A randomized, controlled trial to confirm the beneficial effects of the water method on U.S. veterans undergoing colonoscopy with the option of on-demand sedation

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.

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.

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).

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.

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.

Comparing adenoma and polyp miss rates for total underwater colonoscopy versus standard CO2: a randomized controlled trial using a tandem colonoscopy approach

BACKGROUND AND AIMS

Although water exchange may improve adenoma detection compared with CO₂, it is unclear whether water is a better medium to fill the lumen during withdrawal and visualize the mucosa. Total underwater colonoscopy (TUC) involves the use of water exchange with the air valve off during insertion followed by the inspection of the mucosa under water. Our goal was to compare miss rates for TUC with standard CO₂ for polyps and adenomas using a tandem colonoscopy design.

METHODS

We randomized participants to undergo tandem colonoscopies using TUC or CO₂ first. In TUC, water exchange was performed during insertion, and withdrawal was performed under water. For the CO₂ colonoscopy, both insertion and withdrawal were performed with CO₂. The main outcomes were miss rates for polyps and adenomas for the first examination calculated as the number of additional polyps/adenomas detected during the second examination divided by the total number of polyps/adenomas detected for both examinations. Inspection times were calculated by subtracting the time for polypectomy, and care was taken to keep the times equal for both examinations.

RESULTS

A total of 121 participants were randomized with 61 having CO₂ first. The overall miss rate for polyps was higher for the TUC-first group (81/237; 34%) compared with the CO₂-first cohort (57/264; 22%) (P = .002). In addition, the overall miss rate for all adenomas was higher for the TUC-first group (52/146; 36%) compared with the CO₂ group (37/159; 23%) (P = .025). However, 1 of the 3 endoscopists had higher polyp/adenoma miss rates for CO₂, but these were not statistically significant differences. The insertion time was longer for TUC than for CO₂. After adjusting for times, participant characteristics, and bowel preparation, the miss rate for polyps was higher for TUC than for CO₂.

CONCLUSIONS

We found that TUC had an overall higher polyp and adenoma miss rate than colonoscopy performed with CO₂, and TUC took longer to perform. However, TUC may benefit some endoscopists, an issue that requires further study. (Clinical trial registration number: NCT03231917.).

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.

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.

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.

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.

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.

Painless Colonoscopy: Available Techniques and Instruments

During colonoscopy, air insufflation to distend the lumen and facilitate careful inspection and scope insertion can induce pain and cause discomfort. Carbon dioxide (CO₂) insufflation can decrease abdominal pain and discomfort during and after colonoscopy. The advantage of CO₂ insufflation is the rapid absorption of the gas across the intestine. Another painless option is water-assisted colonoscopy. Two methods for water-assisted colonoscopy are available: water immersion and water exchange. In a recent direct comparison, the water exchange method was superior to water immersion, CO₂ insufflation, and air insufflation with respect to pain during colonoscopy, although it still had the disadvantage of being a time-consuming procedure. Cap-assisted colonoscopy is a simple technique involving the use of a small transparent cap attached to the tip of the scope. Three studies showed an advantage of this technique in terms of reduced patient discomfort compared with the conventional method. Three robotic colonoscopy systems (Endotics System [Era Endoscopy], NeoGuide [NeoGuide Systems Inc.], and Invendoscope [Invendo Medical]) have been introduced to evaluate pain reduction during colonoscopy, but none has been widely adopted and used in practice. In this review, clinical trials of several techniques and new devices for painless colonoscopy are described and summarized.

Development of a murine colonoscopic polypectomy model (with videos)

BACKGROUND AND AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Retrospective comparison of sedated and non-sedated colonoscopy in an outpatient practice

Although sedation and analgesia for patients undergoing colonoscopy are the standard practice in western countries, non-sedated colonoscopy is still in practice in Europe and the Far East. This variation in sedation practice relies on the different cultural attitudes of both patients and endoscopists across these countries. Data from the literature consistently report that, in non-sedated patients, the use of alternative techniques, such as water irrigation or carbon dioxide insufflation, can allow a high-quality and well-tolerated examination. We retrospectively reviewed prospectively collected performance improvement in endoscopy unit at King Khalid Hospital, Najran, Saudi Arabia. The tolerance of colonoscopy without sedation in terms of patient's ability to return to routine work and drive if necessary on the same day of procedure was evaluated. A total of 538 patients who underwent a colonoscopy at King Khalid Hospital endoscopy unit (Najran, Kingdom of Saudi Arabia) were reviewed from September 2011 to November 2013. All of the procedures were performed by two expert endoscopists, assisted by well-trained nursing staff. Insertion of the colonoscope was aided by insufflations of air, and in a few instances, by water through the colonoscope to minimize air insufflations. IV sedatives were administered upon the judgment of the physician when patient was unable to tolerate the procedure. Of 538 patients who underwent a colonoscopy, 79 patients required sedation. Forty-seven during the procedure and 32 requested pre-procedure sedation, most of them below 20 years of age. Thirty-two who requested pre-procedure sedation were excluded from our statistics. Of the remaining 506 cases, 47 (9.3 %) required sedation during procedure while 459 (90.7 %) tolerated the procedure without sedation. This shortened the hospital stay time, improved the ability to return to work much earlier, and undertake daily activities such as driving. It is also cost effective. The approach of non-sedative colonoscopy and use of sedation on-demand with minimal air insufflation or water infusion when needed during the procedure were well tolerated by approximately 91 % of patients at a single center in Saudi Arabia.

Evidence to suggest adoption of water exchange deserves broader consideration: Its pain alleviating impact occurs in 90% of investigators

AIM: To determine whether observations were reproducible among investigators.

METHODS: From March 2013 through June 2014, 18-85-year-old diagnostic and 50-70-year-old screening patients were enrolled at each center to on-demand sedation colonoscopy with water exchange (WE), water immersion (WI) and insufflation with air or CO₂ for insertion and withdrawal [air or carbon dioxide (AICD)]. Data were aggregated for analysis. Primary outcome: Variations in real-time maximum insertion pain (0 = none, 1-2 = discomfort, 10 = worst).

RESULTS: One thousand and ninety-one cases analyzed: WE (n = 371); WI (n = 338); AICD (n = 382). Demographics and indications were comparable. The WE group had the lowest real-time maximum insertion pain score, mean (95%CI): WE 2.8 (2.6-3.0), WI 3.8 (3.5-4.1) and AICD 4.4 (4.1-4.7), P < 0.0005. Ninety percent of the colonoscopists were able to use water exchange to significantly decrease maximum insertion pain scores. One investigator had high insertion pain in all groups, nonetheless WE achieved the lowest real-time maximum insertion pain score. WE had the highest proportions of patients with painless unsedated colonoscopy (vs WI, P = 0.013; vs AICD, P < 0.0005); unsedated colonoscopy with only minor discomfort (vs AICD, P < 0.0005), and completion without sedation (vs AICD, P < 0.0005).

CONCLUSION: Aggregate data confirm superiority of WE in lowering colonoscopy real-time maximum insertion pain and need for sedation. Ninety percent of investigators were able to use water exchange to significantly decrease maximum insertion pain scores. Our results suggest that the technique deserves consideration in a broader scale.

Water Exchange Is the Least Painful Colonoscope Insertion Technique and Increases Completion of Unsedated Colonoscopy

BACKGROUND & AIMS

Unsedated colonoscopy is acceptable for diagnostic, surveillance, and screening indications worldwide. However, insertion of the colonoscope can be painful; it is not clear which technique is least painful and thereby increases the likelihood of colonoscopy completion. We performed a head-to-head comparison of air insufflation (AI), carbon dioxide (CO2) insufflation, water immersion (WI), and water exchange (WE) to determine which combination of insertion techniques produces the least amount of pain.

METHODS

In a patient-blinded prospective trial, 624 subjects were assigned randomly to groups that underwent colonoscopy with AI-AI, CO2-CO2, WI-AI, WE-AI, WI-CO2, or WE-CO2 insertion and withdrawal techniques, including on-demand sedation, at the St. Barbara Hospital (Iglesias, Italy) or the Vìtkovice Hospital (Ostrava, Czech Republic), from October 2013 through June 2014. The primary outcome was real-time maximum insertion pain (0 = none, 10 = worst), recorded by an unblinded nurse assistant. At discharge, a blinded observer recorded the recalled maximum insertion pain and patients' and investigators' guesses about method or gas used.

RESULTS

Patients and investigators correctly guessed the method used for fewer than 44% of procedures, confirming adequate blinding. The correlation between real-time and recalled maximum insertion pain (r = 0.9; P < .0005) confirmed internal validation of the primary outcome. The WE group had the lowest scores: mean pain values were 5.2 for AI-AI (95% confidence interval [CI], 4.6-5.8), 4.9 for CO2-CO2 (95% CI, 4.3-5.4), 4.3 for WI-CO2 (95% CI, 3.8-4.9), 4.0 for WI-AI (95% CI, 3.5-4.5), 3.1 for WE-CO2 (95% CI, 2.7-3.4), and 3.1 for WE-AI (95% CI, 2.7-3.6) (P < .0005). The highest proportions of patients completing unsedated colonoscopy were in the WE groups. WE groups also had significantly better colon cleanliness, particularly in the transverse and right colon (P < .0005). One limitation of the study was that colonoscopists and assistants were not blinded to water-aided insertion methods.

CONCLUSIONS

In a prospective study of colonoscopy insertion methods, CO2 insufflation did not reduce real-time maximum insertion pain. Compared with AI or CO2, WI and WE reduced insertion pain. The least painful technique was WE, which significantly increased completion of unsedated colonoscopy and bowel cleanliness without prolonging insertion time. ClinicalTrials.gov number: NCT01954862.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

Diagnostic and therapeutic applications of water-immersion colonoscopy

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

Water infusion versus air insufflation for colonoscopy

BACKGROUND

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

OBJECTIVES

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

SEARCH METHODS

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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

Water-aided colonoscopy

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

A randomized, controlled trial comparing real-time insertion pain during colonoscopy confirmed water exchange to be superior to water immersion in enhancing patient comfort

BACKGROUND

A recent American Society for Gastrointestinal Endoscopy Technology Status Evaluation Report recommended comparative studies of water-aided colonoscopy methods to refine the optimal insertion technique.

OBJECTIVE

Air insufflation (AI), water immersion (WI), and water exchange (WE) were compared head-to-head to test the hypothesis that WE produces the least insertion pain.

DESIGN

Patient-blinded, prospective, randomized, controlled trials.

SETTING

Two community hospitals in Italy.

PATIENTS

First-time diagnostic or screening colonoscopy in unsedated patients with the option of on-demand sedation.

INTERVENTION

Colonoscopy with AI, WI, or WE.

MAIN OUTCOME MEASUREMENTS

Real-time maximum insertion pain (0 = none, 10 = worst). To avoid interventional bias, the timing of recording was at the discretion of the nurse assistant. Adjunct measures were implemented to ensure patient perception of minimal discomfort. Recalled pain and patients' guess of insertion methods were recorded after colonoscopy.

RESULTS

Results were merged for 576 randomized patients. Correct patient guesses lower than 33% confirmed adequate blinding. Significant correlation (Pearson coefficient 0.6, P < .0005) between real-time and recalled pain provided internal validation of the former as the primary outcome. Real-time pain (95% confidence interval [CI]: AI, 4.1 [3.7-4.5]; WI, 3.5 [3.0-3.9]; and WE, 2.5 [2.2-2.9] [P < .0005] was the lowest in the WE group. The proportions of patients completing unsedated colonoscopy based on the assigned methods were significantly different (WE, 74.7% vs WI, 62.4%; P = .009; vs AI, 65.3%; P = .04). WE required the least implementation of adjunct maneuvers.

LIMITATIONS

Unblinded colonoscopists.

CONCLUSION

The current findings with an internally validated primary outcome in adequately blinded patients support the hypothesis that WE is superior to WI in attenuating real-time insertion pain and enhancing completion of unsedated colonoscopy.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Endoscopy in the elderly: risks, benefits, and yield of common endoscopic procedures

There has been limited research examining the risks, benefits, and use of common endoscopic procedures in the elderly. Furthermore, gastroenterology training programs do not routinely incorporate elderly concerns when dealing with common gastrointestinal issues. There exists a broad array of endoscopic procedures with varying inherent risks that must be weighed with each elderly patient in mind. This article discusses the benefits and drawbacks of the most common procedures and indications for endoscopy including upper endoscopy, colonoscopy, endoscopic retrograde cholangiopancreatography, endoscopic ultrasound, percutaneous endoscopic gastrostomy, and deep enteroscopy.

Endoscopic innovations to increase the adenoma detection rate during colonoscopy

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

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

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

Water injection versus air insufflation for colonoscopy in elderly patients

AIM: To compare the impact of water injection versus air insufflation for colonoscopy on cecal intubation rate, cecal intubation time and pain degree in elderly patients.

METHODS: Two hundred elderly patients (aged 65-82 years) who underwent non-narcotic colonoscopy were randomly divided into two groups: water injection and air insufflation. The cecal intubation rate, cecal intubation time and pain degree were compared between the two groups.

RESULTS: There were no significant differences in cecal intubation rate (98% vs 94%, P > 0.05) or cecal intubation time (7.83 min ± 1.58 min vs 8.01 min ± 1.26 min, P > 0.05) between the water injection and air insufflation groups. Abdominal pain score was significantly lower in the water injection than in the air insufflation group (3.23 ± 1.71 vs 4.87 ± 1.94, P < 0.05).

CONCLUSION: Compared with air insufflation colonoscopy, water injection colonoscopy has similar cecal intubation rate and cecal intubation time, but is associated with significantly lower pain in elderly patients.

Water-aided colonoscopy

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

Cap-assisted water immersion for minimal sedation colonoscopy: prospective, randomized, single-center trial

BACKGROUND AND AIM

Water immersion insertion is able to reduce discomfort and need for sedation during colonoscopy. A cap attached to the colonoscope tip may improve insertion during air insufflation colonoscopy. According to several reports, both techniques alone may result in higher detection of neoplastic lesions. Our study was designed to evaluate the efficacy of cap-assisted water immersion compared to water immersion colonoscopy in minimally sedated patients.

METHODS

A total of 208 consecutive outpatients were randomized to either cap-assisted water immersion (Cap Water) or water immersion colonoscopy (Water). The primary endpoint was cecal intubation time.

RESULTS

Cecal intubation time was 6.9 ± 2.9 min in Cap Water and 7.4 ± 4.2 min in the Water arm (P = 0.73). Success rate of minimal sedation colonoscopy was equal in both groups (92.9%, P = 1.00). From the endoscopist's point of view, there were non-significant trends towards lower discomfort (P = 0.06), less need for abdominal compression (P = 0.06) and lower difficulty score (P = 0.05) during Cap Water colonoscopy. Adenoma detection rate was similar in both arms (44% in Cap Water vs 45% in the Water group, P = 0.88). There were no complications recorded in the present study.

CONCLUSIONS

In comparison with water immersion without cap, cap-assisted water immersion colonoscopy was not able to shorten the cecal intubation time. However, it has the possibility of reducing patient discomfort and difficulty of colonoscope insertion. Potential impact on improved detection of neoplastic lesions has to be evaluated by further studies.

Water infusion versus air insufflation for colonoscopy: a meta-analysis of randomized controlled trials

BACKGROUND

The aim of this meta-analysis was to determine whether water infusion colonoscopy (WIC) is a more effective diagnostic tool than standard air insufflation colonoscopy (AIC).

METHODS

All articles pertinent to a comparison of water-related methods and air insufflation to facilitate insertion of the colonoscope were retrieved from PubMed, Web of Science, Embase, and Cochrane databases. Pooling results were derived by using the Review Manager Software. Outcomes were assessed using the weighted mean difference (MD) with 95 % confidence intervals (CI) for continuous variables and the odds ratios (OR) with 95 % CI for dichotomous variables.

RESULTS

Eighteen studies involving 2,797 patients were included. WIC was associated with a significantly higher cecal intubation rate than AIC (OR = 1.90; 95 % CI 1.21-2.99; p = 0.005). The intubation time was similar for the two types of colonoscopy, but in WIC there was a significantly lower visual analog scale score for abdominal pain than in AIC (MD = -1.30; 95 % CI -2.03 to -0.58; p < 0.001) without sacrificing the polyp detection rate (OR = 1.17; 95 % CI 0.78-1.77; p = 0.44). Statistically, the patient's willingness to repeat colonoscopy was significantly greater for WIC than for AIC (OR = 1.74; 95 % CI 1.14-2.67; p < 0.01). Furthermore, in the subgroup for trainees, the WIC group achieved a higher cecal intubation rate (OR = 1.83; 95 % CI 1.15-2.93; p = 0.01) and a shorter intubation time (MD = -1.72 min; 95 % CI -3.34 to -0.11; p = 0.04) than the AIC group.

CONCLUSIONS

In contrast to AIC, WIC improved cecal intubation, alleviated abdominal pain, and increased patients' willingness to repeat the procedure.

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

BACKGROUND

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

OBJECTIVE

To investigate the application of WEC in such patients.

DESIGN

Prospective, randomized, controlled, patient-blinded study.

SETTING

Tertiary-care referral center in China.

PATIENTS

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

INTERVENTION

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

MAIN OUTCOME MEASUREMENTS

Cecal intubation rate.

RESULTS

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

LIMITATIONS

Single center; unblinded but experienced endoscopists.

CONCLUSION

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

CLINICAL TRIAL REGISTRATION NUMBER

NCT01485133.).

Water intubation method can reduce patients' pain and sedation rate in colonoscopy: a meta-analysis

Several randomized controlled trials (RCT) have shown that water infusion in lieu of air insufflation reduces sedation rate and pain score and increases cecal intubation rate in colonoscopy. The aim of the present study was to confirm the beneficial effects of the water intubation method over the air method. Electronic databases were searched to identify RCT reporting colonoscopy detection using the water method. The pooled data of sedation rate, pain score and other procedure-related outcomes were analyzed. Then, 15 full-text articles were selected and assessed. Nine trials with high-quality scores were enrolled into this meta-analysis including a total of 1414 participants. Pooled odds ratio (OR) of sedation rate was 0.392 (95% confidence interval (CI): 0.288-0.533, P = 0.000). Pooled weighted mean difference (WMD) of pain score was -1.543 (95% CI: -2.107--1.069,P = 0.000). Pooled OR of cecal intubation rate was 1.90 (95% CI: 1.29-2.82, P = 0.001). Pooled OR of polyp detection rate and adenoma detection rate were 0.805 (95% CI: 0.606-1.069, P = 0.134) and 0.913 (95% CI: 0.681-1.223, P = 0.168), respectively. Pooled WMD of cecal intubation time was 0.701 (95% CI: -0.486-1.889, P = 0.247). This meta-analysis confirmed that the water method significantly reduced sedation rate and degree of pain without decreasing cecal intubation rate and disease detection rate and without requiring more cecal intubation time, suggesting that the novel water method is better than the conventional air method in colonoscopy detection.

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.

Comparative effectiveness of water infusion vs air insufflation in colonoscopy: a meta-analysis

AIM

Colonoscopy with air insufflation is known to result in abdominal pain and discomfort. We aimed to determine the effectiveness of water infusion during colonoscopy through a meta-analysis.

METHOD

Original papers and abstracts published up to October 2011 were searched in MEDLINE, EMBASE, Cochrane Library Database and important meeting abstracts. Clinical appraisal and data extraction were conducted by two reviewers independently. Statistical analysis was performed by meta-analysis using a fixed effects model or a random effects model.

RESULTS

Seven studies involving 872 patients were included. Meta-analysis showed that the water infusion group had fewer patients requiring abdominal compression or position change [risk ratio (RR) 0.73, 95% CI 0.59, 0.91], a lower mean pain score (RR -1.10, 95% CI -1.26, -0.95), lower maximum pain score (RR -2.34, 95% CI -2.92, -1.76) and fewer patients requiring on-demand sedation (RR 0.45, 95% CI 0.31, 0.66) than the air insufflation group during colonoscopy. There were no significant differences in caecal intubation rate, caecal intubation time, total procedure time and adenoma detection rate.

CONCLUSION

Water infusion significantly decreases patient discomfort and abdominal pain during colonoscopy without affecting operation time and intubation success rate.

Warm water infusion during sedated colonoscopy does not decrease amount of sedation medication used

BACKGROUND

Water infusion versus air insufflation during colonoscope insertion has been suggested to reduce patient discomfort and decrease sedation medication requirements. Warm water is thought to further facilitate colonoscopy perhaps by decreasing colon spasm.

OBJECTIVE

To compare the utility of warm (35°-38°C) versus cool (20°-23°C) water infused during colonoscopic insertion by measuring patient sedation medication use and discomfort scores between the warm and cool water groups.

DESIGN

Randomized, controlled, double-blinded study.

SETTING

Outpatient endoscopy unit at an academic medical center.

PATIENTS

A total of 175 adults.

INTERVENTION

Elective outpatient sedated screening colonoscopies.

MAIN OUTCOME MEASUREMENTS

Sedation medication used, pain scores, cecal intubation rate, endoscopy times, satisfaction scores, and patient willingness to repeat procedures.

RESULTS

There was no significant difference in sedation medication requirement during colonoscopy with the use of warm or cool water (fentanyl 83.6 ± 29.0 μg vs 87.6 ± 39.6 μg; P = .45; midazolam 3.3 ± 1.2 mg vs 3.3 ± 1.3 mg; P = .91). There was no significant difference in patient pain scores or satisfaction scores. Cecal intubation rates (100%) were similar. There was no significant difference in cecal intubation times (6 minutes 40 seconds ± 4 minutes 9 seconds vs 7 minutes 49 seconds ± 4 minutes 0 seconds; P = .06) between the warm and cool water groups. All patients were willing to repeat the colonoscopy by using the same method in both groups.

LIMITATIONS

Limited generalizability to patients undergoing screening sedated colonoscopies with good to excellent bowel preparation.

CONCLUSION

Water does not need to be warmed before infusion in patients undergoing sedated colonoscopies.

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.

Colonoscopic enema as rescue for inadequate bowel preparation before colonoscopy: a prospective, observational study

AIM

Colonoscopy may need to be rescheduled because of inadequate bowel preparation. We evaluated the effectiveness of colonoscopic enema as rescue for an inadequate 1-day bowel preparation before colonoscopy.

METHOD

Patients referred for afternoon colonoscopy were prospectively enrolled in the study during a 1-year period. Patients took bowel preparation (polyethylene glycol) solution on the morning of the endoscopy. If during colonoscopy the bowel preparation was poor, an enema of polyethylene glycol solution (500 ml) was instilled into the colon at the level of the hepatic flexure via the biopsy channel of the colonoscope which was then removed. The patient was allowed to recover from the propofol sedation and used the bathroom to evacuate the enema. The colonoscope was then introduced and the examination continued.

RESULTS

Of 504 patients undergoing colonoscopy, 26 (4.9%) received an enema. The median age was 59 (29-79) years and 19 (73%) were female. A subsequent successful colonoscopy was achieved in 25/26 (96%). There were no complications. The mean time spent for the entire colonoscopy from the initial preparation to the end of the examination including the enema was 7.6± 1.1h (5.4 h preparation, 0.2h first colonoscopy+enema, 0.66h waiting in the lavatory, 0.33h second colonoscopy and 1 h for recovery).

CONCLUSION

Colonoscopic enema was highly successful as rescue for patients with inadequate bowel preparation and avoided postponement of the procedure.

Water immersion simplifies cecal intubation in patients with redundant colons and previous incomplete colonoscopies

BACKGROUND

Interest in effective ways to complete colon examinations in patients who had previously undergone failed colonoscopies has increased recently.

OBJECTIVE

To determine whether water immersion decreased the need for ancillary equipment to achieve cecal intubation in patients who had previously undergone incomplete colonoscopies.

DESIGN

Retrospective cohort study.

SETTING

Tertiary academic center.

PATIENTS

A total of 345 consecutive patients referred to a tertiary center for the indication of a previous incomplete colonoscopy.

INTERVENTIONS

Colonoscopy with or without water immersion insertion.

MAIN OUTCOME MEASUREMENTS

Cecal intubation rates, type of equipment, and maneuvers used.

RESULTS

Cecal intubation was achieved in 332 of 345 patients (96.2%) and was similar in those with and without water immersion (170/178, 95.5% vs 162/167, 97%, P = .58). An external straightening device was used in 6 of 178 cases with water immersion (3.4%) compared with 25 of 168 cases with air insufflation (15%) (P < .0001). Among patients with a redundant colon as the sole cause of previously incomplete examinations, water immersion required an external straightener in 7% compared with 37% with air insufflation during insertion (P < .0001), and position change was required in 5% of those with water immersion compared with 22% with air insufflation (P = .01).

LIMITATIONS

Retrospective review; single-center, single-endoscopist study.

CONCLUSION

Water immersion decreases the need for external straightening devices and position change maneuvers in patients with redundant colons and previously incomplete colonoscopies.

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.

Combination of water immersion and carbon dioxide insufflation for minimal sedation colonoscopy: a prospective, randomized, single-center trial

OBJECTIVE

Water immersion insertion and carbon dioxide (CO2) insufflation, as alternative colonoscopic techniques, are able to reduce patient discomfort during and after the procedure. We assessed whether the combination of water immersion and CO2 insufflation is superior in efficacy and patient comfort to other colonoscopic techniques.

METHODS

In a prospective, randomized study, a total of 420 patients were randomized to either water immersion insertion and CO2 insufflation during withdrawal (water/CO2), water insertion and air insufflation during withdrawal (water/air), CO2 insufflation during both insertion and withdrawal (CO2/CO2), or air insufflation during both insertion and withdrawal (air/air). The main outcome was the success of minimal sedation colonoscopy, which was defined as reaching the cecum without switching to another insertion method and without additional sedation beyond the initial 2 mg of midazolam. Patient comfort during and after the procedure was assessed.

RESULTS

A total of 404 patients were analyzed. The success rate of minimal sedation colonoscopy in the water insertion arm (water/CO2 and water/air) was 97% compared with 83.3% in the gas insertion arm (CO2/CO2 and air/air; P<0.0001). Intraprocedural pain and bloating were significantly lower in the water/CO2 group than in all other groups. Patient discomfort in the water/CO2 group during 24 h after the procedure was comparable with that in the CO2/CO2 group and significantly lower than that in the air groups (water/air and air/air). No complications were recorded during the study.

CONCLUSION

The combination of water immersion and CO2 insufflation appears to be an effective and safe method for minimal sedation colonoscopy. Overall patient discomfort was significantly reduced compared with that in other techniques.