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

Effectiveness of Water-Assisted Colonoscopy without Sedation in Patients with Ulcerative Colitis

BACKGROUND

Studies have found that water-assisted colonoscopy (WAC) including water immersion colonoscopy (WIC) and water exchange colonoscopy (WEC) is superior to air insufflation colonoscopy (AIC) in terms of the cecal intubation rate. However, the application of WAC in ulcerative colitis (UC) has rarely been reported. This study aimed to explore the effectiveness of WAC without sedation in patients with UC.

METHODS

One hundred and seventy-two UC patients were randomly divided into the AIC group (n = 56), WIC group (n = 58), and WEC group (n = 58). The cecal intubation rate, abdominal pain score, operator difficulty, bowel cleanliness, insertion, and total time were compared.

RESULTS

The cecal intubation rate was higher in the WIC (91.4% vs. 75.0%; mean difference = 16.4%; 95% CI: 3.0-29.8%) and WEC (93.1% vs. 75.0%; mean difference = 18.1%; 95% CI: 5.0-31.2%) compared to the AIC group, while there was no difference between the WIC and WEC groups. The abdominal pain score and operator difficulty were lower in the WIC and WEC groups than in the AIC group, while there was no difference between the WIC and WEC groups. The bowel cleanliness during withdrawal was higher in the WIC and WEC groups than in the AIC group, while the WEC was superior to WIC. Compared with the AIC and WIC groups, the insertion time and total time were longer in the WEC group, and there was no difference in the AIC group and WIC group.

CONCLUSION

In comparison with AIC, WAC can increase the cecal intubation rate, reduce abdominal pain scores and improve bowel cleanliness in patients with UC.

Application of robotic technologies in lower gastrointestinal tract endoscopy: A systematic review

BACKGROUND

Conventional optical colonoscopy is considered the gold standard investigation for colorectal tract pathology including colorectal malignancy, polyps and inflammatory bowel disease. Inherent limitations exist with current generation endoscopic technologies, including, but not limited to, patient discomfort, endoscopist fatigue, narrow field of view and missed pathology behind colonic folds. Rapid developments in medical robotics have led to the emergence of a variety of next-generation robotically-augmented technologies that could overcome these limitations.

AIM

To provide a comprehensive summary of recent developments in the application of robotics in lower gastrointestinal tract endoscopy.

METHODS

A systematic review of the literature was performed from January 1, 2000 to the January 7, 2021 using EMBASE, MEDLINE and Cochrane databases. Studies reporting data on the use of robotic technology in ex vivo or in vivo animal and human experiments were included. In vitro studies (studies using synthetic colon models), studies evaluating non-robotic technology, robotic technology aimed at the upper gastrointestinal tract or paediatric endoscopy were excluded. System ergonomics, safety, visualisation, and diagnostic/therapeutic capabilities were assessed.

RESULTS

Initial literature searching identified 814 potentially eligible studies, from which 37 were deemed suitable for inclusion. Included studies were classified according to the actuation modality of the robotic device(s) as electromechanical (EM) (n = 13), pneumatic (n = 11), hydraulic (n = 1), magnetic (n = 10) and hybrid (n = 2) mechanisms. Five devices have been approved by the Food and Drug Administration, however most of the technologies reviewed remain in the early phases of testing and development. Level 1 evidence is lacking at present, but early reports suggest that these technologies may be associated with improved pain and safety. The reviewed devices appear to be ergonomically capable and efficient though to date no reports have convincingly shown diagnostic or therapeutic superiority over conventional colonoscopy.

CONCLUSION

Significant progress in robotic colonoscopy has been made over the last couple of decades. Improvements in design together with the integration of semi-autonomous and autonomous systems over the next decade will potentially result in robotic colonoscopy becoming more commonplace.

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.

Hydro-jet propelled colonoscopy: proof of concept in a phantom colon

BACKGROUND

Colonoscopy is a widely used and effective procedure, but it often causes patient discomfort and its execution requires considerable skill and training. We demonstrate an alternative approach to colonoscope propulsion with the potential to minimise patient discomfort by reducing the forces exerted on the colonic wall and mesentery, and to reduce the level of skill required for execution.

METHODS

A prototype colonoscopic device is described, consisting of a tethered capsule that is propelled and manoeuvred through a water-filled colon (hydro-colonoscopy) by an array of water jets. As an initial proof of concept, experiments were performed to assess the ability of the device to navigate through a simplified PVA cryogel human colon phantom arranged in various anatomical configurations.

RESULTS

The prototype was capable of successfully navigating through three out of four colon configurations: a simple layout, alpha loop and reverse alpha loop. It was unable to negotiate the fourth configuration involving an "N loop", but this was attributed to problems with the colon phantom. In the successful test replicates, mean complete insertion (i.e. caecal intubation) time was 4.7 min. Measured pressures, temperatures and forces exerted on the colon appeared to be within a physiologically acceptable range. The results demonstrate the viability of propelling a colonoscope through a colon phantom using hydro-jets.

CONCLUSIONS

Results indicate that this approach has the potential to enable rapid and safe caecal intubation. This suggests that further development towards clinical translation is worthwhile.

Colonoscopic techniques in polyp detection: An Egyptian study

INTRODUCTION AND AIMS

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

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

GOALS

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

BACKGROUND

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

STUDY

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

RESULTS

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

CONCLUSIONS

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

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.

Pin1 inhibition exerts potent activity against acute myeloid leukemia through blocking multiple cancer-driving pathways

Background

The increasing genomic complexity of acute myeloid leukemia (AML), the most common form of acute leukemia, poses a major challenge to its therapy. To identify potent therapeutic targets with the ability to block multiple cancer-driving pathways is thus imperative. The unique peptidyl-prolyl cis-trans isomerase Pin1 has been reported to promote tumorigenesis through upregulation of numerous cancer-driving pathways. Although Pin1 is a key drug target for treating acute promyelocytic leukemia (APL) caused by a fusion oncogene, much less is known about the role of Pin1 in other heterogeneous leukemia.

Methods

The mRNA and protein levels of Pin1 were detected in samples from de novo leukemia patients and healthy controls using real-time quantitative RT-PCR (qRT-PCR) and western blot. The establishment of the lentiviral stable-expressed short hairpin RNA (shRNA) system and the tetracycline-inducible shRNA system for targeting Pin1 were used to analyze the biological function of Pin1 in AML cells. The expression of cancer-related Pin1 downstream oncoproteins in shPin1 (Pin1 knockdown) and Pin1 inhibitor all-trans retinoic acid (ATRA) treated leukemia cells were examined by western blot, followed by evaluating the effects of genetic and chemical inhibition of Pin1 in leukemia cells on transformed phenotype, including cell proliferation and colony formation ability, using trypan blue, cell counting assay, and colony formation assay in vitro, as well as the tumorigenesis ability using in vivo xenograft mouse models.

Results

First, we found that the expression of Pin1 mRNA and protein was significantly increased in both de novo leukemia clinical samples and multiple leukemia cell lines, compared with healthy controls. Furthermore, genetic or chemical inhibition of Pin1 in human multiple leukemia cell lines potently inhibited multiple Pin1 substrate oncoproteins and effectively suppressed leukemia cell proliferation and colony formation ability in cell culture models in vitro. Moreover, tetracycline-inducible Pin1 knockdown and slow-releasing ATRA potently inhibited tumorigenicity of U937 and HL-60 leukemia cells in xenograft mouse models.

Conclusions

We demonstrate that Pin1 is highly overexpressed in human AML and is a promising therapeutic target to block multiple cancer-driving pathways in AML.

Electronic supplementary material

The online version of this article (10.1186/s13045-018-0611-7) contains supplementary material, which is available to authorized users.

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.

Can Water Exchange Improve Patient Tolerance in Unsedated Colonoscopy A Prospective Comparative Study

Background & Aims

Unsedated colonoscopy can be painful, poorly tolerated by patients, and associated with unsatisfactory technical performance. Previous studies report an advantage of water exchange over conventional air insufflation in reducing pain during unsedated colonoscopy. Our goal was to analyze the impact of water exchange colonoscopy on the level of maximum pain reported by patients submitted to unsedated colonoscopy, compared to conventional air insufflation.

Methods

We performed a single-center, patient-blinded, prospective randomized comparative study, where patients were either allocated to the water group, in which the method of colonoscopy used was water exchange, or the standard air group, in which the examination was accomplished with air insufflation.

Results

A total of 141 patients were randomized, 70 to the water and 71 to the air group. The maximum level of pain reported by patients during unsedated colonoscopy, measured by a numeric scale of pain (0-10), was significantly lower in the water group (3.39 ± 2.32), compared to the air group (4.94 ± 2.10), p < 0.001. The rate of painless colonoscopy was significantly higher in the water group (12.9 vs. 1.4%, p = 0.009). There were no significant differences between the two groups regarding indications for the procedure, quality of bowel preparation, cecal intubation time, withdrawal time, number of position changes, adenoma detection rate, and postprocedural complications. Only the number of abdominal compressions was significantly different, showing that water exchange decreases the number of compressions needed during colonoscopy.

Conclusions

Water exchange was a safe and equally effective alternative to conventional unsedated colonoscopy, associated with less intraprocedural pain without impairing key performance measures.

Prospective multicenter randomized controlled trial comparing adenoma detection rate in colonoscopy using water exchange, water immersion, and air insufflation

BACKGROUND AND AIMS

Adenoma detection rate (ADR), defined as the proportion of patients with at least one adenoma of any size, is a quality indicator. We tested the hypothesis that water exchange (WE) improves ADR but water immersion (WI) has no adverse effect on ADR compared with air insufflation (AI).

METHODS

A prospective study was conducted at the Dalin Tzu Chi Hospital in southern Taiwan and the Hualien Tzu Chi Hospital in eastern Taiwan on patients randomly assigned to WE, WI, or AI with stratification by the 3 study colonoscopists. The primary outcome was ADR.

RESULTS

From July 2013 to December 2015, 651 patients were recruited and randomized into 3 groups with a 1:1:1 ratio (217 patients per group). Overall, ADR met quality standards: WE 49.8% (95% CI, 43.2%-56.4%), AI 37.8% (95% CI, 31.6%-44.4%), and WI 40.6% (95% CI, 34.2%-47.2%). Compared with AI, WE significantly increased ADR (P = .016). There was no difference between WI and WE. ADRs of WI and AI were comparable. Compared with AI, WE confirmed a longer insertion time, higher cleanliness score, but similar adenoma per positive colonoscopy (APPC) and withdrawal time with polypectomy. Subgroup analysis found WE significantly increased ADR in propofol-sedated patients. Multivariate generalized linear mixed model analysis revealed that age ≥50 years, WE (vs AI), colonoscopy indication, no previous history of colonoscopy, and withdrawal time >8 minutes were significant predictors of increased ADR.

CONCLUSIONS

Confirmation of prior reports showing WE, but not WI, increased ADR further strengthened the validity of our observations. WE significantly increased ADR in propofol-sedated patients. The outcome differences justify assessment of the role of WE in colorectal cancer prevention. Similar APPC and withdrawal times suggest that adequate inspection was performed on colonoscope withdrawal in each of the study arms. (Clinical trial registration number: NCT01894191.).

Is Unsedated Colonoscopy Gaining Ground Over Sedated Colonoscopy?

Colorectal cancer (CRC) is a prevalent cancer with high global incidence and a leading cause of cancer death worldwide. CRC screening is important for early cancer detection and prevention. Most premalignant adenomas can be identified and removed before they become malignant. Colonoscopy plays a vital role in reducing the risk for developing CRC. Although screening programs with colonoscopy have been implemented in many countries and considered beneficial for a number of people, this technique is generally associated with anxiety, embarrassment, pain, and discomfort, resulting in lack of adherence to the recommended screening guidelines. In the US, colonoscopy is mostly performed under sedation, thereby causing amnesia and analgesia. In contrast to sedated colonoscopy, which has been associated with some disadvantages, unsedated colonoscopy exhibits advantages and has been preferred over sedated colonoscopy in numerous cancer centers worldwide. This review enumerates the features of sedated and unsedated colonoscopy with the use of the current relevant evidence-based literature. Unsedated colonoscopy can be a reasonable option for routine and unscheduled CRC screening.

Technical interventions to increase adenoma detection rate in colonoscopy

Adenoma detection rate (ADR) is the most robust colonoscopy quality metric and clinical studies have adopted it as the ideal method to assess the impact of technical interventions. Areas covered: We reviewed papers focusing on the impact of colonoscopy technical issues on ADR, including withdrawal time and technique, second evaluation of the right colon, patient positional changes, gastrointestinal assistant participation during colonoscopy, water-aided technique, optimization of bowel preparation and antispasmodic administration. Expert commentary: Overall, technical interventions are inexpensive, available worldwide and easy to implement. Some of them, such as the adoption of split dose regimen and slow scope withdrawal to allow a careful inspection, have been demonstrated to significantly improve ADR. Emerging data support the use of water-exchange colonoscopy. According to published studies, other technical interventions seem to provide only marginal benefit to ADR. Unfortunately, the available evidence has methodological limitations, such as small sample sizes, the inclusion of expert endoscopists only and the evaluation of single technical interventions. Additionally, larger studies are needed to clarify whether these interventions might have a higher benefit on low adenoma detectors and whether the implementation of a bundle of them, instead of a single technical maneuver, might have a greater impact on ADR.

A hydraulically driven colonoscope

BACKGROUND

Conventional colonoscopy requires a high degree of operator skill and is often painful for the patient. We present a preliminary feasibility study of an alternative approach where a self-propelled colonoscope is hydraulically driven through the colon.

METHODS

A hydraulic colonoscope which could be controlled manually or automatically was developed and assessed in a test bed modelled on the anatomy of the human colon. A conventional colonoscope was used by an experienced colonoscopist in the same test bed for comparison. Pressures and forces on the colon were measured during the test.

RESULTS

The hydraulic colonoscope was able to successfully advance through the test bed in a comparable time to the conventional colonoscope. The hydraulic colonoscope reduces measured loads on artificial mesenteries, but increases intraluminal pressure compared to the colonoscope. Both manual and automatically controlled modes were able to successfully advance the hydraulic colonoscope through the colon. However, the automatic controller mode required lower pressures than manual control, but took longer to reach the caecum.

CONCLUSIONS

The hydraulic colonoscope appears to be a viable device for further development as forces and pressures observed during use are comparable to those used in current clinical practice.

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.

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

AIMS

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Total Colonic Decompression After Colonoscopy Decreases Postcolonoscopy Abdominal Pain: A Randomized Double-Blind Controlled Trial

GOALS

The purpose of this study was to determine whether total colonic decompression after colonoscopy decreased postcolonoscopy abdominal pain.

BACKGROUND

Abdominal pain that occurs after a colonoscopy may cause significant discomfort in some patients, and residual bowel gas is thought to be a key contributor to this abdominal pain.

STUDY

Asymptomatic 300 patients who underwent colonoscopy under sedation were randomized to either the decompression group or the control group. Initial colonoscopic procedure was performed uniformly in both the groups. After the colonoscopy examination was completed, the colonoscope was reinserted into the cecum, and the intraluminal air was aspirated during withdrawal in the decompression group. Abdominal pain was assessed before discharge and 24 to 48 hours after colonoscopy using a 10-point visual analogue scale (VAS).

RESULTS

The 2 groups were similar with regard to clinical, demographic, and procedural factors. Among 288 patients, the incidence of abdominal pain (VAS≥1) after colonoscopy was 38 (26.6%) of 143 patients in the decompression group and 95 (65.5%) of 145 patients in the control group (VAS 0.68±1.35 vs. 2.14±2.15, P<0.001). There was an 86.1% reduction rate of abdominal pain by colonic decompression, based on multivariate analysis (odds ratio 0.139 [95% confidence interval, 0.077-0.250], P<0.001). Furthermore, independent factors for abdominal pain included female gender and total duration of procedure >800 seconds. There were no reinsertion-related complications in the decompression group.

CONCLUSION

Total colonic decompression after colonoscopy has a beneficial effect and can reduce postcolonoscopy abdominal pain without additional complications.

What Influences the Quality of Prevention Colonoscopy?

Background

Colorectal cancer still has a high incidence and mortality. Although colonoscopy is considered as gold standard of colorectal cancer screening, there still exists an unsatisfactory level of adenomas missed in screening and surveillance colonoscopy. Furthermore, patients bear the burden of potentially unpleasant and painful examination and preparation procedures.

Method

A search of the literature using PubMed was carried out, supplemented by a review of the programs of the Digestive Disease Week (DDW) and the United European Gastroenterology Week (UEGW) 2011-2013.

Results

Several new approaches to colonoscopy were described: water, CO₂ and cap colonoscopy, and application of spasmolytics such as hyoscine butylbromide and glucagon. The use of these methods does not necessitate the purchase of new endoscopes. They are feasible and safe, facilitate achieving the aim of more comfort and less pain, and perhaps allow lower doses of sedatives to be used. However, a clear effect on procedure time is lacking. Furthermore, the published data do not consistently answer the question of whether these techniques have a positive impact on the most important goal, the better detection of carcinoma precursors.

Conclusion

More efforts to optimize bowel preparation have to be made to improve visualization of the mucosal surface. The most reliable criteria for the quality of screening and surveillance colonoscopy remain a minimum cecal intubation rate of >90%, a withdrawal time of at least 6 or better 9 min, and an adenoma detection rate of >20%. These results should be achieved with a complication rate lower than 1%, including polypectomy.

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.

Water exchange vs. water immersion during colonoscope insertion

Water exchange (water infusion with water removal primarily during insertion) and water immersion (water infusion with water removal during withdrawal) reduce patient discomfort during colonoscope insertion compared with air insufflation, and represent a major achievement in colonoscopy. Hsieh et al. found that water exchange, relative to water immersion, resulted in more painless insertions to the cecum and improved adenoma detection in the right colon. However, water exchange is also associated with better bowel cleansing and longer insertion and procedure times. These factors are not specific to water exchange, but could account for all or part of the better results with water exchange. Additional controlled investigation is needed to define the benefits of water exchange compared with water immersion.