Spontaneous respiration versus controlled ventilation anaesthesia with halothane for intra-ocular surgery.

One hundred and thirty-seven patients were randomly allocated to receive halothane anaesthesia for intra-ocular surgery either by IPPV (n = 71) or breathing spontaneously (n = 66). Both techniques provided satisfactory operating conditions in 87% and 80% of procedures, respectively. Intra-ocular pressure was reduced in a similar majority of patients, rose in a similar percentage (spontaneous = 11%, controlled = 21%) and remained unchanged in a few. Surgeons' reports of good operative conditions correlated very well with intra-ocular pressure changes whether they rose or fell intra-operatively. The duration of anaesthesia and the time taken to achieve full recovery following the two techniques were similar. Post-operative vomiting, headache, sore throat and confusion occurred with similar frequency, and analgesic and antiemetic requirements were not influenced by the technique. Resumption of ambulation, oral intake and micturation occurred similarly. In both groups, patients with a low normal pre-operative intra-ocular pressure tended to show a rise in intra-ocular pressure during anaesthesia, and those with a high normal pre-operative intra-ocular pressure tended to show a fall.