Greenhouse gas emissions usually conjure up images of cars and factories belching smoke, but one of the lesser-known contributors to global climate change involves Dr. Brian Cheseboro’s medical specialty: anesthesiology.

While carbon dioxide is the most common greenhouse emission, the gases used to keep patients asleep and comfortable during surgery are many times more potent, Cheseboro said during a recent presentation in Missoula.

Along with these gases, the electricity used to keep surgical centers running and the waste produced during procedures, the health-care system contributes about 10 percent of all greenhouse gas emissions in the United States.

An anesthesiologist and physician at Providence Portland Medical Center in Oregon, Cheseboro visited Providence St. Patrick Hospital to share his research and data with Missoula Anesthesiology, a group of physicians who provide anesthesia services to local hospitals and medical centers.

Cheseboro studied eight other Providence hospitals in Oregon, and provided St. Patrick’s medical staff with personalized and national data from electronic medical records. His goal: to change the use of anesthesia.

“It’s a topic that some anesthesiologists are familiar with, but most actually are not,” Cheseboro said. “It’s not something that we’re taught during our training program.”

When gas is exhaled after a patient wakes, it travels into the atmosphere and becomes a greenhouse gas, just like carbon dioxide. Administering the right amount of gas for a patient is hard to calculate, Cheseboro said, and most of the time, extra gas is wasted.

Desflurane, Sevoflurane and Isoflurane are the three drugs commonly used to put patients to sleep.

Out of the three, Desflurane is the most potent and expensive, Cheseboro said. And it lasts up to 14 years in the atmosphere. Sevoflurane is less potent and more affordable, and remains in the atmosphere for a significantly shorter time – one year.

“They’re all greenhouse gases, but their potency in the atmosphere is very different,” he said. “Sevoflurane is the least potent greenhouse gas and Desflurane is the most potent. They differ from each other by a factor of 20 to 25 times difference.”

Because technology to capture gas in the operating room is still new, Cheseboro hopes that providers will choose to use Sevoflurane to reduce their carbon footprint.

By doing so, Providence Portland Medical center reduced costs by $130,000 per year and cut gas emissions by 1,100 metric tons of carbon dioxide, the equivalent of 1.2 million miles driven with a Hummer.

“It’s totally achievable and we turned that around in six months, which is pretty easy to do. Everyone has to buy in because it’s really a collective impact. Everyone has to embrace it and welcome the change,” he said.

If all hospitals in Oregon converted to Sevoflurane for a majority of their cases, it would reduce costs by about $750,000 and would keep about 4,500 metric tons of carbon dioxide out of the atmosphere.

At St. Patrick, practice patterns are consistent with baseline practices in most hospitals that were studied, Cheseboro said.

“They are a classic example of a mixed group of people whose practice habits have migrated to rely on one drug or the other most of the time,” he said. “They could probably reduce their financial costs by about 40 percent and reduce their environmental footprint by about 85 or 90 percent as a group, which would be great.”

Beth Schenk, a nurse scientist and sustainability coordinator at St. Patrick Hospital, said that educating hospitals in places like Montana has long been in the works.

Anesthesia gas is exempt from regulation of proper disposal because it is deemed as medically necessary. Recycling gas using emerging technology isn’t fully approved by the FDA, so the drugs are considered an expense for the hospital.

“Because waste anesthesia gas is not regulated as a waste, that decision would be purely on the basis of the hospital,” Schenk said. “In other words, there is no regulatory need to dispose of it carefully and therefore it is seen as just an added expense.”

St. Patrick has adopted different sustainable practices over the years, introducing groundwater cooling in 1992, a food garden and recycling 36 percent of their waste stream in 2017.

Now, as the first hospital in Montana to be given emission information about these gases, Schenk hopes that Missoula Anesthesiology and others will consider changing their habits.

Anesthesiologist Dr. Cristi Sullivan, who works with Missoula Anesthesiology, said the group responded well to Cheseboro’s presentation, and she’s optimistic that many in the group will heed his advice.

Providers often become accustomed to using one drug, Sullivan said, and a few may have a hard time adjusting to Sevoflurane. Sullivan uses Sevoflurane for a majority of her patients.

“We all develop habits of how we work, and once it’s ingrained in us, we don’t really think about them as much and we’re just going through our normal workflow,” she said.

While all anesthesia drugs safely and adequately put patients to sleep, one of the biggest concerns anesthesiologists have with converting to a different drug is the change in rate at which a patient wakes up.

For most operating rooms, it costs a hospital about $20 per minute to run, and having patients wake up quickly is vital, Sullivan said.

With data from thousands of surgeries, Cheseboro was able to show the group the rates in which a patient wakes up with the two drugs. For Sevoflurane cases, it took eight minutes while it took seven minutes for Desflurane cases.

“I would encourage anesthesiologists to try providing Sevoflurane only anesthesia for a month, and they will be able to anticipate and have that reliable wake-up that they seem to have with Desflurane,” she said.

She said that 65 to 70 percent of anesthesiologists with Missoula Anesthesiology use Sevoflurane, while 30 to 35 percent use Desflurane.

“It would be wonderful to see, in another six to 12 months, if we could reduce the percent of our patients who are Desflurane cases significantly,” she said.

In the end, Cheseboro says it’s all about someone’s choice. He hopes to share his research with hospitals in Alaska, Washington and California in the coming months.

“We have choices as anesthesiologists,” he said. “We have choices about which drugs we use and how we use them, and those choices that we make as individuals drives the impact to the hospital’s bottom line and the atmosphere as a whole.”