Anaesthesia and intra‐ocular pressure: a comparison of total intravenous anaesthesia using etomidate with conventional inhalation anaesthesia

Intra-ocular pressure (IOP) was measured in two comparable groups of anaesthetised patients under standardised conditions. Group 1 received etomidate 0.3 mg/kg fentanyl 100 micrograms and droperidol 5 mg. with etomidate 20 microgram/kg/minute for maintenance. Group 2 received thiopentone 3.5 mg/kg and were maintained with halothane 0.5% in nitrous oxide (60%) with oxygen. Both groups of patients were ventilated to normocapnia. Blood pressure, heart rate, central venous pressure and IOP were measured in 5 minute intervals from pre-induction to 30 minutes postinduction. A significantly greater reduction in mean IOP (p less than 0.05) occurred in group 1. A maximum fall in IOP of 61% was obtained, compared to a maximum fall of 45% in group 2. Blood pressure fell in both groups. The fall was greater (23%) in group 2 than in group 1 (18%) and in no case was considered excessive. Total intravenous anaesthesia using etomidate is suggested as a useful technique for open eye surgery.