[The use of low dose midazolam for the management of spinal anesthesia].

The present study was designed to evaluate the effects of low dose midazolam (MZ) on memories and ease of management of spinal anesthesia. MZ was administered to 103 patients (ASA 1-2), of whom 50 patients were premedicated with atropine sulfate 0.5mg and pethidine hydrochloride (group P), with 53 patients receiving no premedication (group nP). A double blind randomized trial was conducted with the dose of MZ (0, 0.01, 0.02, 0.04, 0.08 mg.kg-1), and MZ was administered i.v. to patients just prior to spinal puncture. The short-term and long-term memories were impaired after administration of MZ in both groups. But the recovery from impairment of memories was more rapid in the short-term memory than in the long-term memory, suggesting that MZ impairs mainly the acquisition of memories. A dose-dependent decrease in SpO2 was observed in group P. We conclude that MZ is a useful drug to relieve anxiety of patients during surgery, but it accompanies the risk of respiratory depression.