MUSC studies effects of popular diabetes and weight loss drugs on surgical patients

August 07, 2023
four people in scrubs and medical masks look down toward the camera lens. One woman holds a tube to deliver anesthesia.
MUSC is conducting two clinical trials focusing on the effects of GLP-1 agonists such as Ozempic on surgical patients. iStock

The patient had done everything right – fasting and temporarily going off Ozempic, which she took for diabetes – but something was off. As anesthesiologist Renuka George, M.D., documented on X, formerly known as Twitter, the patient’s stomach was full as the team at MUSC Health prepared to operate.

“The volume of stomach content was surprising given all the precautions the patient had taken,” George said. “We emptied the stomach with an orogastric tube to be safe.”

She posted about it as a cautionary tale for colleagues across the country, reminding them to be conservative and not take chances. George, fellowship director of Regional Anesthesia and Acute Pain Medicine at the Medical University of South Carolina, said a full stomach during surgery is dangerous.

“What happens with some of these drugs that we're seeing is that that food stays in your stomach,” she said.

Dr. Renuka George

“It doesn't move forward and doesn't clear out as it normally does. And so that runs a risk of what we in anesthesia get concerned about, which is pulmonary aspiration where that food can come up through the esophagus and then go down the trachea into your lungs." 

While George was surprised by the amount of food that remained in the patient’s stomach, she and her colleagues at MUSC knew food retention was a possibility. Ozempic falls into a category of diabetes and weight drugs called GLP-1 agonists. They slow the passage of food through the body.

But how long do the effects last when someone temporarily stops taking them before surgery? Do doctors need to change their standard procedures, and if so, how? The American Society of Anesthesiology recently released guidance to help them.

"Aspiration is a big concern for anesthesiologists – enough that we're talking about GLP-1 at all our national conferences. Here at MUSC, our department is taking measures to make sure that everyone on the perioperative team is educated regarding GLP-1 agonists and the ASA guidance, offering gastric ultrasound training to attendings and residents and conducting research studies so that we can promote evidence-based care,” George said.

MUSC is conducting two clinical trials focusing on the effects of GLP-1 agonists on surgical patients. “This is where I think MUSC is doing a fabulous job. We've, as far as I'm concerned, been out ahead of the game,” George said.

Ultrasound study

Christopher Wolla, M.D., an anesthesiologist and assistant professor in the College of Medicine, is leading one of the studies.“My research employs the use of point-of-care ultrasound, or bedside ultrasound, to evaluate gastric/stomach contents prior to surgery,” he said.

“All patients coming for elective surgeries will have fasted, typically at least eight hours for solid foods and two hours for clear liquids, so they have an empty stomach in order to prevent aspiration of gastric contents into the lungs, which can have serious effects, including pneumonia or even staying on a ventilator after surgery.”

Wolla said while there’s anecdotal evidence, such as George’s experience, along with a small number of case reports, there haven’t been any randomized clinical trials looking at the effects of GLP-1 agonists on gastric emptying before surgery. 

“My study will enroll diabetic patients coming to MUSC for elective surgeries. We will then perform a bedside gastric ultrasound prior to surgery and measure the amount of food/fluid in the stomach comparing the amount between patients that take GLP-1 receptor agonists versus patients that do not take GLP-1 receptor agonists.”

Wolla plans to start enrolling 250 patients in his trial this week. 

Endoscopy study

Ryan Wilson, M.D., also an anesthesiologist and assistant professor, is coming at the effects of GLP-1 agonists on surgical patients from another angle: the upper endoscopy. It uses a flexible tube with a camera to let doctors see what’s in the stomach. 

“We know that GLP-1 receptor agonist medications slow the movement of food out of the stomach and forward in the GI tract, but we don't currently know how long this effect remains or how severe it will be in any one patient,” he said.

“Our study will investigate the frequency with which patients who undergo upper endoscopy have retained stomach contents visualized by the camera during their study after appropriate fasting times. We will compare this statistic between patients on GLP-1 RA medications and the general population, with the hypothesis that retained stomach contents will be found more frequently in patients taking these medications, thereby presenting an increased risk of aspiration during anesthesia,” he said. 

Both studies will give doctors data on which to base their decisions, something that’s currently lacking. “These GLP-1 RA medications, like Ozempic, have been discussed incredibly often in the public sphere within the past year, usually associated with their impressive weight loss effects, and more and more patients have started to take these medications,” Wilson said. 

“As an anesthesiologist, this is an example of our unique role in being a mediator between a patient's long-term health goals – good glycemic control in diabetes and continued weight loss efforts in obesity care – and their short-term perioperative safety. Accurately assessing risk-benefit decisions is something we do on a daily basis.”

Patients’ roles

George, the anesthesiologist who posted about her patient’s full stomach on X, said patients have a role to play, too. “Be as upfront as possible with your anesthesiologist. I get it. Not many people want to advertise that they're on a weight loss supplement. But this is one of those situations that you want to be as honest as possible.”

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