The water method for aiding colonoscope insertion: the learning curve of an experienced colonoscopist

BACKGROUND: The water method has promising features for colonoscopy but the learning curve to master the technique is unknown. AIMS: To describe the learning phase, and pitfalls of the water method and its impact on procedural outcomes by an experienced colonoscopist. DESIGN: Review of prospectively collected data in a performance improvement project SETTING: endoscopy Unit at a VA medical center PATIENTS: 200 consecutive veterans undergoing colonoscopy METHODS: An experienced colonoscopist examined 4 consecutive groups of 25 patients each using the water method to define the learning curve. Outcomes were compared to a historical cohort (n=100) examined by the same colonoscopist using usual air insufflation. MAIN OUTCOME MEASURES: Intent-to-treat (ITT) cecal intubation rate. RESULTS: ITT cecal intubation rate increased from 76% (first) to 96% (fourth quartile). Cecal intubation time in the first 2 quartiles was significantly longer (8.9±1.0 and 8.2±0.8 min, respectively) than that in the historical cohort (5.8±0.4 min) but decreased and became comparable to control values in the next 2 quartiles (7.2±0.9 and 6.6±0.6 min, respectively). Overall adenoma detection rate as a group (55%), compared favorably to the historical cohort (46%). CONCLUSIONS: The water method is relatively easy to learn for an experienced colonoscopist. Mastery of the method resulted in cecal intubation rate and overall adenoma detection rate meeting quality performance standards.