Residual Gastric Volume After Bowel Preparation With Polyethylene Glycol for Elective Colonoscopy: A Prospective Observational Study

GOAL:To examine the residual gastric volume (RGV) in colonoscopy after bowel preparations with 3-L polyethylene glycol (PEG). BACKGROUND:Obstacles to high-volume bowel preparation by anesthesia providers resulting from concerns over aspiration risk are common during colonoscopy. STUDY:Prospective measurements of RGV were performed in patients undergoing esophagogastroduodenoscopy (EGD) and morning colonoscopy with split-dose PEG preparation, patients undergoing EGD and afternoon colonoscopy with same-day PEG preparation, and patients undergoing EGD alone under moderate conscious sedation. Colonoscopy patients were allowed to ingest clear liquids until 2 hours before the procedure. Patients undergoing EGD alone were instructed to eat/drink nothing after midnight. RESULTS:There were 860 evaluated patients, including 330 in the split-dose preparation group, 100 in the same-day preparation group, and 430 in the EGD-only group. Baseline demographics and disease/medication factors were similar. The mean RGV in patients receiving the same-day preparation (35.4 mL or 0.56 mL/kg) was significantly higher than that in patients receiving the split-dose preparation (28.5 mL or 0.45 mL/kg) and in patients undergoing EGD alone (22.8 mL or 0.36 mL/kg) (P=0.023 and P3 hours. The shape of the distribution and the range of RGV among the 3 study groups were similar. No aspiration occurred in any group. CONCLUSIONS:PEG bowel preparations increase RGV mildly, but seem to have no clinical significance. These results support the current fasting guidelines for colonoscopy.