Comparison of personal pollution monitoring techniques for use in the operating room.

Three personal pollution monitors (adsorption tubes, diffusion dosimeters and evacuated bottles) have been tested, in routinely used operating rooms and under controlled laboratory conditions, for their accuracy and reproducibility relative to one another and to measurements by infra-red spectroscopy. All the techniques provide time-weighted average measurements of pollutant concentrations. Tubes and dosimeters measure halothane with greater accuracy than that required by N.I.O.S.H. regulations, but neither technique can measure inorganic pollutants such as nitrous oxide. The prototype evacuated bottles tested are unsatisfactory at their present stage of development for the measurement of both halothane and nitrous oxide concentrations. We believe that, at the present time, surveys of operating room pollution can best be carried out using adsorption tubes of diffusion dosimeters for personal halothane concentrations and a portable infra-red spectrometer for measurement of background nitrous oxide concentrations.

Survey of operating room pollution within an N.H.S. district.

Pollution by waste anaesthetic gases was measured in all operating departments in a typical N.H.S. district. Methods were chosen to provide time-weighted average levels over the period of each operating session. The results showed that air-conditioning alone could not guarantee pollution levels below suggested maximum levels and that to meet those requirements air-conditioning plus scavenging was necessary. Background pollution levels were found to be representative of the personal exposure of nursing staff but approximated to only one third of the anaesthetists' personal exposure. Dental clinics presented special problems, namely the very high levels of pollution to which the dentist and his assistants were exposed.

A chemical adsorption system for the sampling of gaseous organic pollutants in operating theatre atmospheres.

The development of an air sampler and its use in measuring organic pollutants in operating theatre atmospheres are described. Air was sampled continuously during an operating session and the results obtained represent the average pollution at the sample site during that session. The technique involved the chemical adsorption of organic vapours to polymer beads and pollutants thus trapped could be stored for several days before thermal desorption and analysis by gas chromatography. The three most abundant organic pollutants were ethanol, propan-2-ol (isopropanol) and halothane.

Gas chromatographic determination of Ostwald solubility coefficients for cyclopropane, halothane and trichloroethene (trichloroethylene).

Gas chromatographic methods using solvent extraction for the analysis of cyclopropane and and trichloroethene (trichloroethylene) are described and evaluated; cyclopropane was extracted into carbon tetrachloride and trichloroethene into carbon disulphide, using chloroform and toluene respectively as the internal standards. Ostwald solubility coefficients were measured for cyclopropane, halothane and trichloroethene in Krebs solution: at 310 K the respective values +/- SEM of the Ostwald coefficients are 0.181 +/- 0.009, 0.78 +/- 0.02 and 1.54 +/- 0.02; over the temperature range 295-310 K the respective temperature coefficients of solubility are -2.27, -4.18 and -3.81 in units of per cent/K at 310 K.