Recovery from day-case anaesthesia. The effect of different inhalational anaesthetic agents

Sixty unpremedicated patients undergoing dilatation and curettage were allocated randomly to receive one of three inhalational agents (halothane, enflurane or isoflurane) to supplement 67% nitrous oxide in oxygen after induction of anaesthesia with methohexitone. Recovery was assessed by the time patients took to open their eyes, to give their correct date of birth, to regain their pre-operative level of manipulative skill with a children's postbox toy, and by comparing pre-operative and postoperative performance of a paper and pencil test (the p-deletion test). There was no difference in the time to open eyes or to regain their pre-operative score with the postbox whether the patients received halothane, enflurane or isoflurane. Patients in the isoflurane group took longer than patients in the enflurane group to give their correct date of birth, but they performed better in the p-deletion test postoperatively, completing more lines with the same number of errors. Patients receiving enflurane committed more errors postoperatively in the p-deletion test. The incidence of complications was low and was not influenced by the choice of inhalational agent.