Immunotoxicity induced by occupational inhalation exposure to waste anesthetic gases: a historical cohort study

Background: This study was undertaken to ascertain whether long-term occupational exposure to inhalational anesthetic, was associated with any significant alteration in the parameters of immune function. Materials and methods: This was a historical cohort study in which 30 male participants with at least one year of work experience in the operating room at the time of the study and 30 unexposed referent subjects were investigated. Exposure levels were quantified by measuring the urinary concentrations of nitrous oxide (N2O), isoflurane, and sevoflurane gases by headspace gas chromatography-mass spectrometry. Serum concentrations of interleukin-4 (IL-4), Th2-type cytokines, and interferon-gamma (IFN-γ) were measured by the ELISA method. Additionally, an automated hematology analyzer was used for the white blood cell count and white blood cell differential test. The data were analyzed using SPSS software for Windows version 21. Results: Mean urinary concentrations of N2O, isoflurane, and sevoflurane were found to be 211.57±75.15, 4.06±0.96, and 19.51±12.96 ppb, respectively. In simplistic statistical data analysis, significant differences were noted between exposed and control groups as far as the mean serum cytokines levels (IFN-γ, IL-4) were concerned. Furthermore, after adjusting for important confounders, statistical analysis showed that the IFN-γ, IL-4, and the ratio of IFN-γ/IL-4 were significantly higher in the exposed group than in the referent subjects. Conclusion: These findings provide corroborative evidence to further substantiate the contention that exposure to anesthetics agents (N2O, isoflurane, and sevoflurane) is associated with subtle, subclinical, prepathological changes in the parameters of immune function. The long-term ramification of these changes requires further investigation.