부산대학교 도서관

AbstractObjectives. Assessment of individual exposures to sevoflurane plus nitrous oxide (N2O) by biological monitoring of unmodified analytes in post-shift urine of exposed personnel.Methods. Anaesthetics in urine and breathing area were monitored in 124 subjects in 11 operating theatres. Passive samplers were collected after 2.5–7 h of exposure, at the same time as post-shift urinary samples, to evaluate the individual time-weighted average (TWA) exposures to sevoflurane and N2O. A static headspace sampler coupled with a gas chromatograph mass spectrometer was used for analytical determinations (sensitivity sufficient to reveal biological/environmental exposures of 0.1 µg/lurine and 50 ppb for sevoflurane, and 1 µg/lurine and 80 ppb for N2O).Results. Median (range) post-shift urinary and environmental values were 1.2 µg/lurine (0.1–5.0) and 0.4 ppm (0.05–3.0) for sevoflurane (n=107) and 10.9 µg/lurine (0.5–74.9) and 8.6 ppm (0.2–123.4) for N2O (n=121) (all low-exposure range). At log–log regression, urinary levels closely correlated with environmental data (sevoflurane, r2=0.7538; N2O, r2=0.8749). Biological equivalent limits (BELs) based on National Institute for Occupational Safety and Health (NIOSH) TWA exposure limits, calculated as means of regression slope and y-intercept, were 3.6 µg/lurine for sevoflurane (corresponding to 2 ppm) and 22.3 µg/lurine for N2O (corresponding to 25 ppm). Individual "mixture BELs", which we calculated by applying the American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value (TLV)mix formula to biomarker values and using the obtained NIOSH-based BELs as a reference, closely correlated with mixture TLVs (ρ=0.816, Lin's concordance test).Conclusions. We propose urinary sevoflurane as a new, specific, internal dose biomarker for routine biological monitoring of personal exposures among operating-theatre personnel, and use of reliable "mixture BELs" to provide safer levels of internal exposure for workers exposed to mixtures of sevoflurane and N2O, and conceivably also to other mixtures of toxicants with possible additive effects.