[The effect of midazolam on the memory during cesarean section and the modulation by flumazenil]

In 30 patients (ASA-1) for elective Cesarean section who had given informed consent, characteristics of amnesia induced by midazolam (M) and their modulation by flumazenil (F) were examined. Spinal anesthesia was performed with dibucaine. After the delivery, the baby was shown to the mother. Then 21 patients were given bolus intravenous injection of M until the patient got into sleep and the inhalation of nitrous oxide mixed with oxygen was started. At the end of surgery bolus injection of F 0.1 mg was cumulatively repeated until the patient awoke. Nine patients were given only nitrous oxide and oxygen inhalation after the delivery. The remembrance of the baby face and the doses of M and F were compared. In group given M, 14 patients recalled their baby's face whereas 7 did not. The average doses of M and F in patients with memory were 69 micrograms.kg-1 and 2.5 micrograms.kg-1, respectively, whereas the average dose of M and F in patients without memory were 94 micrograms.kg-1 and 4.2 micrograms.kg-1, respectively. In the patients without M injection, all could recall the face of the baby. These results suggest that M could produce retrograde amnesia, when combined with nitrous oxide inhalation, which is not reversed by F.