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Cola

Colonoscopy will be performed in the standard fashion, with the minimal air insufflation required to aid insertion and allowing for washing as needed. Considered to be standard procedure.

Air will not be insufflated until the cecum is reached. It will be allowed only 3 times and no more than 10 seconds each time (ITT failure if \>3) if the lumen cannot be seen. Infusion of water during the insertion phase of colonoscopy mainly to open the colonic lumen and progress to the cecum immersed in the water environment thus created, without attempting to clear the colon contents. Residual air in the colon will not be removed. Infused water and residual feces will be suctioned back predominantly during withdrawal.

Air will not be insufflated until the cecum is reached. Infusion of a sufficient amount of water to render the lumen of the colon a slit to progress with the colonoscope. Part of the infused water will be constantly suctioned back exchanging clean for dirty or hazy water. Suction of water will also be applied when colonoscope insertion proceeds smoothly. Air pockets will be always aspirated to collapse the lumen. After cecal intubation as much residual water as possible will be aspirated before beginning the withdrawal phase. During withdrawal residual water and feces will be suctioned.

Air Insufflation method.

Water Immersion method.

Water Exchange method.

Sergio Cadoni, MD

Water-aided method for colonoscopy can be broadly subdivided into two major categories. Water Immersion (WI), characterized by suction removal of the infused water predominantly during the withdrawal phase of colonoscopy, and Water Exchange (WE), characterized by suction removal of infused water predominantly during the insertion phase of colonoscopy. Several studies showed that WE significantly reduces pain compared to WI and colonoscopy with traditional air insufflation (AI), increases the number of unsedated procedures and adenoma detection rate (ADR), in particular proximal ADR. This randomized controlled trial will be a direct comparison of Air Insufflation, Water Immersion and Water Exchange to test the hypothesis that WAC (particularly WE) would significantly decrease pain score during colonoscopy in diagnostic patients. Several other secondary outcomes will also be analyzed.

Introduction Water-aided methods for colonoscopy can be broadly subdivided into two major categories.

Water Immersion (WI) is characterized by suction removal of the infused water predominantly during the withdrawal phase of colonoscopy and Water Exchange (WE) is characterized by suction removal of infused water predominantly during the insertion phase of colonoscopy.

Several studies showed that WE significantly reduces pain compared to WI and colonoscopy with traditional air insufflation (AI), increases the number of unsedated procedures and adenoma detection rate (ADR), in particular proximal ADR. This randomized controlled trial will be a direct comparison of Air Insufflation, Water Immersion and Water Exchange to test the hypothesis that WAC (particularly WE) would significantly decrease pain score during colonoscopy in diagnostic patients. Several other secondary outcomes will also be analyzed.

Method

Examinations will be allocated to Water Exchange, Water Immersion or Air Insufflation during the insertion phase of colonoscopy based on a computer generated random list. Procedures will be started by 6 board-certified endoscopists, three with experience in 8,000-10,000 and three with experience in 2,000-5,000 colonoscopies with AI, 285 with WI and 890 with WE overall.

High-resolution wide-angle variable-stiffness adult video colonoscopes (Olympus HD 180 series; Olympus Corp, Hamburg, Germany) will be used. Need to change to a smaller caliber colonoscope will be considered ITT failure.

Patients will have a low volume split dose bowel preparation with 2L of polyethylene glycol (PEG) solution or Sodium Picosulfate. Investigators will be blinded to the colon preparation used. Before starting the procedure, a questionnaire recording demographic data, previous abdominal surgery, co-morbidities and current medications will be administered by the endoscopists. The patients, but not endoscopists and assisting nurses, will be blinded to the method used. At discharge the patient will be asked to guess which method has been used. If no more than half of the responses are correct, patients' blinding will be considered adequate.

Colonoscopy will begin with the patients in the left lateral position, without premedication. The withdrawal phase will be identical in all arms of the study using air insufflation to obtain adequate distension of the colonic lumen for mucosal inspection, biopsy and/or polypectomy.

Patients randomized to the water-aided colonoscopy group, during the insertion phase after reaching the rectosigmoid junction, will have the colon irrigated with water at 37°C maintained with a water bath. Infusions will be performed using flushing pumps (Olympus OFP2, Olympus, Hamburg, Germany or Velocity irrigation pump, US Endoscopy, OH, USA). There will be no restriction of the overall volume of water that can be infused to get adequate lumen distention and reach the cecum. With the patient in the left lateral position water infused into the colon at the rectal sigmoid junction flows into the descending colon. The weight of the water in the left side of the colon straightens the sigmoid segment increasing the ease of insertion and reducing the risk of loop formation. The air pump will be turned off to avoid inadvertent insufflation.

Water Immersion will involve the infusion of water during the insertion phase of colonoscopy mainly to open the colonic lumen and progress to the cecum immersed in the water environment thus created, without attempting to clear the colon contents. Use of water as an adjunct to air insufflation to facilitate insertion and removal of infused water predominantly during withdrawal are characteristic features of WI. This traditional adjunct facilitates passage through the sigmoid colon with severe diverticulosis, speeds arrival to the splenic flexure, decreases colonic spasm, minimizes pain, and even enhances cecal intubation in previously incomplete colonoscopies.

Residual air in the colon will not be removed. The infused water and residual feces will be suctioned back only during withdrawal. Air insufflation will be allowed if the lumen cannot be seen and the endoscopists judges unsafe to advance the colonoscope. It will last no more than 10 seconds and will be recorded in the patient data sheet. If more than 3 episodes of air insufflation will be recorded the procedure will be considered ITT failure.

Water Exchange will involve complete exclusion of air insufflation, removal of residual colonic air and feces and of infused water predominantly during insertion to assist identification of the lumen. WE minimizes loop formation and decreases discomfort. By providing salvage cleansing during insertion, WE allows the colonoscopist to devote a greater proportion of the withdrawal to inspection. WE will involve the infusion of a sufficient amount of water to open the lumen of the colon to allow passage of the instrument, thus rendering the colonic lumen a slit to progress with the colonoscope. If the lumen does not open, the colonoscope will be slightly retracted and the infusion started again. Part of the infused water will be constantly suctioned back exchanging clean for dirty or hazy water. Suction of infused water will also be applied when colonoscope insertion proceeds smoothly. Air pockets, when encountered, will be always aspirated to collapse the lumen: the absence of air space forces the colonoscopist to use water to clear residual feces and to find the way through the colon. Removal of the air also shortens the colon and takes out all the sharp turns at the flexures and redundant segments, reducing the risk of loop formation: water instillation does not elongate the colon as much as air insufflation does. In a collapsed, airless colon turbulences created at the tip of the instrument facilitate the removal by suction of residual feces adherent to the mucosa. This provides salvage cleansing during the insertion phase. After cecal intubation as much residual water as possible will be aspirated before beginning the withdrawal phase. During withdrawal scarce amounts of water are left to aspirate, and residual water and feces will be suctioned.

In the AI group, colonoscopy will be performed in the standard fashion, allowing for washing as needed. In all groups abdominal compression and position change were applied as needed.

Cecal intubation will be defined as passage of the tip of the colonoscope to a point proximal to the ileocecal valve with adequate visualization of the cecum and appendix orifice. A stopwatch will be used to time the procedures. Cecal intubation time will be defined as the time for passage of the colonoscope from the rectum to the cecum. The withdrawal phase will last at least 6 minutes. Polyp resection will be done during withdrawal in all groups. Time for polypectomy or biopsy will add to the total colonoscopy time. Pathology reports of all polyps will be reviewed and recorded to evaluate adenoma detection rate (ADR, defined as the proportion of subjects with at least one adenoma of any size), the location, the total number of adenomas resected per subject(ARR), and the percentage of subjects with advanced adenomas. The amount of water infused during insertion and withdrawal, the number of position changes and any adverse outcome will be recorded. Cardiopulmonary function will be monitored. Significant oxygen desaturation (\<85% for \>15 seconds) will be recorded. Vagal reaction will be defined as heart rate \<60 beats per minute accompanied by excessive sweating, nausea and/or vomiting.

A Comparison of Air Insufflation, Water Immersion and Water Exchange Colonoscopy in Diagnostic Patients

A Randomized, Controlled Trial Comparing Air Insufflation, Water Immersion and Water Exchange During on Demand Sedation Colonoscopy in Diagnostic Patients

Change in patient position as needed if advancement of the colonoscope fails.

Applied as needed if advancement of the colonoscope fails.

Amount of infused water during insertion and withdrawal.

Bloating felt by patients at completion of examination on a 10 point visual analogue scale.

Bloating felt by patients at discharge measured on a ten point visual analogue scale.

Patients willingness to repeat the examination based on overall satisfaction about procedure. Measured at discharge on a yes/no question.

Significant oxygen desaturation will be recorded when values less than 85% will be maintained for more than 15 seconds.

Vagal reaction is defined as heart rate \<60 beats per minute accompanied by excessive sweating, nausea and/or vomiting.

Pain will be assessed using a visual analogue scale (VAS) with a score 0=absence of pain, 2=simply "discomfort", 10=the worst possible pain. Before the procedure, an endoscopic nurse will explain the VAS scoring system to the patients. The patient will be informed that the request for pain information is not to remind the patient that the examination should be uncomfortable, but to let the colonoscopist be alerted to the need to use maneuvers to minimize discomfort (e.g. loop reduction, removal of colonic content, abdominal compression and/or change in patient position). At regular intervals during colonoscopy (e.g. every 2-3 minutes) patients will be asked about discomfort or pain. The responses will be recorded, and the maximum pain score noted.

Sedation and analgesia will be available on demand. Medication will be offered when VAS score reaches ≥2 (discomfort). Patients can accept or decline the medication. If patients agree to accept the medication, it will be given. Midazolam, no more than 5 mg per patient, will be used. When pain is reported, sedation will be started with midazolam with a single intravenous dose of 2 mg, plus incremental doses of 1 mg if the patient still continues to complain about pain. To avoid bias by the colonoscopist, sedation medication will be administered based on the patients' confirmation that the pain is no longer tolerable, and not at the discretion of the colonoscopist. No other analgesic or sedative medications will be administered. The colon segment in which patients requests sedation will be recorded.

After the procedure and at discharge from the Endoscopy Unit, an assistant nurse blinded to the procedure will ask patients about overall pain using the same VAS when neither the endoscopist nor the assistant nurse who performed the colonoscopy were present. Patients will be asked to quantify the degree of pain experienced and to place a mark over the VAS accordingly.

Cecal intubation will be defined as passage of the tip of the colonoscope beyond the ileocecal valve so that the medial wall of the cecum proximal to the ileocecal valve will be observed. This will be analyzed on an intention- to-treat basis according to group allocation.

Cecal intubation time will be defined as the time for passage of the colonoscope from the rectum to the cecum.

Total procedure time (including time required for polyp resection or biopsy).

Proportion of subjects with at least one adenoma of any size.

Total number of adenomas resected per subject.

Total number of advanced adenomas: diameter ≥10mm, or high grade dysplasia, or with ≥20% villous components.

Presidio Ospedaliero Santa Barbara

Responsabile Servizio Endoscopia Digestiva

Digestive System Diseases

Polyps

Colorectal Neoplasms

Intestinal Neoplasms

Gastrointestinal Neoplasms

Digestive System Neoplasms

Gastrointestinal Diseases

Colonic Diseases

Intestinal Diseases

Rectal Diseases

Colonoscopy performed in the standard fashion, with the minimal air insufflation required to aid insertion and allowing for washing as needed. Considered to be standard procedure.

Infusion of water during the insertion phase of colonoscopy mainly to open the colonic lumen and progress to the cecum immersed in the water environment thus created, without attempting to clear the colon contents. Residual air in the colon will not be removed. Infused water and residual feces will be suctioned back predominantly during withdrawal. Insufflation not used until the cecum is reached. It will be allowed only 3 times and no more than 10 seconds each time (ITT failure if \>3) if the lumen cannot be seen. Withdrawal phase done using air insufflation.

Insufflation not used until the cecum is reached. Infusion of a sufficient amount of water to render the lumen of the colon a slit to progress with the colonoscope. Part of the infused water will be constantly suctioned back exchanging clean for dirty or hazy water. Air pockets will be always aspirated to collapse the lumen. After cecal intubation as much residual water as possible will be aspirated before beginning the withdrawal phase. During withdrawal residual water and feces will be suctioned. Withdrawal phase done using air insufflation.

Air insufflation method.

Water Immersion during insertion, air insufflation during withdrawal.

Water Exchange during insertion, air insufflation during withdrawal.

The degree of protection afforded by colonoscopy against proximal colorectal cancer (CRC) appears to be related to the quality of the procedure, and the incomplete removal of lesions has been shown to increase the subsequent risk of developing a colon cancer.

Some studies suggest that small polyps with advanced histology are more common in the right than in the left colon (right colon proximal to splenic flexure, left colon distal to the splenic flexure). The average size of polyps in the right colon with advanced pathology or containing adenocarcinoma was ≤9 mm, whereas in the left colon their average size was \>9 mm, P\<0.001. Inadequate prevention of right-sided CRC incidence and mortality may be due to right-sided polyps with advanced histology or that harbor malignancy. These presumptive precursors of cancer are smaller and possibly more easily obscured by residual feces, and more likely to be missed at colonoscopy.

Water-aided colonoscopy (WAC) can be subdivided broadly into two major categories: water immersion (WI), characterized by suction removal of the infused water predominantly during the withdrawal phase of colonoscopy, and water exchange (WE), characterized by suction removal of infused water predominantly during the insertion phase of colonoscopy.

In some reports WE appeared to be superior to both WI and air insufflation colonoscopy (AI) in terms of pain reduction and adenoma detection, particularly for \<10 mm adenomas in the proximal colon.

In this multicenter, double-blinded randomized controlled trial (RCT) we test the hypothesis that that WE, compared to AI and WI, will enhance overall Adenoma Detection Rate (ADR) in CRC screening patients. Confirmation of the primary hypothesis will provide evidence that WE enhances the quality of screening colonoscopy.

We also hypothesize that WE may be more effective in detecting proximal colon adenomas than WI and AI, particularly \<10 mm adenomas, thus increasing proximal colon ADR and proximal colon ADR \<10 mm. Confirmation of secondary hypotheses will provide justification for further testing that WE may provide a strategy to improve prevention of colorectal cancer by increasing detection of adenomas in screening colonoscopy.

Unlike previous reports of single colonoscopist studies, the insertion and withdrawal phases of colonoscopy will be done by different investigators. The second investigator will be blinded to the method used to insert the instrument, thus eliminating possible bias about procedure related issues.

Several secondary outcomes will also be analysed.

Design: Prospective double-blinded multicenter randomized controlled trial. Methods: Colonoscopy with Air Insufflation, Water Immersion, Water Exchange to aid insertion of colonoscope; split dose bowel preparation. Sedation available at the start of the procedure or on-demand.

Control method: Air insufflation colonoscopy. Study methods: Water Immersion colonoscopy, Water Exchange colonoscopy.

Population: Consecutive 50 to 70 year-old screening patients. After informed consent, assignment to control or study arms based on computer generated randomization list with block allocation and stratification.

Primary outcome: overall Adenoma Detection Rate. Secondary outcomes: proximal colon ADR, Mean Adenomas resected per Procedure (MAP), cecal intubation rate and time, total procedure time (including biopsy and/or polypectomy), maximum pain during colonoscopy assessed during insertion and at discharge, the need for sedation/analgesia and its dosage. In addition loop reduction maneuvers, position changes, abdominal compression, the amount of infused and suctioned water during insertion and withdrawal, and patients willingness to repeat the examination will be evaluated.

Water-aided Colonoscopy vs Air Insufflation Colonoscopy in Colorectal Cancer Screening

A Randomized, Controlled Trial Comparing Air Insufflation, Water Immersion and Water Exchange for Adenoma Detection Rate in Screening Colonoscopy

Compression of abdomen if advancement of the colonoscope fails.

Amount of water infused and aspirated during insertion and withdrawal.

Proportion of subjects with at least one adenoma of any size in the proximal colon.

Proportion of subjects with at least one adenoma \<10 mm in the proximal colon.

Cecal intubation will be defined as passage of the tip of the colonoscope beyond the ileocecal valve so that the medial wall of the cecum proximal to the ileocecal valve will be observed.

Pain will be measured on a visual analogue scale (VAS) with a score 0=absence of pain, 1-2=simply "discomfort", 10=the worst possible pain. Before the procedure, an endoscopic nurse will explain the VAS scoring system to the patient. Patient will be informed that the request for pain information is not to remind that the examination should be uncomfortable, but to let the colonoscopist be alerted to the need to use maneuvers to minimize discomfort (e.g. loop reduction, removal of colonic content, abdominal compression and/or change in patient position). At regular intervals during colonoscopy (e.g. every 60 seconds) patients will be asked about discomfort or pain. The responses will be recorded, and the maximum pain score noted.

After the procedure and at discharge from the Endoscopy Unit, an assistant nurse blinded to the procedure will ask patients about maximum pain during insertion phase of the procedure using the same VAS when neither the endoscopist nor the assistant nurse who performed the colonoscopy will be present. Patients will be asked to quantify the degree of pain experienced and to place a mark over the VAS accordingly.

All patients will be offered sedation for the procedure. Patients can accept or decline the medication. If they accept, the procedure will be started with the administration of 2 mg of Midazolam intravenously (minimal sedation). If the patient will choose on-demand sedation, minimal sedation will be offered when pain score reaches ≥2 on the VAS. Patients can accept or decline the offered medication. If they accept, minimal sedation will be administered as described above. To avoid bias by the colonoscopist, sedation medication will be administered based on the patients' confirmation that the pain is no longer tolerable, and not at the discretion of the colonoscopist. The colon segment in which patients requests sedation will be recorded. If additional medication will be required despite the abovementioned maneuvers and/or minimal sedation, it will be provided according to local standards and it will be recorded.

Study title	NCT ID	Conditions	Interventions	Eligibility	Organization
A Comparison of Air Insufflation, Water Immersion and Water Exchange Colonoscopy in Diagnostic Patients	NCT01781650	Pain Colorectal Aden... Colorectal Canc...	Air Insufflatio... Water Immersion... Water Exchange ...	18 Years - 85 Years	Presidio Ospedaliero Santa Barbara
Water-aided Colonoscopy vs Air Insufflation Colonoscopy in Colorectal Cancer Screening	NCT02041507	Colorectal Canc... Colorectal Aden... Colorectal Poly... Pain	Air insufflatio... Water Immersion... Water Exchange ...	50 Years - 70 Years	Presidio Ospedaliero Santa Barbara
A Comparison of Air Insufflation, Water Immersion and Water Exchange Colonoscopy in Diagnostic Patients	NCT01781650	Pain Colorectal Aden... Colorectal Canc...	Air Insufflatio... Water Immersion... Water Exchange ...	18 Years - 85 Years	Presidio Ospedaliero Santa Barbara

Spots Global Cancer Trial Database for water exchange method.