November 23, 2023

A painful debate: shrinking the carbon footprint of anaesthetics

If there is any profession which seems remote from the Sturm und Drang of climate change, it must be anaesthetists. After all their job is making you go to sleep.

Not so. Behind closed doors of operating theatres, there is a vigorous debate about the impact of inhaled anaesthetic gases on global warming. In a forum for the Journal of Medical Ethics, four British doctors write that “Those seemingly innocuous anaesthetic gases are actually powerful greenhouse gases. The most notorious, desflurane, is thousands of times better than carbon dioxide at trapping heat energy from the sun, thereby causing global warming.”

What should be done?

The problem is well known amongst anaesthetists. Last year the American Society of Anesthesiologists issued a guidance statement which advises its members: “Providers should avoid inhaled anesthetics with disproportionately high climate impacts, such as desflurane and nitrous oxide”. But little is happening, say the JME authors: “change has been patchy and inconsistent. The revolution is pending.”

Should gases like desflurane be abandoned? A tricky ethical question is involved here. Traditionally, treatment options should be assessed by the benefit to patients, not the benefit to the environment. There is no suggestion that anaesthetics should be banned to save the planet, even if some doctors might believe that anaesthetic gases are better than IV anaesthetic drugs.

However, the JME authors insist that a revolution is needed in their profession. There are four avenues to persuade doctors to stop global warming: consensus (impossible), education (too slow), abandoning desflurane completely (unlikely), and nudges (possible). So They suggest simple steps like placing gas canisters in a different room to make inhalant gases more difficult to use. “The crucial advantage of nudges,” they say, is that they can be effective in bringing about change but don’t force anaesthetists to make certain decisions and they can be implemented without consensus.”

There is always another side in any debate. In a letter to The Guardian in 2021, Dame Julia Slingo, a former Met Office chief scientist and Dr Mary Slingo, an anaesthetist, claimed that the effect of anaesthetic gases is insignificant. “Even for an abundant, well-mixed and long-lived gas like CO2 we are still not certain how sensitive our global and regional climate will be. For anaesthetic gases, any impact of its tiny emissions and radiative forcing on our climate system will, quite frankly, be ‘lost in translation’.”

Dr Sligo also wrote an article in the British Journal of Anaesthesia. In it she described some disadvantages of the alternative: “Although life-cycle analysis of anaesthetic agents may appear to favour i.v. [intravenous] anaesthesia, these calculations have again been made using misplaced CO2 equivalence. Thus, moving away from inhalational anaesthesia to TIVA may actually increase the addition of long-lived carbon to the atmosphere because of the vast quantity of plastic required.”