[Laughing gas as the principle substance in assessing occupational exposure to inhalation anesthetics]. / Lachgas als Leitsubstanz zur Beurteilung der Arbeitsplatz-belastung mit Narkosegasen.

PURPOSE: In the Federal Republic of Germany limits for the chronic exposure to nitrous oxide and volatile anaesthetics have been prescribed by legislation. According to the technical rules for the handling of hazardous substances TRGS 402 it is legal to measure a single substance in a mixture of hazards, unless the behaviour of all substances is known. Studies about corresponding concentrations of nitrous oxide and volatile anaesthetics in anaesthetic working areas have not yet been carried out. METHODS: During one working week each the concentrations of nitrous oxide, enflurane and desflurane were measured by infrared spectrometry in a working area equipped with air condition and in a non-ventilated operating theatre. Corresponding concentrations of nitrous oxide were measured from the same gas samples. RESULTS: Statistical calculations showed linear correlations of the enflurane and nitrous oxide concentrations in all anaesthetic areas. No linear regression was found between the desflurane and nitrous oxide concentrations. In the working area where desflurane anaesthesias were carried out, significantly higher concentrations of nitrous oxide were observed. Nevertheless the Chi2-test showed no significant differences in the distribution of categorised measurement values. DISCUSSION: Although it is not possible to calculate desflurane concentrations from the nitrous oxide concentrations, measurement of nitrous oxide as leading substance is a valid procedure to assess the exposure of the anaesthesiology workplace to nitrous oxide and volatile anaesthetics. Significant higher nitrous oxide concentrations during desflurane anaesthesia result from early extubation of patients expiring higher concentrations of nitrous oxide.

[The effect of anesthetic method on enflurane air pollution in non-air conditioned operating rooms]. / Einfluss des Narkoseverfahrens auf die Enfluran-Raumluft-belastung in nichtklimatisierten OP-Arbeitsbereichen.

UNLABELLED: Pollution of work areas by volatile anaesthetics and nitrous oxide occurs during general anaesthesia. Short anaesthesia procedures are often carried out in operating theatres that are not equipped with air-conditioning systems. Methods of lowering exposure during short procedures, where mask anaesthesia is the usual procedure, are double masks and the laryngeal mask. The aim of our investigation was to determine the possibility of lowering the pollution of the environment to below national and international thresholds in a non-air-conditioned work area and to find out which method of anaesthesia is the most effective in environmental protection, i.e. which has the lowest leakage rate. METHODS: In our investigation, at two points of the work area the mean enflurane [2-chloro-1-(difluor-omethoxy)-1,1,2-trifluoro-ethane] concentrations were measured under daily routine conditions in a non-ventilated anaesthesiological work area by a gas chromatography. Anaesthesia with single masks, double masks, laryngeal masks or endotracheal intubation was carried out. RESULTS: No differences were found in the mean concentration of enflurane during the anaesthesia procedures. The leakage rates of endotracheal intubation anaesthesia were the lowest. DISCUSSION: In unventilated work areas, it was not possible to lower the exposure of the personnel by changing the method of anaesthesia. The application of procedures like double or laryngeal masks does not avoid the need for installation of air-conditioning systems in all work areas were anaesthesia is performed.