[Exposure to anesthetic gases].

In recent years there has been a growing awareness of possible hazards caused by anaesthetic gases in operating theatres. Our study monitored ambient nitrous oxide (N2O) levels in the operating theatres and recovery rooms at the University Hospital in Tromsø. The results show that exposure to waste anaesthetic gases occurs because of leaks in the anaesthetic equipment. The three major sources of leaks are masks, high pressure fittings and exhalation valves. Prevention of leakage from equipment is very important, and a leakage testing programme should be an essential part of the daily control strategy. Good working practices and tracheal intubation results in low exposure to nitrous oxide in the breathing zone of the anesthetic personnel. During mask anaesthesia we have observed nitrous oxide concentrations above 1500 ppm, owing to mask leakage. A closely fitting scavenging mask and good working practices lead to in lower nitrous oxide concentrations. Nitrous oxide exhalation from the patient in the recovery room is only a minor problem.