Trial Information

A Randomized, Controlled Trial Comparing Water Exchange, Water Immersion and Air Insufflation Methods During Colonoscopy With the Option of on Demand Sedation

The patients will be allocated into 3 groups by computerized randomization. In group A
(water exchange), water will be infused and removed at the same time throughout the entire
colon during the insertion phase with the air pump turned off. In group B (water immersion),
water will be infused in the insertion phase and removed in the withdrawal phase. The water
will be used mainly to open the lumen, without attempting to clear the colon contents. In
group A and B, warm-to-touch water will be infused mainly infused through the accessory
channel of the colonoscope using a foot-switch controlled water pump (JW2, Fujinon, Saitama,
Japan). Air insufflation not used until the cecum has been reached. . In group C, air
insufflation will be used throughout the procedure. Aliquots of 30 to 50 ml of water will be
used for washing residual stool, as needed. In all three groups, loop reduction maneuvers,
abdominal compression and change of patient position will be utilized at the discretion of
the colonoscopist and recorded. Intubation of the cecum will be defined as successful only
if the base of the cecum is touched with the tip of the colonoscope. Detailed examinations
will be undertaken during the withdrawal phase.

During colonoscopy, a study nurse will ask the patient to report the level of pain (0 =
none, 10 = most severe) at 2 to 3-minute intervals or at any time the patient voiced
discomfort. For pain scores ≧2, maneuvers to minimize pain will be implemented. Immediately
thereafter, the nurse will offer sedation, which the patients can accept or decline. If
accepted, after an initial bolus of 1 mg/kg or 0.5 mg/kg for patients over 65 years propofol
(Diprivan, Astra-Zeneca, Stockholm, Sweden) will be titrated in 20- to 30-mg increments to
achieve an adequate level of sedation. The need of additional drug will be estimated by
patient pain response (moans, grimaces and movements). Usually no more propofol will be
added during the withdrawal phase. The initial amount of propofol, and those before and
after arrival to the cecum will be recorded.

The following parameters will be evaluated and recorded on the patient data sheet: quality
of bowel preparation, cecal intubation time, withdrawal time total procedure time, use of
abdominal pressure, need for changing position, presence of polyps and reasons for
incomplete colonoscopy.