Fig. 2. Patients in group C (epidural saline–intravenous saline) moving or not moving in response to tetanic electrical stimulation at predetermined end-tidal sevoflurane concentrations. When a patient did not move in response to tetanic electrical stimulation, an “x” was recorded and the sevoflurane concentration was decreased by 0.2% in the following patient. When the patient did move in response to tetanic electrical stimulation, an “o” was recorded, and the sevoflurane concentration was increased by 0.2% in the following patient. Minimum alveolar concentration (MAC) values are calculated by the up-and-down method and are reported with 95% CI.