflurane on arterial oxygenation during one lung ventilation

We have compared the effects of sevoflurane and isoflurane on arterial oxyg enation, heart rate and mean arterial pressure during one lung anaesthesia in a prospective, crossover study. We studied 28 patients undergoing oesoph agogastrectomy, allocated alternately to one of two groups. Patients in gro up I/S (n=14) received 1 MAC (1.1%) of isoflurane in oxygen from induction until the end of 30 min of open chest one lung ventilation (OLV) in the lat eral position. This was followed by 1 MAC (2.1%) of sevoflurane in oxygen f or the next 30 min of OLV. Patients in group S/I (n=14) received the two an aesthetic agents in the reverse order. We found no significant difference i n arterial oxygenation, heart rate or mean arterial pressure between the tw o potent inhalation agents. In the subgroup of patients with pulmonary arte ry catheters (n=12), we found a significant increase (P<0.05) in derived sh unt during sevoflurane anaesthesia. There was no significant difference in mixed venous saturation and cardiac output. We conclude that during one lun g ventilation, the choice between sevoflurane and isoflurane did not signif icantly influence arterial oxygenation.