Abstract
Midazolam, a new benzodiazepine was compared with diazepam as intraoperative sedative during spinal anaesthesia in a double blind study. Eighty five patients participated in this clinical trial (placebo 25, midazolam 30, diazepam 30). Drug treatment was administered after spinal anaesthesia at 5 min of supine position. Level of spinal anaesthesia in terms of sympathetic blocade was similar in all the patients. Dosage of drug were tailored to the needs of each patient till the end point of undisturbed sleep. Intraoperative sedation based on predetermined criteria, recovery by Trieger's test at 4 hr after the drug administration, antegrade amnesia by memory card and haemodynamics were assessed. Mean doses of 240 μg kg(-1) and 500 μg kg(-1) of midazolam and diazepam were required to induce sleep which suggest an equivalent dose ratio of midazolam: diazepam as 1: 2.1. Both the drugs produced effective sedation during spinal anaesthesia, 86.6% patient with midazolam and 93.3% patients with diazepam had deep undisturbed sleep. Clinical recovery was fast in midazolam administered patients but did not meet the criteria of early discharge by Trieger's test at 4 hr after the administration of the drug. There were no gross changes in the circulatory effects of the two drugs. Decrease in mean systolic pressure (<10%) and marginal increase in heart rate was seen. The frequency of antegrade amnesia was greater with midazolam. Global assessment as judged by anaesthesiologist and patients satisfaction for anaesthesia and recovery was higher (93.3%) with midazolam as compared to (79.9%) diazepam.