Induction Rooms Research Articles

Occupational exposure to anaesthetics in 20 hospitals.

The nitrous oxide and halothane contamination in the inspired air of anaesthetists and in the atmospheres of operating theatres, anaesthetic induction and recovery rooms, were measured during normal unmodified working sessions in 20 hospitals using integrated personal samplers. The nitrous oxide (and halothane) levels ranged from < 10 to 3000 ppm (< 0.1 to 60 ppm) in the different areas with an average of 388.5 ppm (2.8 ppm) for the inspired air of the anaesthetists during 2 hour sampling periods. There was no correlation between the levels of the anaesthetists' exposures and those in the static air samples and this appeared to be due primarily to a wide variation in work practices and techniques. Thus it is potentially misleading to assess anaesthetists' occupational exposure by collecting ambient air samples in the operating rooms. Comparisons with more prolonged measurements in one hospital indicated that the installation of relatively simple active scavenging devices will be effective in most hospitals.

MEASUREMENT AND REDUCTION OF OCCUPATIONAL EXPOSURE TO INHALED ANAESTHETICS

The occupational exposure of hospital staff to inhaled anaesthetics was investigated using a personal sampling device that provides a measure of the average concentrations breathed by a person over a period of time, as distinct from the spot sampling in the general environment. The anaesthetist9s average exposure to nitrous oxide and halothane during complete operating sessions was twice that expected from simple dilution of the escaping gases by the operating room ventilation. The sampling technique was also used to evaluate the effect of (1) redirection of the waste gas outflow; (2) active scavenging connected to the piped vacuum system. Short-period studies under controlled conditions in the operating theatres and anaesthesia induction rooms showed that the anaesthetist9s exposure could be reduced two- or fourfold by redirecting the outflow and another four- to sixfold by active scavenging. Exposures during complete operating sessions were reduced two- to seven-fold by scavenging.

Measurement and reduction of occupational exposure to inhaled anaesthetics.

The occupational exposure of hospital staff to inhaled anaesthetics was investigated using a personal sampling device that provides a measure of the average concentrations breathed by a person over a period of time, as distinct from the spot sampling in the general environment. The anaesthetist's average exposure to nitrous oxide and halothane during complete operating sessions was twice that expected from simple dilution of the escaping gases by the operating room ventilation. The sampling technique was also used to evaluate the effect of (1) redirection of the waste gas outflow; (2) active scavenging connected to the piped vacuum system. Short-period studies under controlled conditions in the operating theatres and anaesthesia induction rooms showed that the anaesthetist's exposure could be reduced two- or fourfold by redirecting the outflow and another four- to sixfold by active scavenging. Exposures during complete operating sessions were reduced two- to seven-fold by scavenging.

Exposure to anesthetic gases and ethanol during work in operating rooms.

The concentration of halothane and ethanol in operating rooms was measured during 37 routine operations performed in nine different departments of surgery at six different hospitals. The time-weighted halothane concentrations in the respiratory zones of anesthetic and surgical nurses were 0.3--34.0 ppm (time-weighted average 7.2 ppm) and 0.1--9.2 ppm (time-weighted average 2.5 ppm), respectively, in the different operating departments. The corresponding ethanol concentrations were 0.3--36.5 ppm (time-weighted average 12.5 ppm) for anesthetic nurses and 1.5--46.6 ppm (time-weighted average 15.3 ppm) for surgical nurses. The anesthetic technique influences the exposure of the operating staff to anesthetic gases, but it does not affect exposure to ethanol. In controlled experiments volunteers were exposed to low concentrations of halothane or ethanol. About 60% of both substances was retained. The content of ethanol in the end-expired air approached zero within a few minutes after the end of exposure, while low residual concentrations of halothane were demonstrable for more than 1 h. Although exposure to ethanol is insignificant in relation to the metabolic capacity of the body, ethanol indicates the presence of volatile disinfectant components, and its spread through the room atmosphere should be kept in mind when the ventilation of operating rooms is designed. The effective elimination of airborne pollutants in operating rooms calls for good general ventilation in conjunction with local exhaust close to the sources of anesthetic gas leakage. General ventilation mainly affects the concentration of substances well-mixed with the room atmosphere, such as volatile disinfectant components and anesthetic vapor that has spread beyond the actual work zones of the medical staff. For a significant reduction in the concentration of anesthetic gases in the respiratory zones of the medical staff, the gases must be vented at the source of leakage. Since airborne anesthetics occur not only in operating rooms, general ventilation has to meet certain minimum requirements also in anesthetic induction rooms and recovery rooms. Operating rooms and anesthetic induction rooms must also be supplied with local exhaust systems.