1 A new imidazo‐pyridine hypnotic (zolpidem 10 mg and 20 mg) was compared with placebo as premedication before general anaesthesia in female patients undergoing minor gynaecological surgery. Efficacy and tolerance before and after anaesthesia were assessed. Psychomotor testing was used to study recovery from anaesthesia. 2 Both doses of zolpidem produced good sedation pre‐operatively but only the higher dose was associated with anterograde amnesia. 3 Premorbid anxiety scores were low in the group of patients studied and were unaffected by either dose of zolpidem. 4 There were no significant effects on the course of anaesthesia. However, postoperatively there was a tendency for wake‐up to be delayed in those patients who received either dose of zolpidem. 5 Postoperative recovery, as indicated by tests of psychomotor performance, was noticeably delayed with a dose of 20 mg compared with placebo whilst psychomotor performance had returned towards baseline levels 3 h after wake‐up in those patients who had received placebo. The zolpidem 10 mg group was intermediate. 6 Zolpidem may be a suitable premedicant when hypnosis and amnesia only are required.

This study was designed to evaluate the usefulness of three commonly used tests of psychomotor function and one test of short-term memory in assessing recovery from a brief nitrous oxide, oxygen and halothane anaesthetic. Twenty-six female patients undergoing minor gynaecological surgery were allocated to one of three treatment groups depending on premedication (placebo, low dose and high dose). Immediate recovery was most rapid in the placebo group. Both the tests of simple reaction time and picture recall were able to differentiate between the post-anaesthetic recovery of the high-dose group and that of the other two groups. Neither component of the letter cancellation test showed a clear difference in recovery pattern. Tests of critical flicker fusion were too unreliable to be of use in clinical decision making. Our results suggest that tests of reaction time and memory were more sensitive than letter cancellation in assessing recovery.

The characteristics of the train-of-four (TOF) response have been studied electromyographically during the onset and the spontaneous offset of neuromuscular blockade induced with vecuronium or gallamine. During the onset of blockade, at 75% depression of initial twitch height, gallamine was associated with significantly more TOF fade than vecuronium. Both agents were associated with significantly less fade during onset than during spontaneous offset. When the two neuromuscular blocking drugs were compared during spontaneous offset they showed a similar degree of fade during early offset (up to 50% recovery of initial twitch height). However, during late spontaneous offset, when the initial twitch height had recovered to 75% of control values, vecuronium was associated with more fade than gallamine.

The ability to evoke reversal of dense vecuronium- and pancuronium-induced paralysis (T1 10% of control) with edrophonium 1.0 mg.kg-1 was studied using train-of-four nerve stimulation and electromyographic monitoring. Two different end-points, train-of-four ratios of 0.5 and 0.7, were used to define "adequate reversal", and the results for both relaxants were compared. Reversal was reliable and rapid for vecuronium if either ratio was used with times of 2.8 (1.5) and 9 (3) min required to achieve ratios of 0.5 and 0.7, respectively. However, if the block was due to pancuronium, reversal was unreliable with 2 of 9 and 4 of 9 patients not achieving ratios of 0.5 and 0.7, respectively. Reversal was also markedly prolonged in this group with a mean time of 37 (23) min to achieve a ratio of 0.7, and in almost half these patients a supplementary dose of edrophonium was required.