Patients can't eat or drink before surgery, but can they safely chew gum? Apparently so, according to a study presented at the annual meeting of the American Society of Anesthesiologists in New Orleans.

Researchers studied 67 patients who underwent gastrointestinal endoscopic procedures, 34 of whom were allowed to chew any amount and any kind of gum beforehand. Suction of the patients' stomach contents showed gum chewers had higher average gastric volume, but there was no significant difference in acidity values.

Pre-op fasting is intended to limit stomach contents and gastric acidity levels, which lowers risk of potentially deadly pulmonary aspiration. Guidelines issued by the ASA classify gum as a clear liquid, and suggest it shouldn't be chewed before surgery.

Basavana Goudra, MD, study lead author and assistant professor of clinical anesthesiology and critical care at Perelman School of Medicine at the University of Pennsylvania in Philadelphia, says policies about pre-op gum chewing have been debated by healthcare professionals and unknown by some patients, who risk having procedures delayed or cancelled by popping a few pieces in the hours leading up to surgery.

"We found that although chewing gum before surgery increases the production of saliva and therefore the volume of stomach liquids, it does not affect the level of stomach acidity in a way that would elevate complication risks," explains Dr. Goudra.

He says patients shouldn't be encouraged to chew gum before procedures involving anesthesia, but the habit shouldn't necessitate the cancellation or delay of scheduled cases if other aspiration risk factors aren't present.

Daniel Cook