Retrospective analysis showing the water method increased adenoma detection rate - a hypothesis generating observation

The Effectiveness of Right- vs Left-lateral Starting Position in Unsedated Diagnostic Colonoscopy with Modified-water Immersion Method: A Randomized Controlled Trial Study

OBJECTIVE

A colonoscopy study in sedated patients with air insufflation showed that right-lateral starting position (RLP) improved abdominal discomfort and reduced cecal intubation time. The aim of this study was to determine if RLP vs left-lateral starting position (LLP) may produce similar results in unsedated patients examined with a modified-water immersion (m-WI) method.

METHODS

Consecutive patients for diagnostic colonoscopy meeting the inclusion criteria were randomized. Patients and colonoscopist were unblinded. The m-WI method entailed suction during insertion not only for fecal debris evacuation but also to facilitate passage through difficult or angulated colonic flexures. Water was infused as needed when any difficulty was encountered during insertion. A bowel visualization scale (BVS) (0=totally blurred visualization; 1=blurred lumen visualization; 2=small fecal debris with clear mucosa visualization; 3= clear visualization) was used to evaluate the interference of fecal debris with cecal intubation rate and time.

RESULTS

A total of 142 patients (72 in RLP and 70 in LLP) were enrolled. The respective pain score, visual analog scale, (VAS) and cecal intubation rate were not significantly different. The cecal intubation time was nearly significantly different (13.4±4.5 min vs 11.7±5.4 min; p=0.054) and was significantly different in the constipation subgroup (16.0±3.5 min vs 8.6±3.8 min; p=0.001). The cecal intubation time based on BVS showed significant difference between RLP and LLP in Scale 2 (13.9±4.6 min vs 10.3±4.2 min; p=0.003) and Scale 2 and 3 combined (13.2±4.3 min vs 10.6±4.8 min; p=0.01), respectively.

CONCLUSION

RLP did not improve the pain score, and LLP showed better performance in unsedated m-WI colonoscopy patients (ClinicalTrial.gov, NCT03489824).

Endoscope-connected water pump with high flow rates improves the unsedated colonoscopy performance by water immersion method

OBJECTIVES

The aim of this study was to determine if different water pump flow rates influence the insertion time of water immersion method in unsedated patients. We tested the hypothesis that high flow rate (HFR) is more effective than low flow rate (LFR) in facilitating insertion. Clinical registration number: NCT01869296.

METHODS

Consecutive symptomatic patients without prior abdominal surgery were consented and enrolled. They were randomized to an HFR (10.4 mL/s) or LFR (1.7 mL/s) group. The patients were not informed about the flow rate of the water pump (single blinded). Patients underwent unsedated colonoscopy examination with standard colonoscope. Demographic and procedural parameters were recorded. Data were analyzed with Student's t-test or Chi-square test as appropriate.

RESULTS

A total of 132 patients (66 in HFR and 66 in LFR group) were recruited. The HFR group showed significantly shorter cecal intubation time (12.5±6.2 min in HFR vs 16.3±7.3 min in LFR, p=0.004), shorter time to pass rectosigmoid (3.6±2.2 min in HFR vs 6.2±4.6 min in LFR, p<0.001), and lower pain score (4.2±2.8 in HFR vs 5.3±2.6 in LFR, p=0.024). The cecal intubation rate was not significantly different (87.9% in HFR vs 80.3% in LFR, p=0.34), and 29 (14 in HFR and 15 in LFR) patients with signs of colon redundancy were successfully intubated to the cecum after repeated loop reduction and position changes.

CONCLUSION

Compared to LFR, HFR of the water infusion pump significantly reduced colonoscopy insertion time and pain score in unsedated patients. Significantly shorter time to pass the rectosigmoid appeared to play a contributory role.

Carbon dioxide insufflation or warm-water infusion for unsedated colonoscopy: A randomized controlled trial in patients with chronic constipation in China

AIMS

The effect of carbon dioxide (CO2) insufflation and warm-water infusion during colonoscopy on patients with chronic constipation remains unknown. We evaluated CO 2 insufflation and warm-water irrigation versus air insufflation in unsedated patients with chronic constipation in China.

PATIENTS AND METHODS

This randomized, single-center, controlled trial enrolled 287 consecutive patients, from January 2014 to January 2015, who underwent colonoscopy for chronic constipation. Patients were randomized to CO2 insufflation, warm-water irrigation and air insufflation colonoscopy insertion phase groups. Pain scores were assessed by the visual analog scale (VAS). The primary outcome was real-time maximum insertion pain, recorded by an unblinded nurse assistant. At discharge, the recalled maximum insertion pain was recorded. Meanwhile, patients were requested to select the VAS at 0, 10, 30, and 60 min after the procedure. In addition, cecal intubation and withdrawal time, total procedure time, and adjunct measures were recorded.

RESULTS

A total of 287 patients were randomized. The correlation between real-time and recalled maximum insertion pain ((Pearson coefficient r = 0.929; P < 0.0001) confirmed internal validation of the primary outcome. The mean real-time maximum pain scores during insertion 2.9 ± 2.1 for CO2, 2.7 ± 1.9 for water achieved a significantly lower pain score compared with air (5.7 ± 2.5) group (air vs CO2 P < 0.001; air vs water P < 0.001). However, no significant pain score differences were found between the patients in the CO2 and water groups (CO2 vs water, P = 0.0535). P values in painless colonoscopy and only discomfort colonoscopy (pain 1-2) were, respectively, 6 (6.4%) and 8 (8.5%) for air; 17 (17.7%) and 29 (30.2%) for CO2; 16 (16.5%) and 31 (31.9%) for water. At 0, 10, 30, and 60 min postprocedure, pain scores showed in the CO2 and water groups had significantly reduced than in air group. Insertion time was significantly different between air (10.6 ± 2.5) and CO2 ( 7.2 ± 1.4) (air vs CO2 P < 0.001), air and water (6.9 ± 1.3) (air vs water P < 0.001). However, CO2 and was not significantly different in cecum-intubated time (CO2 vs water, P = 0.404). CO2 and water group in extubation time were significantly different, respectively, CO2 (7.9 ± 1.1) and water (8.0 ± 1.1) (CO2 vs water, P = 0.707). CO2 or water group required less implementation of adjunct measures and more willingness to repeat the procedure.

CONCLUSIONS

Compared with air, the CO2 or water-aided method reduced real-time maximum pain and cecum-intubated time for chronic constipated patients in unsedated colonoscopy. The CO2 insufflation or warm-water irrigation may be a simple and inexpensive way to reduce discomfort in unsedated patients with constipation. This study demonstrated an advantage of using CO2 insufflation and warm-water irrigation during colonoscopy in unsedated constipated patients in China.

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.

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.

Carbon dioxide insufflation or warm-water infusion versus standard air insufflation for unsedated colonoscopy: a randomized controlled trial

BACKGROUND

The increasing demand for colonoscopy has renewed the interest for unsedated procedures. Alternative techniques, such as carbon dioxide insufflation and warm-water infusion, have been advocated to improve patient tolerance for colonoscopy in comparison with air insufflation.

OBJECTIVE

The aim of this study was to evaluate the benefits of carbon dioxide insufflation and warm-water irrigation over air insufflation in unsedated patients.

DESIGN

This study was a randomized, controlled trial.

SETTING

This study was conducted at a nonacademic single center.

PATIENTS

Consecutive outpatients agreeing to start colonoscopy without premedication were included.

INTERVENTIONS

Patients were assigned to either carbon dioxide insufflation, warm-water irrigation, or air insufflation colonoscopy insertion phase. Sedation/analgesia were administered on patient request if significant pain or discomfort occurred.

MAIN OUTCOME MEASURES

The primary outcome measured was the percentage of patients requiring sedation/analgesia. Pain and tolerance scores were assessed at discharge by using a 100-mm visual analog scale.

RESULTS

Three hundred forty-one subjects (115 in the carbon dioxide, 113 in the warm-water, and 113 in the air group) were enrolled. Intention-to-treat analysis showed that the proportion of patients requesting sedation/analgesia during colonoscopy was 15.5% in the carbon dioxide group, 13.2% in the warm-water group, and 25.6% in the air group (p = 0.04 carbon dioxide vs air; p = 0.03 warm water vs air). Median (interquartile range) scores for pain were 30 (10-50), 28 (15-50), and 46 (22-62) in the carbon dioxide, warm-water, and air groups (carbon dioxide vs air, p < 0.01; warm water vs air, p < 0.01); corresponding figures for tolerance were 20 (5-30), 19 (5-36), and 28 (10-50) (carbon dioxide vs air, p < 0.01; warm water vs air, p < 0.01).

LIMITATIONS

This investigation was limited because it was a single-center study and the endoscopists were not blinded to randomization.

CONCLUSIONS

Carbon dioxide insufflation was associated with a decrease in the proportion of patients requesting on-demand sedation, improved patient tolerance, and decreased colonoscopy-related pain in comparison with air insufflation. The findings regarding warm-water irrigation confirmed the previously reported advantages, so that warm-water irrigation and carbon dioxide insufflation could represent competitive strategies for colonoscopy in unsedated patients.

Colonoscopy for colorectal cancer screening

Colorectal cancer (CRC) is the second leading cause of cancer death in the United States. Many, if not most, cases arise from premalignant lesions (adenomas) which may be identified and removed prior to becoming frankly malignant. For over a decade, colonoscopy has been the preferred modality for both CRC screening and prevention in the US. Early reports suggested that colonoscopic screening imparted a 90% risk reduction for colorectal cancer. Subsequent studies showed that estimate to be overly optimistic. While still an outstanding CRC screening and detection tool, colonoscopy has several important limitations. Some of these limitations relate to the mechanics of the procedure such as the risk of colonic perforation, bleeding, adverse consequences of sedation, and the inability to detect all colonic polyps. Other limitations reflect issues with patient perception regarding colonoscopy which, at least in part, drive patient non-adherence to recommended testing. This review examines the literature to address several important issues. First, we analyze the effect of colonoscopy on CRC incidence and mortality. Second, we consider the patient-based, periprocedural, and intraprocedural factors which may limit colonoscopy as a screening modality. Third, we explore new techniques and technologies which may enhance the efficacy of colonoscopy for adenoma detection. Finally, we discuss the short and long-term future of colonoscopy for CRC screening and the factors which may affect this future.

Advances in gastrointestinal endoscopy

Gastrointestinal endoscopy has undergone a remarkable expansion in its capabilities as a result of sophisticated technological advances in recent years. New imaging technologies, novel ablation and resection techniques, cutting-edge endoscope development and creative extraluminal applications have taken gastrointestinal endoscopy to an exciting new level. An update on some of these advances is presented for the physician audience.

Water-aided colonoscopy: a systematic review

BACKGROUND

Water-aided methods for colonoscopy are distinguished by the timing of removal of infused water, predominantly during withdrawal (water immersion) or during insertion (water exchange).

OBJECTIVE

To discuss the impact of these approaches on colonoscopy pain and adenoma detection rate (ADR).

DESIGN

Systematic review.

SETTING

Randomized, controlled trial (RCT) that compared water-aided methods and air insufflation during colonoscope insertion.

PATIENTS

Patients undergoing colonoscopy.

INTERVENTION

Medline, PubMed, and Google searches (January 2008-December 2011) and personal communications of manuscripts in press were considered to identify appropriate RCTs.

MAIN OUTCOME MEASUREMENTS

Pain during colonoscopy and ADR. RCTs were grouped according to whether water immersion or water exchange was used. Reported pain scores and ADR were tabulated based on group assignment.

RESULTS

Pain during colonoscopy is significantly reduced by both water immersion and water exchange compared with traditional air insufflation. The reduction in pain scores was qualitatively greater with water exchange as compared with water immersion. A mixed pattern of increases and decreases in ADR was observed with water immersion. A higher ADR, especially proximal to the splenic flexure, was obtained when water exchange was implemented.

LIMITATIONS

Differences in the reports limit application of meta-analysis. The inability to blind the colonoscopists exposed the observations to uncertain bias.

CONCLUSION

Compared with air insufflation, both water immersion and water exchange significantly reduce colonoscopy pain. Water exchange may be superior to water immersion in minimizing colonoscopy discomfort and in increasing ADR. A head-to-head comparison of these 3 approaches is required.

Indigocarmine added to the water exchange method enhances adenoma detection - a RCT

PURPOSE

Chromoendoscopy with dye spray and the water method both increase adenoma detection.

HYPOTHESIS

Adding indigocarmine to the water method will enhance further the effectiveness of the latter in adenoma detection.

METHODS

Screening colonoscopy was performed with the water method (control) or with 0.008% indigocarmine added (study) by two endoscopists. Randomization was based on computer-generated codes contained in blocks of pre-arranged opaque sealed envelopes. High resolution colonoscopes were used. Upon insertion into the rectum, air was suctioned. With the air pump turned off, water was infused using a blunt needle adaptor connected to the scope channel and a foot pump to facilitate scope insertion until the cecum was reached. Residual stool causing cloudiness was suctioned followed by infusion of clear or colored water (water exchange) to facilitate scope passage with minimal distention of the colonic lumen. Upon seeing the appendix opening under water, water was suctioned and air was insufflated to facilitate inspection on scope withdrawal.

STATISTICS

Sample size calculation revealed 168 patients (84/group) needed to be randomized. Study was IRB-approved and registered (NCT01383265).

RESULTS

There were no significant differences in mean age, gender distribution, BMI, and family history of colon cancer. Cecal intubation success rate was 100% in both groups. The overall adenoma detection rate was 44% (water only) versus 62% (water with indigocarmine), respectively (p=0.03). One cancer was detected in each group.

CONCLUSION

In a RCT, indigocarmine at 0.008% concentration, added to the water method, significantly enhanced further the effectiveness of the latter in detecting adenomas.

A pilot study to assess feasibility of the water method to aid colonoscope insertion in community settings in the United States

BACKGROUND: The water method decreases patient discomfort and sedation requirement. Applicability in non-veteran community settings in the United States (U.S.) has not been reported. AIMS: Our aim is to perform a pilot study to establish feasibility of use the water method at 2 community sites. We tested the hypothesis that compared with air insufflation patients examined with the water method would require less sedation without adverse impact on outcomes. METHODS: Two performance improvement projects were carried out. Consecutive patients who consented to respond to a questionnaire after colonoscopy were enrolled. Project 1: The design was single-blinded (patient only); quasi-randomized - odd days (water), even days (air). Colonoscopy was performed by a staff attending. Project 2: A supervised trainee performed the reported procedures. In both, patient demographics (age, gender and body mass index), amount of sedation required during colonoscopy and procedure-related variables were recorded. The patients completed a questionnaire that enquired about discomfort during colonoscopy and willingness to repeat the procedure within 24 hours after the procedure. RESULTS: Project 1: Significantly lower doses of fentanyl and midazolam were used and a higher adenoma detection rate (ADR) was demonstrated in the water group. Project 2: 100% cecal intubation rate was achieved by the supervised trainee. CONCLUSION: This is the first pilot report in the U.S. documenting feasibility of the water method as the principal modality to aid colonoscope insertion in both male and female community patients. In a head-to-head comparison, significant reduction of sedation requirement is confirmed as hypothesized. No adverse impact on outcomes was noted.

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

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

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

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

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

BACKGROUND: The water method has promising features for colonoscopy but the learning curve to master the technique is unknown. AIMS: To describe the learning phase, and pitfalls of the water method and its impact on procedural outcomes by an experienced colonoscopist. DESIGN: Review of prospectively collected data in a performance improvement project SETTING: endoscopy Unit at a VA medical center PATIENTS: 200 consecutive veterans undergoing colonoscopy METHODS: An experienced colonoscopist examined 4 consecutive groups of 25 patients each using the water method to define the learning curve. Outcomes were compared to a historical cohort (n=100) examined by the same colonoscopist using usual air insufflation. MAIN OUTCOME MEASURES: Intent-to-treat (ITT) cecal intubation rate. RESULTS: ITT cecal intubation rate increased from 76% (first) to 96% (fourth quartile). Cecal intubation time in the first 2 quartiles was significantly longer (8.9±1.0 and 8.2±0.8 min, respectively) than that in the historical cohort (5.8±0.4 min) but decreased and became comparable to control values in the next 2 quartiles (7.2±0.9 and 6.6±0.6 min, respectively). Overall adenoma detection rate as a group (55%), compared favorably to the historical cohort (46%). CONCLUSIONS: The water method is relatively easy to learn for an experienced colonoscopist. Mastery of the method resulted in cecal intubation rate and overall adenoma detection rate meeting quality performance standards.

Removal of infused water predominantly during insertion (water exchange) is consistently associated with an increase in adenoma detection rate - review of data in randomized controlled trials (RCTs) of water-related methods

INTRODUCTION: Variation in outcomes in RcTs comparing water-related methods and air insufflation raises challenging questions regarding the new approach. This report reviews impact of water exchange - simultaneous infusion and removal of infused water during insertion on adenoma detection rate (ADR) defined as proportion of patients with a least one adenoma of any size. METHODS: Medline (2008-2011) searches, abstract of 2011 Digestive Disease Week (DDW) meeting and personal communications were considered to identify RcTs that compared water-related methods and air insufflation to aid insertion of colonoscope. RESULTS: Since 2008, eleven reports of RcTs (6 published, 1 submitted and 4 abstracts, n=1728) described ADR in patients randomized to be examined by air and water-related methods. The water-related methods differed in timing of removal of the infused water -predominantly during insertion (water exchange) (n=825) or predominantly during withdrawal (water immersion) (n=903). Water immersion was associated with both increases and decreases in ADR compared to respective air method patients and the net overall change (-7%) was significant. On the other hand water exchange was associated with increases in ADR consistently and the net changes (overall, 8%; proximal overall, 11%; and proximal <10 mm, 12%) were all significant. CONCLUSION: Comparative data generated the hypothesis that significantly larger increases in overall and proximal colon ADRs were associated with water exchange than water immersion or air insufflation during insertion. The hypothesis should be evaluated by RCTs to elucidate the mechanism of water exchange on adenoma detection.

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

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

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

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

The water method significantly enhances detection of diminutive lesions (adenoma and hyperplastic polyp combined) in the proximal colon in screening colonoscopy - data derived from two RCT in US veterans

PURPOSE: Emerging data indicate a colonoscopist-controlled method is needed to avoid missing proximal colon pre-malignant lesions. Screening colonoscopy does not prevent all proximal colon cancers. Even diminutive lesions in the proximal colon harbor dysplasia. In addition to adenomas (presumptive cancer precursors), recent proposals to reevaluate proximal colon hyperplastic polyps as serrated polyps which could be pre-malignant or harbingers of interval neoplasia dramatize the importance of attending to these lesions. The finding that the water method increased yield of proximal diminutive adenomas prompted assessment of the hypothesis that the water method increases yield of all proximal diminutive lesions (adenoma and hyperplastic polyp) in screening cases. METHODS: Two RCT assessed the water method with primary outcome of completion of unsedated colonoscopy when the option of scheduled, unsedated or sedation on demand was used. Diminutive (<10 mm) lesions proximal to the splenic flexure were tracked. RESULTS: In screening cases, 31% and 6% of the water and air group had at least one proximal diminutive lesion (p=0.0012). Regression analysis revealed withdrawal time, method and volume of water used were significant predictors of proximal diminutive lesions. Effect of the water method on detection of proximal diminutive lesions was independent of age, body mass index, endoscopist, sedation, cecal intubation rate, bowel cleanliness score on withdrawal and total procedure time. LIMITATION: Male subject predominance, analysis of secondary outcomes of pooled RCT data. CONCLUSION: The hypothesis that the water method effectively enhances proximal diminutive lesion detection in screening colonoscopy in diverse clinical settings should be tested.

The water method combined with chromoendoscopy enhances adenoma detection

BACKGROUND: The water method is easy-to-learn and improves colonoscopy outcomes. Dye-spray chromoendoscopy enhances ADR but has not been widely accepted for routine application in screening or surveillance colonoscopy. HYPOTHESIS: With dye added to the water used in the water method, ADR can be enhanced compared with the water or air method alone. OBJECTIVE: To compare ADR determined by the air method, water method alone, and water method with indigo carmine (0.008%) added. DESIGN: Review of prospectively collected data in a performance improvement program. SETTING: VA endoscopy unit. PATIENT: Screening or surveillance colonoscopy. METHODS: Patients (n=50/group) underwent colonoscopy with each of the three methods. Water method involved warm water infusion in lieu of air insufflation coupled with removal of residual air by suction and residual feces by water exchange. ADR and procedural data were collected prospectively to monitor performance. MAIN OUTCOME MEASUREMENTS: ADR. RESULTS: ADR in the air method, water method alone and water method with indigo carmine were 36%, 40% and 62%, respectively. Water method with indigo carmine produced significantly higher ADR than the air or water method alone (p<0.05). LIMITATIONS: Non-randomized data, single VA site, retrospective comparison. Absence of significant difference between air and water methods could be a type II error due to small number of patients CONCLUSIONS: The approach with indigo carmine added to the water used in the water method yielded significantly higher ADR than the water or the air method alone. The data suggest that a prospective RCT to compare the different methods is warranted.

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

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

Unsedated colonoscopy: is it feasible?

Unsedated colonoscopy has been an evolving subject ever since its initial description four decades ago. Failure in unsedated diagnostic cases due to patient pain led to the introduction of sedation. Extension to screening cases, albeit logical, created a sedation-related barrier to colonoscopy screening. In recent years a water method has been developed to combat the pain during unsedated colonoscopy in the US. In randomized controlled trials the water method decreases pain, increases cecal intubation success, and enhances the proportion of patients who complete unsedated colonoscopy. The salvage cleansing of suboptimal bowel preparation by the water method serendipitously may have increased the detection of adenoma in both unsedated and sedated patients. The state-of-the-art lecture concludes that unsedated colonoscopy is feasible. The hypothesis is that recent advances, such as the development of the water method, may contribute to reviving unsedated colonoscopy as a potentially attractive option for colon cancer screening and deserves to be tested.

The water method significantly enhances proximal diminutive adenoma detection rate in unsedated patients

BACKGROUND: Colonoscopy has been reported to fail to prevent some post screening colonoscopy incident cancers or minimize cancer mortality in the proximal colon. These reports question the effectiveness of colonoscopy in detecting all proximal adenomas. Diminutive ones which can be obscured by residual feces are particularly at risk. The water method provides salvage cleansing of sub-optimal preparations. OBJECTIVE: To test the hypothesis that the water method enhances proximal diminutive adenoma detection rate (ADR). DESIGN: The data bases of two parallel RCT were combined and analyzed. SETTING: Two Veterans Affairs endoscopy units. PATIENT AND METHODS: The water and air methods were compared in these two parallel RCT examining unsedated patients. MAIN OUTCOME MEASUREMENTS: The combined data on diminutive and overall ADR in the proximal colon, overall ADR, cecal intubation rate, withdrawal time and global bowel cleanliness score. RESULTS: Data in the water (n=92) and the air (n=90) groups were assessed. The water method yielded a significantly higher proximal diminutive ADR, 28.3% vs. 14.4% (p=0.0298); cecal intubation rate, 99% vs. 90% (p=0.0091); mean withdrawal time 19 (10) vs. 15 (8) min (p=0.0065) and mean global bowel cleanliness score during withdrawal, 2.6 (0.7) vs. 2.3 (0.6) (p=0.0032). Increase in proximal overall ADR in the water group approached significance, 29.3% vs. 16.7% (p=0.0592). LIMITATION: Small number of predominantly male veterans. CONCLUSION: The significantly higher cecal intubation rate, longer mean withdrawal time and better mean global bowel cleanliness score favor the outcome of significantly enhanced proximal diminutive ADR in the water group.