[Pollution of the workplace by anesthetic gases. Causes and prevention]

Waste anesthetic gas concentrations were measured in areas corresponding to the breathing zones of the anesthetists and operating room nurses for personal exposure (n = 27, time-weighted values) and during special work practices (n = 65). Leaks related to anesthetic machines and high-pressure nitrous oxide components were investigated during (n = 60) and after anesthesia (n = 85). The effect of a local scavenging system on occupational exposure during inhalation induction of anesthesia in children was studied (n = 60). Concentrations of nitrous oxide, halothane, isoflurane, and enflurane were determined by using active dosimeters (SKC 222) and different infrared gas-analyzers. Factors that increase waste anesthetic gas concentrations in operating rooms can be divided into several categories, such as low air conditioning systems, anesthetists' work practices, equipment leakage, including leakage from high-pressure nitrous oxide systems, and inadequate scavenging devices. Equipment leakage is almost invariably present in low-pressure components of the anesthesia machine because so many seals and joints are necessary to permit disassembly for cleaning and replacement. Waste anesthetic gases are also distributed in the exhaled air of patients recovering from anesthesia. To restrict the levels, exposure must be as low as can be achieved with reasonable efforts. Thus, the anesthetic equipment should be designed to avoid leakage, leakage tests should be performed before the use of anesthetic machines, and waste anesthetic gases should be scavenged by central as well as by local systems. Regular and periodic use of a trace gas analyzer permits direct observation of gas leakage and enables anesthetists to modify their work technique in order to reduce avoidable leakage.