Sustainable Anesthesia

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Nurse anesthetists should focus on environmental concerns associated with operative waste

The practice of anesthesia is one of the most significant innovations in modern medicine. The continued progress in the development of safer, more effective anesthetic agents has improved outcomes and contributed to decreased mortality and overall patient safety. With these achievements in medicine, however, come the unintended effects of environmental pollution and threats to population health.1 Socially, the trends towards more environmentally friendly behaviors are becoming more widely adopted and so to should our anesthetic practice.

Recognizing the very real effects of climate change and the finiteness of our resources are compelling motivations for anesthetists to raise awareness in our clinical and educational settings to what is referred to as “sustainable anesthesia.”2 The American Association of Nurse Anesthetists recognizes that there are many environmentally challenging issues facing anesthetists ranging from disposal of waste anesthetic agents, medical wastes, plastics, and disposable materials.3

As such, it is the anesthetists’ professional responsibility to promote awareness of environmentally friendly practice, the costs associated with disposal of medical and infectious wastes, and promote overall conditions of safety within our workplaces.2 As we commonly identify the potentially caustic effects associated with medical and pharmaceutical wastes and our abundant production of trash, one of the foremost (and often overlooked) considerations is that of waste inhalational anesthetic agent.

Lasting Environmental Effects

Currently, there is a large repository of literature that reflects the lasting caustic effects of the anesthetic agents we use and their effects in our environment. All halogenated anesthetic agents accumulate in the environment contributing to ozone layer depletion and the propensity for furthering intractable damage by acting as compounds similar to chlorofluorocarbons (CFCs).4,5 In fact, the estimated 50 million general anesthetics that are provided yearly produce as many carbon emissions as a million automobiles.4,6 Desflurane and Nitrous Oxide possess such lasting degradation times (8.9 – 21 years and 114 years, respectively) that experts suggest sparingly using these agents unless it will significantly impact patient/clinical outcomes.5,7 The agent with the shortest lifetime (1.2-4 years) is Sevofluane.5

The overall stability of these agents permits the direct passing into our stratosphere wherein their chemical structure and atmospheric interactions promote ozone degradation.8 The more prevailing and ominous factor associated with halogenated agents, however, is their significantly more potent effect on global warming potential (GWP) – which have thousands of times more effect than CO2.4 With growing consumption of anesthetic agents the waste gasses will continue to accumulate into already measurable atmospheric levels as we exceed and estimated 280 tons yearly.9 Yet, there seems to be very little impetus to enact significant educational awareness or implement meaningful practice change commensurate with these very compelling (and frankly, well-known) findings.

Thus, it begins within our educational programs and clinical practices. An overall investment in the dissemination of these facts and other compelling relevant data needs to become a mainstay in our professional organizations mission and our own individual practices.

Better Preparation is Needed

In addition, much more attention and consideration need to be given to the choice of anesthetic agent and plan in preparation for surgical procedures. Regional anesthetics, when appropriate, may be more desirable given their non-dependence on inhalational agents and accompanying high safety index. When general anesthesia is absolutely necessary, a much more deliberate selection of anesthetic agent needs to take into consideration the patient’s specific history and length of surgery. The anesthetists’ management during the case may improve environmental conditions by employing agent-sparing techniques (such as low-flows) and making reasonable attempts to keep agent doses minimal (i.e. maintaining depth at 1 MAC or less as tolerated). Outside of these rather traditional considerations – it is incumbent upon the anesthetist to be more environmentally conscientious.

Our clinical and didactic curriculums need to evolve with the aforementioned trends of environmental safety to include a more diverse topical focus on the deliberate choices we make in concert with environmental concerns. Safest anesthetic practice will always be our foremost goal but they may not always be mutually exclusive. Outside of (inhalational) anesthetic agents, equal attentions need to be considered in our choice of anesthesia drugs based on likeliness of utilization and requisite needs. The American Society of Anesthesiologists (ASA) PBT (persistence, bioaccumulation, and toxicity) Index highly rates both Propofol and Fentanyl (9, 8, respectively).10 The PBT Index is a summation of the three categories on a 1-3 basis on each metric thus suggesting that each of these agents is highly persistent, toxic, and has significantly lengthy degradation times.11 Indeed, the ASA position on waste reduction calls for a more conscientious appraisal of our needs and patient requirements as a means of reducing our medications.

If a more serious consideration to the environmental effects of our clinical approaches for anesthetic management of patients is achieved, it is very likely that we can make significant reductions to the cumulative effects of waste anesthetic gases and other anesthetic agents. Modifications within our clinical practices in very reasonable ways by making more thoughtful choices in our management of cases may significantly improve environmental outcomes – for everyone.

References

1. Herring, A. (2012). The environmental impact of anesthetic gases. Retrieved from http://www.northeastern.edu/news/2012/05/anesthetic-gases/

2. Ryan, S. & Sherman, J. (2012). Sustainable Anesthesia [Editorial]. International Anesthesia Research Society, 114(5), pp. 921-923.

3. Kole, T. E. (1992). Reduce, reuse, and recycle in the anesthesia workplace [Guest Editorial]. Journal of the American Association of Nurse Anesthetists, 60(2), pp.109-112.

4. Ishizawa, Y. (2011). General anesthetic gases and the global environment. International Anesthesia Research Society, 112(1), pp.213-217.

5. Bosenberg, M. (2011). Anaesthetic gases: Environmental impact and alternatives. Southern African Journal of Anaesthesia and Analgesia, 17(5), pp. 345-348.

6. Nusca, A. (2010). Surgical anesthesia is eating the ozone, study says. Retrieved from
http://www.zdnet.com/article/surgical-anaesthesia-is-eating-the-ozone-layer-study-says/

7. International Anesthesia research Society (2012). Special issue of Anesthesia & Analgesia looks at ‘sustainable anesthesia.’ Retrieved from http://newswise.com/articles/special-issue-of-anesthesia-analgesia-looks-at-sustainable-anesthesia

8. Goyal, R. & Kapoor, M. C. (2011). Anesthesia: Contributing to pollution? Journal of Anaesthesiology Clinical Pharmacology, 27(4), pp. 435-437.

9. Gray, R. (2015). Anaesthetic is warming the planet: Gases used to knock out patients during surgery are contributing to climate change. Retrieved from http://www.dailymail.co.uk/sciencetech/article-3030881/Anesthetic-WARMING-planet-
Gases-used-knock-patients-surgery-contributing-climate-change.html

10. American Society of Anesthesiologists (2012). Greening the operating room: Reduce, reuse,recycle, and redesign. Retrieved from
http://www.asahq.org/…/madom/madom-2016/20160426madomwinter2016chapter3/en/1

11. Whitacre, D., M. (2009). Reviews of Environmental Contamination and Toxicology, 119, (Chapter 1, p. 15). New York, NY: Springer.

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About Author

Richard R. Tennesen, CRNA, MS, BSN

Richard R. Tennesen is a certified registered nurse anesthetist at the Reading Hospital in Reading, Pa.

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