A comparison of two anaesthetic techniques for daycase arthroscopy

A randomised, double-blind study of 100 patients admitted for daycase arthroscopy was undertaken. Fifty patients received alfentanil 500 micrograms and midazolam 5 mg, and 50 received alfentanil 500 micrograms alone, in each case 2 minutes before induction of anaesthesia with methohexitone. Anaesthesia was maintained in both groups with nitrous oxide, oxygen and enflurane. Recovery was assessed quantitatively by measuring time to when they awoke and by a comparison of pre- and postoperative performance of p-deletion and postbox tests. Qualitative assessment of recovery and of postoperative pain was also undertaken. Patients completed a questionnaire to record the incidence of any anaesthetic-related symptoms on the first and second postoperative days. Patients who received midazolam required a reduced dose of methohexitone but their initial recovery time was prolonged significantly. The incidences of anaesthetic-related side effects and postoperative pain were similar in the two groups and while the questionnaires did not reveal any statistically significant differences in symptoms on the first 2 postoperative days, the results indicated that patients who received a larger induction dose of methohexitone were subjectively drowsier on the first day after operation.