Is there a place for sedationless colonoscopy?

Endoscopic retrograde cholangiopancreatography training and education

Endoscopic retrograde cholangiopancreatography (ERCP) is an advanced endoscopic technique used to diagnose and treat biliary and pancreatic diseases. It is one of the most technically demanding endoscopic procedures. ERCP training programs must ensure trainees have adequate knowledge of the anatomy and physiology associated with biliopancreatic diseases. The variety of ERCP procedures included in training programs should provide sufficient basic training for novice trainees and advanced training for experienced endoscopists. The main endoscopic procedures should be trained in ascending order of difficulty. Incorporating models capable of simulating various clinical and anatomical conditions could provide an effective means of fulfilling training requirements, although they are not easily available due to expensive facilities and void of standard assessment. Competency assessment is crucial in ERCP training to ensure trainees can independently and safely perform ERCP. Because of the rapid advancement of diagnostic and therapeutic methods, postgraduate training is critical for ERCP practitioners. Once certificates are attained, practitioners are solely responsible for maintaining their competency, credentialing, and quality.

Training in endoscopic retrograde cholangio-pancreatography: a critical assessment of the broad scenario of training programs and models

Introduction: Endoscopic Retrograde Cholangio-Pancreatography (ERCP) applications are rapidly evolving toward increasingly complex therapeutic approaches alongside with technological innovations. There are no globally agreed indications on the ERCP training path, which often requires too much time and does not always guarantee adequate skills.Areas covered: Frequency and difficulty of execution are the main objective criteria on which to draw up a training program: novel trainees should approach ERCP first through the simplest and most frequent procedures. An extensive use of training models would reduce the patient's performer-related risks. Amongst a wide variety of models, mechanical simulators have received large approval. In fact, they can be best-suited to each trainee's learning curve thanks to their precision and safety and by virtue of the unlimited repeatability of their use. However, more solid evidences are still needed.Expert opinion: Hands-on ERCP training should systematically employ mechanical simulators at least in the early stages of the learning process. An implementation of these models through sensors that objectively detect abnormalities in the movements would provide detailed feedbacks and deeper awareness. Simulators might also be useful for expert endoscopists to refine their skills. Rapid prototyping and 3D printing might be the way to create customized training models for successful training programs.

Impact of second forward-view examination on adenoma detection rate during unsedated colonoscopy: a randomized controlled trial

Objectives

Colorectal cancer on the right side of the colon has been suggested to be harder to detect by colonoscopy. The aim of this study was to evaluate whether a second forward-view examination of the right side of the colon could increase the adenoma detection rate (ADR) and/or polyp detection rate (PDR).

Methods

This was a single-centre randomized controlled trial. Patients undergoing colonoscopy were recruited and randomly assigned to the second forward-view examination (SFE) group, in which the right side of the colon was examined twice or the traditional colonoscopy (TC) group in which the colonoscopy was performed in a standard manner. The primary outcome was the ADR of right colon. The overall PDR and ADR, PDR of the right colon, per-adenoma miss rate of the right colon, and advanced lesion detection rate were also recorded and compared.

Results

A total of 392 patients were included in the study (SFE group 197 vs. TC group 195). The ADR and PDR of the right colon in the SFE group were significantly higher than those in the TC group (ADR 10.7% vs. 5.1%; P = 0.042); PDR 17.8% vs. 9.7%, P = 0.021). No significant difference was found in overall PDR/ADR, or advanced lesion detection rate between the two groups.

Conclusions

This prospective controlled study revealed that a second forward-view examination could modestly increase the ADR and PDR of the right colon during unsedated colonoscopies. This simple, safe and time-effective technique might be recommended for routine unsedated colonoscopy.

Trial registration: Clinical Trials.gov, NCT03619122. Registered on 7/8/2018.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-01783-9.

Soft Liver Phantom with a Hollow Biliary System

Hepatobiliary interventions are regarded as difficult minimally-invasive procedures that require experience and skills of physicians. To facilitate the surgical training, we develop a soft, high-fidelity and durable liver phantom with detailed morphology. The phantom is anatomically accurate and feasible for the multi-modality medical imaging, including computer tomography (CT), ultrasound, and endoscopy. The CT results show that the phantom resembles the detailed anatomy of real livers including the biliary ducts, with a spatial root mean square error (RMSE) of 1.7 ± 0.7 mm and 0.9 ± 0.2 mm for the biliary duct and the liver outer shape, respectively. The sonographic signals and the endoscopic appearance highly mimic those of the real organ. An electric sensing system was developed for the real-time quantitative tracking of the transhepatic puncturing needle. The fabrication method herein is accurate and reproducible, and the needle tracking system offers a robust and general approach to evaluate the centesis outcome.

Feasibility of a transmucosal sublingual fentanyl tablet as a procedural pain treatment in colonoscopy patients: a prospective placebo-controlled randomized study

Since patients often experience pain and unpleasantness during a colonoscopy, the present study aimed to evaluate the efficacy and safety of sublingually administered fentanyl tablets for pain treatment. Furthermore, since the use of intravenous drugs significantly increases colonoscopy costs, sublingual tablets could be a cost-effective alternative to intravenous sedation. We conducted a prospective placebo-controlled randomized study of 158 patients to evaluate the analgesic effect of a 100 µg dose of sublingual fentanyl administered before a colonoscopy. Pain, sedation, nausea, and satisfaction were assessed during the colonoscopy by the patients as well as the endoscopists and nurses. Respiratory rate and peripheral arteriolar oxygen saturation were monitored throughout the procedure. There were no differences between the fentanyl and placebo groups in any of the measured variables. The median pain intensity values, as measured using a numerical rating scale, were 4.5 in the fentanyl group and 5 in the placebo group. The sedation and oxygen saturation levels and the respiratory rate did not differ between the groups. The majority of the colonoscopies were completed.Our results indicate that a 100 µg dose of sublingual fentanyl is not beneficial compared to the placebo in the treatment of procedural pain during a colonoscopy.

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.

Editorial: Polyps, Pain, and Propofol: Is Water Exchange the Panacea for All?

Water exchange (WE) is a relatively new method of endoscope insertion during colonoscopy. Although its origin is rooted in the insertion phase of colonoscopy, allowing the procedure to proceed with more ease, less discomfort, and less or no sedation, its most important value may reside in the withdrawal phase. In this issue, a randomized, prospective study from China specifically designed to examine the effect of WE on adenoma detection rate (ADR) confirms previous findings: WE improves ADR. Here we discuss the trial results, the benefits of WE, and the challenges that may preclude or delay widespread WE implementation.

Psychomotor and cognitive effects of 15-minute inhalation of methoxyflurane in healthy volunteers: implication for post-colonoscopy care

Background and study aims: Colonoscopy with portal inhaled methoxyflurane (Penthrox) is highly feasible with low sedation risk and allows earlier discharge. It is unclear if subjects can return to highly skilled psychomotor skill task shortly after Penthrox assisted colonoscopy. We evaluated the psychomotor and cognitive effects of 15-minute inhalation of Penthrox in adults. Patients and methods: Sixty healthy volunteers (18 to 80 years) were studied on 2 occasions with either Penthrox or placebo in a randomized, double-blind fashion. On each occasion, the subject's psychomotor function was examined before, immediately, 30, 60, 120, 180 and 240 min after a 15-minute inhalation of studied drug, using validated psychomotor tests (Digit Symbol Substitution Test (DSST), auditory reaction time (ART), eye-hand coordination (EHC) test, trail making test (TMT) and logical reasoning test (LRT). Results: Compared to placebo, a 15-minute Penthrox inhalation led to an immediate but small impairment of DSST (P < 0.001), ART (P < 0.001), EHC (P < 0.01), TMT (P = 0.02) and LRT (P = 0.04). In all subjects, the performance of all 5 tests normalized by 30 minutes after inhalation, and was comparable to that with placebo. Although increasing age was associated with a small deterioration in psychomotor testing performance, the magnitude of Penthrox effects remained comparable among all age groups. Conclusions: In all age groups, a 15-minute Penthrox inhalation induces acute but short-lasting impairment of psychomotor and cognitive performance, which returns to normal within 30 minutes , indicating that subjects who have colonoscopy with Penthrox can return to highly skilled psychomotor skills tasks such as driving and daily work the same day.

Colonoscopy without sedation: Patient factors alone are less likely to influence its uptake

BACKGROUND AND STUDY AIMS

Conscious sedation during colonoscopy minimizes discomfort, improves polyp detection rates, and reduces technical failure, but carries medication-related risks and requires dedicated and costly recovery services. Sedation-free procedures may offer a safer alternative. We aimed to compare this group with those receiving sedation to determine differences in patient characteristics, cecal intubation rates, polyp detection rates, discomfort levels and safety in patients for whom anesthesia is high risk.

PATIENTS AND METHODS

Prospectively collected data from all colonoscopies performed over a 1-year period at three district general hospitals were analyzed. Conscious sedation was offered to all patients and outcomes in those who refused were compared with outcomes in those who received sedation.

RESULTS

One hundred ninety-four of 1694 (11 %) colonoscopies were performed without sedation (61 % male, P < 0.001) but rates varied between hospitals. Of these, 55 % were American Society of Anesthesiologists (ASA) grade 3 or more and 5 % experienced moderate discomfort, compared to 40 % (P < 0.0001) and 10 % (P = 0.023) respectively of those receiving sedation. They were more likely to have indications of rectal bleeding or frequency of stool and less likely to have anaemia or macroscopic inflammation at colonoscopy. Complications, completion. and polyp detection rates were similar in both groups.

CONCLUSIONS

Colonoscopy without sedation can be completed successfully in select patients without compromising comfort or polyp detection rates and is safe in those for whom anesthesia is high risk. It is therefore a safe alternative for clinicians concerned about sedation, but the findings suggest that hospital, rather than patient factors, may prevent its uptake.

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.

Do it yourself: building an ERCP training system within 30 minutes (with videos)

BACKGROUND

Ex vivo training of ERCP by using simulators is desirable before trainees perform endoscopy in patients.

OBJECTIVE

We aimed to construct a simple and inexpensive but realistic simulator for ERCP training.

DESIGN

Construction and establishment of an ERCP simulator.

SETTING

Endoscopy suite.

INTERVENTION

An ERCP simulator was assembled by using a polyvinylchloride hose, insulated wire end sleeves, a plastic board, and hose clamps.

MAIN OUTCOME MEASUREMENTS

Application of the simulator for endoscopic training, with focus on endoscope maneuverability as well as on alignment and intubation of the papilla and assessment of simulator performance by a short questionnaire.

RESULTS

Because of the sufficient diameter of the hose and varying orientations of the wire end sleeves, the system allows for realistic endoscope maneuvering and wire intubation of the "papillary orifices." Trainees feel better prepared and more confident in the technique before performing ERCP in patients for the first time.

LIMITATIONS

Extensive validation and statistical evaluation is lacking.

CONCLUSION

The construction offers the opportunity to provide a readily available simulator for initial access to basic ERCP techniques.

Safety and effectiveness of propofol sedation during and after outpatient colonoscopy

AIM

To study the safety and effectiveness of propofol sedation for outpatient colonoscopy.

METHODS

Propofol was given by bolus injection with an age-adjusted standard protocol consisting of 60 mg for patients < 70 years old, 40 mg for patients age 70-89 years, and 20 mg for those ≥ 90 years, and additional injections of 20 mg propofol were given up to a maximum of 200 mg. The principal parameters were the occurrence of adverse events within 24 h after colonoscopy and overall satisfaction for this procedure. Secondary parameters included successful procedure, respiratory depression, and other complications.

RESULTS

Consecutive patients were entered prospectively and all 2101 entered successfully completed outpatient colonoscopy. The mean dose of propofol used was 96.4 mg (range 40-200 mg). Younger patients required higher doses of propofol than older patients (20-40 years vs ≥ 61 years: 115.3 ± 32 mg vs 89.7 ± 21 mg, P < 0.001). Transient supplemental oxygen supply was needed by five patients (0.2%); no other complications occurred. The questionnaires were completed by 1820 (87%) of 2101 patients and most rated their overall satisfaction as excellent (80%) or good (17%). The majority (65%) of patients drove home or to their office after their colonoscopy. Most (99%) were willing to repeat the same procedure. No incidents occurred within 24 h after colonoscopy.

CONCLUSION

Propofol sedation using a dose < 200 mg proved both safe and practical for outpatient colonoscopy.

Magnetic endoscope imaging (ScopeGuide) elucidates the mechanism of action of the pain-alleviating impact of water exchange colonoscopy - attenuation of loop formation

BACKGROUND

The explanation why water exchange colonoscopy produces a significant reduction of pain during colonoscopy is unknown. A recent editorial recommended use of magnetic endoscope imaging (MEI) to elucidate the explanation.

OBJECTIVE

In unselected patients to show that MEI documents less frequent loop formation when water exchange is used.

DESIGN

Observational, performance improvement.

SETTING

Veterans Affairs outpatient endoscopy.

PATIENTS

Routine colonoscopy cases.

INTERVENTIONS

Colonoscopy using air or water exchange method was performed as previously described. The MEI equipment (ScopeGuide, Olympus) with built-in magnetic sensors displays the configuration of the colonoscope inside the patient. During sedated colonoscopy the endoscopist was blinded to the ScopeGuide images which were recorded and subsequently reviewed.

MAIN OUTCOME MEASURES

Loop formation based on a visual guide provided by Olympus.

RESULTS

There were 41 and 32 cases in the water exchange and air group, respectively. The sigmoid N loop was most common, followed by the sigmoid alpha loop, and exaggeration of scope curvature at the splenic flexure/transverse colon. Of these, 20/32 vs. 9/41 patients (p=0.0007) had sigmoid looping, and 17/32 vs. 9/41 patients (p=0.0007) had sigmoid/splenic looping when the scope tip was in the transverse colon, in the air and water exchange group, respectively.

LIMITATIONS

Colonoscopy method was not blinded and non randomized.

CONCLUSION

MEI data objectively demonstrated significantly fewer loops during water exchange colonoscopy, elucidating its mechanism of pain alleviation - attenuation of loop formation. Since MEI feedback enhances cecal intubation by trainees, the role of MEI combined water exchange in speeding up trainee learning curves deserves further evaluations.

The water exchange method for colonoscopy-effect of coaching

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

Head-to-head comparison of practice with endoscopic retrograde cholangiopancreatography computer and mechanical simulators by experienced endoscopists and trainees

BACKGROUND AND AIM

  The endoscopic retrograde cholangiopancreatography (ERCP) mechanical simulator (EMS) and computer simulator (ECS) are described herein. No direct hands-on comparison has been reported to reflect the perception of trainers and trainees regarding the efficacy of each model for trainee ERCP education. We compared the trainers' and trainees' assessments of the EMS and ECS for trainee education.

METHODS

  Eighteen gastrointestinal trainees and 16 trainers with varying ERCP experience completed a questionnaire survey before and after practice with each simulator at hands-on ERCP practice workshops. They carried out scope insertion, selective bile duct cannulation, guidewire negotiation of a bile duct stricture, biliary papillotomy and insertion of a single biliary stent using both simulators. Main outcome measurement was respondents' assessments of comparative efficacy of EMS and ECS practice for trainee education.

RESULTS

  Compared to pre-practice evaluation, both EMS and ECS received higher scores after hands-on practice. Both trainers and trainees showed significantly greater increases in scores for EMS when compared with ECS in facilitating understanding of ERCP procedure, enhancing confidence in carrying out ERCP and the simulator as a credible option for supplementing clinical ERCP training (P < 0.05). Participants also scored EMS significantly higher in realism and usefulness as an instructional tool.

CONCLUSIONS

  Both computer and mechanical simulators are accepted modalities for ERCP training. The current data (based on a head-to-head comparison of hands-on practice experience) indicate EMS practice is rated higher than ECS practice in supplementing clinical ERCP training. EMS offers the additional advantage of coordinated practice with real equipment and accessories.

Health care providers' acceptance of unsedated colonoscopy before and after a state-of-the-art lecture on the feasibility of the option

BACKGROUND/AIM

The impact of education on acceptance of unsedated colonoscopy by health care providers is unknown. To test the hypothesis that knowledge imparted by a lecture on unsedated colonoscopy is associated with its enhanced acceptance.

SETTINGS AND DESIGN

At the State-of-the-Art Lecture on "Unsedated colonoscopy: Is it feasible?" presented at the 8 th Pan-Arab Conference on Gastroenterology, February, 2011, Riyadh, Saudi Arabia, a questionnaire survey of the audience was undertaken.

MATERIALS AND METHODS

An expectation questionnaire was administered before and after the lecture. Attendees responded anonymously.

STATISTICAL ANALYSIS USED

The responses of a convenient sample of 49 attendees who provided completed responses to the questionnaire both before and after the lecture were analyzed. Data are expressed as frequency counts and means±SEM. Repeated measures analysis of variance (ANOVA), ANOVA with contrasts and Chi-square analysis (Statview II Program for Macintosh computers) were used to assess the data. A P value of <0.05 is considered significant.

RESULTS AND CONCLUSIONS

The mean±SEM credibility score (maximum possible score=50) was 25.8 ± 1.8 before and 33.3 ± 2.1 after the lecture, with a significant improvement in mean score of 7.5 ± 1.3 (P=0.001, paired t test). Nineteen (39%) respondents were not willing to consider unsedated colonoscopy for themselves before the lecture. This number decreased to 13 (27%) after the lecture. Before the lecture only 4 (8%) respondents were willing to consider unsedated colonoscopy for themselves. After the lecture this number increased to 8 (16%). The data suggest education of healthcare professionals regarding the feasibility of unsedated colonoscopy appears to enhance its acceptance as a credible patient care option at a Pan-Arab Gastroenterology Conference.

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 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.

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.

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.