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Comparative Efficacy of Water & Indigo Carmine vs Water or Air Method

45 Years
75 Years
Open (Enrolling)
Colorectal Neoplasms

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Trial Information

Comparative Efficacy of Water & Indigo Carmine vs Water or Air Method

1. Design: Prospective, single center, patient blinded, randomized controlled trial

2. Methods: Colonoscopy with traditional air insufflation, water exchange or water
exchange plus indigocarmine to aid insertion of colonoscope; split dose bowel
preparation; all patients will receive sedation; assessment of serum electrolytes level
before and after colonoscopy

1. Control method: Traditional air insufflation method.

2. Study methods:

- Water exchange method.

- Water method combined with chromoendoscopy (0.008% indigo carmine).

3. Population to be studied Veterans between age 50 and 75 referred for first time
screening colonoscopy

4. Unit(s) of analysis

1. Primary outcome: overall adenoma detection rate.

2. Secondary outcomes: patient demographic variable and procedure related measures.

5. Sampling strategy: all veterans referred for screening colonoscopy will be offered
enrollment in the study.

1. Sample size calculation. A total of 480 subjects will be recruited and randomized
with 160 in each group.

5. Subject recruitment: patients referred for screening colonoscopy come from three sources.

6. Description of base population and groups to be studied and method of randomization.

Veterans between age 50 and 75 referred for first time screening colonoscopy. After informed
consent, assignment to control or study arm based on computer generated random number codes
stored in pre-arranged opaque envelopes.

Inclusion Criteria:

- asymptomatic veterans scheduled for first time screening colonoscopy and agree to be
randomized will be enrolled.

Exclusion Criteria:

- patients who decline to be randomized, non screening cases.

Type of Study:


Study Design:

Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Parallel Assignment, Masking: Single Blind (Subject), Primary Purpose: Treatment

Outcome Measure:

Proximal diminutive (<10 mm) adenoma detection rate

Outcome Description:

Proximal diminutive adenoma detection rate (ADR) in screening colonoscopy performed with the unusual air method, versus the water (exchange) method and with dye added to the water (exchange) method

Outcome Time Frame:

36 months

Safety Issue:


Principal Investigator

Joseph W. Leung

Investigator Role:

Principal Investigator

Investigator Affiliation:

VA Northern California Health Care System, Mather, CA


United States: Federal Government

Study ID:




Start Date:

May 2013

Completion Date:

September 2015

Related Keywords:

  • Colorectal Neoplasms
  • adenoma detection
  • screening colonoscopy
  • water exchange method
  • chromoendoscopy
  • Neoplasms
  • Colorectal Neoplasms



VA Northern California Health Care System, Mather, CASacramento, California  95655