Genetic damage in operating room personnel exposed to isoflurane and nitrous oxide.

Abstract

Objectives-To evaluate genetic damage as the frequency of sister chromatid exchanges and micronuclei in lymphocytes of peripheral blood of operating room personnel exposed to waste anaesthetic gases. Methods-Occupational exposure was measured with a direct reading instrument. Venous blood samples were drawn from 10 non-smokers working in the operating room and 10 non-smoking controls (matched by age, sex, and smoking habits). Lymphocytes were cultured separately over 72 hours for each assay with standard protocols. At the end of the culture time, the cells were harvested, stained, and coded for blind scoring. The exchanges of DNA material were evaluated by counting the number of sister chromatid exchanges in 30 metaphases per probe or by counting the frequency of micronuclei in 2000 binucleated cells. Also, the mitotic and proliferative indices were measured. Results-The operating room personnel at the hospital were exposed to an 8 hour time weighted average of 12.8 ppm nitrous oxide and 5.3 ppm isoflurane. The mean (SD) frequency of sister chromatid exchanges was significantly higher (10.2 (1.9) v 7.4 (2.4)) in exposed workers than controls (p=0.036) the proportion of micronuclei (micronuclei/500 binucleated cells) was also higher (8.7 (2.9) v 6.8 (2.5)), but was not significant (p=0.10). Conclusion-Exposure even to trace concentrations of waste anaesthetic gases may cause dose-dependent genetic damage. Concerning the micronuclei test, no clastogenic potential could be detected after average chronic exposure to waste anaesthetic gas. However, an increased frequency of sister chromatid exchanges in human lymphocytes could be detected. Although the measured diVerences were low, they were comparable with smoking 11-20 cigarettes a day. Due to these findings, the increased proportion of micronuclei and rates of sister chromatid exchanges may be relevant long term and need further investigation. (Occup Environ Med 1999;56:433-437)

Exposure to anaesthetic trace gases during general anaesthesia: CobraPLA vs. LMA classic

“…Anaesthetic trace concentrations measured in this trial are in the range of previously published data comparing different types of airway management 20–22, 24 . After endotracheal intubation, Hoerauf et al 24 measured N 2 O exposure levels of 15.77 p.p.m.…”

“…Genotoxicity of volatile anaesthetics is among the major concerns. In chronically exposed personnel, a higher rate of chromosomal aberrations, sister chromatide exchanges, 6,22,34 the formation of micronucleoli and an increased number of spontaneous abortion 5 are discussed. Furthermore, impairment of neurologic functions such as decreased performance and cognitive dysfunctions, 35 general fatigue, headache and an increased risk of development of multiple sclerosis 9,10 have been reported and extensively reviewed 11,12 …”

“…Potential confounding effects such as humidity, air pressure, temperature, SEV, N 2 O, isopropanol, water and CO 2 were compensated during calibration by the system software. Data sampling was performed in accordance with preceding studies by Hoerauf and colleagues 20–23 . Time‐weighted average gas concentrations have been calculated as described by Hoerauf et al 24 …”

Desflurane anaesthesia increases sister chromatid exchanges in human lymphocytes

“…It has a molecular weight of 168, blood gas solubility coefficient of 0.42, and lower tissue solubility than any other inhalation agent. However, most of the human cytogenetic studies have examined enflurane (6), isoflurane (7), halothane (6), sevoflurane (8), and nitrous oxide (7) but not desflurane.…”

Commentary on Nilsson R, Björdal C, Andersson M, Björdal J, Nyberg A, Welin B & Wilman A (2005) Health risks and occupational exposure to volatile anaesthetics: a review with a systematic approach. Journal of Clinical Nursing 14, 173–186

“…provided further evidence that the health of workers exposed to volatile anaesthetic agents should not be adversely affected except for those who have been exposed to levels far exceeding the recommended levels in USA and Europe. However, some results seem to be inconsistent which may be due to insufficient exposure measure to determine dose–response relation (Hoerauf et al . 1999), absence of a more detailed measurement of exhaled air analysis to exclude accurately other interfering substances in the environment (Summer et al .…”