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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Feasibility of salvage colonoscopy by water exchange for failed air-insufflated patients: a prospective, randomized, controlled trial

BACKGROUND

A complete colonoscopy is crucial for screening colorectal diseases and colorectal cancer. However, a failure rate of up to 43% still exists. Several studies have indicated that the water exchange method can enhance the cecal intubation rate while reducing discomfort of the patient. Water exchange colonoscopy (WEC) might be a salvage treatment for the patients who failed from air insufflation colonoscopy (AIC). We aimed to assess the feasibility of WEC as a salvage measure following the failure of conventional AIC.

METHODS

Patients willing to undergo unsedated colonoscopy at a tertiary-care referral center in China were randomly assigned 1:1 to WEC or AIC group for salvage after the initial AIC attempt failed. Patients were blinded to group assignment. The primary outcome was cecal intubation rate, the secondary outcomes included time to the cecum, maximum pain scores, and technical difficulty level.

RESULTS

Recruited 104 patients were randomized to the WEC (n = 52) or AIC (n = 52) group. WEC significantly increased the cecal intubation rate (92.3% vs 73.1%; p = .02). The maximum pain scores and technical difficulty level in the WEC group were significantly lower than the AIC group during salvage procedure (p < .001).

CONCLUSIONS

This randomized, controlled trial confirms that the WEC significantly enhanced cecal intubation rate in difficult colonoscopy in unsedated patients after the failure of standard AIC. The increased cecal intubation rate, lower pain scores and technical difficulty level suggest WEC is a good alternative for incomplete unsedated colonoscopy. Clinical trial registration number: ChiCTR2100051483.

Water exchange-assisted versus carbon dioxide-insufflated single-balloon enteroscopy: a randomized controlled trial

BACKGROUND

Single-balloon enteroscopy (SBE) is a valuable but difficult modality for the diagnosis and treatment of small-bowel disease. The water exchange method has the advantage of facilitating intubation during colonoscopy. Here, we evaluated the effects of water exchange on procedure-related variables related to SBE.

METHODS

This randomized controlled trial was conducted in a tertiary-care referral center in China. Patients due for attempted total enteroscopy were randomly allocated to undergo water exchange-assisted (water exchange group) or carbon dioxide-insufflated enteroscopy (CO₂ group). All patients were planned to undergo both anterograde and retrograde procedures. The primary outcome was the total enteroscopy rate. Secondary outcomes included the maximal insertion depth, positive findings, procedural time, and adverse events.

RESULTS

In total, 110 patients were enrolled, with 55 in each group. Baseline characteristics between the two groups were comparable. Total enteroscopy was achieved in 58.2 % (32/55) of the water exchange group and 36.4 % (20/55) of the control group (P = 0.02). The mean (standard deviation) estimated intubation depth was 521.2 (101.4) cm in the water exchange group and 481.6 (95.2) cm in the CO₂ group (P = 0.04). The insertion time was prolonged in the water exchange group compared with the CO₂ group (178.9 [45.1] minutes vs. 154.2 [27.6] minutes; P < 0.001). Endoscopic findings and adverse events were comparable between the two groups.

CONCLUSIONS

The water exchange method improved the total enteroscopy rate and increased the intubation depth during SBE. The use of water exchange did not increase the complications of enteroscopy.

Efficacy of a small-caliber colonoscope for pain in female patients during unsedated colonoscopy: a randomized controlled study

Background and study aims  Female sex has been identified as a factor increasing patients' pain during colonoscopy. The aim of this randomized controlled study was to investigate the efficacy of a small-caliber colonoscope, PCF-PQ260 L, for limiting pain in women during unsedated colonoscopy. Patients and methods  Women who underwent unsedated colonoscopy were randomly allocated to either the small-caliber or standard colonoscope group. The primary outcome was overall pain and secondary outcomes were maximum pain and procedural measures. In addition, the effects of colonoscope type were analysed using analysis of covariance and logistic regression with adjustment for stratification factors, age and prior abdomino-pelvic surgery. Results  A total of 220 women were randomly assigned to the small-caliber (n = 110) or standard (n = 110) colonoscope groups. Overall and maximum pain scores were significantly lower in the small-caliber colonoscope group than the standard colonoscope group (overall pain, 20.0 vs. 32.4, P < 0.0001; maximum pain, 28.9 vs. 47.2, P < 0.0001). The small-caliber colonoscope group achieved a superior cecal intubation rate (99 % vs. 93 %, P = 0.035). The rate of patient acceptance of unsedated colonoscopy in the future was higher in the small-caliber colonoscope group than in the standard colonoscope group (98 % vs. 87 %, P = 0.003). In addition, the small-caliber colonoscope was superior with respect to reducing pain and improving the rate of patient acceptance of unsedated colonoscopy with adjustment. Conclusions  This study demonstrates the efficacy of the small-caliber colonoscope for reducing pain in women and improving their rate of acceptance of unsedated colonoscopy.

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.

Effect of water exchange method on adenoma miss rate of patients undergoing selective polypectomy: A randomized controlled trial

BACKGROUND

Adenomas may be missed in up to 40% of screening colonoscopies. Although the water exchange (WE) method can improve ADR, as shown in several RCTs, it remains uncertain whether it can increase the detection of missing adenomas compared with standard air-insufflated (AI) colonoscopy.

METHODS

Patients aged 18-80 years who underwent selective polypectomy were randomly allocated to the WE or AI group. The primary endpoint was the adenoma miss rate (AMR), defined as the number of patients with one or more additional adenomas during the polypectomy procedure divided by the total number of patients in each group.

RESULTS

A total of 450 patients were enrolled, with 225 in each group. The overall AMRs were 45.8% (103/225) in the WE group and 35.6% (80/225) in the AI group (p = 0.035). More patients in the WE group had at least one missed adenoma in the proximal colon (38.2% vs 24.4%, p = 0.002). The adenoma-level miss rate was also higher in the WE group than in the AI group (35.1% vs 29.0%, p = 0.036). Subgroup analysis showed that patients in the WE group had more missed adenomas located in the proximal colon or with flat shapes.

CONCLUSIONS

This study confirmed that substantial adenomas were missed in patients undergoing selective polypectomy. The WE method significantly improved the detection of missed adenomas, especially those located in the proximal colon or with flat shapes. (ClnicalTrials.gov number: NCT02880748).

Magnetic endoscopic imaging as a rational investment for specific colonoscopies: a systematic review and meta-analysis

BACKGROUND

Magnetic endoscopic imaging (MEI) was regarded as an adjuvant device to improve procedural efficacy and patients' comfort during colonoscopy.

METHODS

Several electronic databases were searched to identify eligible studies. Based on the heterogeneity of included studies, random-effects or fixed-effects models were used to calculate pooled risk ratios (RR), risk difference (RD) or mean difference (MD) along with 95% confidence intervals (CIs).

RESULTS

Twenty-one randomized controlled trials (RCTs) were selected for meta-analysis, with a total of 7,060 patients. Although there is a slightly lower risk of cecal intubation failure with the adjuvant of MEI (RD 3%; P < 0.00001) compared to the control group, the updated studies show no significant benefits. Similarly, the cecal intubation time, pain scores, and loop formation with the adjuvant of MEI did not show any advantages. However, considerable significant benefits were found in the subgroup of technically difficult colonoscopy and inexperienced colonoscopists. Moreover, MEI was associated with lower loop intubation time, lower abdominal compression times, and better lesion localization.

CONCLUSION

The clinical benefits of MEI could be exaggerated. However, MEI has considerable advantages in technically difficult colonoscopies, the assistance for inexperienced colonoscopists, loop resolving, and lesion localization.

Current status of water-assisted colonoscopy

Compared with the traditional air insufflation method, water-assisted colonoscopy has many advantages in clinical application with regard to reduced abdominal pain, increased cecal intubation rate, increased detection rate of colon adenoma, and increased complete resection rate of larger polyps. It has gradually attracted more and more attention both in China and other countries. The aim of this article is to elaborate the invention, development, and therapeutic applications of water-assisted colonoscopy, as well as its advantages and shortcomings.

A review of water exchange and artificial intelligence in improving adenoma detection

Water exchange (WE) and artificial intelligence (AI) have made critical advances during the past decade. WE significantly increases adenoma detection and AI holds the potential to help endoscopists detect more polyps and adenomas. We performed an electronic literature search on PubMed using the following keywords: water-assisted and water exchange colonoscopy, adenoma and polyp detection, artificial intelligence, deep learning, neural networks, and computer-aided colonoscopy. We reviewed relevant articles published in English from 2010 to May 2020. Additional articles were searched manually from the reference lists of the publications reviewed. We discussed recent advances in both WE and AI, including their advantages and limitations. AI may mitigate operator-dependent factors that limit the potential of WE. By increasing bowel cleanliness and improving visualization, WE may provide the platform to optimize the performance of AI for colonoscopies. The strengths of WE and AI may complement each other in spite of their weaknesses to maximize adenoma detection.

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).

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.

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.

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

Background

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

Methods

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

Results

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

Conclusions

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

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

BACKGROUND AND AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

Background

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

Objective

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

Methods

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

Results

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

Conclusion

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

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

BACKGROUND/AIMS

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

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.

Difficult colonoscopy: air, carbon dioxide, or water insufflation?

Background/Aims

This study aimed to compare tolerance to air, carbon dioxide, or water insufflation in patients with anticipated difficult colonoscopy (young, thin, obese individuals, and patients with prior abdominal surgery or irradiation).

Methods

Patients with body mass index (BMI) less than 18 kg/m² or more than 30 kg/m², or who had undergone previous abdominal or pelvic surgeries were randomized to air, carbon dioxide, or water insufflation during colonoscopy. The primary endpoint was cecal intubation with mild pain (less than 5 on visual analogue scale [VAS]), without use of sedation.

Results

The primary end point was achieved in 32.7%, 43.8%, and 84.9% of cases with air, carbon dioxide and water insufflation (P<0.001). The mean pain scores were 5.17, 4.72, and 3.93 on the VAS for air, carbon dioxide, and water insufflation (P<0.001). The cecal intubation rate or procedure time did not differ significantly between the 3 groups.

Conclusions

Water insufflation was superior to air or carbon dioxide for pain tolerance. This was seen in the subgroups with BMI <18 kg/m² and the post-surgical group, but not in the group with BMI >30 kg/m².

Effect of left lateral tilt-down position on cecal intubation time: a 2-center, pragmatic, randomized controlled trial

BACKGROUND AND AIMS

Colonoscopy insertion is technically challenging, time-consuming, and painful, especially for the sigmoid. Several pilot studies indicated that the (left) tilt-down position could facilitate the insertion procedure, but no formal trials have been published to demonstrate its efficacy. We performed this study to verify the benefits of the left lateral tilt-down position (LTDP) on the insertion process.

METHODS

This 2-center prospective trial randomized unsedated patients to the LTDP or left lateral horizontal position (LHP) to aid insertion. The primary outcome measure was cecal intubation time (CIT). Secondary outcome measures included decending colon intubation time (DIT), pain score of insertion, acceptance of unsedated colonoscopy for future examinations, difficulty score for insertion, and the adverse event rate of colonoscopy.

RESULTS

Two hundred fifty-eight patients were randomized to the LTDP (128) or LHP (130) in 2 centers. The median CIT and DIT were shorter with patients positioned in LTDP than in LHP (CIT, 280.0 vs 339.5 s, P < .001; DIT, 53.0 vs 69.0 s, P < .001, respectively) and patients with high and low body mass index (BMI) benefited more from LTDP than from LHP, as opposed to patients with normal BMI. In addition, colonoscopy insertion in LTDP was less painful (3.4 ± 1.6 vs 4.0 ± 1.7, P = .02) and less difficult (3.1 ± 1.9 vs 3.7 ± 1.4, P < .001), showing a higher tendency to acceptance of unsedated colonoscopy (82.9% vs 73.8%, P = .08). The rates of adverse events were extremely low and did not differ significantly in the 2 groups.

CONCLUSIONS

LTDP for colonoscopy insertion can reduce insertion time and pain, and potentially improves patients' acceptance of unsedated colonoscopy. (Clinical trial registration number: NCT02842489.).

Water Exchange Method Significantly Improves Adenoma Detection Rate: A Multicenter, Randomized Controlled Trial

OBJECTIVES

Adenoma detection rate (ADR) is a key colonoscopy quality indicator in Western clinical literature. Our low ADR prompted us to assess novel methods to improve performance. Western retrospective reports suggested that water exchange (WE) could increase ADR. However, most of these studies used pain score or intubation rate as the primary outcome. Here we test the hypothesis that WE significantly increases ADR among Chinese colonoscopists and design a prospective randomized controlled trial using ADR as our primary outcome.

METHODS

This prospective, randomized controlled trial was performed at six centers in China. Screening, surveillance, and diagnostic cases were randomized to be examined by WE or traditional air insufflation (AI) method. The primary outcome was ADR.

RESULTS

From April 2014 to July 2015, 3,303 patients were randomized to WE (n=1,653) and AI (n=1,650). The baseline characteristics were comparable. Overall ADR was 18.3% (WE) and 13.4% (AI) (relative risk 1.45, 95% confidential interval: 1.20-1.75, P<0.001). ADR in screening patients using AI was 25.8% (male) and 15.7% (female). ADR in screening patients aged >50 years old was 29.4% (WE) and 22.9% (AI) (relative risk 1.09, 95% confidential interval: 1.00-1.19, P=0.040). The increase by WE was reproducibly observed in all indication categories, and significant in screening and diagnostic cases. The limitation imposed by the unblinded investigators was mitigated by comparable inspection times in cases without polyps, similar adenoma per positive colonoscopy, and reproducible enhancement of ADR and adenoma per colonoscopy by WE across all eight investigators.

CONCLUSIONS

This prospective study confirms Western retrospective data that WE significantly improves ADR among Chinese colonoscopists. WE may be superior to AI for screening colonoscopy in China. Colonoscopists elsewhere with low ADR might consider evaluating WE for performance improvement.

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.

What Can We Do to Optimize Colonoscopy and How Effective Can We Be?

In the USA, colorectal cancer is the third most common cancer and third leading cause of cancer death among both men and women. Declining rates of colon cancer in the past decade have been attributed in part to screening and removal of precancerous polyps via colonoscopy. Recent emphasis has been placed on measures to increase the quality and effectiveness of colonoscopy. These have been divided into pre-procedure quality metrics (bowel preparation), procedural quality metrics (cecal intubation, withdrawal time, and adenoma detection rate), post-procedure metrics (surveillance interval), and other quality metrics (patient satisfaction and willingness to repeat the procedure). The purpose of this article is to review the data and controversies surrounding each of these and identify ways to optimize the performance of colonoscopy.

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

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.

Difficult colonoscopy score identifies the difficult patients undergoing unsedated colonoscopy

Background

Many factors have been found to affect the difficulty of colonoscope insertion, such as age, gender, body mass index (BMI), history of abdominal surgery and operator etc. However, a scoring system may be more useful to predict the difficulty during colonoscopy.

Methods

The individual and procedure-related data of 616 patients undergoing colonoscopy were prospectively collected from December 2013 through February 2014 in Xijing Hospital of Digestive Diseases. Cox regression analysis was used to identify high-risk factors associated with difficulty of colonoscopy. A predicting model with the difficult colonoscopy score (DCS) was developed.

Results

Total cecum intubation rate was 98.9% (609/616). Advanced age, lower BMI, inexperienced operator and fair or poor sleep quality were identified as independent factors of prolonged insertion time (all p < 0.05), which were used to develop the DCS. Based on the score, patients could be divided into high-risk and low-risk groups with distinct incomplete rates within 10 min (42.0% vs. 16.5%, p < 0.001). Compared with those with DCS ≤ 1, patients with DCS > 1 had increased insertion time (10.6 ± 0.7 min vs. 6.9 ± 0.2 min, p < 0.001) and pain score (1.9 ± 1.5 vs. 1.4 ± 1.4, p = 0.002). More abdominal compression (36.9% vs. 16.8%, p < 0.001) and position change (51.4% vs. 22.6%, p < 0.001) were needed in this group of patients.

Conclusion

Patients with DCS > 1 had longer insertion time, higher pain score and needed more abdominal compression and position changes. DCS was useful for predicting the difficulty of colonoscope intubation.

(ClinicalTrials.gov NCT02105025 05/05/2014).

Electronic supplementary material

The online version of this article (doi:10.1186/s12876-015-0273-7) contains supplementary material, which is available to authorized users.

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.

Time trends in quality indicators of colonoscopy

BACKGROUND

There is considerable variation in the quality of colonoscopy performance. The Norwegian quality assurance programme Gastronet registers outpatient colonoscopies performed in Norwegian endoscopy centres. The aim of Gastronet is long-term improvement of endoscopist and centre performance by annual feedback of performance data.

OBJECTIVE

The objective of this article is to perform an analysis of trends of quality indicators for colonoscopy in Gastronet.

METHODS

This prospective cohort study included 73,522 outpatient colonoscopies from 73 endoscopists at 25 endoscopy centres from 2003 to 2012. We used multivariate logistic regression with adjustment for relevant variables to determine annual trends of three performance indicators: caecum intubation rate, pain during the procedure, and detection rate of polyps ≥5 mm.

RESULTS

The proportion of severely painful colonoscopies decreased from 14.8% to 9.2% (relative risk reduction of 38%; OR = 0.92 per year in Gastronet; 95% CI 0.86-1.00; p = 0.045). Caecal intubation (OR = 0.99; 95% CI 0.94-1.04; p = 0.6) and polyp detection (OR = 1.03; 95% CI 0.99-1.07; p = 0.15) remained unchanged during the study period.

CONCLUSIONS

Pain at colonoscopy showed a significant decrease during years of Gastronet participation while caecal intubation and polyp detection remained unchanged - independent of the use of sedation and/or analgesics and level of endoscopist experience. This may be due to the Gastronet audit, but effects of improved endoscopy technology cannot be excluded.

Feasibility study of novel endoscopic Cerenkov luminescence imaging system in detecting and quantifying gastrointestinal disease: first human results

OBJECTIVES

Cerenkov luminescence imaging (CLI) provides potential to use clinical radiotracers for optical imaging. The goal of this study was to present a newly developed endoscopic CLI (ECLI) system and illustrate its feasibility and potential in distinguishing and quantifying cancerous lesions of the GI tract.

METHODS

The ECLI system was established by integrating an electron-multiplying charge-coupled device camera with a flexible fibre endoscope. Phantom experiments and animal studies were conducted to test and illustrate the system in detecting and quantifying the presence of radionuclide in vitro and in vivo. A pilot clinical study was performed to evaluate our system in clinical settings.

RESULTS

Phantom and mice experiments demonstrated its ability to acquire both the luminescent and photographic images with high accuracy. Linear quantitative relationships were also obtained when comparing the ECLI radiance with the radiotracer activity (r (2) = 0.9779) and traditional CLI values (r (2) = 0.9025). Imaging of patients revealed the potential of ECLI in the identification and quantification of cancerous tissue from normal, which showed good consistence with the clinical PET examination.

CONCLUSIONS

The new ECLI system shows good consistence with the clinical PET examination and has great potential for clinical translation and in aiding detection of the GI tract disease.

KEY POINTS

• CLI preserves the characteristics of both optical and radionuclide imaging. • CLI provides great potential for clinical translation of optical imaging. • The newly developed endoscopic CLI (ECLI) has quantification and imaging capacities. • GI tract has accessible open surfaces, making ECLI a potentially suitable technique. • Cerenkov endoscopy has great clinical potential in detecting GI disease.

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.