[Occupational exposure in the operating room by isoflurane when using the laryngeal mask]

Success of intraocular surgery depends in part on low intraocular pressure, sufficient muscle relaxation during the operative period, and avoidance of coughing during emergence from anaesthesia. Isoflurane (ISO) guarantees deep anaesthesia and Laryngeal Mask Airway (LM) makes emergence smoother than when using conventional endotracheal intubation. Occupational exposure to isoflurane appears unavoidable near the potential main source of leakage, the "patient's mouth". Due to the short distance between the patient's mouth and the working area, the risk of exposure for the surgeon could be high. Traces of anesthetic gases may cause various negative effects on the health of the personnel. Higher abortion rates are reported on in recent literature. The aim of this study was to quantify trace amounts of ISO and then to compare these values with international threshold limits. In this study, trace concentrations of ISO were measured directly by means of a high sensitive photoacoustic infrared spectrometry analyser. Measurements were done continuously every 120 seconds at the working places of the surgeon, anaesthetist and the assisting nurse. One possible leakage source, the patient's mouth, was also analysed. 10 cataract operations under general anaesthesia were included in the study. All the measured values were low, the majority under 2 ppm isoflurane. The national threshold values (10 ppm) were not exceeded. We conclude that the use of the LMA in ventilated patients is not associated with high concentrations of isoflurane in the working environment of the operating theatre personnel during eye surgery. Trace concentrations of isoflurane using the LMA are comparable with those using ET under these working conditions. Under other working conditions, higher concentrations may be expected should therefore be controlled.