An unexpected forever chemical - sevoflurane and other volatile anesthetics!
Patrick Monette, MD
Polyfluoroalkyl substances (PFAS), colloquially known as "forever chemicals", are now accepted to be omnipresent in our consumption of food and goods. When most people think of "forever chemicals", they think of additives in products such as packaging, fabrics, cookware, and cosmetics.
Volatile anesthetics used by anesthesia providers such as sevoflurane, isoflurane, and desflurane, already have a reputation in the environmental science community due to their contributions to greenhouse gas emissions. One reason is sevoflurane and desflurane are categorized as hydrofluorocarbons (HFCs) and isoflurane is categorized as a chlorofluorocarbon (CFC) meaning it also has ozone-depleting properties. By definition, PFAS contain one fully fluorinated carbon and are considered "highly stable, mobile, and resistant to degradation."[1] Turns out, volatile anesthetics are also considered PFAS, and until recently were rarely discussed as such in medical literature.[1] They also are not currently subject to many of the same regulations and restrictions as other PFAS compounds since these regulations are based on the individual compounds themselves, not the class as a whole.[2]
Figure from Kalmar et al.[3] Figure reproduced under Elsevier's Open Access policy under the CC BY-NC-ND license. (http://creativecommons.org/licenses/by-nc-nd/4.0/).
The authors of a recent Letter in BJA Open point out that these gases have negative impacts on climate change and chemical pollution of the environment.[3] As seen in the figure, whether sevoflurane is exhaled by a patient into the air or metabolized and excreted via urine, the compound is degraded into a terminal PFAS known as trifluoroacetic acid - lingering in the ecosystem thereafter. Unlike the volatile anesthetics, propofol – an intravenous anesthetic – can be degraded and removed from wastewater.
The implications of brief human exposure to these volatile agents for surgery remains unknown. They have been exhaustively studied, and frequently compared head-to-head to other anesthesia agents such as propofol. Sevoflurane is nearly completely removed unchanged the same way it is delivered (the lungs) with only a small fraction metabolized by the liver and then excreted bye kidney. Any significant health effect by now would have been detected, and volatile anesthetics remain a widely used and largely safe method of providing anesthesia to patients undergoing surgery. Yet, as anesthesia providers and perioperative team members continue to consider ways to reduce operating room waste and subsequent environmental harm, the use of volatile anesthetics has yet another reason to draw scrutiny. Whether the degree of their usage will be altered in the future by cultural or regulatory changes remains to be seen.
Patrick Monette, MD is an anesthesiology resident at the University of Virginia. His clinical and research interests include cardiothoracic anesthesia and the perioperative health effects of environmental toxins.
Kalmar AF, Groffen T, Vereecke H, Teunkens A, Dewinter G, Mulier H, Struys MM, Rex, S. Volatile anaesthetics and PFAS forever chemicals: A critical gap in environmental impact assessments. Best Pract Res Clin Anaesthesiol. 2024; 38(4), 342-348. doi.org/10.1016/j.bpa.2024.12.002.
Kalmar AF, Zieleskiewicz L, Grimaldi D, Kampman JM, Rex S. Environmental harm from anaesthesia: the importance of clinical realism and chemical persistence. BJA Open. 2025;16:100490. Published 2025 Oct 8. Doi:10.1016/j.bjao.2025.100490
Chohan A, Petaway H, Rivera-Diaz V, Day A, Colaianni O, Keramati M. Per and polyfluoroalkyl substances scientific literature review: water exposure, impact on human health, and implications for regulatory reform. Rev Environ Health. 2020;36(2):235-259. Published 2020 Sep 30. doi:10.1515/reveh-2020-0049
