Effect of sevofl urane versus isoflurane on middle ear pressureduring tonsillectomy operation

Background Increase in middle ear pressure (MEP) (mmHO) is an undesirable condition because of its potential complications. The aim of this randomized study was to compare the effects of isoflurane and sevoflurane on MEP.Patients and methodsPatients in American Society of Anesthesiologists (ASA) group I–II between 6 and 14 years of age undergoing tonsillectomy operation were randomized into two groups. Group 1 received isoflurane and group 2 received sevoflurane for maintenance of anesthesia after induction with thiopental and suxamethonium in both groups. MEPs were measured and recorded 1 day before the operation (T0), with the patient lying supine on the operating table (T1), after the induction of anesthesia and endotracheal intubation (T2), and soon after withdrawal of anesthesia (T3). Finally, MEP values were compared intragroup with the baseline value (T0) and between groups.ResultsIn comparison with the baseline value in T0, MEP was significantly increased in T1, T2, and T3 in the two groups. There were no differences between groups at all times, but at the end of anesthesia at T3, the increase in MEP was significantly lower in group 1 (isoflurane group) than in group 2 (sevoflurane groups) (103 ± 68 vs. 138 ± 99, P 0.01 in the right ear and 112 ± 82 vs. 141 ± 101, P 0.01 in the left ear).ConclusionThere was an increase in MEP after anesthesia with both the inhalational anesthetics, but the increase in MEP was significantly lower during isoflurane anesthesia, which makes it moresuitable during middle ear surgery.