Impact of Colonoscopy Insertion Techniques on Adenoma Detection.

BACKGROUND: Low adenoma detection rate (ADR) predicts development of interval cancers, found mainly in the right (cecum-ascending) colon, where poor bowel preparation is an associated factor. Single-site studies reported increased detection of adenomas in the proximal colon segments by water exchange (WE). Data about colon cleansing revealed that WE had the greatest impact in the right colon. AIMS: To test the hypothesis that WE had the greatest impact on ADR in colon segments with the most favorable bowel cleanliness scores, namely the right colon. METHODS: We pooled right colon and overall ADR data of three similarly designed colonoscopy trials that compared WE, water immersion (WI) and insufflation of air or carbon dioxide (AICD) in a mixed gender European population. RESULTS: In this study, 1200 (704 males) subjects and were included. 288 were screening cases. Demographic and procedural data were comparable. Water exchange achieved significantly higher right colon <10 mm ADR (11.9 %, vs WI 6.9 %, p = 0.016; vs AICD 7.2 %, p = 0.025). Water exchange achieved the lowest proportions of poor bowel preparation and the highest right colon and overall Boston bowel preparation scale scores (p range 0.003, <0.0005). In patients with right colon excellent bowel cleanliness, water exchange was the only method significantly associated with right colon adenoma detection. One of the limitations is unblinded colonoscopists. CONCLUSIONS: In a mixed gender European population, water exchange is confirmed to be a superior insertion technique showing a significant increase in <10 mm right colon adenoma detection, achieving the cleanest colon and lowest proportions of poor bowel preparation requiring repeat procedures. CLINICALTRIALS. GOV NO: NCT01781650, 01954862, 01780818.

A randomized, controlled trial comparing real-time insertion pain during colonoscopy confirmed water exchange to be superior to water immersion in enhancing patient comfort.

BACKGROUND: A recent American Society for Gastrointestinal Endoscopy Technology Status Evaluation Report recommended comparative studies of water-aided colonoscopy methods to refine the optimal insertion technique. OBJECTIVE: Air insufflation (AI), water immersion (WI), and water exchange (WE) were compared head-to-head to test the hypothesis that WE produces the least insertion pain. DESIGN: Patient-blinded, prospective, randomized, controlled trials. SETTING: Two community hospitals in Italy. PATIENTS: First-time diagnostic or screening colonoscopy in unsedated patients with the option of on-demand sedation. INTERVENTION: Colonoscopy with AI, WI, or WE. MAIN OUTCOME MEASUREMENTS: Real-time maximum insertion pain (0 = none, 10 = worst). To avoid interventional bias, the timing of recording was at the discretion of the nurse assistant. Adjunct measures were implemented to ensure patient perception of minimal discomfort. Recalled pain and patients' guess of insertion methods were recorded after colonoscopy. RESULTS: Results were merged for 576 randomized patients. Correct patient guesses lower than 33% confirmed adequate blinding. Significant correlation (Pearson coefficient 0.6, P < .0005) between real-time and recalled pain provided internal validation of the former as the primary outcome. Real-time pain (95% confidence interval [CI]: AI, 4.1 [3.7-4.5]; WI, 3.5 [3.0-3.9]; and WE, 2.5 [2.2-2.9] [P < .0005] was the lowest in the WE group. The proportions of patients completing unsedated colonoscopy based on the assigned methods were significantly different (WE, 74.7% vs WI, 62.4%; P = .009; vs AI, 65.3%; P = .04). WE required the least implementation of adjunct maneuvers. LIMITATIONS: Unblinded colonoscopists. CONCLUSION: The current findings with an internally validated primary outcome in adequately blinded patients support the hypothesis that WE is superior to WI in attenuating real-time insertion pain and enhancing completion of unsedated colonoscopy.

Evidence to suggest adoption of water exchange deserves broader consideration: Its pain alleviating impact occurs in 90% of investigators.

AIM: To determine whether observations were reproducible among investigators. METHODS: From March 2013 through June 2014, 18-85-year-old diagnostic and 50-70-year-old screening patients were enrolled at each center to on-demand sedation colonoscopy with water exchange (WE), water immersion (WI) and insufflation with air or CO2 for insertion and withdrawal [air or carbon dioxide (AICD)]. Data were aggregated for analysis. PRIMARY OUTCOME: Variations in real-time maximum insertion pain (0 = none, 1-2 = discomfort, 10 = worst). RESULTS: One thousand and ninety-one cases analyzed: WE (n = 371); WI (n = 338); AICD (n = 382). Demographics and indications were comparable. The WE group had the lowest real-time maximum insertion pain score, mean (95%CI): WE 2.8 (2.6-3.0), WI 3.8 (3.5-4.1) and AICD 4.4 (4.1-4.7), P < 0.0005. Ninety percent of the colonoscopists were able to use water exchange to significantly decrease maximum insertion pain scores. One investigator had high insertion pain in all groups, nonetheless WE achieved the lowest real-time maximum insertion pain score. WE had the highest proportions of patients with painless unsedated colonoscopy (vs WI, P = 0.013; vs AICD, P < 0.0005); unsedated colonoscopy with only minor discomfort (vs AICD, P < 0.0005), and completion without sedation (vs AICD, P < 0.0005). CONCLUSION: Aggregate data confirm superiority of WE in lowering colonoscopy real-time maximum insertion pain and need for sedation. Ninety percent of investigators were able to use water exchange to significantly decrease maximum insertion pain scores. Our results suggest that the technique deserves consideration in a broader scale.

Insertion water exchange increases right colon adenoma and hyperplastic polyp detection rates during withdrawal.

BACKGROUND: Single site studies in male Veterans in the U.S. reported increased detection of presumptive cancer precursors (adenomas, hyperplastic polyps) in the proximal colon (cecum-splenic flexure) by water exchange. AIMS: Assess the reproducibility of the observation. METHODS: Analysis of secondary outcomes collected prospectively in 3 similarly designed randomized controlled trials using water exchange, water immersion and insufflation (air or carbon dioxide). MAIN OUTCOME: detection rates of adenomas and hyperplastic polyps in proximal, transverse and right colon (cecum-ascending). RESULTS: 704 males (173 screening) were evaluated. In the proximal colon, WE showed increased detection of small adenomas (p=0.009) and adenomas plus hyperplastic polyps (p=0.015) (vs insufflation); increased detection of adenomas plus hyperplastic polyps of any size (p=0.045) and of small size (p=0.04) (vs water immersion). In the right colon water exchange increased detection of small adenomas (19% vs 12.1%, p=0.04) (vs insufflation); small adenomas (19% vs 12%, p=0.038), adenomas plus hyperplastic polyps of any size (25% vs 16.7%, p=0.028) and of small size (23.7% vs 14.6%, p=0.012) (vs water immersion). Water exchange significantly improved bowel cleanliness. Sedation had no impact on lesion detection. CONCLUSIONS: Water exchange is a superior insertion technique for detection of adenomas and hyperplastic polyps primarily in the right colon, especially those of small size.