Comparison of Adenoma Detection Rate Among Water, Carbon Dioxide and Air Methods of Minimal Sedation Colonoscopy

Significance: ADR is an independent predictor of risk of post screening colonoscopy colon cancer. A simple method solely controlled by the colonoscopist that enhances proximal ADR holds the promise of rectifying some of the unresolved shortcomings of screening colonoscopy in failing to reduce the occurrence of post screening incident cancers in the proximal colon and the associated cancer mortality. Hypotheses \& Specific Aims: Primary Hypothesis: In patients undergoing first time screening a higher ADR will be found in the proximal colon in those randomized to the water method compared to those randomized to the air method or CO2 method. Secondary Hypotheses: The examination method but not co-variables, procedure-related or patient-centered outcomes, is an independent predictor of proximal colon ADR. Specific Aims: This is a prospective, randomized, single-blinded controlled study to compare the study (water) and control 1 (air) method and control 2 (CO2 method) to aid insertion of the colonoscope. The proximal colon ADR, total ADR, co-variables, procedure-related and patient-centered outcomes and adverse event during and within 30 days of colonoscopy will be recorded and compared between the study and control methods.