Water-aided Colonoscopy: water immersion & water exchange

1. Water-aided Colonoscopy: water immersion & water exchange Felix W. Leung, MD, FACG, Professor of Medicine David Geffen School of Medicine at UCLA Chief of GI Sepulveda Ambulatory Care Center, VAGLAHS Disclosure: None for this lecture. Research work supported in part by ACG, ASGE and VA funding.

2. Growing Interest in Water-aided Colonoscopy 

3. Background Nurse shortage → unsedated option CIR = overseas air  length, angulations pain limits success Challenge – painless? Air is the culprit - omit all air Can colonoscopy be done without air? Leung FW. Unsedated colonoscopy introduced as a routine option to ensure access is acceptable o a subgroup of US veterans. DDAS 2008;53(10):2719-22. Leung FW. Promoting informed choice of unsedated colonoscopy - patient-centered care for a subgroup of U.S. veterans. DDAS 2008;53(11):2955-9.

4. Water infusion in left colon minimizes looping Water as Adjunct to Air - Immersion • Widely used (~300 ml) • Facilitates passage - Tic segment • enhances speed & success • Attenuates pain • Warm water decreases spasm • Water removed predominantly during withdrawal • Can water be used in lieu of air? Leung FW. Methods of reducing discomfort during colonoscopy. DDAS 2008;53(6): 1462-7. Leung FW. Water-related method for performance of colonoscopy. DDAS 2008;53(11):2847-50. Leung CW, et al. Colonoscopy insertion technique using water immersion versus standard technique: a randomized trial showing promise for minimal-sedation colonoscopy. Endoscopy 2010;42:557-562.

5. Water Immersion • adjunct to usual air insufflations • water removed predominantly during withdrawal • facilitates passage through the sigmoid colon with severe diverticulosis • speeds arrival to the splenic flexure • decreases colonic spasm, minimizes pain • enhances cecal intubation in previously incomplete colonoscopies • For experienced colonoscopist, additional “training and practice” to use a syringe to infuse water is not needed

6. Water Exchange C A B D Leung FW, Leung JW, Mann SK, Friedland S, Ramirez FC. Innovation Forum - The water method significantly enhances the outcome of colonoscopy in sedated and unsedated patients. Endoscopy. In press 2011. Avoid colon elongation - air pump off Minimize angulations - remove air Identify lumen - infuse water Clear view - exchange water

7. Water Exchange • evolved from water immersion • assist in identification of the lumen • facilitate completion of colonoscopy without discomfort in unsedated patients in the US • complete exclusion of air insufflations • removal of residual colonic air, coupled with infusion of water, removal of residual feces •  CIR in unsedated patients

8. Water Exchange • infused water is removed during insertion to minimize distension • requires additional “training and practice” to master the maneuvers • prevents excessive colon elongation •  loop formation •  discomfort •  need for compression and position change • provides salvage cleansing during insertion

9. Pre-insertion Check • Confirm everything is working • air and water pump on the colonoscope • accessory water pump used for water exchange • Adjust suction to about 1/2 maximum • Turn off the air pump • obviate inadvertent insufflation of air which can elongate the colon • Endoscopy assistant can perform checks

10. Infuse water to move forward • Direct scope tip to abut where • folds converge • or slit-like opening ahead • No obvious opening ahead • pull back to get “big” picture • move tip in a large circle while infusing & suctioning water • common channel - in rapid succession • separate channel - simultaneously

11. Infuse water to identify the lumen • Infuse water to confirm • lumen ahead opens up to allow passage • Stop water infusion • if lumen does not open • pull back, redirect scope tip • repeat process • Slow deliberate movements • more likely to be effective

12. How to avoid suction of the mucosa • Adjust (decrease) intensity of wall suction • Streamline maneuvers • Initiate water infusion to push the mucosa away from the tip • Then, press on suction button • Position suction port • towards center of lumen • see more mucosa on the left side and the upper part of the monitor screen

13. Salvage cleansing • Bowel prep suboptimal – patience • Remove as much of suspended residual feces as possible • Then, infuse clean water for visualization of the lumen • It is easier to clean the mucosa in a collapsed water-filled colon during insertion with water exchange than in a distended air-filled colon during withdrawal with the water jet

14. Salvage cleansing Fair prep - sediment at bottom Fair to goodprep Good prep Assistant can stay ahead endoscopist - ensure water bottles and suction bottles are always ready Air Water

15. Don’t rush • When the insertion is going smoothly • do not forget to suction the water • A water distended colon • increases patient discomfort • predisposes to loop formation • “Round" lumen ahead • likely too much water in the colon • more suction needs to be implemented

16. Under-water landmarks • Diverticular openings • avoid excessive infusion of water into tic lumen • Cecal intubation • red suction marks - cecum • appendix orifice • IC valve • TI

17. A D J G H B E K I C F L

18. Prepare to withdrawal • Definition of water exchange • removal of infused water predominantly during insertion • Before starting withdrawal, remove • as much of the water in the cecum as possible • Then, insufflate air • to begin the inspection process

19. Other standard maneuvers • Loop reduction, abdominal compression, position change • integral components of all insertion method • Employ if necessary • lumen ahead not seen, paradoxical movement • These maneuvers • needed less often with water exchange, but are necessary from time to time

20. No significant impact on electrolytes

21. Lower pain scores Pain score: 0=none, 10=most severe; R, rectum; S, sigmoid; DC, descending, TC, transverse; AC, ascending; C, cecum Data are mean pain scores, * vs respective air method, p< 0.05, t test.

22. Pain Score in Meta-analysis Pain score in water group is lower than air group. The same results also show in subgroup analysis.

23. New Challenges • Post colonoscopy interval cancers • missed lesions • Proximal colon cancer mortality • not reduced • or reduced at best by ~50% • ? difference in tumor biology (left vs. right) • ? incomplete resection • ? missed lesions during colonoscopy Leung FW, Leung JW, Siao-Salera RM, Mann SK. The water method significantly enhances proximal diminutive adenoma detection rate in unsedated patients. J Interv Gastroenterol 2011;1(1):8-13.

24. New Challenges • Proximal small lesions are prone to harbor advanced pre-malignant features (e.g. flat lesions, dysplasia, etc.) Leung FW, Leung JW, Siao-Salera RM, Mann SK. The water method significantly enhances proximal diminutive adenoma detection rate in unsedated patients. J Interv Gastroenterol 2011;1(1):8-13.

25. ADR in Meta-analysis (WI vs WE) No significant difference between water and air; but in subgroup analysis, water exchange is superior in ADR; water immersion is same as air.

26. Water Exchange ↑ ADR - Why? Enhanced cleanliness – plausible explanation Reduced distraction during withdrawal ↑ proportion of time devoted to inspection Air Water

27. New Challenges • Adjunct measures (e.g. dye, cap, NBI, water immersion, insertion polypectomy, retroflexed exam, …) show conflicting impacts on ADR Leung FW, Leung JW, Siao-Salera RM, Mann SK. The water method significantly enhances proximal diminutive adenoma detection rate in unsedated patients. J Interv Gastroenterol 2011;1(1):8-13.

28. Adjuncts have mixed impact on ADR

29. Adjuncts have mixed impact on ADR

30. New Challenges • The inconsistent effects raise questions about unrecognized limitations of insertion by air insufflation on withdrawal inspection • Insertion platform besides air insufflation is needed to support evaluation of new adjuncts Leung FW, Leung JW, Siao-Salera RM, Mann SK. The water method significantly enhances proximal diminutive adenoma detection rate in unsedated patients. J Interv Gastroenterol 2011;1(1):8-13.

31. WE consistently increased ADR

32. WE and other adjuncts • WE plus dye or cap • Pilot data suggest consistent increase in ADR

33. WE vs WE plus IC Data are mean (SD). *t-test; ** Fisher’s exact test, ADR – adenoma detection rate, SSP – sessile serrated polyp

34. WE plus cap Data are frequency count (%), mean (SD). ADR, adenoma detection rate; APC, adenomas per colonoscopy; PDR, polyp detection rate; SD, standard deviation; SP, serrated polyp; SPDR, serrated polyp detection rate; SPPC, serrated polyps per colonoscopy; WCC, water exchange and cap-assisted colonoscopy. *t-test; **Fisher’s exact test

35. Unrecognized limitations of AI & remedy • The inconsistencies of adjuncts raise concern that conventional insertion with AI imposes unrecognized limitations • New insertion platform is needed to support evaluation of adjuncts to improve ADR • Retrospective studies show WE during insertion  ADR during withdrawal inspection • Pilot data reproducibly show higher ADR with WE plus dye or cap vs AI

36. Anything to replace AI? • Since 2010 six RCT have assessed impact of WE on primary outcomes of insertion pain, cecal intubation rate and ADR • Proper use of WE was ascertained via site-visits or by e-mails • Uniform use of WE justifies merging ADR data for analyses

37. Pooling of WE data – even randomization AI, air insufflation; WE, water exchange. ADR, adenoma detection rate; CIR, cecal intubation rate; CIRMPMS, cecal intubation rate with minimal pain (≤2) and minimal sedation (≤2 mg Midazolam). Data are expressed as mean and percent (%) of total.

38. Pooling of WE data -  pain Time, minutes. Pain score (0=none, 10=maximum) AI, air insufflation; WE, water exchange. Data are expressed as mean or mean (SD). *P<0.05, t-test. †Maximum pain score during colonoscopy; ††Overall pain score after colonoscopy before discharge.

39. Pooling of WE data -  ADR AI, air insufflation; WE, water exchange. ADR, adenoma detection rate. Data are expressed as mean and percent (%) of total. *P<0.05, t-test. †Maximum pain score during colonoscopy; ††Overall pain score after colonoscopy before discharge.

40. New insertion platform- water exchange ? • The consistently higher ADR supports water exchange as a suitable insertion platform to replace air insufflation in planned evaluation of new adjunct measures to improve ADR

41. Acknowledgement VAGLAHS Attending - S Aharonian, P Guth, S Borowski, C Menz, R Chitayat, M Finerman, F Gletten, L Jacob Fellow - S Chu, B Nguyen, P Simpson Nurse - M Broderick, E Emory, G Jackson, K Okamoto, L Skilman Coordinator - N Jamgotchian, O Behbahani Statistician - J Harker Approved unsedated option - P Guze, J Pisegna, M Golub, D Norman Phoenix VAMC Attending - FC Ramirez Palo Alto VAMC Attending – S Friedland Buddhist Dalin Tzu Chi General Hosp, Chia-Yi; Buddhist Tzu Chi University, School of Medicine, Hwalien; National Chung Cheng Uni, Chia-Yi, Taiwan Yu-Hsi Hsieh, Jin-Jian Hsieh Eastern Hepatobiliary Hosp, Second Military Med Uni, Shanghai, China Hu, Bing, Wu, Jun VANCHCS Attending - J Leung, S Mann, A Yen GI fellow - C Hasyagar, B Lim, D Yen, C Ngo, K Ransibrahmanakul, I Nastaskin Resident - D Parikh Nurse - R Gutierrez, W Canete, L Samson, R Siao-Salera, & colleagues S. Barbara Hospital, Iglesias; N. S. di Bonaria Hosp, San Gavino Monreale (VS); Uni Cagliari, Cagliari (CA); Italy S Cadoni, P Gallittu, S Sanna, V Fanari, ML. Porcedda, M Erriu Funding UC Davis CW Law Research Funds ASGE Research Funds ACG Clinical Research Award VA Clinical Merit Research Funds ASGE Career Development Award