Evaluation of waste isoflurane gas exposure during rodent surgery in an Australian university

ABSTRACT

Biomedical researchers use of inhalational anesthetics has increased in recent years. Use of isoflurane as an inhalational anesthetic may result in human exposure to waste anesthetic gas. Potential health effects from exposure include genotoxic and hepatotoxic effects with some evidence of teratogenic and reproductive effects. Research suggests that exposure to waste anesthetic gas within human hospital settings has improved substantially but exposures to biomedical researchers and veterinarians still requires improvement. A number of biomedical research facilities are located at The University of Queensland, Australia, where researchers and animal handlers are potentially exposed to waste isoflurane gas. There is limited published data on the exposures received by biomedical researchers performing routine procedures. This project aimed to assess isoflurane exposure received during routine rodent anesthetic protocols performed at the university. Atmospheric concentrations of isoflurane were assessed via two methods—personal active gas sampling using sorbent tubes and direct readings using infrared spectroscopy. Total procedure and isoflurane exposure times ranged from 135–268 min. Personal sorbent tube sampling detected isoflurane levels from below detectable limits (<0.01 ppm) to a Time Weighted Average for the task (TWA-Task) of 6.20 ppm (0.73 ± 9.13). Participants were not exposed to isoflurane outside of the sampling period during the remainder of the workday. TWA-8 hr adjusted levels ranged from below the limit of detection to 1.76 ppm isoflurane (0.69 ppm ± 0.61 ppm). The infrared spectroscopy readings taken in the breathing zone of participants ranged from 0.1–68 ppm. Results indicate that if adequately controlled through good room ventilation, effective active gas scavenging and well constructed anesthetic equipment, waste anesthetic exposures are minimal. However, where industry standards are not met exposures may occur, including some high peak exposures.

KEYWORDS:

• Anesthetics
• biomedical research
• inhalation
• occupational exposure

Funding

We would like to thank the University of Queensland's Biological Resources Department and the School of Biomedical Sciences for funding this study.