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

ENDOANGEL versus water exchange for the detection of colorectal adenomas

Background

Recently, the ENDOANGEL (EN) system, a computer-assisted detection technique, and water exchange (WE) assisted colonoscopy have both been shown to increase the colorectal adenoma detection rate (ADR).

Objectives

The aim of this study was to compare the ADR between EN- and WE-assisted colonoscopy.

Design

This was a retrospective study.

Methods

Data from patients who underwent either EN- or WE-assisted colonoscopy between October 2021 and August 2022 were analysed consecutively. The primary outcome measure was the ADR.

Results

The ADR was found to be similar between the EN and WE groups, with 80 out of 199 (40.2%) patients in the EN group compared to 78 out of 174 (44.8%) patients in the WE group [1.21; 95% confidence interval (CI), 0.80-1.83]. In the analysis using stabilized inverse probability treatment weighting after adjustment for confounding factors, both colonoscopy methods had similar performance in terms of ADR (1.41; 95% CI, 0.88-2.27).

Conclusion

EN was found to be comparable to WE in terms of ADR during colonoscopy, and both methods may be effectively used in clinical practice.

Outcome of Water Exchange and Air Insufflation Colonoscopy Performed by Supervised Trainee and Their Assessment of the Training Experience

GOALS

The hypotheses that supervised trainees would provide a more favorable assessment of the learning experience and could achieve superior results with water exchange (WE) compared with air insufflation were tested.

BACKGROUND

WE decreased pain, increased cecal intubation rate (CIR), and polyp detection rate (PDR).

STUDY

In a prospective pilot observational study, the trainees were taught WE in unsedated and WE and air insufflation in alternating order in sedated veterans. Trainee scores and procedural outcomes were tracked.

RESULTS

83 air insufflation and 119 WE cases were included. Trainee evaluations of the respective methods were scored based on a 5-point scale [1 (strongly agree) to 5 (strongly disagree, with lower scores being more favorable]. Evaluation scores [mean (SD)] were as follows: my colonoscopy experience was better than expected: WE 2.02 (1.00) versus air insufflation 2.43 (1.19), P =0.0087; I was confident with my technical skills using this method: WE 2.76 (0.91) versus air insufflation 2.85 (0.87), P =0.4822. Insertion time was 40 (21) min for WE and 30 (20) min for air insufflation ( P =0.0008). CIR were 95% (WE, unsedated); 99% (WE, overall), and 89% (air insufflation, overall). WE showed significantly higher CIR (99% vs. 89%, P =0.0031) and PDR (54% vs. 32%, P =0.0447).

CONCLUSIONS

The long air insufflation insertion time indicated the trainees were inexperienced. The significantly longer WE insertion time confirmed that learning WE required extra time. This pilot study revealed that supervised trainees reported more favorable learning experience with WE and equivalent confidence in technical skills scores. They completed both unsedated and sedated colonoscopy in over 89% of cases achieved significantly higher CIR and PDR with WE than air insufflation. It appeared that trainee education in WE might be an acceptable alternative to augment air insufflation to meet the challenges of training posed by traditional air insufflation colonoscopy.

Efficacy of combination colonoscopy using modified cap-assisted and water-exchange colonoscopy with prone position for detection of colorectal adenomas

The efficacy of cap-assisted and water-exchange colonoscopy, individually or in combination for adenoma detection is well documented. Moreover, prone positioning colonoscopy may also improve adenoma detection by decreasing loop formation. However, the efficacy of triple-combination colonoscopy using the above methods for adenoma detection is unclear. This study aimed to compare the effectiveness of combining modified cap-assisted and water-exchange colonoscopy with prone position (CWP) and conventional colonoscopy (CC) for adenoma detection. A total of 746 patients who underwent either CWP or CC, performed by 2 board-certified gastroenterologists between December 2019 and March 2020, were investigated retrospectively. Cap-assisted colonoscopy was modified using hooking and dragging maneuver. We evaluated the polyp detection rate (PDR), adenoma detection rate (ADR), and the mean number of adenomas detected per procedure (MAP). There was no significant difference in sex, age, the indication of colonoscopy and quality of bowel preparation between the 2 groups. PDR, ADR, and proximal colon MAP were significantly higher in the CWP group than in the CC group (PDR: 84.9% vs 59.8%, P < .01; ADR: 70.1%, vs 49.2%, P < .01; proximal colon MAP: 1.24 vs 0.55, P < .01). CWP is more effective than CC for PDR, ADR, and proximal colon MAP. Although it may facilitate adenoma detection, further studies assessing the synergistic or complementary effects of combining these methods are needed.

Minimal water exchange by the air-water valve versus left colon water exchange in unsedated colonoscopy: a randomized controlled trial

BACKGROUND

Water exchange colonoscopy is the least painful method for unsedated colonoscopies. Simplified left colon water exchange (LWE) reduces the cecal intubation time but it is difficult to avoid the use of an additional pump. Minimal water exchange (MWE) is an improved novel method that eliminates the need for pumps, but it is not clear whether MWE has the same efficiency as LWE.

METHODS

This was a prospective, randomized, controlled, noninferiority trial conducted in a tertiary hospital. Enrolled patients were randomized 1:1 to the LWE group or MWE group. The primary outcome was recalled insertion pain measured by a 4-point verbal rating scale. Secondary outcomes included adenoma detection rate (ADR), cecal intubation time, volume of water used, and patient willingness to repeat unsedated colonoscopy.

RESULTS

226 patients were included (LWE n = 113, MWE n = 113). The MWE method showed noninferior moderate/severe pain rates compared with the LWE method (10.6 % vs. 9.7 %), with a difference of 0.9 percentage points (99 % confidence interval [CI] -9.5 to 11.3; threshold, 15 %). ADR, cecal intubation time, and willingness to repeat unsedated colonoscopy were not significantly different between the two groups, but the mean volume of water used was significantly less with MWE than with LWE (163.7 mL vs. 407.2 mL; 99 %CI -298.28 to -188.69).

CONCLUSION

Compared with LWE, MWE demonstrated a noninferior outcome for insertion pain, and comparable cecal intubation time and ADR, but reduced the volume of water used and eliminated the need for a water pump.

A survey of colonoscopists with and without in-depth knowledge of water-aided colonoscopy

BACKGROUND AND AIM

Endoscopy featured water-aided colonoscopy (WAC) as novel in the Innovation Forum in 2011. Gastrointestinal Endoscopy published a modified Delphi consensus review (MDCR) that supports WAC for clinical practice in 2021. We tested the hypothesis that experience was an important predictor of WAC use, either as water immersion (WI), water exchange (WE), or a combination of WI and WE.

METHODS

A questionnaire was sent by email to the MDCR authors with an in-depth knowledge of WAC. They responded and also invited colleagues and trainees without in-depth knowledge to respond. Logistic regression analysis was used with the reasons for WAC use treated as the primary outcome. Reports related to WAC post MDCR were identified.

RESULTS

Of 100 respondents, > 80% indicated willingness to adopt and modify practice to accommodate WAC. Higher adenoma detection rate (ADR) incentivized WE use. Procedure time slots ≤ 30 and > 30 min significantly predicted WI and WE use, respectively. Co-authors of the MDCR were significantly more likely to perform WAC (odds ratio [OR] = 7.5, P = 0.037). Unfamiliarity with (OR = 0.11, P = 0.02) and absence of good experience (OR = 0.019, P = 0.002) were associated with colonoscopists less likely to perform WAC. Reports related to WAC post MDCR revealed overall and right colon WE outcomes continued to improve. Network meta-analyses showed that WE was superior to Cap and Endocuff. On-demand sedation with WE shortened nursing recovery time.

CONCLUSIONS

An important predictor of WAC use was experience. Superior outcomes continued to be reported with WE.

Factors associated with prolonged cecal insertion time in patients undergoing water exchange colonoscopy

BACKGROUND AND AIM

Water exchange is superior to air insufflation in reducing discomfort and increasing adenoma detection during colonoscopy. However, prolonged cecal insertion time is a drawback. This study aims to investigate the factors affecting cecal insertion during water exchange colonoscopy.

METHODS

We pooled data from five randomized clinical trials that included patients undergoing water exchange colonoscopy. Logistic analysis was performed to determine the independent factors associated with prolonged cecal insertion time (> 15 min).

RESULTS

The cohort included 912 patients (493 men and 419 women) with a median age of 57 years (interquartile range, 49-64 years). The median cecal insertion time was 13.5 min (interquartile range, 10.9-17.0 min). Multivariate logistic regression analysis indicated that female sex, body mass index < 25 kg/m² , a history of constipation, no sedation, less experienced endoscopist, Boston Bowel Preparation Scale score ≤ 6, infused water volume during insertion ≥ 1000 mL, and scope length at the cecum ≥ 85 cm were associated with prolonged cecal insertion time. With increasing volume of infused water (1000-2000 mL), the median cecal insertion time increased gradually from 11.4 to 23.0 min (P < 0.001).

CONCLUSIONS

The current study identified independent factors associated with prolonged cecal insertion time during water exchange colonoscopy. Several factors are modifiable to achieve a shorter insertion time, including better bowel preparation, the use of sedation, more experienced endoscopist, infusing less water during insertion, and maintaining a shorter scope length.

Comparison of Procedural Sequences in Sedated Same-Day Bidirectional Endoscopy with Water-Exchange Colonoscopy: A Randomized Controlled Trial

Background: Previous studies have favored esophagogastroduodenoscopy (EGD) followed by colonoscopy as the optimal sequence in bidirectional endoscopy (BDE) with air insufflation. However, the optimal sequence in same-day BDE with WE colonoscopy is unclear. Methods: A total of 200 patients undergoing BDE with propofol sedation from May 2018 to January 2021 were randomized to either the EGD-first group (n = 100) or the colonoscopy-first group (n = 100). Results: The EGD-first group required a longer cecal-intubation time (median 16.0 min vs. 13.7 min, p < 0.001) and a lower Boston Bowel Preparation Scale score (8.5 vs. 9, p = 0.030) compared with the colonoscopy-first group. However, the EGD-first group needed a significantly lower dose of propofol (200 mg vs. 250 mg, p < 0.001) and a shorter recovery time (7 min vs. 13.5 min, p < 0.001), resulting in a shorter turnover time of the endoscopy room (39.5 min vs. 42.6 min, p = 0.004). There were no differences in the sedation-related adverse events, patients’ satisfaction scores, adenoma-detection rates, or the outcomes of EGD between the two groups. Conclusions: During propofol-sedated BDE, EGD followed by WE colonoscopy was more efficient with a shorter turnover time despite a longer cecal-intubation time (NCT03638713).

Comparison of Right Colon Adenoma Miss Rates Between Water Exchange and Carbon Dioxide Insufflation: A Prospective Randomized Controlled Trial

GOALS

To test the hypothesis that water exchange (WE), when compared with carbon dioxide (CO2) insufflation, significantly reduces the right colon adenoma miss rate (rAMR) in a blinded randomized controlled trial with cap-assisted colonoscopy.

BACKGROUND

The unblinded consecutive group observational data showed that WE significantly decreased rAMR. The unblinded data are limited by potential bias.

STUDY

Consecutive patients aged 45 years or more were randomized to undergo insertion with WE or CO2. Withdrawal and polypectomy were performed with CO2 in both groups to the hepatic flexure. The colonoscope was reinserted to the cecum. A second colonoscopist re-examined the right colon. The second colonoscopist was unaware, but made a guess, of the initial insertion method. The number of additional adenomas divided by the total number detected in both examinations equaled rAMR.

RESULTS

Among 262 patients (131/group), demographic variables were similar. The body mass index was significantly higher in the WE group. Compared with CO2, WE significantly decreased rAMR [18.0% (33/183) vs. 34.6% (62/179), P=0.0025] and right colon serrated polyp miss rate [17.4% (27/155) vs. 39.3% (33/84), P=0.002]. Multivariate logistic regression analysis showed that WE was an independent predictor of rAMR (odds ratio, 0.42; 95% confidence interval, 0.21-0.86), and so was ≥2 adenomas in the right colon (odds ratio, 2.35; 95% confidence interval, 1.17-4.76). Whether the second colonoscopist guessed the insertion method correctly or not, and demographic and procedure variables were not associated with rAMR.

CONCLUSIONS

The randomized controlled trial validated unblinded observational data showing that WE significantly decreased rAMR and right colon serrated polyp miss rate (clinical trial registration number: NCT03845933).

Clinical effects of left-colon water exchange colonoscopy vs conventional air-insufflation colonoscopy

BACKGROUND

The left colon is difficult to detect via conventional air-injection colonoscopy, and patients may have obvious discomfort during intubation. Studies have reported that water exchange technology can significantly reduce the pain and discomfort of patients during endoscopy. However, there are still few studies comparing the clinical effects of left-colon water exchange (WE) colonoscopy with conventional air-insufflation (AI) colonoscopy.

AIM

To compare the clinical effects of left-colon WE colonoscopy and conventional AI colonoscopy.

METHODS

Consecutive patients who underwent colonoscopy at our hospital from June 2020 to December 2020 were collected and randomly divided into either a left-colon WE colonoscopy group or a conventional AI colonoscopy group at a ratio of 1:1. The success rate of ileocecal insertion, time to cecal insertion, time to colonoscope withdrawal, adenoma detection rate (ADR), visual analogue scale (VAS) score of pain, and rate of complications were recorded in the two groups.

RESULTS

A total of 276 patients were included according to the inclusion and exclusion criteria, including 139 cases in the left-colon WE colonoscopy group and 137 cases in the conventional AI colonoscopy group. There were no statistical differences in the success rate of ileocecal insertion, time to colonoscope withdrawal, or adenoma detection rate between the two groups (P > 0.05). However, time to cecal insertion was significantly shorter (4.6 min vs 5.3 min, P < 0.05) and VAS score was significantly lower (2.7 vs 3.1, P < 0.05) in the left-colon WE colonoscopy group than in the conventional AI colonoscopy group. No examination-related complications such as perforation occurred in either group.

CONCLUSION

Compared with conventional AI colonoscopy, left-colon WE colonoscopy significantly shortens the time to ileocecal insertion and reduces the pain and discomfort of the patients.

Water-assisted colonoscopy: an international modified Delphi review on definitions and practice recommendations

BACKGROUND AND AIMS

Since 2008, a plethora of research studies has compared the efficacy of water-assisted (aided) colonoscopy (WAC) and underwater resection (UWR) of colorectal lesions with standard colonoscopy. We reviewed and graded the research evidence with potential clinical application. We conducted a modified Delphi consensus among experienced colonoscopists on definitions and practice of water immersion (WI), water exchange (WE), and UWR.

METHODS

Major databases were searched to obtain research reports that could potentially shape clinical practice related to WAC and UWR. Pertinent references were graded (Grading of Recommendations, Assessment, Development and Evaluation). Extracted data supporting evidence-based statements were tabulated and provided to respondents. We received responses from 55 (85% surveyed) experienced colonoscopists (37 experts and 18 nonexperts in WAC) from 16 countries in 3 rounds. Voting was conducted anonymously in the second and third round, with ≥80% agreement defined as consensus. We aimed to obtain consensus in all statements.

RESULTS

In the first and the second modified Delphi rounds, 20 proposed statements were decreased to 14 and then 11 statements. After the third round, the combined responses from all respondents depicted the consensus in 11 statements (S): definitions of WI (S1) and WE (S2), procedural features (S3-S5), impact on bowel cleanliness (S6), adenoma detection (S7), pain score (S8), and UWR (S9-S11).

CONCLUSIONS

The most important consensus statements are that WI and WE are not the same in implementation and outcomes. Because studies that could potentially shape clinical practice of WAC and UWR were chosen for review, this modified Delphi consensus supports recommendations for the use of WAC in clinical practice.

WASh multicentre randomised controlled trial: water-assisted sigmoidoscopy in English NHS bowel scope screening

OBJECTIVES

The English Bowel Cancer Screening Programme invites 55 year olds for a sigmoidoscopy (Bowel Scope Screening (BSS)), aiming to resect premalignant polyps, thus reducing cancer incidence. A national patient survey indicated higher procedural pain than anticipated, potentially impacting on screening compliance and effectiveness. We aimed to assess whether water-assisted sigmoidoscopy (WAS), as opposed to standard CO₂ technique, improved procedural pain and detection of adenomatous polyps.

DESIGN

The WASh (Water-Assisted Sigmoidoscopy) trial was a multicentre, single-blind, randomised control trial for people undergoing BSS. Participants were randomised to either receive WAS or CO₂ from five sites across England. The primary outcome measure was patient-reported moderate/severe pain, as assessed by patients on a standard Likert scale post procedure prior to discharge. The key secondary outcome was adenoma detection rate (ADR). The costs of each technique were also measured.

RESULTS

1123 participants (50% women, mean age 55) were randomised (561 WAS, 562 CO₂). We found no difference in patient-reported moderate/severe pain between WAS and CO₂ (14% in WAS, 15% in CO2; p=0.47). ADR was 15% in the CO₂ arm and 11% in the WAS arm (p=0.03); however, it remained above the minimum national performance standard in both arms. There was no statistical difference in mean number of adenomas nor overall polyp detection rate. There was negligible cost difference between the two techniques.

CONCLUSION

In the context of enema-prepared unsedated screening sigmoidoscopies performed by screening-accredited endoscopists, no difference in patient-reported pain was seen when using either a CO₂ or WAS intubation technique.

TRIAL REGISTRATION NUMBER

ISRCTN81466870.

Adenoma and Advanced Adenoma Detection Rates of Water Exchange, Endocuff, and Cap Colonoscopy: A Network Meta-Analysis with Pooled Data of Randomized Controlled Trials

BACKGROUND AND AIMS

A network meta-analysis showed that low-cost optimization of existing resources was as effective as distal add-on devices in increasing adenoma detection rate (ADR). We assessed the impacts of water exchange (WE), Endocuff, and cap colonoscopy on ADR and advanced adenoma detection rate (AADR). We hypothesized that WE may be superior at improving ADR and AADR.

METHODS

The literature was searched for all randomized controlled trials (RCTs) that reported ADR as an outcome and included the keywords colonoscopy, and water exchange, Endocuff, or cap. We performed traditional network meta-analyses with random effect models comparing ADR and AADR of each method using air insufflation (AI) as the control and reported the odds ratios with 95% confidence interval. Performances were ranked based on P-score.

RESULTS

Twenty-one RCTs met inclusion criteria. Fourteen RCTs also reported AADR. Both WE [1.46 (1.20-1.76)] and Endocuff [1.39 (1.17-1.66)] significantly increase ADR, while cap has no impact on ADR [1.00 (0.82-1.22)]. P-scores for WE (0.88), Endocuff (0.79), cap (0.17), and AI (0.17) suggest WE has the highest ADR. WE [1.38 (1.12-1.70)], but not Endocuff [0.96 (0.76-1.21)] or cap [1.06 (0.85-1.32)], significantly increases AADR. P-scores for WE (0.98), cap (0.50), AI (0.31), and Endocuff (0.21) suggest WE is more effective at increasing AADR. The results did not change after adjusting for age, proportion of males, and withdrawal time.

CONCLUSION

WE may be the modality of choice to maximally improve ADR and AADR.

Room temperature water infusion during colonoscopy insertion induces rectosigmoid colon mucus production

BACKGROUND

Water filling during colonoscopy improves several colonoscopy outcomes. We evaluated an anecdotal observation that room temperature water filling during colonoscope insertion results in mucus production in the left colon, which may impair mucosal visualization during withdrawal.

METHODS

We performed 55 colonoscopies with either water or saline filling during insertion, and video recorded the examinations. Three blinded observers scored the amount of mucus visible on the video recordings.

RESULTS

29 patients had water filling and 26 patients had saline filling during insertion. Demographic features, procedure indications, volume of infused fluid, and insertion time to the cecum were similar in the two groups. All three blinded observers rated the mucus as greater after water filling than after saline (median 3 out of 5 vs. 1 out of 5; P < 0.001), with a kappa value for interobserver agreement of 0.364 (P < 0.001).

CONCLUSION

Room temperature water filling is associated with mucus production by the rectosigmoid colon, requiring additional cleansing during withdrawal.

Will purposely seeking detect more colorectal polyps than routine performing during colonoscopy?

BACKGROUND & GOALS

We observed that the number of colorectal polyps found intraoperatively was often higher than that encountered preoperatively during elective colonoscopic polypectomy. To evaluate whether more polyps can be detected when they are purposely sought than when they are routinely examined during colonoscopy.

MATERIALS AND METHODS

Patients undergoing colonoscopy were randomized into groups A and B. Before colonoscopy was performed, endoscopists were instructed to seek polyps for group A purposely but not for group B. Polypectomy was electively completed. In groups A and B, the cases of elective polypectomy were named groups AR and BR, including groups AR-1 and BR-1, during the first colonoscopy and groups AR-2 and BR-2 during the second colonoscopy for polypectomy, respectively. The following data were calculated: the number of polyps detected (NPD) and the polyp detection rate (PDR) in all cases and the number of polyps missed (NPM) and partial polyp miss rate (PPMR) in the cases of colorectal polyps.

RESULTS

A total of 419 cases were included in group A, 421 in group B, 43 in group AR, and 35 in group BR. No significant differences in PDR were found between groups A and B and in PPMR between groups AR-1 and BR-1 (P > .05), although PPMR in group AR-1 was higher than in group AR-2 (P < .05), similar results were found in PPMR between groups BR-1 and BR-2 (P < .05).

CONCLUSION

Purposely seeking for colorectal polyps did not result in more polyps detected compared with routine colonoscopy.

Underwater versus conventional endoscopic mucosal resection for small size non-pedunculated colorectal polyps: a randomized controlled trial : (UEMR vs. CEMR for small size non-pedunculated colorectal polyps)

BACKGROUND

Underwater endoscopic mucosal resection (UEMR) is a recently developed technique and can be performed during water-aided or ordinary colonoscopy for the treatment of colorectal polyps. The objective of this clinical trial was to evaluate the efficacy and safety of UEMR in comparison with conventional endoscopic mucosal resection (CEMR) of small non-pedunculated colorectal polyps.

METHODS

Patients with small size, non-pedunculated colorectal polyps (4-9 mm in size) who underwent colonoscopic polypectomy were enrolled in this multicenter randomized controlled clinical trial. The patients were randomly allocated to two groups, an UEMR group and a CEMR group. Efficacy and safety were compared between groups.

RESULTS

In the intention-to-treat (ITT) analysis, the complete resection rate was 83.1% (59/71) in the UEMR group and 87.3% (62/71) in the CEMR group. The en-bloc resection rate was 94.4% (67/71) in the UEMR group and 91.5% (65/71) in the CEMR group (difference 2.9%; 90% CI - 4.2 to 9.9%), showed noninferiority (noninferiority margin - 5.7% < - 4.2%). No significant difference in procedure time (81 s vs. 72 s, P = 0.183) was observed. Early bleeding was observed in 1.4% of patients in the CEMR group (1/71) and 1.4% of patients in the UEMR group (1/71). None of the patients in the UEMR group complained of postprocedural bloody stool, whereas two patients in the CEMR group (2/64) reported this adverse event.

CONCLUSION

Our results indicate that UEMR is safer and just as effective as CEMR in En-bloc resection for the treatment of small colorectal polyps as such, UEMR is recommended as an alternative approach to excising small and non-pedunculated colorectal adenomatous polyps.

TRIAL REGISTRATION

Clinical Trials.gov, NCT03833492 . Retrospectively registered on February 7, 2019.

Cecal intubation time between the use of one-channel and two-channel water exchange colonoscopy: A randomized controlled trial

BACKGROUND AND AIM

Water exchange (WE) colonoscopy is the least painful insertion technique with high adenoma detection rate but requires a longer intubation time. In the published literature, some investigators used the instrument channel for both infusing and suctioning of water (one channel), while others use colonoscopes with an integrated water-jet channel specifically designed for infusing water (two channel). The aim of this study was to compare cecal intubation time between one-channel and two-channel WE.

METHODS

A total 120 patients undergoing colonoscopy from May 2017 to April 2019 at a regional hospital in southern Taiwan were randomized to either a two-channel group (n = 60) or a one-channel group (n = 60). The primary outcome was cecal intubation time.

RESULTS

The mean cecal intubation time was significantly shorter in the two-channel group compared with the one-channel group (14.0 ± 4.0 vs 17.4 ± 6.7 min, P < 0.001). The two-channel group required less water infused during insertion (564.8 ± 232.4 vs 1213.3 ± 467.5 mL, P < 0.001) but achieved a significantly higher Boston Bowel Preparation Scale score (8.4 ± 0.8 vs 7.5 ± 1.1, P < 0.001) than did the one-channel group. The adenoma detection rate was comparable in the two groups (50.0% vs 48.3%, P = 0.855).

CONCLUSIONS

In comparison with the one-channel WE, two-channel WE showed a shorter cecal intubation time, required less amount of water during insertion, and provided a better salvage cleansing effect. (NCT03279705).

Colonoscopic techniques in polyp detection: An Egyptian study

INTRODUCTION AND AIMS

The polyp detection rate (PDR) is defined as the percentage of colonoscopies in which one or more polyps are detected, and has been shown to be highly correlated with the adenoma detection rate. The aim of the present study was to evaluate the PDR at the Endoscopy Unit of the Kasr Al-Ainy Hospital, Cairo University, Egypt, through the i-SCAN, Endocuff, and underwater colonoscopy techniques.

MATERIALS AND METHODS

The study was conducted on 100 Egyptian subjects over 50 years of age. Their polyp detection rate was measured through 4 different colonoscopic techniques. An equal number of patients were divided into 4 groups: i-SCAN, Endocuff, underwater colonoscopy, and controls. The control group was examined using standard white light colonoscopy. The colonoscopy evaluation included the type of agent utilized for bowel preparation, preparation grade, and colonoscopy withdrawal time.

RESULTS

The general PDR was 48%. The i-SCAN technique had the highest rate (56%), followed by the underwater (52%) and the Endocuff (48%) techniques.

CONCLUSION

The i-SCAN and underwater colonoscopy techniques produced higher PDR than the Endocuff-assisted and standard techniques, but with no statistical significance.

How to increase proximal adenoma detection rate: a meta-analysis comparing water exchange, water immersion and air/CO2 insufflation methods for colonoscopy

Background

Recent meta-analyses have demonstrated a higher adenoma detection rate using the water exchange method (WE), compared to water immersion (WI) and air/CO₂ insufflation (ACI). Proximal adenomas have a high miss rate owing to their location and appearance. We performed a systematic review and meta-analysis of studies comparing the WE and WI methods to the ACI method, with a primary focus on proximal adenoma detection rate.

Methods

The following databases were searched for our systematic review: Medline, Embase, Cochrane Library, CINAHL, and Web of Sciences. We included both randomized controlled trials and cohort studies. The primary outcome was proximal adenoma detection rate, and secondary outcomes were right adenoma detection rate and cecal intubation rate.

Results

A total of 12 studies (17 arms) with 5660 patients (2260 ACI, 2281 WE, and 1119 WI) were included. A higher proximal adenoma detection rate (risk ratio [RR] 1.30, 95% confidence interval [CI] 1.11-1.53; P=0.001) and right adenoma detection rate (RR 1.43, 95%CI 1.19-1.71; P≤0.001; I²=0%) were noted for the WE group compared to the ACI group. The WI group did not demonstrate a better detection rate of proximal or right adenomas.

Conclusions

The water exchange method for colonoscopy holds promise and should be encouraged in the clinical setting to increase proximal and right adenoma detection rates. This will in turn decrease the incidence of colorectal cancer.

Feasibility of sedation on demand in Taiwan using water exchange and air insufflation: A randomized controlled trial

BACKGROUND AND AIM

Completion of colonoscopy without sedation eliminates sedation cost and complications. Reported in the United States and Europe, on-demand sedation is not routine practice in Taiwan. Water exchange (WE), characterized by infusion and nearly complete removal of infused water during insertion, reduces insertion pain compared to air insufflation (AI) during colonoscopy. We evaluated the feasibility of on-demand sedation in Taiwan. In a randomized controlled trial of WE vs AI colonoscopy, we also aimed to determine if WE augmented the implementation by reducing insertion pain and decreasing sedation requirement.

METHODS

This prospective patient-blinded study randomized patients to AI or WE (75 patients/group) to aid insertion. The primary outcome was the proportion of patients completing without sedation.

RESULTS

In the AI and WE groups, 76.0% and 93.3% (P = 0.006) completed without need for sedation, respectively. The WE group had lower insertion pain score (mean [SD]) (4.0 [2.9] vs 2.1 [2.6], P < 0.001), lower doses of propofol (25.7 [52.7] mg vs 9.1 [35.6] mg, P = 0.012), and less time in the recovery room (3.4 [7.4] vs 1.5 [5.5], P = 0.027) than the AI group. Patient satisfaction scores and willingness to repeat if needed in the future were similar.

CONCLUSION

On-demand sedation was feasible in Taiwan. The completion rate without sedation was high in patients (76.0% with standard AI) open to the option (no prior intent to receive the standard of full or minimal sedation). WE augmented the implementation by reducing insertion pain and decreasing sedation requirement without adversely affecting patient satisfaction or willingness to repeat.

The WASh Trial: water-assisted sigmoidoscopy in the English Bowel Scope Screening Programme: study protocol for a randomized multicenter trial

Background and study aims  The English National Bowel Scope Screening Programme (BSSP) invites 55-year-olds for a one-off, unsedated flexible sigmoidoscopy (FSIG). Data from BSSP participant-reported experience studies shows 1 in 3 participants report moderate or severe discomfort. Water-assisted colonoscopy (WAS) may improve participants' comfort. The primary objective of this study is to ascertain if post-procedural participant-assessed pain is reduced in WAS compared with carbon dioxide (CO ₂ ) insufflation, in invitees undergoing FSIG in BSSP. Patients and methods  This is a multicenter, prospective, randomized, two-arm, single-blinded trial designed to evaluate the performance of WAS versus CO ₂ insufflation in BSSP. Participants will be randomized to either CO ₂ or WAS and will be asked to rate pain post-procedure. Key procedure-related data will be analyzed, including adenoma detection rates (ADR) and degree of sigmoid looping. A cost-effectiveness analysis of WAS versus CO ₂ and a discrete choice experiment exploring preferences of participants for attributes of sigmoidoscopy will also be performed. Discussion  This is the first trial in the United Kingdom (UK) to investigate the effects of WAS in a screening setting. If the trial shows WAS either reduces pain or increases ADR, this may result in a practice change to implement WAS in screening and non-screening endoscopic practice directly impacting on 256,000 people a year who will undergo BSSP FSIG by 2020. Trial funding came from National Institute for Health Research (NIHR) Research for Patient Benefit (RfPB) supported by the NIHR Clinical Research Network. The trial is actively recruiting. ID: 35866 ISRCTN: 81466870.

Compared Abilities of Endoscopic Techniques to Increase Colon Adenoma Detection Rates: A Network Meta-analysis

BACKGROUND AND AIMS

Adenoma detection rate (ADR) is a quality metric for colorectal cancer screening. We performed a systematic review and network meta-analysis to assess the overall and comparative efficacies of different endoscopic techniques in adenoma detection.

METHODS

We performed a systematic review of published articles and abstracts, through March 15, 2018, to identify randomized controlled trials of adults undergoing colonoscopy that compared the efficacy of different devices in detection of adenomas. Our final analysis included 74 2-arm trials that comprised 44948 patients. These studies compared efficacies of add-on devices (cap, endocuff, endo-rings, G-EYE), enhanced imaging techniques (chromoendoscopy, narrow-band imaging, flexible spectral imaging color enhancement, blue laser imaging), new scopes (full-spectrum endoscopy, extra-wide-angle-view colonoscopy, dual focus), and low-cost optimizing existing resources (water-aided colonoscopy, second observer, dynamic position change), alone or in combination with high-definition colonoscopy or each other. Primary outcome was increase in ADR. We performed pairwise and network meta-analyses, and appraised quality of evidence using GRADE.

RESULTS

Low-cost optimizing existing resources (odds ratio [OR], 1.29; 95% CI,1.17-1.43), enhanced imaging techniques (OR,1.21; 95% CI, 1.09-1.35), and add-on devices (OR,1.18; 95% CI, 1.07-1.29) were associated with a moderate increase in ADR compared with high-definition colonoscopy; there was low to moderate confidence in estimates. Use of newer scopes was not associated with significant increases in ADR compared with high-definition colonoscopy (OR, 0.98; 95% CI, 0.79-1.21). In our comparative efficacy analysis, no specific technology for increasing ADR was superior to others. We did not find significant differences between technologies in detection of advanced ADR, polyp detection rate, or mean number of adenomas/patient.

CONCLUSIONS

In a network meta-analysis of published trials, we found that low-cost optimization of existing resources to be as effective as enhanced endoscopic imaging, or add-on devices, in increasing ADR during high-definition colonoscopy.

Underwater Endoscopic Mucosal Resection

Although an established standard, conventional endoscopic mucosal resection (EMR) has disseminated despite an absence of studies demonstrating the value of submucosal injection. Several consequences of poorly executed submucosal injection may increase the difficulty and risk of EMR. Underwater EMR (UEMR), an alternative resection method for colonic neoplasms, avoids the need for submucosal injections. In comparison with reported outcomes of EMR, UEMR achieves similar rates of complete resection with comparable safety, with lower rates of recurrence and fewer repeat procedures. UEMR also compares favorably with endoscopic submucosal dissection in terms of procedure time and rates of complete resection, recurrence, and complications.

Water exchange colonoscopy decreased adenoma miss rates compared with literature data and local data with CO2 insufflation: an observational study

Background

Reports showed adenoma miss rates (AMRs) of 22.5–27% in the right colon and 23.4–33.3% in the proximal colon. Missed lesions could contribute to postcolonoscopy cancers. Water exchange (WE) with near-complete removal of infused water during insertion increased adenoma detection rate but the impact on AMR had not been reported. We hypothesized that WE could reduce AMRs. Study 1 compared the AMRs of WE with literature data. Study 2 developed local AMR data with CO₂ insufflation.

Methods

The lead author attended a research seminar in 2017 on WE colonoscopy. For performance improvement, study 1 was undertaken. When data in study 1 confirmed WE produced a considerably lower AMRs in the right and proximal colon, study 2 with CO₂ insufflation was performed.

Results

Eighty-six patients completed each study. In study 1, WE removed 89% of infused water upon arrival to the cecum. The AMRs of right colon (17.5%) and proximal colon (15.5%) were considerably lower than those in the literature. Upon completion of study 2, compared with local data of CO₂ insufflation, WE showed a significantly lower AMR in the right (17.5% vs. 33.8%, P = 0.034) and proximal (15.5% vs. 30.4%, P = 0.018) colon, respectively. The major limitation was that the investigation consisted of two consecutive observational studies, not a randomized controlled trial (RCT).

Conclusions

WE with near-complete (89%) removal of infused water during insertion significantly decreased AMRs in the right and proximal colon compared with literature data and those of CO₂ insufflation in our hands. The provocative data warrant confirmation in a RCT.

Trial registration

NCT03832322 (Retrospectively registered on February 2, 2019).

Factors Associated With Adenoma Detection in Propofol-sedated Patients

GOALS

To assess the factors associated with adenoma detection in propofol-sedated patients.

BACKGROUNDS

Low adenoma detection rate (ADR) are linked to increased risk of interval cancer and related deaths. Compared with air insufflation (AI) colonoscopy, the method of water exchange (WE) significantly decreased insertion pain and increased ADR in unsedated patients. Deep sedation with propofol has been increasingly used in colonoscopy. One report suggested that WE significantly increased ADR in propofol-sedated patients, but the factors associated with adenoma detection were not analyzed.

STUDY

Post hoc multiple logistic regression analyses were performed based on pooled data from 2 randomized controlled trials to assess the factors associated with adenoma detection in propofol-sedated patients.

RESULTS

Propofol-sedated patients (n=510) were randomized to AI and WE. The baseline characteristics were comparable. Multiple logistic regression analyses show that age, withdrawal time, indications (screening vs. diagnostic), and WE were significantly and independently associated with higher ADR. WE had fewer patients with inadequate Boston Bowel Preparation Scale score of <6. Despite a significantly shorter inspection time, WE had significantly higher overall ADR than AI, especially in those with adequate Boston Bowel Preparation Scale of ≥6. Right colon ADR (17.5% vs. 10.5%), flat ADR (32.3% vs. 19.4%), combined advanced and sessile serrated ADR (13.1% vs. 7.4%) of WE were significantly higher than those of AI.

CONCLUSIONS

WE enhanced quality of colonoscopy in propofol-sedated patients by significantly improving colon cleanliness and overall ADR. Colonoscopists with patients under propofol sedation might consider evaluating WE method for performance improvement.

Comparison of polyp detection during both insertion and withdrawal versus only withdrawal of colonoscopy: A prospective randomized trial

BACKGROUND AND AIMS

Polyps seen and not removed during colonoscope insertion are sometimes unable to be found during withdrawal. We aimed to evaluate whether additional inspection and polypectomy during insertion increases adenoma detection rate (ADR) compared with inspection and polypectomy entirely during withdrawal.

METHODS

A total of 421 patients aged ≥ 45 years and undergoing colonoscopy were prospectively randomized to receive inspection and polypectomy during both insertion and withdrawal (study group) or inspection and polypectomy entirely during withdrawal (control group). The primary outcome was the ADR. Secondary outcomes included other adenoma-related parameters and procedure-related measures.

RESULTS

Baseline demographics, procedure indications, preparation quality, total procedure time, sedative doses, colonoscopy difficulty, and patient discomfort were similar between the groups. The insertion time was significantly longer in the study group (11.1 ± 4.8 vs 6.2 ± 4.7 min, P < 0.0001). The withdrawal time was significantly longer in the control group (29.2 ± 9.8 vs 23.1 ± 7.9 min, P < 0.0001). There was no significant difference in the ADR (63.5% [study group] vs 68.1% [control group]), the mean adenoma per procedure (1.6 ± 2.0 vs 1.9 ± 2.4), or the mean adenoma per positive procedure (2.5 ± 2.0 vs 2.7 ± 2.5) between groups. The proximal colon ADR was significantly higher in the control group compared with the study group (56.2% vs 46.0%, P = 0.041).

CONCLUSIONS

Additional inspection and polypectomy during colonoscope insertion did not improve ADR compared with inspection and polypectomy entirely during withdrawal. These results do not support an additional role for routine inspection during insertion (clinical trial registration number: NCT03444090).

Water Exchange Produces Significantly Higher Adenoma Detection Rate Than Water Immersion: Pooled Data From 2 Multisite Randomized Controlled Trials

GOALS

To test the hypothesis that water exchange (WE) significantly increases adenoma detection rates (ADR) compared with water immersion (WI).

BACKGROUND

Low ADR was linked to increased risk for interval colorectal cancers and related deaths. Two recent randomized controlled trials of head-to-head comparison of WE, WI, and traditional air insufflation (AI) each showed that WE achieved significantly higher ADR than AI, but not WI. The data were pooled from these 2 studies to test the above hypothesis.

STUDY

Two trials (5 sites, 14 colonoscopists) that randomized 1875 patients 1:1:1 to AI, WI, or WE were pooled and analyzed with ADR as the primary outcome.

RESULTS

The ADR of AI (39.5%) and WI (42.4%) were comparable, significantly lower than that of WE (49.6%) (vs. AI P=0.001; vs. WI P=0.033). WE insertion time was 3 minutes longer than that of AI (P<0.001). WE showed significantly higher detection rate (vs. AI) of the >10 mm advanced adenomas. Right colon combined advanced and sessile serrated ADR of AI (3.4%) and WI (5%) were comparable and were significantly lower than that of WE (8.5%) (vs. AI P<0.001; vs. WI P=0.039).

CONCLUSIONS

Compared with AI and WI, the superior ADR of WE offsets the drawback of a significantly longer insertion time. For quality improvement focused on increasing adenoma detection, WE is preferred over WI. The hypothesis that WE could lower the risk of interval colorectal cancers and related deaths should be tested.

Diagnostic application of water exchange colonoscopy: A meta-analysis of randomized controlled trials

Background

Few well-designed studies have investigated water exchange colonoscopy (WE). We performed a meta-analysis to comprehensively evaluate the clinical utility of WE based on high-quality randomized controlled trials (RCTs) and to compare the impacts of WE, water immersion colonoscopy (WI), and gas-insufflation colonoscopy.

Methods

We searched the Cochrane Library, MEDLINE, Embase, PubMed, Elsevier, CNKI, VIP, and Wan Fang Data for RCTs on WE. We analyzed the results using fixed- or random-effect models according to the presence of heterogeneity. Publication bias was assessed by funnel plots.

Results

Thirteen studies were eligible for this meta-analysis. The colonoscopic techniques included WE as the study group, and WI and air- or CO₂-insufflation colonoscopy as control groups. WE was significantly superior to the control procedures in terms of adenoma detection rate, proportion of painless unsedated colonoscopy procedures, and cecal intubation rate according to odds ratios. WE was also significantly better in terms of maximal pain score and patient satisfaction score according to mean difference.

Conclusions

WE can remarkably improve the adenoma detection rate, proportion of painless unsedated colonoscopy procedures, patient satisfaction, and cecal intubation rate, as well as reducing the maximal pain score in patients undergoing colonoscopy.

Impact of water exchange colonoscopy on endoscopy room efficiency: a systematic review and meta-analysis

BACKGROUND AND AIMS

Separate randomized controlled trials (RCTs) showed water exchange (WE) colonoscopy outperformed other techniques in minimizing insertion pain and optimizing adenoma detection rate. Longer insertion time required for removal of infused water, residual air, and feces might have hampered its wider adoption. We evaluate the impact of WE compared with air or carbon dioxide insufflation (GAS) on room turnaround efficiency measured by cecal intubation, withdrawal, and total procedure times.

METHODS

With a systematic search in PubMed, Embase, and Cochrane Library, we identified RCTs (published before March 18, 2018) that compared WE with GAS. We focused on parameters of turnaround efficiency and patient-centered outcomes.

RESULTS

We analyzed 8371 subjects from 17 studies. Demographics and indications were comparable. Mean cecal intubation time (± standard deviation) was WE 12.5 ± 6.1 minutes versus GAS 11.1 ± 7.0 minutes, with a mean difference of 1.4 ± 3.4 minutes. Six studies showed significant differences in insertion time, with mean cecal intubation times of 11.6 ± 5.1 minutes for WE versus 7.7 ± 5.2 minutes for GAS, with a mean difference of 3.9 ± 1.1 minutes. Mean withdrawal time was similar. Mean total procedure time was WE 26.0 ± 9.7 versus GAS 24.2 ± 9.6, with a mean difference of 1.8 ± 6.2 minutes. All mean procedure times were significantly different. Patient-centered outcomes revealed that patients examined with WE had significantly lower real-time insertion pain score, less need for sedation, and higher willingness to repeat the procedure.

CONCLUSIONS

Based on parameters of procedural time, the impact of WE colonoscopy on endoscopy room turnaround yields an increase in total procedure time of about 2 minutes and is associated with significant improvement in specific patient-centered outcomes.

Reduction of multitasking distractions underlies the higher adenoma detection rate of water exchange compared to air insufflation - blinded analysis of withdrawal phase videos

Background

Experts have hypothesized that a reduction of multitasking distractions and improved bowel cleanliness can explain why insertion water exchange enhances adenoma detection rate.

Objective

The purpose of this study was to test the role of both distractions during withdrawal and bowel cleanliness in enhancing adenoma detection rate using coded video records of colonoscopy.

Methods

The withdrawal phase of videos of 299 consecutive colonoscopies from two randomized controlled trials comparing water exchange versus air insufflation at a regional hospital in Taiwan were coded. The primary outcome was distractions; activities that preclude full attention being paid to inspection of the mucosa for polyps. A single blinded reviewer collected the data.

Results

There were significant agreements in inter-rater reliability indexes. Compared to air insufflation, water exchange had significantly fewer distractions; higher diagnostic yield (intervention time and number), adenoma detection rate, and Boston Bowel Preparation Scale score. Water exchange had a higher withdrawal technique score (predominantly adequacy of cleaning). The association between increased adenoma detection rate and water exchange was mediated by the number of distractions and withdrawal time, but not the Boston Bowel Preparation Scale score.

Conclusion

The speculation by experts that a reduction of multitasking distractions underlies the significantly higher adenoma detection rate of water exchange is supported by the current study. Increased bowel cleanliness did not contribute to the increased adenoma detection rate by use of water exchange.

Water exchange versus air insufflation for colonoscopy: A meta-analysis

BACKGROUND/AIMS

To compare water exchange (WE) method with conventional air insufflation (AI) method for colonoscopy, evaluating the technical quality, screening efficacy, and patients' acceptance.

MATERIALS AND METHODS

Electronic databases were systematically searched for randomized controlled trials comparing WE colonoscopy with AI colonoscopy. The pooled data of procedure-associated and patient-related outcomes were assessed, using the weighted mean difference (WMD) with 95% confidence interval (CI) for continuous variables and relative risk (RR) with 95% CI for dichotomous variables, respectively.

RESULTS

A total of 13 studies involving 7056 patients were included. The cecum intubation rate was similar between WE and AI methods (RR = 1.01, 95% CI = 0.99-1.02,P = 0.37); however, a significantly longer cecum intubation time was shown in WE group (WMD = 1.56, 95% CI = 0.75-2.37,P = 0.002). Compared with AI, WE was associated with a higher risk of adenoma detection rate (ADR) (RR = 1.28, 95% CI = 1.18-1.38,P < 0.00001) and polyp detection rate (PDR) (RR = 1.30, 95% CI = 1.21-1.39,P < 0.00001). Patients in WE group experienced significantly less maximum pain score (WMD = -1.99, 95% CI = -2.68 to -1.30,P < 0.00001) and less requested on-demand sedation (RR = 0.58, 95% CI = 0.44-0.77,P = 0.0002). Likewise, they also experienced less abdominal compression (RR = 0.62, 95% CI = 0.51-0.74,P < 0.00001) and reposition (RR = 0.74, 95% CI = 0.63-0.86,P = 0.0001). Moreover, patients' willingness to repeat colonoscopy was significantly greater for WE (RR = 1.14, 95% CI = 1.07-1.21,P < 0.0001).

CONCLUSION

This meta-analysis confirmed that WE method could significantly increase ADR/PDR and improve patients' acceptance of colonoscopy, while reducing the degree of pain and minimize the need for on-demand sedation and adjunct maneuvers, despite requiring more cecal intubation time.

Water exchange colonoscopy increases adenoma detection rate: a systematic review with network meta-analysis of randomized controlled studies

BACKGROUND AND AIMS

Water-aided colonoscopy techniques, such as water immersion (WI) and water exchange (WE), have shown different results regarding adenoma detection rate (ADR). We determined the impact of WI and WE on ADR and other procedural outcomes versus gas (air, AI; CO₂) insufflation colonoscopy.

METHODS

A systematic search of multiple databases for randomized controlled trials comparing WI and/or WE with AI and/or CO₂ and reporting ADR was conducted. A network meta-analysis with mixed comparisons was performed. Primary outcome was ADR (overall, in the right side of the colon and by colonoscopy indication).

RESULTS

Seventeen randomized controlled trials (10,350 patients) were included. WE showed a significantly higher overall ADR versus WI (odds ratio [OR], 1.31; 95% credible interval [CrI], 1.12-1.55) versus AI (OR, 1.40; CrI, 1.22-1.62) versus CO₂ (OR, 1.48; 95% CrI, 1.15-1.86). WE achieved the highest ADR also in the right side of the colon and in colorectal cancer screening cases (both significant vs AI and WI) as well as in patients taking a split-dose preparation (significant vs all the other techniques). The Boston Bowel Preparation Scale cleanliness score (vs AI and WI) was significantly higher for WE. Both WI and WE showed increased proportion of unsedated examinations and decreased real-time insertion pain, with WE being the least-painful insertion technique. Withdrawal time was comparable across techniques, but WE showed the longest insertion time (3-5 additional minutes).

CONCLUSIONS

WE significantly increases overall ADR, ADR in screening cases, and in the right side of the colon; it also improves colon cleanliness but requires a longer insertion time.

Is water exchange superior to water immersion for colonoscopy? A systematic review and meta-analysis

Background/Aims

Recently, water exchange (WE) instead of water immersion (WI) for colonoscopy has been proposed to decrease pain and improve adenoma detection rate (ADR). This systematic review and meta-analysis is conducted to assess whether WE is superior to WI based on the published randomized controlled trials (RCTs).

Materials and Methods

We searched studies from PubMed, Cochrane Central Register of Controlled Trials, EMBASE, and MEDLINE. Only RCTs were eligible for our study. The pooled risk ratios (RRs), pooled mean difference (MD), and pooled 95% confidence intervals (CIs) were calculated by using the fixed-effects model or random-effects model based on heterogeneity.

Results

Five RCTs consisting of 2229 colonoscopies were included in this study. WE was associated with a significantly higher ADR than WI (RR = 1.18; CI = 1.05-1.32; P = 0.004), especially in right colon (RR = 1.31; CI = 1.07-1.61; P = 0.01). Compared with WI, WE was confirmed with lower pain score, higher Boston Bowel Preparation Scale score, but more infused water during insertion. There was no statistical difference between WE and WI in cecal intubation rate and the number of patients who had willingness to repeat the examination. Furthermore, both total procedure time and cecal intubation time in WE were significantly longer than that in WI (MD = 2.66; CI = 1.42-3.90; P < 0.0001; vs MD = 4.58; CI = 4.01-5.15; P < 0.0001).

Conclusions

This meta-analysis supports the hypothesis that WE is superior to WI in improving ADR, attenuating insertion pain and providing better bowel cleansing, but inferior in time and consumption of infused water consumption during insertion.

Colonoscopic withdrawal time and adenoma detection in the right colon

Shorter colonoscopic withdrawal time (CWT) has been associated with lower adenoma detection rate (ADR), which can increase the risk of interval colorectal cancer (ICC) that commonly arises in the right colon (RC). Therefore, a better ADR in the RC could decrease the incidence of ICC. We analyzed the relationship between CWT and ADR in the RC and entire colon.We retrospectively reviewed the patients who had undergone screening colonoscopy at Chungnam National University Hospital between March 2015 and February 2016. We enrolled 5370 patients in whom colonoscopies were performed by 7 gastroenterologists. We categorized patients into 4 groups in the RC and 6 groups in the entire colon by CWT. Multivariable analysis was used for detection of adenoma in the RC and entire colon.In the RC, the odds ratio (OR) of CWT longer than 3 minutes was 3.70, compared to CWT of <2 minutes [3.06-4.85, 95% confidence interval (CI), P < .001]. In the entire colon, the OR of CWT between 9 to 10 minutes and longer than 10 minutes was 3.34 [2.61-4.27, 95% CI, P < .001] and 3.49 [2.80-4.33, 95% CI, P < .001] compared to CWT of <6 minutes.Based on our result, we suggest that the optimum CWT in the RC should exceed 3 minutes, and considering the "ceiling effect," the optimum CWT in the entire colon should exceed 9 minutes.

Is water exchange superior to water immersion in detecting adenomas during colonoscopies? Results from a Bayesian network meta-analysis

AIM

Water-assisted colonoscopy (water exchange [WE] and water immersion [WI]) has been shown to improve the adenoma detection rate. However, few studies have compared these two methods head-to-head. Thus, we conducted a network meta-analysis to integrate both direct and indirect evidence comparing the effectiveness of these two procedures.

METHOD

We searched PubMed, Web of Science, and the Cochrane Central Register of Controlled Trials for original papers and abstracts published up to March 2018. Randomized controlled trials (RCTs) reporting data in accordance with the eligibility criteria were included in this study. We performed a Bayesian random effects network meta-analysis with mixed comparisons.

RESULTS

Twenty-nine studies (n = 11464 patients) including 6 direct and 23 indirect comparisons were included in this network meta-analysis. There was a statistically significant difference in the efficacy of adenoma detection when WE was compared with WI (risk ratio [RR]: 1.2, 95% credible interval [CrI]: 1.1-1.3), air insufflation (AI; RR: 1.3, 95% CrI: 1.1-1.4), and carbon dioxide (CO2) insufflation (RR: 1.2, 95% CrI: 1.1-1.5). The different methods were ranked in order from the most to least effective in adenoma detection as follows: WE, WI, AI, and CO2. Moreover, although there were no significant differences in pain scores, willingness to repeat, caecal intubation rate, or total procedure time between WI and WE colonoscopy, WE required a longer caecal intubation time than WI.

CONCLUSION

This network meta-analysis supposes that WE may be superior to WI in detecting adenomas during colonoscopies without affecting other technical features or patient acceptance.

Characteristics of right-sided colonic neoplasia and colonoscopy barriers limiting their early detection and prognosis: a review of the literature

Colonoscopy provides less protection from colorectal cancer in the right colon than the left. Areas covered: This review examines patient outcomes and colonoscopy success rates to identify factors that limit the protective effect of colonoscopy in the right colon. The MEDLINE and Embase databases were searched for literature from 2000 onwards, on the long-term outcomes and differences in screening practice between the right and left colon. In total, 12 systematic reviews (including nine meta-analyses) and 44 primary data records were included. Differences in patient outcomes and colonoscopy practice were identified between the right and left colon, suggesting that several factors, many of which disproportionally affect the right colon, impact lesion detection rates. Shorter withdrawal times reduce detection rates, while longer times significantly increase detection; mostly of adenomas in the right colon. Colonoscope attachments often only show a significant improvement in detection rates in the right colon, suggesting detection is more challenging due to visibility of the right colonic mucosa. Higher bowel cleansing grades significantly improve detection rates in the right colon compared to the left. Expert commentary: These findings confirm the need for continued improvement of colonoscopy effectiveness, and obligatory quality assessment, overall and especially in the right colon.

Bayesian network meta-analysis: Efficacy of air insufflation, CO2 insufflation, water exchange, and water immersion in colonoscopy

BACKGROUND AND AIM

Colonoscopy is an excellent screening tool for colorectal cancer. There are four colonoscopy techniques: air insufflation, CO₂ insufflation, water exchange, and water immersion. Some studies reported that the latter three methods are better than the criterion standard (air insufflation), whereas some studies did not. In order to evaluate the efficacy of the four colonoscopy techniques, a network meta-analysis was carried out.

METHODS

We searched randomized controlled trials (RCT) published up to September 2017 from PubMed, Embase, Cochrane library, and Web of Science. Studies referencing the comparison between at least two of air insufflation, CO₂ insufflation, water exchange, and water immersion were selected. Primary outcomes included pain score during insertion, polyp detection rate, and adenoma detection rate, and secondary outcomes included cecal intubation time and cecal intubation rate. Mean differences or odds ratios and their corresponding 95% credible intervals were pooled with Bayesian modeling.

RESULTS

Forty RCT with 13 734 patients were included in this network meta-analysis. Our analysis showed that air insufflation had the highest pain score (surface under the cumulative ranking curve [SUCRA]: 98.8%) and the lowest detection rate of adenoma (SUCRA: 21.3%) and polyp (SUCRA: 16.8%). Water exchange had the lowest pain score (SUCRA: 1.1%) and highest detection rate of adenoma (SUCRA: 96.0%) and polyp (SUCRA: 98.9%), although it led to the longest cecal intubation time (SUCRA: 86.9%).

CONCLUSIONS

Air insufflation might be the most unsatisfactory colonoscopy. Meanwhile, water exchange might be the most efficient colonoscopy.

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.

Cecal intubation time between cap-assisted water exchange and water exchange colonoscopy: a randomized-controlled trial

BACKGROUND AND AIM

The water exchange (WE) method can decrease the discomfort of the patients undergoing colonoscopy. It also provides salvage cleansing and improves adenoma detection, but a longer intubation time is required. Cap-assisted colonoscopy leads to a significant reduction in cecal intubation time compared with traditional colonoscopy with air insufflation. The aim of this study was to investigate whether combined cap-assisted colonoscopy and water exchange (CWE) could decrease the cecal intubation time compared with WE.

PATIENTS AND METHODS

A total of 120 patients undergoing fully sedated colonoscopy at a regional hospital in southern Taiwan were randomized to colonoscopy with either CWE (n=59) or WE (n=61). The primary endpoint was cecal intubation time.

RESULTS

The mean cecal intubation time was significantly shorter in CWE (12.0 min) compared with WE (14.8 min) (P=0.004). The volume of infused water during insertion was lower in CWE (840 ml) compared with WE (1044 ml) (P=0.003). The adenoma detection rate was 50.8 and 47.5% for CWE and WE, respectively (P=0.472). The Boston Bowel Preparation Scale scores were comparable in the two groups. Results from the multiple linear regression analysis indicated that WE with a cap, a higher degree of endoscopist's experience, a higher Boston Bowel Preparation Scale score, and a lower volume of water infused during insertion, without abdominal compression, without change of position, and without chronic laxative use, were significantly associated with a shorter cecal intubation time.

CONCLUSION

In comparison with WE, CWE could shorten the cecal intubation time and required lower volume of water infusion during insertion without compromising the cleansing effect of WE.