Genomic instability detected in anaesthesiologists exposed to trace concentrations of waste anaesthetic gases

Faculdade de Medicina de Botucatu, UNESP - Univ Estadual Paulista, Departamento de Anestesiologia, Botucatu, Brazil

Background and Goal of Study: Occupational exposure to anaesthetic gases may result in adverse health effects. There is still controversy about genotoxic potential of anesthetic gases. Thus, the aim of this study was to determine the trace concentrations of waste anaesthetic gases and to evaluate cytogenetic damage in anaesthesiologists.
Materials and Methods: After the approval of the study from the Ethical Committee, the study was conducted in a Brazilian tertiary teaching hospital (Botucatu Medical School, Botucatu, SP). Buccal cells samples were collected from 57 physicians: 30 anaesthesiologists exposed to waste anesthetic gases (the halogenated isoflurane, sevoflurane and desflurane, and the gas nitrous oxide - N2O) for at least 2 years, and 27 physicians (internal medicine) with no occupational exposure. The groups were matched by age, sex and lifestyle. Chromosomal damage was evaluated by using the buccal micronucleus cytome assay (BMCyt), a minimally invasive method to detect genomic instability. Coded slides were stained, two thousand differentiated cells per subject were analysed, and micronucleus (MN) frequency was presented per thousand. The trace concentrations of waste anaesthetic gases were determined during inhalational anaesthesia in the breathing zone of anaesthesiologists, by using a portable infrared spectrophotometer, and the values were expressed in parts per million (ppm).
Results and Discussion: There was no significant differences between groups regarding demographic data (p > 0.05). The exposed group showed higher frequencies of MN when compared to the controls (p = 0.034). The mean concentrations of waste anesthetic gases were 5.5 ± 4.4 ppm for isoflurane, 7.7 ± 8.7 ppm for sevoflurane, 16.4 ± 6.0 ppm for desflurane and 150.3 ± 135.7 ppm for N2O.
Conclusion: The current study showed that the occupational exposure to waste anesthetic gases is related with genomic instability assessed by BMCyt in anaesthesiologists exposed to the trace concentrations found in the current study, suggesting that these professionals can be considered in potential risk for harmful genetic effects. 

Acknowledgements: This study was supported by the grants #2013/05084-8, São Paulo Research Foundation (FAPESP) and #471604/2013-5, The National Council for Scientific and Technological Development (CNPq). FAPESP and CNPq are Brazilian government agencies dedicated to promoting scientific research.