title: Residual Gastric Volume After Bowel Preparation With Polyethylene Glycol for Elective Colonoscopy: A Prospective Observational Study.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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 P<0.0001, respectively). Within the bowel-preparation groups, patients with fasting times of 2 to 3 hours had similar RGV compared with patients who had fasting times >3 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.
authors.affiliation: *Department of Medicine, Division of Gastroenterology, Zhongli Evergreen Hospital †Department of Medicine, Division of Gastroenterology, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan ‡Department of Medicine, Division of Gastroenterology, Taipei Medical University Hospital, Taipei, Taiwan.
authors.forename: Chi-Liang
authors.initials: CL
authors.lastname: Cheng
authors.forename: Nai-Jen
authors.initials: NJ
authors.lastname: Liu
authors.forename: Jui-Hsiang
authors.initials: JH
authors.lastname: Tang
authors.forename: Yen-Lin
authors.initials: YL
authors.lastname: Kuo
authors.forename: Cheng-Hui
authors.initials: CH
authors.lastname: Lin
authors.forename: Yi-Ning
authors.initials: YN
authors.lastname: Tsui
authors.forename: Bai-Ping
authors.initials: BP
authors.lastname: Lee
authors.forename: Yun-Chiu
authors.initials: YC
authors.lastname: Tai
authors.forename: Ming-Yao
authors.initials: MY
authors.lastname: Su
authors.forename: Cheng-Tang
authors.initials: CT
authors.lastname: Chiu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003113:Colonoscopy; D016292:Procedural Sedation; D004334:Drug Administration Schedule; D017558:Elective Surgical Procedures; D016145:Endoscopy, Digestive System; D005260:Female; D005766:Gastrointestinal Contents; D006801:Humans; D008297:Male; D008875:Middle Aged; D011092:Polyethylene Glycols / Q000008:administration & dosage*; D011300:Preoperative Care; D011446:Prospective Studies; D013270:Stomach / Q000502:physiology*
chemical_list: D011092:Polyethylene Glycols