Abstract
The effects of midazolam sedation on the level of spinal anesthesia were investigated by using both cold-sensation and pin-prick tests in 40 patients. After spinal anesthesia, 0.05mg•kg-1 of midazolam was administered intravenously for intraoperative sedation. After surgery, block levels were evaluated twice: under midazolam sedation and 4 min after intravenous injection of either flumazenil, 0.2mg (n=20) or saline 1ml (n= 20). Blood concentrations of midazolam were measured after surgery in the flumazenil group. In the flumazenil group, 10 of 20 patients (50%) showed a change in anesthetic level at more than one segment 4 min after flumazenil injection. In contrast, only 1 of 20 patients (5%) showed a change in anesthetic level in the control group 4 min after saline injection. There was no significant relationship between the changes in anesthetic level and blood concentrations of midazolam. It is concluded that midazolam may affect the level of spinal anesthesia. This must be borne in mind when treating patients with high spinal anesthesia.
