Impact of Carbon Dioxide Insufflation and Water Exchange on Post-Colonoscopy Outcomes

Study Overview
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Brief Summary
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Room air insufflated during colonoscopy cannot be completely suctioned, is not easily absorbed and remains in the bowel for quite some time, resulting in prolonged bowel distension with the discomfort of bloating. Sufferers often experience a sensation of fullness and abdominal pressure, relieved only after expulsion of the residual gas, often accompanied by colic pain. This can be a lengthy process, and some patients continue to report pain as long as 24 hours after the procedure. Abdominal discomfort after colonoscopy is an adverse event commonly reported by patients, and definitely associated with the procedure. Published reports show that the use of carbon dioxide (CO2) insufflation significantly decreases bloating and pain up to 24 hours post-procedure. Preliminary results of the investigators' previous study about on-demand sedation colonoscopy in diagnostic patients showed that, compared with CO2 insufflation, the water exchange group (WE, infusion of water to distend the lumen during insertion; suction of infused water, residual air pockets an feces predominantly during insertion) achieved significantly lower real-time insertion pain scores. Moreover (insertion-withdrawal method) WE-CO2 had the lowest bloating scores just after the procedure and at discharge, comparable with those achieved by CO2-CO2. Compared with WE-CO2, the use of WE-air insufflation (AI) showed significantly higher bloating scores just after the procedure and at discharge; compared with CO2-CO2 differences were significant only at discharge. The investigators decided to conduct a prospective randomized controlled trial comparing WE-CO2, WE-AI and CO2-CO2. The investigators will test the hypothesis that patients examined by the combination of WE-CO2 will have significantly lower bloating scores at specific time points after colonoscopy than those examined using WE-AI or CO2-CO2. The investigators will also assess the impact of these three methods on patients comfort and activities in the post-procedure period.

Detailed Description
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Design: Prospective double blinded two-center randomized controlled trial. Methods: Colonoscopy with CO2 insufflation and water exchange-CO2, water exchange-AI; split-dose bowel preparation; on demand-sedation. Control method: CO2 insufflation colonoscopy. Study methods: water exchange-CO2 colonoscopy, water exchange-AI colonoscopy. Population: Consecutive 18 to 80 year-old first-time diagnostic outpatients. After informed consent, assignment to control or study arms based on computer generated randomization list with block allocation and stratification.

Official Title
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Impact of Carbon Dioxide Insufflation and Water Exchange on Post-Colonoscopy Outcomes: A Randomized Controlled Trial

Conditions
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Abdominal Pain

Intervention / Treatment
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* Other: Carbon dioxide method
* Other: Water Exchange-CO2
* Other: Water Exchange-AI


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: consecutive 18 to 80 year-old first-time diagnostic outpatients agreeing to start procedure without premedication Exclusion Criteria: patient unwillingness to start the procedure without sedation/analgesia previous colorectal surgery proctosigmoidoscopy or bidirectional endoscopy patient refusal or inability to provide informed consent inadequate consumption of bowel preparation moderate or severe chronic obstructive pulmonary disease requiring oxygen medical history of CO2 retention history of inflammatory bowel disease

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Carbon dioxide method<br>Colonoscopy performed as usual, with the minimal CO2 insufflation required to aid insertion and adequate distension during withdrawal for exploration. Washing allowed as needed. Considered to be standard procedure. | Other: Carbon dioxide method<br>* Insufflation with CO2 during insertion and withdrawal phases of colonoscopy.<br>|
| Experimental: Water Exchange-CO2<br>Insufflation not used until the cecum is reached. Infusion of a sufficient amount of water to render the lumen a slit to progress with the colonoscope. Part of the infused water will be constantly suctioned back exchanging clean for opaque water. Air pockets and residual feces will be always aspirated. Withdrawal phase done using carbon dioxide insufflation. | Other: Water Exchange-CO2<br>* Insertion using water exchange, withdrawal using CO2 insufflation.<br>|
| Experimental: Water Exchange-AI<br>Insufflation not used until the cecum is reached. Infusion of a sufficient amount of water to render the lumen a slit to progress with the colonoscope. Part of the infused water will be constantly suctioned back exchanging clean for opaque water. Air pockets and residual feces will be always aspirated. Withdrawal phase done using air insufflation. | Other: Water Exchange-AI<br>* Insertion using water exchange, withdrawal using air insufflation.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in abdominal bloating sensation after colonoscopy. | Change of patients' sensation of abdominal bloating. Assessed by blinded observer just after examination, at discharge; and at 1, 3, 6, 12 and 24 hours after the procedure using a questionnaire given to patients. Measured on an eleven-point Numeric Rating Scale (NRS): 0=none, 10=full bloating. Results will be recorded by telephone recall. | Within the first 24 hours after the procedure. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in pain score after colonoscopy. | Assessed by blinded observer just after examination, at discharge; and at 1, 3, 6, 12 and 24 hours after the procedure using a questionnaire given to patients. Measured using an eleven-point NRS (0=none, 10=maximum pain). Results will be recorded by telephone recall. | Within the first 24 hours after the procedure. | 
| Real-time insertion pain. | Pain assessed using a NRS (0=absence of pain, 2=simply discomfort, 10=worst pain). Before the procedure, an endoscopic nurse will explain the NRS scoring system to the patients. At irregular intervals during colonoscopy (around 60 seconds) assisting nurse will ask patients about discomfort or pain. The responses will be recorded, and the maximum pain score noted. Colonoscopists not participating in gathering the informations. | 1 hour. | 
| Number of episodes of incontinence or of soiled underwear experienced in the 6 hours after colonoscopy. | Recorded at discharge and assessed post-procedure up to 6 hours using a questionnaire given to patients. Results will be recorded by telephone recall. | 6 hours. | 
| Number of flatus episodes post-procedure. | Recorded at discharge and assessed post-procedure up to 24 hours using a questionnaire given to patients. Results will be recorded by telephone recall. | 24 hours. | 
| Number of incontinence episodes post-procedure. | Recorded at discharge and assessed post-procedure up to 6 hours using a questionnaire given to patients. Results will be recorded by telephone recall. | 6 hours. | 
| Toilet use for bowel movement post-procedure. | Recorded at discharge and assessed post-procedure up to 6 hours using a questionnaire given to patients. Results will be recorded by telephone recall. | 6 hours. | 
| Patients' satisfaction with the procedure. | Assessed post-procedure after 24 hours using a questionnaire given to patients (0=not satisfied, 10=very satisfied). Results will be recorded by telephone recall. | 24 hours. | 
| Willingness to repeat colonoscopy. | Assessed post-procedure after 24 hours using a questionnaire given to patients (0=not willing to repeat, 10=very likely to repeat). Results will be recorded by telephone recall. | 24 hours. | 
| Interference of colonoscopy on work/normal activities the same day of the procedure. | Assessed post-procedure after 12 hours using a questionnaire given to patients (0=nothing at all, 10=a lot). Results will be recorded by telephone recall. | Up to 12 hours. | 
| Day of work missed the day after the procedure. | Work activities missed the day after colonoscopy due to some effect of the procedure (yes, no). Assessed post-procedure after 24 hours using a questionnaire given to patients. Results will be recorded by telephone recall. | 24 hours. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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colonoscopy, carbon dioxide, water exchange, discomfort, colonoscopy pain