Six unpremedicated patients who had given their informed consent were given vecuronium 0.08 mg kg-1 before elective surgery. Recovery from neuromuscular blockade was measured electrically and mechanically. Neuromuscular blockade was antagonized 1 h after the administration of vecuronium with two doses of neostigmine 2.5 mg (three patients) or edrophonium 0.5 mg kg-1 (three patients). Although the onset of initial recovery was similar, subsequent recovery was faster when measured electrically (EMG) than when measured mechanically. Recovery appeared to be faster in younger patients. Reintroduction of neuromuscular blockade occurred after the second dose of neostigmine 2.5 mg, given to antagonize the block. This did not occur after either dose of edrophonium 0.5 mg kg-1.

SUMMARYOne hundred patients aged 5-13yr were randomly allocated to four groups in a double-blind study of premedication. Drugs studied were lorazepam, diazepam and trimeprazine. A placebo group was included. All the drugs appeared satisfactory as premedicants. Lorazepam induced the most sedation immediately after surgery, but by 4 h lorazepam and diazepam appeared similar. Lorazepam produced better amnesia than the other drugs. There were no untoward side-effects and no cardiorespiratory depression in any group. Lorazepam appears a suitable premedicant for children.Lorazepam has been used successfully as an oral premedicant in adult patients (Paymaster, 1976; Dundee et al., 1977). Its desirable properties include anxiolysis (Harry and Richards, 1972; Maleet al., 1980), anterograde amnesia (Wilson and Ellis, 1973;Pandit, Heisterkamp and Cohen, 1976), minimal effects on cardiovascular and respiratory systems (Cormack, Milledge and Harming, 1976;Dundee, Johnston and Gray, 1976) and the long duration of action makes the timing of premedication less crucial (Fragen and Caldwell, 1976).In children (Boyd and Manford, 1973;Richardson and Manford, 1979;Beeby and Morgan Hughes, 1980) it is now accepted that the administration of premedication by mouth is safe, effective and preferred by the patient (Doughty, 1959). Lorazepam has been studied in children (Mundeleer, 1980) and appeared satisfactory. However, no comparison was made with an established drug.In the present study we have compared, in children, lorazepam, diazepam, trimeprazine and placebo as oral premedicants. PATIENTS AND METHODSOne hundred patients aged 5-13 yr were studied. The operations performed were mainly plastic surgical procedures, ENT operations or minor general surgical procedures. Children were drawn from three wards. Day cases were not included, nor were

Antagonism of atracurium-induced neuromuscular blockade by neostigmine or edrophonium has been studied using the tetanic (50 Hz) and train-of-four (2 Hz) or single twitch responses of the adductor pollicis muscle in 22 anaesthetized patients. A further nine patients not given an anticholinesterase acted as a control group. In two groups (six patients for each anticholinesterase) in whom antagonism was attempted at 95-98% blockade of the tetanic response, recovery of the tetanic response after two or three doses of edrophonium 0.75 mg kg-1 i.v. was not statistically different from that in the control group; recovery after two doses of neostigmine 2.5 mg i.v. was significantly faster (P less than 0.001). Recovery of the single twitch response after antagonism with edrophonium, although longer than that with neostigmine (P less than 0.01), was significantly shorter than in the control group (P less than 0.05). When edrophonium is given at the commencement of recovery, the initial rapid antagonism of tetanic block is not sustained, whereas antagonism by neostigmine is more persistent and the recovery phase is significantly shortened. In a further two groups of patients (n = 5) given atracurium 0.3 mg kg-1 i.v., antagonism was not attempted until the peak height of the tetanic contraction had reached approximately 50% of the control value.(ABSTRACT TRUNCATED AT 250 WORDS)

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