THE LARYNGEAL MASK AIRWAY FOR INTRAOCULAR SURGERY - EFFECTS ON INTRAOCULAR-PRESSURE AND STRESS RESPONSES

Tracheal intubation, performed routinely during general anaesthesia in patients undergoing intraocular surgery, may have adverse effects on cardiovascular function and intraocular pressure. This study assessed the suitability of the laryngeal mask airway (LMA) as a substitute for tracheal intubation. Intraocular and systemic pressor effects, heart rate changes and catecholamine concentrations were measured in two groups of 10 patients receiving standardized anaesthesia with either a tracheal tube (TT) or a LMA. There were significantly smaller changes in the pressor responses to insertion and in concentrations of catecholamines at critical times in the anaesthetic sequence in the LMA group. Mean (SEM) rate-pressure product was significantly smaller in the LMA group compared with the TT group after both insertion (8276 (730) vs 13307 (1348), P < 0.01) and removal (10152 (595) vs 14137 (1044), P < 0.01) of the airway device. The change in intraocular pressure was significantly less in the LMA group at all time points after airway instrumentation than that in the TT group, with the greatest difference after extubation (-2.3 (2.4) mm Hg vs 14.5 (3.4) mm Hg, P < 0.01).