Increased formation of sister chromatid exchanges, but not of micronuclei, in anaesthetists exposed to low levels of sevoflurane.

We have assessed, for the first time, genotoxicity (i.e. sister chromatid exchanges and micronuclei) in anaesthetists exposed to a single volatile anaesthetic (sevoflurane) without nitrous oxide. The anaesthetists were exposed to an 8-h time-weighted average of 0.2 parts per million sevoflurane. Internists served as non-exposed controls. Mean (SD) sister chromatid exchanges per cell were significantly higher in anaesthetists compared to internists (6.6 (0.9) vs 5.1 (0.8); p < 0.001) whereas median (IQR [range]) micronuclei per 1000 binucleated cells did not differ (9.5 (6.3-10.8 [2.0-15.5]) vs 8.5 (6.0-10.5 [3.0-25.5]), respectively). Although the anaesthetists were exposed to rather low concentrations of sevoflurane, this 30% increase of sister chromatid exchanges is in agreement with a recently reported 300% increase with a high level exposure to sevoflurane and nitrous oxide. Omitting nitrous oxide does not normalise increased rates of sister chromatid exchanges.