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

Tracheal intubation, performed routinely during general anaesthesiain patients undergoing intraocular surgery, may have adverseeffects on cardiovascular function and intraocular pressure.This study assessed the suitability of the laryngeal mask airway(LMA) as a substitute for tracheal; intubation. Intraocularand systemic pressor effects, heart rate changes and catecholamineconcentrations were measured in two groups of 10 patients receivingstandardized anaesthesia with either a trachealtube (TT) ora LMA. There were significantly smaller changes in the pressorresponses to insertion and in concentrations of catecholaminesat critical times in the anaesthetic sequence in the LMA group.Mean (SEM) rate-pressure product was significantly smaller inthe LMA group compared with the TT group after both insertion(8276 (730) vs 13307 (1348), P<0.01) and removal (10 152(595) vs 14 137 (1044). P < 0.07; of the airway device. Thechange in intraocular pressure was significantly less in theLMA group at all time points after airway instrumentation thanthat in the TT group, with the greatest difference after extubation(–2.3 (2.4) mm Hg vs 74.5 (3.4) mm Hg. P < 0.071 ^*Present address: Department of Anaesthetics, Victoria Infirmary,Glasgow.