Chewing gum while fasting before surgery is safe, study finds

It is well known that patients should avoid eating and drinking before surgery to help prevent complications while under anesthesia. But is it safe to chew gum? Although chewing gum significantly increases the volume of liquids in the stomach, it is safe to administer sedatives or anesthesia to patients who have chewed gum while fasting before surgery, reports a new study presented at the ANESTHESIOLOGY™ 2014 annual meeting.

“The effect of chewing gum on fasting has been a subject of debate, and unsuspecting patients who chew gum before surgery may face cancellation or delay of their procedure,” said Basavana Goudra, M.D., lead author and assistant professor of clinical anesthesiology and critical care at Perelman School of Medicine at the University of Pennsylvania, Philadelphia.  “We found that although chewing gum before surgery increases the production of saliva and thus the volume of stomach liquids, it does not affect the level of stomach acidity in a way that would elevate the risk of complications."

Preoperative fasting guidelines recommended by the American Society of Anesthesiologists^® (ASA^®) do not allow eating or drinking, for a specific period of time before anesthesia is administered due to the risk of pulmonary aspiration, a serious complication in which stomach contents are drawn into the respiratory tract during breathing.  Fasting helps prevent pulmonary aspiration by keeping stomach contents and acidity levels low.  If stomach contents include very high acidity levels, even a small amount can cause life-threatening pulmonary aspiration.  Although the ASA guidelines do not explicitly mention chewing gum, it is typically considered a non-clear liquid and not allowed before surgery.

In the study, 67 patients scheduled to undergo gastrointestinal endoscopic procedures were randomly divided into two groups. Thirty-four patients were allowed to chew gum until just before the start of their procedure, while 33 patients continued to follow the recommended fasting guidelines. There was no limit on the type, number of gums chewed or duration of chewing. After sedation and endoscope insertion, stomach contents were suctioned and volume and pH (acidity) were measured.

The mean gastric volume, or total amount of liquid in the stomach, was statistically higher in patients who chewed gum before their procedure (13ml) versus those who did not (6ml). However, there was no statistically significant difference in pH values.

“While we wouldn’t actively encourage gum chewing in patients presenting for procedures involving anesthesia, in the absence of other aspiration risk factors, patients who inadvertently chew gum should not face cancellation or delay of a surgery or procedure with anesthesia,” said Dr. Goudra.