Evaluation of the usefulness of the laryngeal mask for general anesthesia in eye microsurgery--preliminary results

Objective: This prospective study was designed to compare intraocular pressure changes and haemodynamic response to insertion of either a laryngeal mask or an orotracheal tube during general anaesthesia for cataract surgery.

Methods: The effect of techniques (tracheal tube-TT, laryngeal mask airway-LMA) securing a clear upper airway on the heart rate changes (HR), arterial pressure (SAP, DAP), oxygen saturation (SpO2), end-tidal carbon-dioxide pressure (Et-CO2), intraocular pressure (IOP) and the incidence of coughing, stridor and sore throat was analysed in 60 patients undergoing cataract surgery during general anaesthesia.

Results: The mean values for HR, SAP, DAP and IOP measured before and after induction of anaesthesia were not different in both groups. After securing a clear airway, mean HR increased in TT group to 95.5/min and decreased to 75.7/min in LMA group. SAP increased in TT group to 131 mmHg, DAP to 82.6 mmHg, whilst in LMA group both values decreased to 98.6 mmHG and 66.3 mmHg, respectively. The significant difference in IOP values was observed after intubation or using laryngeal mask. In TT group, intraocular pressure increased to 15 mmHg in healthy eye and to 13.6 mmHg in ill eye whilst there was a decrease in LMA group to 5.5 and 7.43 mmHg, respectively. Furthermore, a greater incidence of such complications as coughing, stridor and sore throat in TT group was observed.

Conclusions: The results show that using LMA in microsurgery during general anaesthesia is more advantageous and safer for patients in comparison with tracheal intubation.