Leakage of sevoflurane from vaporizer detected by air monitoring system: a case report.

Leakage of inhalational anesthetic gases is an important issue not only to staff health but awareness during general anesthesia. After inhalation of sevoflurane commenced, the audible and visible alarm of our custom-made air monitoring system was activated. The system measured 2-4 ppm of sevoflurane. A thorough search failed to identify the source of the leak. After changing inhalational anesthesia to intravenous anesthesia, the concentration of sevoflurane decreased immediately to zero. The filling level on the vaporizer decreased faster than usual. A thorough check of the vaporizer after surgery identified a worn down seal in the filling device of the vaporizer.