Water-aided colonoscopy: a systematic review

Development of a murine colonoscopic polypectomy model (with videos)

BACKGROUND AND AIMS

Colonoscopy provides a means for screening and removal of colon adenomas, preventing such lesions from progressing to late-stage carcinoma. No preclinical model currently exists that closely parallels the clinical scenario with respect to polyp resection and recovery after endoscopy.

METHODS

When we used the polyposis in rat colon (Pirc) model, a new polypectomy methodology was developed. A novel PLC classification system (polyp number/location/clockwise orientation) also was devised in order to accurately and reproducibly specify the location of each lesion within the colon.

RESULTS

One week after surgery, injuries to the polypectomy site were confined to the submucosa, indicating that little or no damage occurred to the inner muscle layer of the colon. Polypectomy sites occasionally continued to show ulcer formation, whereas others exhibited tissue regeneration. A pilot study (n = 6 animals), involving a total of 37 polypectomies, confirmed that the new methodology could be applied by using either air insufflation or water-assisted techniques, with either hot or cold snare. As a general observation, polyps tended to be more fully distended and less flattened against the colon mucosa by using the water-assisted protocol, increasing the technical ease of ensnaring and resecting lesions. The PLC system proved to be straightforward and facilitated longitudinal studies by allowing the investigator to track each polypectomy site on repeated examination.

CONCLUSIONS

The Pirc model was ideally suited to colonoscopy with polypectomy. Because the main cause of morbidity in the Pirc model is blockage of the colon, polypectomy can be used as a preventive strategy and will likely facilitate long-term investigations of single agent and combination therapies with potential direct clinical relevance.

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.

Feasibility of full-spectrum endoscopy: Korea’s first full-spectrum endoscopy colonoscopic trial

AIM: To evaluate the full-spectrum endoscopy (FUSE) colonoscopy system as the first report on the utility thereof in a Korean population.

METHODS: We explored the efficacy of the FUSE colonoscopy in a retrospective, single-center feasibility study performed between February 1 and July 20, 2015. A total of 262 subjects (age range: 22-80) underwent the FUSE colonoscopy for colorectal cancer screening, polyp surveillance, or diagnostic evaluation. The cecal intubation success rate, the polyp detection rate (PDR), the adenoma detection rate (ADR), and the diverticulum detection rate (DDR), were calculated. Also, the success rates of therapeutic interventions were evaluated with biopsy confirmation.

RESULTS: All patients completed the study and the success rates of cecal and terminal ileal intubation were 100% with the FUSE colonoscope; we found 313 polyps in 142 patients and 173 adenomas in 95. The overall PDR, ADR and DDR were 54.2%, 36.3%, and 25.2%, respectively, and were higher in males, and increased with age. The endoscopists and nurses involved considered that the full-spectrum colonoscope improved navigation and orientation within the colon. No colonoscopy was aborted because of colonoscope malfunction.

CONCLUSION: The FUSE colonoscopy yielded a higher PDR, ADR, DDR than did traditional colonoscopy, without therapeutic failure or complications, showing feasible, effective, and safe in this first Korean trial.

Seeing better - Evidence based recommendations on optimizing colonoscopy adenoma detection rate

Colorectal cancer is one of the three most frequent causes of cancer deaths in men and women in Europe and North America. Diagnosis and resection of adenomas has convincingly demonstrated its utility in diminishing colorectal cancer incidence. Therefore, colonoscopy is now the gold standard for colorectal cancer screening. But it is also known that colonoscopy effectiveness varies among endoscopists. Among different quality indicators, the most used is the adenoma detection rate (ADR) which is the percentage of average-risk patients for colorectal cancer who are found to have at least one adenoma or adenocarcinoma during a screening colonoscopy. There is compelling evidence supporting an inverse correlation between ADR and interval colorectal cancer (cancer found after a screening colonoscopy). Many factors such as quality of precolonoscopy preparation, additional observers, manoeuvres with the endoscope (second view, retroflexion, water inflation rather than air), time spent during withdrawal, changes in patient position, fold-flattener devices, new imaging or endoscopic modalities and use of intravenous or through the scope sprayed drugs, have been studied and developed with the aim of increasing the ADR. This reviews discusses these factors, and the current evidence, to “see better” in the colon and optimize ADR.

Usefulness of oil lubrication during colonoscopy: A comparative study with the conventional technique

BACKGROUND

The different forms of lubrication are among the most simple, accessible, and economic techniques that have been implemented for improving the diagnostic performance of colonoscopy.

AIM

To determine whether the use of oil improved the number of complete colonoscopies, facilitated the procedure, reduced pain, or improved the study's diagnostic performance, compared with the conventional lubrication technique.

PATIENTS AND METHODS

One hundred and seventy-five patients referred for colonoscopy were alternately allocated to receive treatment with the standard lubrication method with chlorhexidine gel (group 1) or lubrication with corn oil administered through the working channel (group II). The number of complete colonoscopies, the length of time needed to reach the cecum, the degree of difficulty estimated by the endoscopist and the assistant, the level of pain at the end of the study estimated by the patient, and the endoscopic findings were all determined.

RESULTS

Eighty-eight patients made up group I and 87 made up group II. No statistically significant differences were found between the two groups in relation to general characteristics, the number of complete colonoscopies (93 vs. 97%, respectively), the time needed to reach the cecum (8:00 vs. 8:41min, respectively), the level of pain at the end of the study, or the detection of polyps. The degree of difficulty was slightly lower in group II, but with no statistical significance.

CONCLUSIONS

Lubrication with oil during colonoscopy did not improve the number of complete colonoscopies, did not facilitate the study, nor did it reduce pain or increase the diagnostic performance of the study, when compared with the conventional technique.

Right Or Left in COLonoscopy (ROLCOL)? A Randomized Controlled Trial of Right- versus Left-Sided Starting Position in Colonoscopy

OBJECTIVES

Colonoscopy is technically challenging and can cause discomfort for patients. We aimed to test whether right-sided starting position for colonoscopy would result in shorter procedure time and greater patient comfort when compared with conventional left-sided starting position.

METHODS

We conducted a randomized controlled trial in which patients were randomized to begin in either the right- (RL) or conventional left-lateral (LL) position. One hundred and sixty-three adult patients undergoing scheduled colonoscopy were stratified by age, gender, body mass index, and experience of the endoscopist. Patients were then randomized 1:1 in permuted blocks. The primary outcome measure was time to cecal intubation and secondary outcome measures included patient comfort that was evaluated by visual analog comfort scale.

RESULTS

Median time to reach the cecum was quicker when colonoscopy began with patients positioned RL rather than LL (P=0.0078). Moreover, patients found RL more comfortable than LL (P=0.02). Multiple linear regression confirmed starting position in colonoscopy as an independent determinant of time to reach the cecum (P=0.007). Women and those who had previously undergone abdominal surgery gained the greatest benefit from right-sided positioning (RL vs. LL: 498 vs. 824 s; P=0.03 and 498 vs. 797 s; P=0.006, respectively).

CONCLUSIONS

Our study reveals that right-sided positioning at the start of colonoscopy results in more comfortable and quicker procedures. Of the factors identified by multiple linear regression to independently have an impact on time to reach the cecum, only starting position is modifiable. Right-sided starting position may therefore be of benefit in colonoscopy, in particular for women and patients who have previously undergone abdominal surgery.

Water-Aided Colonoscopy in Inflammatory Bowel Disease Patients-A Randomised, Single-Centre Trial

BACKGROUND

Water-aided colonoscope insertion reduces patients' discomfort and need for sedation in unsedated and minimally sedated patients. However, water-aided technique has never been studied in inflammatory bowel disease patients, characterised by younger age, structural changes of the colon and need for repeated colonoscopies. Our trial was designed to evaluate discomfort associated with water-aided colonoscopy compared with air insufflation in on-demand sedated patients with known inflammatory bowel disease.

METHODS

In a randomised, single-centre study, 92 patients were randomised to either water-aided insertion and air insufflation during withdrawal [Water] or air insufflation during both insertion and withdrawal [Air]. The main outcome measured was success rate of unsedated colonoscopy, defined as reaching the caecum without requiring sedation and with discomfort during insertion of less than or equal to 5 using 0-10 continuous scale [0 = none, 10 = maximum pain].

RESULTS

Success rate of caecal intubation without sedation or invoking a discomfort score greater than 5 was significantly higher in the Water arm compared with the Air arm [73.9 vs 45.7%, p = 0.01]. Discomfort score during insertion [mean ± SD] was significantly lower in the Water than in the Air arm [3.8±2.4 vs 5.4±1.9, p < 0.001]. Other outcomes including procedural times, success rate of terminal ileum intubation, need for abdominal compression, and repositioning were comparable. There were no complications recorded in the study.

CONCLUSIONS

Compared with air insufflation, water-aided colonoscopy significantly reduces discomfort in on-demand sedated patients with inflammatory bowel disease, achieving comparable procedural outcomes.

Complications during colonoscopy: prevention, diagnosis, and management

Colonoscopy is largely performed in daily clinical practice for both diagnostic and therapeutic purposes. Although infrequent, different complications may occur during the examination, mostly related to the operative procedures. These complications range from asymptomatic and self-limiting to serious, requiring a prompt medical, endoscopic or surgical intervention. In this review, the complications that may occur during colonoscopy are discussed, with a particular focus on prevention, diagnosis, and therapeutic approaches.

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.

New technologies and techniques to improve adenoma detection in colonoscopy

Adenoma detection rate (ADR) is a key component of colonoscopy quality assessment, with a direct link between itself and future mortality from colorectal cancer. There are a number of potential factors, both modifiable and non-modifiable that can impact upon ADR. As methods, understanding and technologies advance, so should our ability to improve ADRs, and thus, reduce colorectal cancer mortality. This article will review new technologies and techniques that improve ADR, both in terms of the endoscopes themselves and adjuncts to current systems. In particular it focuses on effective techniques and behaviours, developments in image enhancement, advancement in endoscope design and developments in accessories that may improve ADR. It also highlights the key role that continued medical education plays in improving the quality of colonoscopy and thus ADR. The review aims to present a balanced summary of the evidence currently available and does not propose to serve as a guideline.

Left-colon water exchange preserves the benefits of whole colon water exchange at reduced cecal intubation time conferring significant advantage in diagnostic colonoscopy - a prospective, randomized controlled trial

OBJECTIVES

Whole-colon water exchange (WWE) reduces insertion pain, increases cecal intubation success and adenoma detection rate, but requires longer insertion time, compared to air insufflation (AI) colonoscopy. We hypothesized that water exchange limited to the left colon (LWE) can speed up insertion with equivalent results.

METHODS

This prospective, randomized controlled study (NCT01735266) allocated patients (18-80 years) to WWE, LWE or AI group (1:1:1). The primary outcome was cecal intubation time.

RESULTS

Three hundred subjects were randomized to the WWE (n = 100), LWE (n = 100) or AI group (n = 100). Ninety-four to ninety-five per cent of patients underwent diagnostic colonoscopy. Baseline characteristics were balanced. The median insertion time was shorter in LWE group (4.8 min (95%CI: 3.2-6.2)) than those in WWE (7.5 min (95%CI: 6.0-10.3)) and AI (6.4 min (95%CI: 4.2-9.8)) (both p < 0.001) groups. The cecal intubation rates in unsedated patients of the two water exchange methods (WWE 99%, LWE 99%) were significantly higher than that (89.8%) in AI group (p = 0.01). The final success rates were comparable among the three groups after sedation was given. Maximum pain scores and number of patients needing abdominal compression between WWE and LWE groups were comparable, both lower than those in AI group (p < 0.05). No significant difference was observed regarding PDR, although the PDR in right colon tended to be higher in WWE group.

CONCLUSION

By preserving the benefits of WWE and reducing insertion time, LWE is appropriate for diagnostic colonoscopy, especially in settings with tight scheduling of patients. The higher PDR in the right colon in WWE group deserves to be further investigated.

Diagnostic and therapeutic applications of water-immersion colonoscopy

Colonoscopy techniques combining or replacing air insufflation with water infusion are becoming increasingly popular. They were originally designed to reduce colonic spasms, facilitate cecal intubation, and lower patient discomfort and the need for sedation. These maneuvers straighten the rectosigmoid colon and enable the colonoscope to be inserted deeply without causing looping of the colon. Water-immersion colonoscopy minimizes colonic distension and improves visibility by introducing a small amount of water. In addition, since pain during colonoscopy indicates risk of bowel perforation and sedation masks this important warning, this method has the potential to be the favored insertion technique because it promotes patient safety without sedation. Recently, this water-immersion method has not only been used for colonoscope insertion, but has also been applied to therapy for sigmoid volvulus, removal of lesions, lower gastrointestinal bleeding, and therapeutic diagnosis of abnormal bowel morphology and irritable bowel syndrome. Although a larger sample size and prospective head-to-head-designed studies will be needed, this review focuses on the usefulness of water-immersion colonoscopy for diagnostic and therapeutic applications.

Water infusion versus air insufflation for colonoscopy

BACKGROUND

Colonoscopy is a widely used diagnostic and therapeutic modality. A large proportion of the population is likely to undergo colonoscopy for diagnosis and treatment of colorectal diseases, or when participating in colorectal cancer screening programs. To reduce pain, water infusion instead of traditional air insufflation during the insertion phase of the colonoscopy has been proposed, thereby improving patients' acceptance of the procedure. Moreover, the water infusion method may improve early detection of precancerous neoplasms.

OBJECTIVES

To compare water infusion techniques with standard air insufflation, specifically evaluating technical quality and screening efficacy, as well as patients' acceptance of the water infusion procedure.

SEARCH METHODS

We searched the Cochrane Colorectal Cancer Group Specialized Register (February 2014), the Cochrane Central Register of Controlled Trials (CENTRAL; 2014, Issue 1), Ovid MEDLINE (1950 to February 2014), Ovid EMBASE (1974 to February 2014), and ClinicalTrials.gov (1999 to February 2014) for eligible randomised controlled trials.

SELECTION CRITERIA

We included randomised controlled trials comparing water infusion (water exchange or water immersion methods) against standard air insufflation during the insertion phase of the colonoscopy.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the studies for inclusion and extracted data from eligible studies. We performed analysis using Review Manager software (RevMan 5).

MAIN RESULTS

We included 16 randomised controlled trials consisting of 2933 colonoscopies. Primary outcome measures were cecal intubation rate and adenoma detection; secondary outcomes were time needed to reach the cecum, pain experienced by participants during the procedure, completion of cecal intubation without sedation/analgesia, and adverse events. Completeness of colonoscopy, that is cecal intubation rate, was similar between water infusion and standard air insufflation (risk ratio 1.00, 95% confidence interval (CI) 0.97 to 1.03, P = 0.93). Adenoma detection rate, that is number of participants with at least one detected adenoma, was slightly improved with water infusion (risk ratio 1.16, 95% CI 1.04 to 1.30, P = 0.007). Assuming the fraction of patients undergoing screening colonoscopy who had one or more adenomas detected was 20 per 100 with standard colonoscopy, the use of water colonoscopy may increase the fraction to 23 per 100 individuals. From our findings, it is possible that up to 68,000 more of the 1.7 million outpatient screening colonoscopies performed annually in the United States, could detect adenomas if water infusion colonoscopy was used. In addition, with water infusion participants experienced significantly less pain (mean difference in pain score on a 0 to 10 scale: -1.57, 95% CI -2.00 to -1.14, P < 0.00001) and a significantly lower proportion of participants requested on-demand sedation or analgesia, or both (risk ratio 1.20, 95% CI 1.14 to 1.27, P < 0.00001). Qualitative analysis suggests that water infusion colonoscopy was not associated with a markedly increased rate of adverse events compared with the standard procedure.

AUTHORS' CONCLUSIONS

Completeness of colonoscopy, that is cecal intubation rate, was not improved by water infusion compared with standard air insufflation colonoscopy. However, adenoma detection, assessed with two different measures (that is adenoma detection rate and number of detected adenomas per procedure), was slightly augmented by the water infusion colonoscopy. Improved adenoma detection might be due to the cleansing effects of water infusions on the mucosa. Detection of premalignant lesions during standard colonoscopy is suboptimal, and so improvements in adenoma detection by water infusion colonoscopy, although small, may help to reduce the risk of interval colorectal carcinoma. The most obvious benefit of water infusion colonoscopy was reduction of procedure-related abdominal pain, which may enhance the acceptance of screening/surveillance colonoscopy.

Low-rank prior in single patches for nonpointwise impulse noise removal

This paper introduces a low-rank prior in small oriented noise-free image patches. Considering an oriented patch as a matrix, a low-rank matrix approximation is enough to preserve the texture details in the optimally oriented patch. Based on this prior, we propose a single-patch method within a generalized joint low-rank and sparse matrix recovery framework to simultaneously detect and remove nonpointwise random-valued impulse noise (e.g., very small blobs). A weighting matrix is incorporated in the framework to encode an initial estimate of the spatial noise distribution. An accelerated proximal gradient method is adapted to estimate the optimal noise-free image patches. Experiments show the effectiveness of our framework in detecting and removing nonpointwise random-valued impulse noise.

Advanced technology for the improvement of adenoma and polyp detection during colonoscopy

Early detection and removal of adenomatous polyps reduces colorectal cancer death. However, many studies have reported that up to 20% of adenomas can be missed during colonoscopy. To improve visualization and reduce the blind spot of the colonic mucosa for an increase in the adenoma detection rate, many endoscopic techniques and technologies have been developed. The benefit of the high-definition endoscope for improving adenoma and polyp detection is marginal. Wide-angle colonoscope has failed to improve adenoma detection compared to standard colonoscopy. Although the cap-assisted colonoscope can reduce cecal intubation times, it does not seem to improve adenoma and polyp detection. The diagnostic accuracy of the colon capsule endoscope is low compared to the conventional colonoscope. Third Eye(®) retroscope(®) , which provides additional retrograde viewing, has revealed significant improvement in adenoma and polyp detection compared to standard colonoscopy. However, this device increases procedural times. Recently developed full-spectrum endoscopy colonoscope and extra-wide-angle-view colonoscope have demonstrated a significantly lower miss rate of polyps. However, clinical trials are mandatory to determine the efficacy of these novel technologies for cancer screening. In addition, education and training for these novel techniques and technologies should seriously be considered to improve adenoma and polyp detection.

Water-aided colonoscopy

The successful intubation of the cecum during screening or surveillance colonoscopy is vital to ensure complete mucosal inspection of the colon on withdrawal. Even when performed by an experienced endoscopist, colonoscope insertion can sometimes be challenging. Water-aided colonoscopy can be used to assist the endoscopist in navigating colons with anatomies that may be challenging owing to severe angulation or redundancy. Water-assisted colonoscopy involves the infusion of water without air and subsequent suctioning during insertion (exchange) or withdrawal (immersion or infusion). This review discusses the technique, effectiveness, safety of water-assisted colonoscopy as well as the application in sedationless endscopy.

Can I improve my adenoma detection rate?

Adenoma detection rate (ADR) has emerged as a key quality metric for colonoscopy. Despite limitations, its major strength is based on its proven correlation with interval colorectal cancer. This has prompted extensive efforts to identify factors and interventions that improve ADR. Potentially modifiable factors that may influence ADR can be patient related (eg, bowel preparation), endoscopist related (eg, withdrawal time, quality of mucosal inspection, additional observers), or procedure related (eg, water infusion, additional examination of right colon, change in position, antispasmodics, colonoscopic equipment, and accessories). Providing endoscopists with educational material and/or feedback also seems to improve ADR.

Adenoma detection at colonoscopy by polypectomy in withdrawal only versus both insertion and withdrawal: a randomized controlled trial

Colonic configuration during insertion phase (IP) and withdrawal phase (WP) is different and some polyps seen during IP are difficult to find during WP and vice versa. To determine if polypectomy performed during both IP and WP of colonoscopy (study arm) increases adenoma detection rate (ADR) compared to WP only (control arm). In this prospective randomized controlled trial, adults undergoing out-patient colonoscopy were enrolled. The primary outcome was mean number of adenomas detected per patient. Secondary outcomes were ADR, defined as the proportion of colonoscopies with at least one adenoma, polyp detection rates (PDR), number of patients classified as high-risk group (presence of ≥3 adenomas of any size, any adenoma ≥1 cm in size, or adenoma with villous component, or high grade dysplasia), procedural times, patients discomfort, and ease of procedure. Among 772 patients enrolled, 610 were included (329 in study arm and 281 in control arm). In both arms, mean number of adenomas detected per patient were similar, 0.78 ± 1.4 vs. 0.74 ± 1.5, P = 0.75. Also, ADR (39.2 vs. 38.1 %, P = 0.77) and PDR (57.1 and 54.1 %, P = 0.45) were similar. Mean insertion time was significantly higher in study arm (10.2 ± 5.8 vs. 9.3 ± 5.6 min, p = 0.046). Proportion of patients identified as high-risk group were significantly higher in study arm (18.8 vs. 11.7 %, P = 0.016).

CONCLUSIONS

Polypectomy performed during both IP and WP compared to the WP only, did not improve ADR or mean number of adenomas detected per patient.

TRIAL REGISTRATION

Clinicaltrials.gov, #NCT01025960.

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.

Water immersion colonoscopy facilitates straight passage of the colonoscope through the sigmoid colon without loop formation: randomized controlled trial

BACKGROUND AND AIM

One of the major causes of pain during colonoscopy is looping of the instrument during insertion through the sigmoid colon, which causes discomfort by stretching the mesentery. There are many studies in colonoscope techniques, but they have not been assessed objectively with respect to colonoscope passage through the sigmoid colon without loop formation. The aim of the present study was to determine whether cap-fitted colonoscopy and water immersion increase the success rate of insertion through the sigmoid without loop formation.

METHODS

A total of 1005 patients were randomized to standard colonoscopy, cap-fitted colonoscopy or water immersion technique. All examinations were carried out under a magnetic endoscope imaging device. Main outcome was the success rate of insertion without loop formation.

RESULTS

Success rate of insertion without loop formation was 37.5%, 40.0%, and 53.8% in the standard, cap, and water groups, respectively (standard vs water P = 0.00014, cap vs water P = 0.00186). There were no significant differences among the groups regarding cecal intubation rate, cecal intubation time and number of polyps ≥5 mm per patient.

CONCLUSIONS

Water immersion increases the success rate of insertion through the sigmoid colon without loop formation. This practical technique, requiring only preparation of a cap and water, is useful without compromising cecal intubation rate, cecal intubation time, or polyp detection rate.

Cool water vs warm water immersion for minimal sedation colonoscopy: a double-blind randomized trial

AIM

Water-aided insertion as an alternative colonoscopy technique reduces patient discomfort. Warm water has been used in most published trials, but the use of cool water is easier and, if equally effective, could support the use of the water-aided technique in routine practice.

METHOD

A double-blind, randomized, single-centre study was performed in which 201 patients were randomized to either cool (20-24 °C) or warm (37 °C) water immersion insertion. The primary outcome was caecal intubation time. The success rate of minimal sedation and patient discomfort were also assessed.

RESULTS

The caecal intubation time for cool and warm water was similar (6.9 ± 3.5 vs 7.0 ± 3.4 min, P = 0.64). The respective success rates of minimal sedation colonoscopy (89.1% vs 90%, P = 1.00) and discomfort (P = 0.51) were no different. All other outcomes except a greater need for abdominal compression in the cool water arm (P = 0.04) were similar including the total procedure time, terminal ileum intubation rate, adenoma detection, length of the inserted scope, water volume, non-standard position rate, difficulty of the procedure and the patient's temperature sensation.

CONCLUSION

The use of cool water did not modify the caecal intubation time compared with warm water. Exception for abdominal compression, all other end-points were no different. Cool water immersion is an alternative to the technically more demanding warm water immersion colonoscopy.

Underwater endoscopic mucosal resection of colorectal neoplasia is easily learned, efficacious, and safe

BACKGROUND

Underwater endoscopic mucosal resection (UEMR) without submucosal injection is a novel endoscopic procedure. It is not known if UEMR can be easily taught and learned, and the efficacy and safety of UEMR has not been demonstrated at multiple medical centers. Our aims were to demonstrate that (1) UEMR is a technique that can be easily learned by an endoscopist trained in traditional EMR, (2) endoscopic ultrasound (EUS) may not be required before UEMR, and (3) UEMR is an efficacious and safe method for resection of large or flat neoplastic colorectal lesions.

METHODS

An experienced interventional endoscopist began performing UEMR after observing UEMR procedures. Colorectal UEMR was performed using a pediatric colonoscope with a cap, a waterjet, and a ‘duck-bill’ snare using blended current. Submucosal injection was not used. Patient data were collected prospectively.

RESULTS

A total of 21 patients (17 men, mean age 64.9 years, range 51-83) referred for polypectomy of large colorectal lesions underwent UEMR. A total of 43 colorectal lesions with a mean size of 20 mm (range 8-50) were resected by UEMR. Lesions were found in the right colon (N = 16), transverse colon (N = 5), left colon (N = 19), and rectum (N = 3). Pathology demonstrated tubular adenoma (N = 29), tubulovillous adenoma (N = 5), high-grade dysplasia (N = 3), serrated sessile adenoma without dysplasia (N = 3), and non-neoplastic tissue (N = 3). EUS was used in only two cases of rectal neoplasia (4.7 %). Of the UEMRs, 97.7 % were successful with complete resection of colorectal polyps. The only adverse event was one case (2.3 %) of delayed post-UEMR bleeding.

CONCLUSIONS

UEMR was easily learned by an endoscopist already skilled in conventional EMR. EUS may not be required prior to most UEMR procedures. UEMR appears to be an efficacious and safe alternative to traditional EMR or ESD for large or flat colorectal neoplasms.

A patient-blinded randomized, controlled trial comparing air insufflation, water immersion, and water exchange during minimally sedated colonoscopy

OBJECTIVES

Minimal sedation obviates patient recovery burdens, but intolerable pain limits success of cecal intubation. Painless or minimally uncomfortable insertion ensures success of cecal intubation, current patient satisfaction, and willingness to repeat future colonoscopy with minimal sedation. Water immersion (WI) and water exchange (WE), when separately compared with air insufflation (AI), significantly reduced insertion pain. To assess comparative effectiveness, we conducted a randomized controlled trial with head-to-head comparison of these three methods. We hypothesized that WE could produce the highest proportion of patients reporting painless insertion.

METHODS

This prospective patient-blinded trial (NCT01535326) enrolled minimally sedated (25 mg intramuscular meperidine) patients randomized to AI, WI, or WE (90 patients/group) to aid insertion. The previously validated primary outcome was the proportion of patients reporting painless insertion.

RESULTS

Painless insertion was reported by 30.0% (AI), 43.3% (WI), and 61.1% (WE) of patients (P<0.001). Multivariate logistic regression analysis revealed that, after adjusting for gender, body mass index, abdominal compression, position change, insertion time to cecum, and length of scope at cecum, only WE was significantly associated with painless insertion compared with AI (odds ratio (OR)=0.08, 95% confidence interval (CI)=0.03-0.24, P<0.001) or WI (OR=0.14, 95% CI=0.05-0.40, P<0.001). Adenoma detection rate (ADR) in the right (cecum and ascending) colon was 11.1% (AI), 14.4% (WI), and 26.7% (WE) (P=0.015). The limitations included single site study with unblinded colonoscopist and assistant.

CONCLUSIONS

This head-to-head comparison of AI vs. WI vs. WE confirmed that WE was superior to WI and AI, with a significantly greater proportion of patients reporting painless insertion. The significantly higher ADR in the right colon in the WE group warrants further investigations.

Effectiveness and clinical results of endoscopic management of sigmoid volvulus using unsedated water-immersion colonoscopy

BACKGROUND AND AIM

Although intestinal obstruction as a result of sigmoid volvulus (SV) may be successfully resolved using endoscopic detorsion, surgical treatment remains the main therapeutic strategy. We evaluated the endoscopic detorsion procedure using unsedated water-immersion colonoscopy for the treatment of SV.

METHODS

A retrospective chart review was conducted on the clinical background and prognosis of 21 SV patients who underwent 71 endoscopic detorsion procedures using unsedated, water-immersion colonoscopy.

RESULTS

In all, 14 (67%) male and seven (33%) female patients, with a mean age of 73 years (range, 54-95 years) were enrolled; 86% were >70 years of age. Among these patients, 90% had a background of key predisposing factors. In the 21 patients, endoscopic detorsion was successfully done using unsedated water-immersion colonoscopy. SV recurred in 10 patients at a median of 180 days. Endoscopic detorsion for recurrent SV was successfully achieved in all cases, and none of the secondary cases became severe. Only male patients were observed to experience three or more recurrent episodes of SV.

CONCLUSIONS

SV occurred most commonly in elderly patients with a surgical risk. Our experience suggests that conservative endoscopic treatment using unsedated water-immersion colonoscopy is a safe, reasonable, conservative endoscopic approach for elderly patients in the absence of necrotic findings. We currently use this procedure in most of our cases.

Endoscopic innovations to increase the adenoma detection rate during colonoscopy

Up to a quarter of polyps and adenomas are missed during colonoscopy due to poor visualization behind folds and the inner curves of flexures, and the presence of flat lesions that are difficult to detect. These numbers may however be conservative because they mainly come from back-to-back studies performed with standard colonoscopes, which are unable to visualize the entire mucosal surface. In the past several years, new endoscopic techniques have been introduced to improve the detection of polyps and adenomas. The introduction of high definition colonoscopes and visual image enhancement technologies have been suggested to lead to better recognition of flat and small lesions, but the absolute increase in diagnostic yield seems limited. Cap assisted colonoscopy and water-exchange colonoscopy are methods to facilitate cecal intubation and increase patients comfort, but show only a marginal or no benefit on polyp and adenoma detection. Retroflexion is routinely used in the rectum for the inspection of the dentate line, but withdrawal in retroflexion in the colon is in general not recommended due to the risk of perforation. In contrast, colonoscopy with the Third-Eye Retroscope^® may result in considerable lower miss rates compared to standard colonoscopy, but this technique is not practical in case of polypectomy and is more time consuming. The recently introduced Full Spectrum Endoscopy™ colonoscopes maintains the technical capabilities of standard colonoscopes and provides a much wider view of 330 degrees compared to the 170 degrees with standard colonoscopes. Remarkable lower adenoma miss rates with this new technique were recently demonstrated in the first randomized study. Nonetheless, more studies are required to determine the exact additional diagnostic yield in clinical practice. Optimizing the efficacy of colorectal cancer screening and surveillance requires high definition colonoscopes with improved virtual chromoendoscopy technology that visualize the whole colon mucosa while maintaining optimal washing, suction and therapeutic capabilities, and keeping the procedural time as low and patient discomfort as optimal as possible.

Impact of water exchange colonoscopy on serum sodium and potassium levels: an observational study

BACKGROUND

Concerns over the hypothetical adverse effects of water absorption and the disturbance of serum sodium and potassium levels prompted a quality assurance evaluation of water exchange (WE) colonoscopy.

AIM

The purpose of this study was to evaluate the balance of water infused and suctioned in WE colonoscopy, and to quantify the acute impact on serum levels of sodium and potassium.

METHODS

Prospectively collected quality monitoring data of patients undergoing screening and surveillance colonoscopy at the Sacramento Veterans Affairs Medical Center were analyzed. Measurements were made of volume infused and suctioned during, and blood samples drawn 10 min before the start of and 10 min after completion of WE colonoscopy. Outcome measures included volume of water infused and suctioned, and serum levels of sodium and potassium.

RESULTS

A total of 140 patients (134M:6F), mean age of 59, underwent WE colonoscopy. Mean total volume of water infused was 1,839 mL. A negative balance of an average of 22 mL was documented. The mean (standard deviation) values (in meq/L) of serum levels of sodium 139.33 (2.27) and 139.28 (2.32), and potassium 3.86 (0.36) and 3.91 (0.39), before and after colonoscopy, respectively, showed no significant change.

CONCLUSION

The WE method allowed most of the water infused during colonoscopy to be recovered by suction at the completion of colonoscopy. Serum sodium and potassium levels did not change significantly within 10 min after completion. The WE method appears to be safe with minimal water retention and is devoid of acute fluctuations in serum levels of sodium and potassium.

Advances in diagnostic and therapeutic colonoscopy

PURPOSE OF REVIEW

We review current studies on endoscopic and technologic advances for the detection and treatment of colorectal neoplasia.

RECENT FINDINGS

Improvements in adenoma detection have been shown to be possible with the use of high definition white light as well as water-related methods such as water exchange. Use of cap assist colonoscopy, when combined with water-related methods, has recently been shown to also improve the detection of adenomas. Narrow band imaging and confocal laser endomicroscopy may have an advantage of offering endoscopists the ability to make an 'optical diagnosis' with the possibility of discarding nonadenomatous tissue. Furthermore, educational interventions aimed at improving adenoma detection may have lasting effects on endoscopists' adenoma detection rates. Lastly, endoscopic mucosal resection and endoscopic submucosal dissection are being applied for the treatment of large colorectal polyps, obviating the need for surgery in most instances. However, further studies are needed to establish the optimal methods for polyp resection.

SUMMARY

Advances in endoscopic technology are being shown to enhance the detection of early cancers and precancerous lesions. However, these tools may be supplementary to a high-quality colonoscopy using excellent techniques, factors that are now being implemented in training programs.

Water-aided colonoscopy

Water-aided methods for colonoscopy include the established water immersion and the recent novel modification of water exchange. Water immersion entails the use of water as an adjunct to air insufflations to facilitate insertion. Water exchange evolved from water immersion to facilitate completion of colonoscopy without discomfort in unsedated patients. Infused water is removed predominantly during insertion rather than withdrawal. A higher adenoma detection rate has been reported with water exchange. Aggregate data of randomized controlled trials suggest that water exchange may be superior to water immersion in attenuating colonoscopy discomfort and optimizing adenoma detection, particularly in the proximal colon.

Physician recommendations and patient adherence after inadequate bowel preparation on screening colonoscopy

BACKGROUND AND AIMS

It has been suggested that bowel preparation quality may influence decision-making about appropriate follow-up interval after screening colonoscopy. We sought: (1) to assess physician recommendations for timing of subsequent colonoscopy in average-risk patients with inadequate bowel preparation on initial screening, and (2) to measure the association between physician recommendations and patient adherence to repeat colonoscopy.

METHODS

Patients undergoing average-risk screening colonoscopy from 2004 to 2009 found to have inadequate bowel preparation were identified. Physician recommendations for timing of subsequent colonoscopy and patient adherence to repeat colonoscopy were assessed through examination of endoscopy records. Data from repeat colonoscopies were collected through August 2010.

RESULTS

There were 373 patients with inadequate bowel preparation on initial screening colonoscopy. There was a wide range of physician recommendations for timing of repeat colonoscopy: next day (4.6 % of patients), 2 days to 6 months (9.9 %), 7 months to 1 year (34.0 %), 2-5 years (38.3 %), 6-10 years (5.1 %), and timing not specified (8.0 %). Physicians were significantly more likely to recommend repeat colonoscopy within 1 year if any polyps were detected (OR = 2.2, p = 0.001). Patients instructed to have next day follow-up were significantly more likely to adhere to the recommendation compared to patients who were instructed to return after longer intervals (OR 4.4, p = 0.005).

CONCLUSIONS

Patients with inadequate bowel preparation on screening colonoscopy were subject to a wide range of physician recommendations for follow-up. Patient adherence to physician recommendations was significantly higher when repeat colonoscopy was recommended the next day.

PDR or ADR as a quality indicator for colonoscopy

Interval (missed) cancers and lower-than-expected mortality reduction of proximal colon cancers after screening colonoscopy drew attention to quality indicators. Small proximal polyps (prone to be advanced neoplasms) missed by colonoscopy are possible contributing factors. In this issue of AJG, the subject of polyp detection rates (PDRs) and adenoma detection rates (ADRs) in the proximal and distal colon is discussed by one group of investigators to address the issue of monitoring performance and to achieve improvement. The authors observed that these two parameters correlated well in segments proximal to the splenic flexure, but not in the left colon. They suggested that caution should be exercised when using PDR as a surrogate for ADR if data from the rectum and sigmoid were included. Avoidance of missed lesions at the time of colonoscopy may require new adjunct measures to enhance ADR. The impact of new adjunct measures on ADR is mixed. In contrast to water immersion, water exchange during insertion has consistently increased ADR during withdrawal inspection. Water exchange may be a suitable alternative platform to replace insertion by air insufflation in the evaluation of new adjunct measures of quality improvement to increase ADR. Payment reforms may be necessary to bring about inclusion of ADR reporting for monitoring of quality performance.

Water exchange enhanced cecal intubation in potentially difficult colonoscopy. Unsedated patients with prior abdominal or pelvic surgery: a prospective, randomized, controlled trial

BACKGROUND

Colonoscopy is widely used for management of colorectal diseases. A history of abdominal or pelvic surgery is a well-recognized factor associated with difficult colonoscopy. Although water exchange colonoscopy (WEC) was effective in small groups of male U.S. veterans with such a history, its application in other cultural settings is uncertain.

OBJECTIVE

To investigate the application of WEC in such patients.

DESIGN

Prospective, randomized, controlled, patient-blinded study.

SETTING

Tertiary-care referral center in China.

PATIENTS

Outpatients with prior abdominal or pelvic surgery undergoing unsedated diagnostic, screening, or surveillance colonoscopy.

INTERVENTION

Patients were randomized to examination by either WEC or conventional air colonoscopy (AC).

MAIN OUTCOME MEASUREMENTS

Cecal intubation rate.

RESULTS

A total of 110 patients were randomized to the WEC (n = 55) or AC (n = 55) group. WEC significantly increased the cecal intubation rate (92.7% vs 76.4%; P = .033). The maximum pain scores (± standard deviation) were 2.1 ± 1.8 (WEC) and 4.6 ± 1.7 (AC), respectively (P < .001). Multivariate analysis showed that the colonoscopy method was the only independent predictor of failed colonoscopy (odds ratio 11.44, 95% confidence interval, 1.35-97.09). A higher proportion of patients examined by WEC would be willing to have a repeat unsedated colonoscopy (90.9% vs 72.7%, P = .013).

LIMITATIONS

Single center; unblinded but experienced endoscopists.

CONCLUSION

This randomized, controlled trial confirms that the water exchange method significantly enhanced cecal intubation in potentially difficult colonoscopy in unsedated patients with prior abdominal or pelvic surgery. The lower pain scores and higher proportion accepting repeat of the unsedated option suggest that WEC is promising. It may enhances compliance with colonoscopy in specific populations. (

CLINICAL TRIAL REGISTRATION NUMBER

NCT01485133.).

Quality colonoscopy: A matter of time, technique or technology?

Quality colonoscopy is defined by the detection of adenomatous polyps at least 25% of the time in men and 15% of the time in women. Recent studies highlight the importance of key aspects of high quality colonoscopy. These include the amount of time spent examining the mucosa or withdrawal time, the quality of withdrawal technique and new technologies which seek to maximize the detection of colonic neoplasia. This review summarizes the latest evidence regarding the role of time, technique and technology in shaping the quality of colonoscopy.

Colorectal cancer screening--optimizing current strategies and new directions

The first evidence that screening for colorectal cancer (CRC) could effectively reduce mortality dates back 20 years. However, actual population screening has, in many countries, halted at the level of individual testing and discussions on differences between screening tests. With a wealth of new evidence from various community-based studies looking at test uptake, screening-programme organization and the importance of quality assurance, population screening for CRC is now moving into a new realm, promising better results in terms of reducing CRC-specific morbidity and mortality. Such a shift in the paradigm requires a change from opportunistic, individual testing towards organized population screening with comprehensive monitoring and full-programme quality assurance. To achieve this, a combination of factors--including test characteristics, uptake, screenee autonomy, costs and capacity--must be considered. Thus, evidence from randomized trials comparing different tests must be supplemented by studies of acceptance and uptake to obtain the full picture of the effectiveness (in terms of morbidity, mortality and cost) the different strategies have. In this Review, we discuss a range of screening modalities and describe the factors to be considered to achieve a truly effective population CRC screening programme.

Use of anesthesia on the rise in gastrointestinal endoscopy

Conscious sedation has been the standard of care for many years for gastrointestinal endoscopic procedures. As procedures have become more complex and lengthy, additional medications became essential for adequate sedation. Often time's deep sedation is required for procedures such as endoscopic retrograde cholangiography which necessitates higher doses of narcotics and benzodiazepines or even use of other medications such as ketamine. Given its pharmacologic properties, propofol was rapidly adopted worldwide to gastrointestinal endoscopy for complex procedures and more recently to routine upper and lower endoscopy. Many studies have shown superiority for both the physician and patient compared to standard sedation. Nevertheless, its use remains highly controversial. A number of studies worldwide show that propofol can be given safely by endoscopists or nurses when well trained. Despite this wealth of data, at many centers its use has been prohibited unless administered by anesthesiology. In this commentary, we review the use of anesthesia support for endoscopy in the United States based on recent data and its implications for gastroenterologists worldwide.

Effectiveness of a simplified "patient friendly" split dose polyethylene glycol colonoscopy prep in Veterans Health Administration patients

BACKGROUND AND OBJECTIVES

Adequate colon cleansing is an important factor in performing quality colonoscopy. Split dose Polyethylene Glycol (PEG) solutions have been shown to improve colon cleansing, but the effectiveness in a large clinical practice of elderly co-morbid patients has not been demonstrated. The aim of this study was to assess the efficacy of a simplified split PEG bowel prep in Veterans Health Administration (VHA) patients.

METHODS

Prospective pre-post study design of VHA patients undergoing routine colonoscopy. Bowel prep quality was assessed using a standardized semi-quantitative 5-point scale. "Standard" 4L PEG prep was consumed once the evening before the procedure. "Split" prep was consumed half in the early evening and half in the late evening or early morning depending on procedure time.

RESULTS

Right colon preps were Excellent/Good in 81.4% of split preps (n=199) vs. 63% of standard preps (n=447, p<0.001). Left colon preps were Excellent/Good in 85.9% of split preps vs. 71.6% of standard preps (p<0.001). Diabetics (n=133) had significantly more right colon preps rated fair or worse compared to non-diabetics irrespective of prep (39.9% vs. 29.0%, p=0.02). Split prep in diabetics resulted in fewer right colon preps rated fair or worse compared to diabetics using standard prep (28.3% vs. 45.9%, p=0.049). Average adenomas detected per colonoscopy were 1.04 for split prep vs. 0.85 for standard prep (p=NS). Patient satisfaction was higher for split preps.

CONCLUSION

System-wide implementation of a split PEG prep resulted in significantly improved bowel cleansing in VHA patients, particularly in the right colon. Improved bowel cleansing with split preps was associated with higher patient satisfaction.

A new method for screening and surveillance colonoscopy: Combined water-exchange and cap-assisted colonoscopy

BACKGROUND & AIMS

Colonoscopy plays an important and central role in current colorectal cancer screening and prevention programs, but it is an imperfect tool. Adjunct techniques may help improve the performance of colonoscopy to increase the detection of polyps with neoplastic potential. This study investigates the novel approach of combined water-exchange and cap-assisted colonoscopy (WCC) and its impact on adenoma detection.

METHODS

A single-center single-colonoscopist consecutive group observational study to compare WCC with conventional air insufflation colonoscopy was performed. Data were collected from 50 consecutive patients undergoing outpatient colorectal cancer screening or polyp surveillance with WCC. Adenoma detection rates (ADR) and adenomas detected per colonoscopy (APC) were compared to a control group of 101 consecutive patients examined with conventional air colonoscopy during the immediate prior period.

RESULTS

Cecal intubation was achieved in all patients. As an emerging and alternative quality metric for colonoscopy, APC was significantly higher in the WCC group (3.08 vs. 1.50, p=0.0021). The conventional quality metric, overall ADR, was higher in the WCC group compared to the air colonoscopy group (70.0% vs. 59.4%, p=0.22). This difference was not statistically significant, likely due to a type II error.

CONCLUSION

The observational data suggest APC is a more sensitive indicator of quality colonoscopy than ADR. WCC shows promise as a novel technique that merges two simple adjunct methods to help improve the performance of colonoscopy. The data suggest larger, prospective studies are necessary to determine the true impact of water-exchange combined with cap-assisted maneuvers.

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.