BACKGROUND: It is stated that spinal anesthesia may alter susceptibility to the soporific effects of sedatives. In the geriatric patients who are susceptible to midazolam, the adequate dosage of midazolam for sedation was evaluated in spinal anesthesia.

METHODS: ASA 1 or 2 50 elderly patients (over 65 years old) who were scheduled for lower abdominal or extremities operations, were randomly assigned into two groups. Midazolam 0.01 mg/kg was administered every 5 minutes until becoming sedated before general anesthesia in the control group, while 0.01 mg/kg was administered every 5 minutes after stabilized for 15 minutes after spinal anesthesia in the study group.

RESULTS: It took 15 ± 5.0 minutes for the control group to fall asleep while the spinal anesthesia group showed significantly less time with 11 ± 4.2 minutes. The total amount of midazolam administered were 1.5 ± 0.6 mg in the control group and 1.2 ± 0.5 mg in the study group, which showed no significance. However, the amount of midazolam compared with the body weight revealed 0.031 mg in the control group and 0.023 mg in the spinal anesthesia group suggesting significantly decreased dosage in the study group.

CONCLUSIONS: Midazolam revealed significant sensitivity as well as sedative susceptibility in the elderly patients who underwent spinal anesthesia. Therefore, the dosage titration of midazolam for the elderly patients in spinal anesthesia should be carefully considered.