The water method for aiding colonoscope insertion: the learning curve of an experienced colonoscopist

Increase your adenoma detection rate without using fancy adjunct tools

The correlation between a low adenoma detection rate (ADR) and interval cancers (ICs) has made ADR one of the most important quality indicators for colonoscopy. Data from nation-wide colorectal cancer (CRC) screening programs showed that there is room for improvement in ADR in order to reduce ICs in Taiwan. Measures with and without adjunct tools have been shown to have the potential to increase ADR, with the latter being more convenient to apply without additional cost. Optimal withdrawal techniques coupled with sufficient withdrawal time, training endoscopists with emphasis on recognition of subtle characteristics of flat lesions, dynamic position changes during the withdrawal phase, removing small polyps found during insertion, and retroflexion in the right colon have all been associated with increased ADR. In particular, water exchange (WE), which is characterized using water in lieu of air and suction removal of infused water during insertion, appears to meet the needs of colonoscopy patients in Taiwan. Analyses of both primary and secondary outcome variables of recently published studies have consistently shown that WE yields higher ADR than traditional air insufflation, even in propofol-sedated patients. Colonoscopists participating in the nationwide CRC screening program in Taiwan should consider applying one or more of the above measures to improve ADR and hopefully reduce ICs.

Can Water Exchange Improve Patient Tolerance in Unsedated Colonoscopy A Prospective Comparative Study

Background & Aims

Unsedated colonoscopy can be painful, poorly tolerated by patients, and associated with unsatisfactory technical performance. Previous studies report an advantage of water exchange over conventional air insufflation in reducing pain during unsedated colonoscopy. Our goal was to analyze the impact of water exchange colonoscopy on the level of maximum pain reported by patients submitted to unsedated colonoscopy, compared to conventional air insufflation.

Methods

We performed a single-center, patient-blinded, prospective randomized comparative study, where patients were either allocated to the water group, in which the method of colonoscopy used was water exchange, or the standard air group, in which the examination was accomplished with air insufflation.

Results

A total of 141 patients were randomized, 70 to the water and 71 to the air group. The maximum level of pain reported by patients during unsedated colonoscopy, measured by a numeric scale of pain (0-10), was significantly lower in the water group (3.39 ± 2.32), compared to the air group (4.94 ± 2.10), p < 0.001. The rate of painless colonoscopy was significantly higher in the water group (12.9 vs. 1.4%, p = 0.009). There were no significant differences between the two groups regarding indications for the procedure, quality of bowel preparation, cecal intubation time, withdrawal time, number of position changes, adenoma detection rate, and postprocedural complications. Only the number of abdominal compressions was significantly different, showing that water exchange decreases the number of compressions needed during colonoscopy.

Conclusions

Water exchange was a safe and equally effective alternative to conventional unsedated colonoscopy, associated with less intraprocedural pain without impairing key performance measures.

Water Exchange Method Significantly Improves Adenoma Detection Rate: A Multicenter, Randomized Controlled Trial

OBJECTIVES

Adenoma detection rate (ADR) is a key colonoscopy quality indicator in Western clinical literature. Our low ADR prompted us to assess novel methods to improve performance. Western retrospective reports suggested that water exchange (WE) could increase ADR. However, most of these studies used pain score or intubation rate as the primary outcome. Here we test the hypothesis that WE significantly increases ADR among Chinese colonoscopists and design a prospective randomized controlled trial using ADR as our primary outcome.

METHODS

This prospective, randomized controlled trial was performed at six centers in China. Screening, surveillance, and diagnostic cases were randomized to be examined by WE or traditional air insufflation (AI) method. The primary outcome was ADR.

RESULTS

From April 2014 to July 2015, 3,303 patients were randomized to WE (n=1,653) and AI (n=1,650). The baseline characteristics were comparable. Overall ADR was 18.3% (WE) and 13.4% (AI) (relative risk 1.45, 95% confidential interval: 1.20-1.75, P<0.001). ADR in screening patients using AI was 25.8% (male) and 15.7% (female). ADR in screening patients aged >50 years old was 29.4% (WE) and 22.9% (AI) (relative risk 1.09, 95% confidential interval: 1.00-1.19, P=0.040). The increase by WE was reproducibly observed in all indication categories, and significant in screening and diagnostic cases. The limitation imposed by the unblinded investigators was mitigated by comparable inspection times in cases without polyps, similar adenoma per positive colonoscopy, and reproducible enhancement of ADR and adenoma per colonoscopy by WE across all eight investigators.

CONCLUSIONS

This prospective study confirms Western retrospective data that WE significantly improves ADR among Chinese colonoscopists. WE may be superior to AI for screening colonoscopy in China. Colonoscopists elsewhere with low ADR might consider evaluating WE for performance improvement.

What Influences the Quality of Prevention Colonoscopy?

Background

Colorectal cancer still has a high incidence and mortality. Although colonoscopy is considered as gold standard of colorectal cancer screening, there still exists an unsatisfactory level of adenomas missed in screening and surveillance colonoscopy. Furthermore, patients bear the burden of potentially unpleasant and painful examination and preparation procedures.

Method

A search of the literature using PubMed was carried out, supplemented by a review of the programs of the Digestive Disease Week (DDW) and the United European Gastroenterology Week (UEGW) 2011-2013.

Results

Several new approaches to colonoscopy were described: water, CO₂ and cap colonoscopy, and application of spasmolytics such as hyoscine butylbromide and glucagon. The use of these methods does not necessitate the purchase of new endoscopes. They are feasible and safe, facilitate achieving the aim of more comfort and less pain, and perhaps allow lower doses of sedatives to be used. However, a clear effect on procedure time is lacking. Furthermore, the published data do not consistently answer the question of whether these techniques have a positive impact on the most important goal, the better detection of carcinoma precursors.

Conclusion

More efforts to optimize bowel preparation have to be made to improve visualization of the mucosal surface. The most reliable criteria for the quality of screening and surveillance colonoscopy remain a minimum cecal intubation rate of >90%, a withdrawal time of at least 6 or better 9 min, and an adenoma detection rate of >20%. These results should be achieved with a complication rate lower than 1%, including polypectomy.

Water exchange method for colonoscopy: learning curve of an experienced colonoscopist in a U.S. community practice setting

BACKGROUND

Water exchange colonoscopy has been reported to reduce examination discomfort and to provide salvage cleansing in unsedated or minimally sedated patients. The prolonged insertion time and perceived difficulty of insertion associated with water exchange have been cited as a barrier to its widespread use.

AIM

To assess the feasibility of learning and using the water exchange method of colonoscopy in a U.S. community practice setting.

SETTING

Quality improvement program in nonacademic community endoscopy centers.

SUBJECTS

Patients undergoing sedated diagnostic, surveillance, or screening colonoscopy.

METHODS

After direct coaching by a knowledgeable trainer, an experienced colonoscopist initiated colonoscopy using the water method. Whenever >5 min elapsed without advancing the colonoscope, conversion to air insufflation was made to ensure timely completion of the examination.

PRIMARY OUTCOME

Water Method Intention-to-treat (ITT) cecal intubation rate (CIR).

RESULTS

Female patients had a significantly higher rate of past abdominal surgery and a significantly lower ITTCIR. The ITTCIR showed a progressive increase over time in both males and females to 85-90%. Mean insertion time was maintained at 9 to 10 min. The overall CIR was 99%.

CONCLUSION

Use of water exchange did not preclude cecal intubation upon conversion to usual air insufflation in sedated patients examined by an experienced colonoscopist. With practice ITTCIR increased over time in both male and female patients. Larger volumes of water exchanged were associated with higher ITTCIR and better quality scores of bowel preparation. The data suggest that learning water exchange by a busy colonoscopist in a community practice setting is feasible and outcomes conform to accepted quality standards.

The water exchange method for colonoscopy-effect of coaching

The growing popularity of water immersion is supported by its long history as an adjunct to air insufflation; after facilitating colonoscope passage, the infused water is conveniently removed during withdrawal. Water exchange, a modification of water immersion to minimize discomfort in scheduled unsedated patients in the U.S. is new. Even though it may be superior in reducing pain and increasing adenoma detection, the paradigm shift to complete exclusion of air during insertion necessitates removal of infused water containing residual feces, a step often perceived as laborious and time-consuming. The nuances are the efficient steps to remove infused water predominantly during insertion to maintain minimal distension and deliver salvage cleansing. Mastery of the novel maneuvers with practice returns insertion time towards baseline. In this observational study the impact of direct verbal coaching on the primary outcome of intention-to-treat cecal intubation was assessed. The results showed that 14 of 19 (74%) experienced colonoscopists achieved 100% intention-to-treat cecal intubation. Initiation of the examination with water exchange did not preclude completion when conversion to the more familiar air insufflation method was deemed necessary to achieve cecal intubation (total 98%). The overall intention-to-treat cecal intubation rate was 88%, 90% in male and 87% in female. Only 2.7% of bowel preparation was rated as poor during withdrawal. The mean volume of water infused and cecal intubation time was 1558 ml and 18 min, respectively. Direct coaching appears to facilitate understanding of the nuances of the water exchange method. Studies of individual learning curves are necessary.

A head-to-head comparison of the water vs. air method in patients undergoing screening colonoscopy

BACKGROUND: The water method facilitates colonoscope insertion in unsedated patients. OBJECTIVE: To compare quality indicators in sedated veterans. DESIGN: Performance improvement. SETTING: VA endoscopy unit. PATIENTS: 368 consecutive screening patients. INTERVENTION: Air or water method assignment (high definition colonoscope) was based on the last digit of social security number. MEASUREMENTS: Adenoma detection rate (ADR), cecal intubation rate; intubation and withdrawal times; sedation requirements and external pressure used. RESULTS: ADR was higher with the water method (57.1% vs. 46.1%, p=0.04). After controlling for age, body mass index, smoking, alcohol, withdrawal time and quality of bowel preparation, the odds of detecting an adenoma was 81% higher with the water method (OR 1.81; 95% cI: 1.12-2.90). In the proximal colon ADR was higher with the water method (45.8% vs. 34.6%, p=0.03), including adenomas <10 mm in size (41.8% vs. 31.4%, p=0.04). The water method showed significantly longer cecal intubation time (6.9±0.3 vs. 5.3±0.3 min, p=0.0001); less external pressure used (11.9% vs. 28.3%, p=0.0001); lower need for additional sedation (17.5% vs. 27.2%, p<0.03). LIMITATIONS: Predominance of males, single unblinded endoscopist with high ADR. CONCLUSIONS: The water method is an independent factor associated with significantly higher ADR. Replication by blinded colonoscopist(s) is indicated.

Feasibility of colonoscopy with water infusion in minimally sedated patients in an Asian Community Setting

BACKGROUND: Investigators in the US described large volume water infusion with marked benefits but acknowledged the limitation of male veteran predominance in the study subjects. The aim of this study was to assess the feasibility of large volume water infusion in Asian patients undergoing minimal sedation diagnostic colonoscopy in a community setting. METHODS: Consecutive patients who underwent colonoscopy were randomized to receive large volume (entire colon) (Group A, n=51), limited volume (rectum and sigmoid colon) (Group B, n=51) water infusion, or air insufflation (Group C, n=51). Pain during insertion, completion rate, cecal intubation and total procedure times, and patient satisfaction were evaluated. Pain and satisfaction were assessed with a 0-10 visual analog scale. RESULTS: The mean pain scores during insertion were lower in the Group A and Group B than in Group C, 3.3±2.4, 3.0±2.2 and 4.4±2.6, respectively (p=0.028 and p=0.004). The completion rates and cecal intubation times were similar among the three groups. The procedure time was significantly longer in Group A than in group C (15.3±5.9 min vs. 13.1±5.4 min, p=0.049). Overall satisfaction with the procedure was greater in Group B than in Group C only (9.7±0.5 vs. 9.4±0.8, p=0.044). CONCLUSIONS: Diagnostic colonoscopy with large volume water infusion without air insufflation appears to be feasible in minimally sedated Asian patients in a community setting. Measures to improve the outcome further are discussed.

Learning and teaching the water method (with videos)

The water method is an insertion technique for colonoscopy which has recently become popular owing to its demonstrated ability to decrease patient pain and sedation requirements. This review focuses on learning and teaching the water method. Data from the United States and Asia suggests that trainees at all levels of experience can safely learn and utilize the water method. Demonstrated benefits in some of the reviewed studies include lessened sedation requirements, less pain for patients and increased cecal intubation rates in minimally sedated patients. These benefits are realized without compromising safety, adenoma detection rates, or procedure times.

A head-to-head comparison of the water vs. air method in patients undergoing screening colonoscopy

BACKGROUND: The water method facilitates colonoscope insertion in unsedated patients. OBJECTIVE: To compare quality indicators in sedated veterans. DESIGN: Performance improvement. SETTING: VA endoscopy unit. PATIENTS: 368 consecutive screening patients. INTERVENTION: Air or water method assignment (high definition colonoscope) was based on the last digit of social security number. MEASUREMENTS: Adenoma detection rate (ADR), cecal intubation rate; intubation and withdrawal times; sedation requirements and external pressure used. RESULTS: ADR was higher with the water method (57.1% vs. 46.1%, p=0.04). After controlling for age, body mass index, smoking, alcohol, withdrawal time and quality of bowel preparation, the odds of detecting an adenoma was 81% higher with the water method (OR 1.81; 95% cI: 1.12-2.90). In the proximal colon ADR was higher with the water method (45.8% vs. 34.6%, p=0.03), including adenomas <10 mm in size (41.8% vs. 31.4%, p=0.04). The water method showed significantly longer cecal intubation time (6.9±0.3 vs. 5.3±0.3 min, p=0.0001); less external pressure used (11.9% vs. 28.3%, p=0.0001); lower need for additional sedation (17.5% vs. 27.2%, p<0.03). LIMITATIONS: Predominance of males, single unblinded endoscopist with high ADR. CONCLUSIONS: The water method is an independent factor associated with significantly higher ADR. Replication by blinded colonoscopist(s) is indicated.

Removal of infused water predominantly during insertion (water exchange) is consistently associated with a greater reduction of pain score - review of randomized controlled trials (RCTs) of water method colonoscopy

INTRODUCTION: Variation in the outcomes in RcTs comparing water-related methods and air insufflation during the insertion phase of colonoscopy raises challenging questions regarding the approach. This report reviews the impact of water exchange on the variation in attenuation of pain during colonoscopy by water-related methods. METHODS: Medline (2008 to 2011) searches, abstracts of the 2011 Digestive Disease Week (DDW) and personal communications were considered to identify RcTs that compared water-related methods and air insufflation to aid insertion of the colonoscope. Results: Since 2008 nine published and one submitted RcTs and five abstracts of RcTs presented at the 2011 DDW have been identified. Thirteen RcTs (nine published, one submitted and one abstract, n=1850) described reduction of pain score during or after colonoscopy (eleven reported statistical significance); the remaining reports described lower doses of medication used, or lower proportion of patients experiencing severe pain in colonoscopy performed with water-related methods compared with air insufflation (Tables 1 and 2). The water-related methods notably differ in the timing of removal of the infused water - predominantly during insertion (water exchange) versus predominantly during withdrawal (water immersion). Use of water exchange was consistently associated with a greater attenuation of pain score in patients who did not receive full sedation (Table 3). CONCLUSION: The comparative data reveal that a greater attenuation of pain was associated with water exchange than water immersion during insertion. The intriguing results should be subjected to further evaluation by additional RcTs to elucidate the mechanism of the pain-alleviating impact of the water method.

DDW 2011 cutting edge colonoscopy techniques - state of the art lecture master class - warm water infusion/CO(2) insufflation for colonoscopy

Pain limits the success of cecal intubation in unsedated patient. Carbon dioxide infusion instead of air insufflation and water infusion as an adjunction to air insufflation have both been investigated as modalities to minimize pain associated with colonoscopy. Multiple RCT support an effect of carbon dioxide in reducing pain after colonoscopy. A modern method of water infusion as the sole modality for aiding colonoscope insertion has been shown to reduce pain during and after colonoscopy. Favorable effects in reducing discomfort have been documented in both sedated and unsedated patients. Because of the need to perform water exchange in the patients with suboptimal bowel perparation, a serendipitous consequence of salvage cleansing is evident with application of the water method. The associated increase in adenoma detection especially in the proximal colon is most intriguing. The hypothesis that the water method during insertion combined with carbon dioxide insufflation during withdrawal will optimally decrease colonoscopy pain should be evaluated. The implications of increased adenoma detection by the water method also deserve to be studied.