title: A head-to-head comparison of the water vs. air method in patients undergoing screening colonoscopy.
abstract: BACKGROUND: The water method facilitates colonoscope insertion in unsedated patients.  OBJECTIVE: To compare quality indicators in sedated veterans.  DESIGN: Performance improvement.  SETTING: VA endoscopy unit.  PATIENTS: 368 consecutive screening patients.  INTERVENTION: Air or water method assignment (high definition colonoscope) was based on the last digit of social security number.  MEASUREMENTS: Adenoma detection rate (ADR), cecal intubation rate; intubation and withdrawal times; sedation requirements and external pressure used.  RESULTS: ADR was higher with the water method (57.1% vs. 46.1%, p=0.04). After controlling for age, body mass index, smoking, alcohol, withdrawal time and quality of bowel preparation, the odds of detecting an adenoma was 81% higher with the water method (OR 1.81; 95% cI: 1.12-2.90). In the proximal colon ADR was higher with the water method (45.8% vs. 34.6%, p=0.03), including adenomas <10 mm in size (41.8% vs. 31.4%, p=0.04). The water method showed significantly longer cecal intubation time (6.9±0.3 vs. 5.3±0.3 min, p=0.0001); less external pressure used (11.9% vs. 28.3%, p=0.0001); lower need for additional sedation (17.5% vs. 27.2%, p<0.03).  LIMITATIONS: Predominance of males, single unblinded endoscopist with high ADR.  CONCLUSIONS: The water method is an independent factor associated with significantly higher ADR. Replication by blinded colonoscopist(s) is indicated.
authors.affiliation: Mayo Clinic Scottsdale, AZ, United States.
authors.forename: Francisco C
authors.initials: FC
authors.lastname: Ramirez
authors.forename: Felix W
authors.initials: FW
authors.lastname: Leung