Relation between middle ear pressure changes and postoperative nausea and vomiting in pediatric strabismus surgery

Study ObjectiveTo investigate the effects of tympanometric changes on the frequency of postoperative nausea and vomiting (PONV).DesignProspective, observational study.SettingUniversity hospital.Patients49 ASA physical status I, nonpremedicated children undergoing elective strabismus surgery.InterventionsFrequency of PONV was assessed at various time intervals (0-2, 2-6, and 6-24 hours) with a 4-point scale (0, no nausea; 1, nausea but no vomiting; 2, one episode of vomiting; 3, two or more episodes of vomiting), and correlation with tympanometric data was investigated.MeasurementsTympanogram was obtained before induction of standardized anesthesia and after full recovery. Fourteen (28.6%) patients had nausea, and 10 (20.4%) patients vomited. The tympanic gradient, compliance, and pressure values were found to be significantly higher in postoperative measurements than their preoperative counterparts (P < 0.05). The volumes of both ears increased postoperatively, but these differences were not statistically significant (P > 0.05). Changes in middle ear pressure, volume, compliance, and gradient did not correlate with PONV (P > 0.05).ConclusionsGradient, compliance, volume, and pressure changes in middle ears were not found to be related to the frequency of nausea and vomiting after strabismus surgery.