Anesthesia in the News
  • New Guidance on Greening Anesthesia

    A new guidance document recently published in the journal Anesthesia provides actionable steps to mitigate greenhouse gas emissions from inhaled anesthetics, particularly desflurane, commonly used in general anesthesia, and nitrous oxide.

    Over the past 2 decades, substantial evidence has emerged on the environmental impact of inhaled anesthetics, but there has been insufficient progress to translate this information into actionable steps to mitigate the problem.

    Data shows world surface temperatures have increased by 0.8ºC (1.4ºF) since 1900.  Humans have accelerated the release of large amounts of greenhouse gases into the atmosphere since the industrial revolution.  The atmospheric concentrations of CO2 have increased by 40% with most accumulation of greenhouse gases occurring after 1970 (National Academy of Sciences. 2014).

    The US healthcare industry accounts for over 8% of total carbon dioxide emissions (Sherman et al. 2012).  Anesthesia contributes to about 5% percent of the total carbon emissions in healthcare.  It has been estimated that the annual effect of all inhalation agents is the equivalent to 1 coal-fired power plant (Campbell et al. 2015).

    According to the CDC, in 2010, 48.3 million hospital-based surgical and nonsurgical procedures performed in the US contributed to global warming (Hall et al. 2010).

    In elucidating the rationale for the new guidance, its authors report that while some hospitals and providers have made environmental improvements, more are considering it and require direction.  Indeed, a survey conducted at Yale by Lipana and colleagues in 2017 concluded there are gaps in knowledge related to the environmental impact of anesthetic practice.

    ‘Very achievable’

    “Inhaled anesthetics are a significant contributor to health care-related greenhouse gas emissions,” stated Jodi Sherman, MD, in a press release accompanying publication of the guidance document.  “However, it is very achievable for the health care community to minimize their impact on the climate through intervention.”

    Sherman, co-author, chair of the American Society of Anesthesiologists’ Committee on Environmental Health, and associate professor of anesthesiology at Yale School of Medicine, New Haven, Connecticut, noted that the guidance summarizes the latest actions health care professionals involved in the administration of inhaled anesthetics can take to mitigate greenhouse gas emissions, while maintaining quality outcomes and patient safety, and potentially saving costs.

    The recommendations in the document are supported by scientific literature, professional society guidelines, and a global consensus statement on principles of environmentally sustainable practice from the World Federation of Societies of Anesthesiologists.

    The anesthetic footprint

    Anesthesiology is a carbon-intensive specialty involving the routine use of inhaled agents which are potent greenhouse gases typically exhausted directly to the atmosphere.  Inhaled anesthetic agents have been estimated to be responsible for 0.01 to 0.10% of the total global carbon dioxide equivalent (CO2e) emissions contributing to global warming (Sherman et al. 2013; Andersen et at. 2012).  Based on atmospheric sampling of volatile anesthetics, states the report, their accumulation is increasing—particularly desflurane.  Inhaled anesthetics account for 5% of acute hospital CO2e emissions and 50% of perioperative department emissions in high-income countries (McGain et al. 2020; MacNeill et al. 2017; Tennison et al. 2021).

    Prioritizing intervention

    The guidance addresses relevant inhaled volatile anesthetics including desflurane, sevoflurane, isoflurane, and halothane, used in general anesthesia, as well as nitrous oxide.  While the environmental impacts of all these agents should be mitigated, the authors counsel, desflurane and nitrous oxide are several times greater in clinically relevant quantities, making them an even greater priority for intervention.  In fact, the authors note that, scaled by clinical potency, the global warming potential of desflurane is ~40 to 50 times that of sevoflurane and isoflurane over a 100-year period (Sherman et al. 2012; Andersen et al. 2012).

    Desflurane is also significantly more expensive than other volatile anesthetics, the guidance states, “with little evidence of clinical benefit justifying its use.”  The authors add that avoiding its use may also result in a cost savings benefit.

    Recommendations and a caution

    The evidence-based recommendations provided in the guidance document include:

    • Providers should avoid inhaled anesthetics with disproportionately high climate impacts, such as desflurane and nitrous oxide.
    • The lowest possible fresh gas flow should be selected when using inhaled anesthetics.
    • Regional anesthesia and intravenous anesthesia should be prioritized and used when appropriate, since they have less of a negative environmental impact.
    • The majority of nitrous oxide is lost, pre-use, and released into the air though leaks in central piping systems that should no longer be used. Portable canisters should be substituted and closed between uses to avoid continuous leaks.
    • Inhalational anesthetic greenhouse gas emissions should be measured at institutional and provider levels, and performance improvement tracked, with clear guidance on science-based targets and timelines for mitigation.
    • More research is needed before recommending investment in the use of technological solutions for capturing or destroying inhaled anesthetic waste, and they should not be considered high mitigation priorities.

    The document also provides guidance on how to educate, implement, measure and review progress on its suggested mitigation actions, along with means to share successes and contribute to the essential global transition towards environmentally sustainable anesthesia.

    Anesthesia providers as global stewards

    “These are practical, evidence-based actions that can be undertaken to reduce the impact of pollution from inhalational anesthetics, without compromising patient care,” write the authors in conclusion.

    “Use of inhalational anesthetics is directly within the control of anesthesia providers and safe alternatives exist; thus, environmental stewardship is an important opportunity for greenhouse gas mitigation and professional sustainability leadership.”

    Click to access the complete guidance document, “Action guidance for addressing pollution from inhalational anaesthetics.”  Included are links to a list of suggested reading, calculators, and other resources to help providers improve environmental performance in peri-operative environments on an individual and organizational level. See also AANA’s Management of Waste Anesthetic Gases, Policy Considerations here.

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