Chewing gum for 1 h does not change gastric volume in healthy fasting subjects. A prospective observational study.

STUDY OBJECTIVE

Perioperative fasting guidelines differ in their approaches to chewing gum in the preoperative period. Current recommendations range from canceling the surgery to proceeding with it. Given this lack of consensus, we performed gastric ultrasound assessments in healthy volunteers before and after a standardized period of chewing gum. The objective of our study was to determine if chewing gum for 1 h change the gastric volume.

DESIGN

Observational prospective analytical study.

SETTING

Bedside gastric ultrasound.

PATIENTS

Following institutional Review Board approval, 55 healthy (American Society of Anesthesiologists class I to II) fasted (non-surgical research) volunteers provided written informed consent to participate in the study. Morbid obesity, renal failure, diabetes mellitus, pregnancy and previous upper abdominal surgery were exclusion criteria.

INTERVENTIONS

Volunteers chewed gum for 1 h between the first and second assessment.

MEASUREMENTS

Four gastric ultrasound assessments were performed, the first one at baseline and then hourly thereafter.

MAIN RESULTS

Fifty-five healthy volunteers were studied. The proportion of subjects who presented a completely empty stomach (Grade 0 antrum) was similar at baseline and after 1 h of gum-chewing [81% vs. 84%, p = 0.19, CI 95% (-12%, 16%)]. Among those subjects who had visible fluid at baseline, the volume remained unchanged throughout the study period.

CONCLUSIONS

One hour of gum-chewing had no significant effect on the gastric fluid volume of healthy volunteers, suggesting that it may be safe for healthy subjects to chew gum prior to elective surgery.