The American Society of Anesthesiologists (ASA) preoperative fasting guidelines outline a certain number of hours patient should fast based on their last intake (ie, 6 hours for a light meal) The goal is to prevent perioperative aspiration of gastric contents into the airway. Fortunately, the new paradigm is now timely preoperative nourishment/hydration up until a few hours before surgery with carbohydrate rich beverages. But what about CHEWING GUM before surgery? Does that impact gastric volume/pH enough to warrant delaying elective cases? Let’s (briefly) review some literature.
A meta-analysis by Ouanes et al. (PMID: 25442242) reviewed 287 patients across four prospective randomized controlled trials (RCTs). Each trial compared a cohort that chewed gum preoperatively (treatment group, 174 patients) to another that did not (control group, 113 patients) and provided documentation of gastric volume and/or pH. The pooled statistics showed a small but statistically significant increase in gastric volume in the group that chewed gum, but no significant change in gastric pH.
A subsequent RCT by Goudra et al. (PMID: 25362513) analyzed the gastric volume/pH of 67 patients (34 who chewed gum and 33 who did not) prior to EGD or combined EGD with colonoscopy under propofol sedation. Similar to the aforementioned meta-analysis, the authors showed a statistically significant increase in gastric volume but not statistically significant difference in gastric pH.
In general, the consensus among my physician anesthesiology colleagues is that the increase in gastric volume in patients who chew gum preoperatively probably does not have any clinical relevance, and should therefore not delay/cancel elective surgeries for this reason alone.
If you are a patient, I am NOT CONDONING chewing gum before your surgery – please follow the instructions provided to you.