Comparison of Methods to Distend the Colon During Insertion: CO2, Air Insufflation, Water-aided Colonoscopy
Condition: Pain; Colorectal Adenomas; Colorectal Cancer
MeSH terms: Adenoma
Study type: Interventional

Summary: 
      Insufflation of the colon, usually with room air, is necessary to distend the lumen for
      exploration. Carbon dioxide (CO2) insufflation instead of room air insufflation (AI) has been
      shown to decrease symptoms of abdominal pain or discomfort during the procedure and
      particularly during the following 24 hours. CO2 is is rapidly absorbed by the intestinal
      mucosa and exhaled through respiration. AI colonoscopy has usually been the reference
      standard to compare colonoscopy using CO2 insufflation. In two recent articles AI was
      compared to either CO2 insufflation and Water-aided colonoscopy (WAC), which entails infusion
      of water to facilitate insertion to the cecum.

      WAC can be categorized broadly in Water Immersion (WI) and Water Exchange (WE). In WI water
      is infused during the insertion phase of colonoscopy, with removal of infused water
      predominantly during withdrawal. Occasional use of insufflation may be allowed. WE entails
      complete exclusion of insufflation, removal of residual colonic air pockets and feces, and
      suction of infused water predominantly during insertion to minimize distention. During the
      withdrawal phase insufflation is used to distend the colonic lumen.

      In the WAC arms of the two mentioned articles the insertion method used was WI, with infusion
      of water at room temperature or at 37°C. During withdrawal, air insufflation or either air or
      CO2 insufflation were employed.

      Compared to AI, CO2 insufflation and WI (using room air insufflation or CO2 insufflation
      during withdrawal) were effective in both studies in decreasing sedation requirement, pain
      and tolerance scores, with patients' higher willingness to repeat the procedure.

      Until now no direct comparison has been made within a single study about pain score during
      colonoscopy using AI, CO2 insufflation, WI/CO2, WE/CO2, WI/AI and WE/AI.

      In this study we test the hypothesis that, compared to AI, CO2 insufflation and WAC/CO2-AI
      methods will decrease pain score during colonoscopy, with reduction of sedation requirement,
      and that WE will achieve the best result. This comparative study has also the aim to test the
      respective peculiarities of each method.
    

Detailed description: 
      Design: Prospective double blinded two-center randomized controlled trial. Methods:
      Colonoscopy with air insufflation, CO2, Water Immersion/CO2, Water Exchange/CO2, Water
      Immersion/AI and Water Exchange/AI to aid insertion of colonoscope; split dose bowel
      preparation; on demand-sedation.

      Control method: Air insufflation colonoscopy. Study methods: CO2 colonoscopy, Water
      Immersion/CO2 colonoscopy, Water Exchange/CO2 colonoscopy, Water Immersion/AI colonoscopy,
      Water Exchange/AI colonoscopy.

      Population: Consecutive 18 to 85 year-old diagnostic in-patients and outpatients. After
      informed consent, assignment to control or study arms based on computer generated
      randomization list with block allocation and stratification.

      Primary outcome: Maximum pain score recorded during colonoscopy. Secondary outcomes: Cecal
      intubation rate and time, total procedure time (including biopsy and/or polypectomy), need
      for sedation and its dosage, overall pain score at discharge. In addition, Adenoma Detection
      Rate, Mean Adenomas per Procedure, position changes, amount of infused and suctioned water
      during insertion and withdrawal will be recorded. Bloating after examination and at discharge
      and patient willingness to repeat the examination will be evaluated.
    

Intervention name(s): Air Insufflation method.; CO2 insufflation; Water Immersion/CO2; Water Exchange/CO2; Water Immersion/AI; Water Exchange/AI
Intervention type(s): Other; Other; Other; Other; Other; Other
Intervention description(s): Air Insufflation method.; CO2 insufflation.; Water Immersion during insertion, CO2 insufflation during withdrawal.; Water Exchange during insertion, CO2 insufflation during withdrawal.; Water Immersion during insertion, AI insufflation during withdrawal.; Water Exchange during insertion, AI insufflation during withdrawal.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Investigator)
Primary purpose: Treatment
Keywords: Water-aided colonoscopy; Water Immersion colonoscopy; Water Exchange colonoscopy; Carbon-dioxide colonoscopy; Painless unsedated colonoscopy; Adenoma detection rate; Mean Adenomas per Procedure