When prepping a patient for surgery, global warming may be the last thing on your mind. But the anesthetics used by a busy hospital contribute as much to global warming as the emissions from hundreds of cars a year, according to a new study published in the July issue of Anesthesia & Analgesia.
Depending on the type of anesthetic used, an average mid-size hospital may equal the environmental impact of 100 to 1,200 cars per year.
"Changes people could make in their practice right away" could improve the health of the community and the health of the planet, Dr. Susan Ryan, a clinical professor of anesthesiology at the University of California, San Francisco, told the Sacramento Bee. She was lead author of the article, which calculates the relative impact of commonly used inhaled anesthetics, which are recognized greenhouse gases.
Three major inhaled anesthetics--sevoflurane, isoflurane and desflurane--undergo little metabolic change in the body. What's exhaled by the patient is almost the same as what was administered by the anesthetist. Anesthetics are usually vented out of the building as medical waste gases, the researchers write.
Most of the organic anesthetic gases remain for a long time in the atmosphere where they have the potential to act as greenhouse gases. And some, such as desflurane, have a much longer lifetime in the atmosphere than other anesthetics studied. Desflurane lasts 10 years, compared with four years for isoflurane. Using desflurane for one hour, the study's authors say, is comparable to driving between 235 and 470 miles.
Ryan and company suggest steps anesthesiologists can take to reduce the impact of anesthesia care on global warming. Avoid nitrous oxide, unless there are medical reasons to use it, and avoid unnecessarily high anesthetic flow rates, especially with desflurane.
To learn more:
- read the press release from the International Anesthesia Research Society
- read the story in the Sacramento Bee