Right before surgery, the climate crisis is probably the last thing on your mind. If you’re under general anesthesia, you actually might not be thinking about much of anything at all. But anesthetics—especially the generalized kind—can have a pretty big impact on the climate. A new study in the journal Regional Anesthesia and Pain Medicine suggests that hospitals should consider switching to local anesthetics whenever possible to reduce those impacts.
Regional and general anesthetics both work as numbing agents, but do so differently. With the local kind, an anesthesiologist makes an injection near a cluster of nerves to numb the specific area of the body that requires surgery, whereas the generalized kind is inhaled as a gas, and makes the patient feel stoned or unconscious. Often, doctors use both together.
The problem is that the most common inhalants used for general anesthesia are nitrous oxide (or laughing gas) and desflurane. Both are greenhouse gases that can stay in the atmosphere for decades and wreak havoc on the climate (they also damage the ozone layer to boot). In fact, nitrous oxide is nearly 300 times more potent than carbon dioxide in terms of planet-warming potential. Desflurane’s potential is up to 3,700 worse than carbon dioxide, making it one of the most intense greenhouse gases in use. The process of using these drugs is also wasteful. When doctors administer these gases, patients inhale just 5% of them. The rest of gets sucked into a ventilation system, and then floats up into the atmosphere.
That all has a big impact on the climate. In 2009, more than one million hip and knee replacement procedures—which are usually done with general anesthesia—were performed in the U.S. alone. The authors calculated that if all of these were done under general anesthetic, that would be the equivalent of nearly 247,000 lbs (112,000 kilograms) of desflurane and nearly 20,000 lbs (9,000 kilograms) of nitrous oxide released into the atmosphere. That’s equivalent to burning more than 3.2 million pounds of coal.
Despite the widespread use of general anesthetic, the study shows it’s possible for hospitals to cut their use of greenhouse gas-based anesthetics using the real-world example of New York’s Hospital for Special Surgery. On average, doctors use generalized anesthetics in 75% of hip and knee replacement surgeries, but in 2019, the hospital chose regional anesthesia in those procedures whenever they could. Out of the 10,485 hip and knee replacements it carried out that year, hospital doctors gave just 4% of patients general anesthetic. Doing so, the study found, saved the greenhouse gas equivalent of burning nearly 27,000 lbs. (12,246 kilograms) of coal.
“Our findings were somewhat surprising as on a daily basis, anesthesiologist often do not consider the environment impact of their choices of anesthetics for our patients,” Christopher L. Wu, an anaesthesiologist at the Hospital for Special Surgery and lead author of the study, told Earther in an email.
The authors recognize that their study is limited, because they didn’t compare the environmental impact of producing general versus regional anesthetics. That could include the use of plastics and other items that might have other impacts on the planet. They also note that some procedures can’t easily be switched to regional anesthesia. Heart surgery, for instance, would be pretty awful for a patient that’s not knocked out.
Nonetheless, the new research shows that medical providers have a massive opportunity to cut its emissions, and that doing so could have a positive impact on the climate crisis. The health care sector accounts for 8% of the U.S. greenhouse gas footprint, and 39% of that impact comes from hospitals.
Cutting those emissions will be important going forward for many reasons, including reducing the burden on the health care system that climate change poses. Research shows that choosing local anesthetics have other benefits, too, including providing more effective pain relief with fewer unpleasant side effects. So by switching, Wu says, “we can not only decrease greenhouse gases and address climate change but also improve patient care and outcomes at the same time.”