Propofol in total intravenous anaesthesia without nitrous oxide
Propofol and methohexitone were evaluated as hypnotics in a total intravenous anaesthesia technique without nitrous oxide in 50 patients of ASA grade 1 or 2. Analgesia was provided by a constant alfentanil infusion and the depth of anaesthesia was controlled by varying the infusion rate of propofol or methohexitone. Induction and intubation responses were smooth and moderate in the propofol group and side effects were few. Control of depth of anaesthesia, blood pressure and pulse rate was relatively easy in this group but more difficult and sometimes inadequate in the methohexitone group, in which side effects were more frequent. The mean infusion rate for propofol was 0.12 mg/kg/minute, similar to those found in studies using nitrous oxide without an opioid. Recovery times were short in both groups but those in the propofol group tended to be shorter. Postoperatively 96% of the propofol patients were clear-headed within 20 minutes, in contrast to only 48% in the methohexitone group. We conclude that propofol together with alfentanil, both given by a bolus plus infusion technique, provide controllable and satisfactory total intravenous anaesthesia without recourse to nitrous oxide or other inhalational agents. Methohexitone was not as satisfactory as propofol.