Environmental Sustainability in Anesthesia
While anesthesia practices have long prioritized safety and cost-efficiency in day-to-day operations, environmental sustainability has typically not been given the same degree of consideration. However, as climate change worsens and increasingly affects health outcomes, hospitals and healthcare practices have begun to consider how they can become more sustainable [1]. American hospitals produce 5.9 million tons of medical waste yearly [2]. Operating rooms, including anesthetic procedures, are responsible for 30% of this waste [1]. Anesthesia practices hoping to lessen environmental impacts can turn to research on the effects of reusable versus disposable materials, as well as on the consequences of greenhouse gases used as anesthetics.
As common sense might suggest, the life cycle assessment (LCA) of reusable materials often—though not always—reveals them to be more sustainable than single-use ones due to their manufacturing and disposal processes. One study found that greenhouse gas emissions from reusable laryngoscopes were less substantial than those from their disposable counterparts, even with disinfection processes taken into account. The use of a disposable multi-part laryngoscope emitted roughly 7 kg of CO2, while laryngoscopes that substituted a multi-use for a single-use handle were found to emit about one-seventh as much CO2. Furthermore, this study found reusable laryngoscopes more cost-effective, implying that reusability might have both environmental and financial benefits [3].
Yet reusable materials can at times have a greater environmental impact than non-reusable ones, largely because of the water and energy involved in the cleaning required to make re-use of such items safe. A study by McGain et al. comparing reusable and single-use central venous catheter (CVC) insertion kits found that, despite their lower cost, reusable kits had a higher environmental impact due to the water and energy consumed in sterilization. CO2 emissions from the reusable kits were 1211g, compared to 407g from disposable ones, while reusable kits used 27.7 L water compared to 2.5 L from disposable ones [4].
While machinery and medical accessories contribute to environmental impact, medications are also an important factor in anesthesia sustainability. Inhaled anesthetics play a significant role—they are, after all, greenhouse gases. Nitrous oxide not only contributes to global warming but also plays a part in eroding the ozone layer. The atmospheric lifetimes of these gases ranges from 14 years for newer agents, to 114 years in the case of nitrous oxide [2]. One simple way to lower emissions is by careful management of fresh gas flow during the maintenance phase of anesthesia: in simulations, a fresh gas flow of 1L per minute compared to 2L per minute reduced waste to a significant degree, although researchers recommend careful monitoring to ensure patient safety [5]. Furthermore, some anesthetics have higher GWP, or global warming potential, than others—with a fresh gas flow of 2L, sevoflurane 2% has a GWP of 130, compared to desflurane 6% at GWP 2,540 [2].
As anesthesia practices seek to embrace sustainability, they may consider the impact of materials such as CVC kits, as well as that of anesthetics themselves. Studies present evidence that reusable and single-use materials each have environmental advantages and flaws, given manufacturing, disinfecting, and waste-disposal processes. Meanwhile, the use of lower-GWP anesthetics when possible, as well as reduction in fresh gas flow during procedures, may lessen the impact of inhaled anesthetics to the environment.
References
[1] Ryan, Susan, and Jodi Sherman. “Sustainable Anesthesia.” Anesthesia & Analgesia, vol. 114, no. 5, 2012, pp. 921–923., doi:10.1213/ane.0b013e31824fcea6.
[2] Axelrod, Deb, et al. “Greening the Operating Room.” Greening the Operating Room | American Society of Anesthesiologists (ASA), American Society of Anesthesiologists, www.asahq.org/about-asa/governance-and-committees/asa-committees/committee-on-equipment-and-facilities/environmental-sustainability/greening-the-operating-room.
[3] Sherman, Jodi D. et al. “Reusable Versus Disposable Laryngoscopes: Environmental and Economic Considerations.” ASA Abstracts, American Society of Anesthesiologists, 2014, www.asaabstracts.com/strands/asaabstracts/abstract.htm;jsessionid=FBA770849359F923D0975208573D614C?year=2014.
[4] McGain, Forbes et al. “A life cycle assessment of reusable and single-use central venous catheter insertion kits.” Anesthesia and Analgesia, vol. 114,5 (2012): 1073-80. doi:10.1213/ANE.0b013e31824e9b6.
[5] Feldman, Jeffrey M. “Managing Fresh Gas Flow to Reduce Environmental Contamination.” Anesthesia and Analgesia, vol. 114, no. 5, 2012, pp. 1093–1101., doi:10.1213/ANE.0b013e31824eee0d.