Neurotoxicity in operating room personnel working with gaseous and nongaseous anesthesia.

Occupational exposure to high concentrations of anesthetic gases (more than 500 ppm of nitrous oxide and more than 15 ppm of halothane and enflurane) can cause neurobehavioral effects in operating room personnel. Factors such as stress and work organization play an additional role in reducing performance capacities. It is still unclear whether these conditions may become the predominant factor in behavioral impairment when exposure to anesthetic gases is reduced; in addition, we wished to ascertain the extent of neurobehavioral and neuroendocrine effects at relatively low levels of exposure to such gases. Therefore the same group of 30 operating room personnel was examined with neurobehavioral tests during gaseous and nongaseous anesthesia. In this way, the neuropsychological performance was examined under the same stress conditions, but with different exposure levels to anesthetic gases. Serum cortisol was measured as an additional "biological stress indicator." Prolactin secretion was examined to study possible interference of anesthetic gases with the dopaminergic system. The results were compared with those in a control group of 20 hospital workers from other departments, with similar characteristics in respect of age, sex, and education. During work with gaseous anesthesia, average airborne concentrations (geometric mean) of nitrous oxide were 50.9 ppm (SD 20.8) on the first day of the working week, and 54.2 ppm (SD 22.1) on the last day of the working week, whereas average urinary nitrous oxide (geometric mean) were 21.54 micrograms/l on the first day of the working week and 25.67 micrograms/l on the last day of the working week. The operating room workers showed slower reaction times at the end of the week with gaseous anesthesia, compared with workers using nongaseous anesthesia and the control group. At the same time they also showed increased secretion of prolactin, whereas cortisol remained unchanged. Therefore, it can be concluded that lower levels of exposure to anesthetic gases (and not only high exposure levels) cause an impairment of neurobehavioral performance, with the action of stress being less relevant. The mechanism of anesthetics' neurotoxic action seems to be related to interference with the dopaminergic system.