Effect of Gum Chewing on the Volume and pH of Gastric Contents: A Prospective Randomized Study

Insufficient fasting prior to endoscopic procedures performed under sedation may result in potential aspiration of gastric contents. Fasting as per ASA guidelines is recommended prior to these procedures. However, the effect of chewing gum on fasting status has been a subject of debate and often leads to procedural delays.

Evaluation of the effect of chewing gum on the gastric volume and pH.

In this randomized controlled prospective observer blinded trail, ASA I-III patients aged more than 18 years scheduled for esophagogastroduodenoscopy (EGD) or a combined EGD and colonoscopy under conscious sedation were studied. Patients randomized to the chewing gum group (Group-C) were allowed to chew gum until just before the start of their procedure; the remaining patients were included into Group-NC. After sedation and endoscope insertion, stomach contents were aspirated under vision of a gastroenterologist (blinded to groups).

Volume and pH of gastric contents aspirated from 67 patients (34 in Group-C and 33 in Group-NC) were analyzed. The demographic parameters of the groups were comparable. Gastric volume (median-interquartile range) was statistically higher in Group-C (13 ml (7.75-40.75) vs Group-NC 6 ml (1.00-14.00) (P < 0.001)]. The mean pH in both groups was comparable: 2.84 ± 2.11 in Group-C and 3.79 ± 2.53 in Group-NC (P = 0.141).

Although our results show gastric volume in patients chewing gum was statistically higher, clinical relevance of such a small difference is questionable. Thus patients who chewed gum inadvertently prior to procedure should not be denied or delayed administration of sedative and anesthetic medications.