Split-dose bowel preparation for colonoscopy and residual gastric fluid volume: an observational study

BackgroundSplit-dose bowel preparations for colonoscopy are more effective and better tolerated than preparations given entirely the day or evening before the procedure; however, some resistance to split-dose preparation stems from concerns about an increased risk of aspiration with same-day preparation.ObjectiveWe sought to evaluate residual gastric volumes in patients after split-dose bowel preparations.DesignProspective measurement of residual gastric volumes in patients undergoing same-day EGD and colonoscopy after split-dose bowel preparations, patients undergoing EGD alone, or patients undergoing EGD and colonoscopy after bowel preparation given entirely the evening before the procedure.SettingTertiary care hospital–based endoscopy unit.PatientsThis study involved 712 patients, including 254 in the split-dose bowel preparation group, 411 in the EGD-only group, and 47 in the evening-before-procedure bowel preparation group.InterventionMeasurement of residual gastric volume before endoscopic procedures.Main Outcome MeasurementsResidual gastric volume.ResultsThe mean residual gastric volume in patients receiving split-dose bowel preparation (19.7 mL) was higher than in patients undergoing EGD alone (14.6 mL) but not different from that in patients receiving bowel preparation the evening before the procedure (20.2 mL). Within the split-dose preparation group, there was no association between the interval from last actual fluid ingestion and procedure start time and the residual gastric volume. The range of residual gastric volumes between study arms was similar.LimitationsNonrandomized study. The number of inpatients undergoing split-dose bowel preparation was small.ConclusionThese data support the safety of split-dose bowel preparation for outpatients undergoing colonoscopy.