A randomized, controlled comparison of warm water infusion in lieu of air insufflation versus air insufflation for aiding colonoscopy insertion in sedated patients undergoing colorectal cancer screening and surveillance

Water-assisted colonoscopy: an international modified Delphi review on definitions and practice recommendations

BACKGROUND AND AIMS

Since 2008, a plethora of research studies has compared the efficacy of water-assisted (aided) colonoscopy (WAC) and underwater resection (UWR) of colorectal lesions with standard colonoscopy. We reviewed and graded the research evidence with potential clinical application. We conducted a modified Delphi consensus among experienced colonoscopists on definitions and practice of water immersion (WI), water exchange (WE), and UWR.

METHODS

Major databases were searched to obtain research reports that could potentially shape clinical practice related to WAC and UWR. Pertinent references were graded (Grading of Recommendations, Assessment, Development and Evaluation). Extracted data supporting evidence-based statements were tabulated and provided to respondents. We received responses from 55 (85% surveyed) experienced colonoscopists (37 experts and 18 nonexperts in WAC) from 16 countries in 3 rounds. Voting was conducted anonymously in the second and third round, with ≥80% agreement defined as consensus. We aimed to obtain consensus in all statements.

RESULTS

In the first and the second modified Delphi rounds, 20 proposed statements were decreased to 14 and then 11 statements. After the third round, the combined responses from all respondents depicted the consensus in 11 statements (S): definitions of WI (S1) and WE (S2), procedural features (S3-S5), impact on bowel cleanliness (S6), adenoma detection (S7), pain score (S8), and UWR (S9-S11).

CONCLUSIONS

The most important consensus statements are that WI and WE are not the same in implementation and outcomes. Because studies that could potentially shape clinical practice of WAC and UWR were chosen for review, this modified Delphi consensus supports recommendations for the use of WAC in clinical practice.

Cecal intubation time between the use of one-channel and two-channel water exchange colonoscopy: A randomized controlled trial

BACKGROUND AND AIM

Water exchange (WE) colonoscopy is the least painful insertion technique with high adenoma detection rate but requires a longer intubation time. In the published literature, some investigators used the instrument channel for both infusing and suctioning of water (one channel), while others use colonoscopes with an integrated water-jet channel specifically designed for infusing water (two channel). The aim of this study was to compare cecal intubation time between one-channel and two-channel WE.

METHODS

A total 120 patients undergoing colonoscopy from May 2017 to April 2019 at a regional hospital in southern Taiwan were randomized to either a two-channel group (n = 60) or a one-channel group (n = 60). The primary outcome was cecal intubation time.

RESULTS

The mean cecal intubation time was significantly shorter in the two-channel group compared with the one-channel group (14.0 ± 4.0 vs 17.4 ± 6.7 min, P < 0.001). The two-channel group required less water infused during insertion (564.8 ± 232.4 vs 1213.3 ± 467.5 mL, P < 0.001) but achieved a significantly higher Boston Bowel Preparation Scale score (8.4 ± 0.8 vs 7.5 ± 1.1, P < 0.001) than did the one-channel group. The adenoma detection rate was comparable in the two groups (50.0% vs 48.3%, P = 0.855).

CONCLUSIONS

In comparison with the one-channel WE, two-channel WE showed a shorter cecal intubation time, required less amount of water during insertion, and provided a better salvage cleansing effect. (NCT03279705).

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.

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.

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.

Increase your adenoma detection rate without using fancy adjunct tools

The correlation between a low adenoma detection rate (ADR) and interval cancers (ICs) has made ADR one of the most important quality indicators for colonoscopy. Data from nation-wide colorectal cancer (CRC) screening programs showed that there is room for improvement in ADR in order to reduce ICs in Taiwan. Measures with and without adjunct tools have been shown to have the potential to increase ADR, with the latter being more convenient to apply without additional cost. Optimal withdrawal techniques coupled with sufficient withdrawal time, training endoscopists with emphasis on recognition of subtle characteristics of flat lesions, dynamic position changes during the withdrawal phase, removing small polyps found during insertion, and retroflexion in the right colon have all been associated with increased ADR. In particular, water exchange (WE), which is characterized using water in lieu of air and suction removal of infused water during insertion, appears to meet the needs of colonoscopy patients in Taiwan. Analyses of both primary and secondary outcome variables of recently published studies have consistently shown that WE yields higher ADR than traditional air insufflation, even in propofol-sedated patients. Colonoscopists participating in the nationwide CRC screening program in Taiwan should consider applying one or more of the above measures to improve ADR and hopefully reduce ICs.

A prospective randomized study of the use of an ultrathin colonoscope versus a pediatric colonoscope in sedation-optional colonoscopy

BACKGROUND

Ultrathin colonoscopes (UTC) reportedly produce less pain during colonoscopy than standard colonoscopes. The aim of this study was to assess the tolerability of an UTC compared with that of a pediatric colonoscope.

METHODS

A total of 270 adult patients scheduled to undergo colonoscopy were randomized, with 134 allocated to the UTC group and 136 to the pediatric colonoscope group. Pain was assessed using a visual analog scale. For all procedures, sedation was administered only if requested. Overall pain, rate and time of cecal and terminal ileum intubation, number of patients requesting sedation, adenoma detection rates (ADR), and rate of complications were measured and analyzed.

RESULTS

Among all patients, the medians of maximum pain and overall pain were significantly lower in the UTC group than in the pediatric colonoscope group (23 vs. 38, P < 0.001; 12 vs. 22, P = 0.0003, respectively). Significantly fewer patients requested sedation in the UTC group than in the pediatric colonoscope group (1.4 vs. 6.6%; P = 0.0269). No significant differences were seen in either the rate and time of successful cecal and terminal ileum intubation, or in other procedure-related outcomes, including ADR.

CONCLUSIONS

Compared with a pediatric colonoscope, the UTC was associated with reduced overall and maximum pain during colonoscopy, with no difference in ADR.

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.

Painless Colonoscopy: Available Techniques and Instruments

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

Accrediting for screening-related colonoscopy services: What is required of the endoscopist and of the endoscopy service?

Colorectal cancer (CRC) screening is widely implemented to reduce CRC incidence and related mortality. The impact of screening as well as the balance between screening burden and benefits strongly depends on the quality of colonoscopy. Besides quality, safety of the endoscopic procedure and patient satisfaction are important outcome parameters for a screening program. Therefore the requirements for both CRC screening endoscopy services and endoscopists focus on technical aspects, patient safety, and patient experience. Stringent quality assurance by means of routine monitoring of quality indicators for the performance of endoscopists and endoscopy units is recommended. This allows setting minimum standards, targeted interventions, and enhancement of the overall quality of population screening. This reviews deals with guidelines and quality standards for colorectal cancer screening, with focus on both endoscopist and endoscopy services.

Complications during colonoscopy: prevention, diagnosis, and management

Colonoscopy is largely performed in daily clinical practice for both diagnostic and therapeutic purposes. Although infrequent, different complications may occur during the examination, mostly related to the operative procedures. These complications range from asymptomatic and self-limiting to serious, requiring a prompt medical, endoscopic or surgical intervention. In this review, the complications that may occur during colonoscopy are discussed, with a particular focus on prevention, diagnosis, and therapeutic approaches.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

Diagnostic and therapeutic applications of water-immersion colonoscopy

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

Water infusion versus air insufflation for colonoscopy

BACKGROUND

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

OBJECTIVES

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

SEARCH METHODS

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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

Water-aided colonoscopy

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

Lung and colorectal cancer treatment and outcomes in the Veterans Affairs health care system

Lung cancer (LC) and colorectal cancer (CRC) are the second- and third-most commonly diagnosed cancers in the Veterans Affairs (VA) health care system. While many studies have evaluated the treatment quality and outcomes of various aspects of VA LC and CRC care, there are no known reviews synthesizing this information across studies. The purpose of this literature review was to describe LC and CRC treatment (ie, surgical and nonsurgical) and outcomes (eg, mortality, psychosocial, and other) in the VA health care system as reported in the existing peer-reviewed scientific literature. We identified potential articles through a search of published literature using the PubMed electronic database. Our search strategy identified articles containing Medical Subject Headings terms and keywords addressing veterans or veterans' health and LC and/or CRC. We limited articles to those published in the previous 11 years (January 1, 2003 through December 31, 2013). A total of 230 articles were retrieved through the search. After applying the selection criteria, we included 74 studies (34 LC, 47 CRC, and seven both LC and CRC). VA provides a full array of treatments, often with better outcomes than other health care systems. More work is needed to assess patient-reported outcomes.

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.

Paradoxical reaction to midazolam in patients undergoing endoscopy under sedation: Incidence, risk factors and the effect of flumazenil

BACKGROUND

The incidence, risk factors and management strategy of paradoxical reaction to midazolam during endoscopy are yet to be clarified.

METHODS

This single center prospective study included 4140 adult patients (2263 males, mean age of 57.7 ± 12.6) undergoing endoscopy under sedation with midazolam and pethidine between September 2011 and December 2011. The characteristics of patients with and without paradoxical reaction were compared. For patients who experienced paradoxical reaction and received flumazenil, their endoscopic images were reviewed to assess whether European Society of Gastrointestinal Endoscopy guidelines were met as quality indicator of endoscopy.

RESULTS

The incidence of paradoxical reaction was 1.4%. In multivariate analyses, male gender, unsuccessful sedation in previous endoscopy, upper endoscopy, higher dose of midazolam, and lower dose of pethidine were identified as independent risk factors for paradoxical reaction. Despite paradoxical reaction, endoscopic procedures were successfully completed in 93.3% of cases when flumazenil was administered. The rates of meeting quality indicator of endoscopy were 92.3% in patients receiving flumazenil for paradoxical reaction and 97.6% in patients without paradoxical reaction.

CONCLUSIONS

For patients with risk factors for paradoxical reaction, active use of pethidine with a dose reduction of midazolam might be helpful to prevent the occurrence of paradoxical reaction. Administration of flumazenil might be positively considered in cases of paradoxical reaction.

Effect of propofol anesthesia on force application during colonoscopy

BACKGROUND

Sedation is frequently used during colonoscopy to control patient discomfort and pain. Propofol is associated with a deeper level of sedation than is a combination of a narcotic and sedative hypnotic and, therefore, may be associated with an increase in force applied to the colonoscope to advance and withdraw the instrument.

OBJECTIVE

To compare force application to the colonoscope insertion tube during propofol anesthesia and moderate sedation.

DESIGN

An observational cohort study of 13 expert and 12 trainee endoscopists performing colonoscopy in 114 patients. Forces were measured by using the colonoscopy force monitor, which is a wireless, handheld device that attaches to the insertion tube of the colonoscope.

SETTING

Community ambulatory surgery center and academic gastroenterology training programs.

PATIENTS

Patients undergoing routine screening or diagnostic colonoscopy with complete segment force recordings.

MAIN OUTCOME MEASUREMENTS

Axial and radial forces and examination time.

RESULTS

Axial and radial forces increase and examination time decreases significantly when propofol is used as the method of anesthesia.

LIMITATIONS

Small study, observational design, nonrandomized distribution of sedation type and experience level, different instrument type and effect of prototype device on insertion tube manipulation.

CONCLUSIONS

Propofol sedation is associated with a decrease in examination time and an increase in axial and radial forces used to advance the colonoscope.

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

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

Patient-controlled analgesia with inhaled methoxyflurane versus conventional endoscopist-provided sedation for colonoscopy: a randomized multicenter trial

OBJECTIVE

Inhaled methoxyflurane (Penthrox, Medical Device International, Melbourne, Australia) has been used extensively in Australasia (Australia and New Zealand) to manage trauma-related pain. The aim is to evaluate the efficacy, safety, and outcome of Penthrox for colonoscopy.

DESIGN

Prospective randomized study.

SETTING

Three tertiary endoscopic centers.

PATIENTS

Two hundred fifty-one patients were randomized to receive either Penthrox (n = 125, 70 men, 51.4 ± 1.1 years old) or intravenous midazolam and fentanyl (M&F; n = 126, 72 men, 54.9 ± 1.1 years old) during colonoscopy.

MAIN OUTCOME MEASUREMENT

Discomfort (visual analogue scale [VAS] pain score), anxiety (State-Trait Anxiety Inventory Form Y [STAI-Y] anxiety score), colonoscopy performance, adverse events, and recovery time.

RESULTS

Precolonoscopy VAS pain and STAI-Y scores were comparable between the 2 groups. There were no differences between groups in (1) pain VAS or STAI Y-1 anxiety scores during or immediately after colonoscopy, (2) procedural success rate (Penthrox: 121/125 vs M&F: 124/126), (3) hypotension during colonoscopy (7/125 vs 8/126), (4) tachycardia (5/125 vs 3/126), (5) cecal arrival time (8 ± 1 vs 8 ± 1 minutes), or (6) polyp detection rate (30/125 vs 43/126). Additional intravenous sedation was required in 10 patients (8%) who received Penthrox. Patients receiving Penthrox alone had no desaturation (oxygen saturation [SaO(2)] < 90%) events (0/115 vs 5/126; P = .03), awoke quicker (3 ± 0 vs 19 ± 1 minutes; P < .001) and were ready for discharge earlier (37 ± 1 vs 66 ± 2 minutes; P < .001) than those receiving intravenous M&F.

LIMITATIONS

Inhaled Penthrox is not yet available in the United States and Europe.

CONCLUSIONS

Patient-controlled analgesia with inhaled Penthrox is feasible and as effective as conventional sedation for colonoscopy with shorter recovery time, is not associated with respiratory depression, and does not influence the procedural success and polyp detection.

Water-aided colonoscopy

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

BACKGROUND

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

OBJECTIVE

To investigate the application of WEC in such patients.

DESIGN

Prospective, randomized, controlled, patient-blinded study.

SETTING

Tertiary-care referral center in China.

PATIENTS

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

INTERVENTION

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

MAIN OUTCOME MEASUREMENTS

Cecal intubation rate.

RESULTS

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

LIMITATIONS

Single center; unblinded but experienced endoscopists.

CONCLUSION

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

CLINICAL TRIAL REGISTRATION NUMBER

NCT01485133.).

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

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

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

BACKGROUND

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

OBJECTIVE

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

DESIGN

This study was a randomized, controlled trial.

SETTING

This study was conducted at a nonacademic single center.

PATIENTS

Consecutive outpatients agreeing to start colonoscopy without premedication were included.

INTERVENTIONS

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

MAIN OUTCOME MEASURES

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

RESULTS

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

LIMITATIONS

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

CONCLUSIONS

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

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

AIM

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

METHOD

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

RESULTS

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

CONCLUSION

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

Predictive factors affecting cecal intubation failure in colonoscopy trainees

BACKGROUND

Successful cecal intubation (SCI) is not only a quality indicator but also an important marker in a colonoscopy trainee's progress. We conducted this study to determine factors predicting SCI in colonoscopy trainees, and to compare these factors before and after trainees achieve technical competence.

METHODS

Design of this study was a cross-sectional studies of two time series design for one year at a single center. From March 2011 to February 2012, a total 2,050 subjects who underwent colonoscopy by four first-year gastrointestinal fellows were enrolled at Christian hospital, Wonju, Republic of Korea. Four gastrointestinal fellows have filled out the colonoscopic documentation. Main outcome measurement was predictive factors affecting cecal intubation failure and learning curves.

RESULTS

Colonoscopy was successfully completed to the cecum in 1,720 patients (83.9%). Success rates gradually increased as trainees performed more colonoscopies: the rate of SCI was 62% in the first 50 cases, and grew to 93% by the 250th case. Logistic regression analysis of factors affecting cecal intubation failure showed that female gender, low BMI (BMI < 18.5 kg/m²), poor bowel preparation, and past history of stomach surgery were more often associated with cecal intubation failure, particularly before the trainees achieved technical competence.

CONCLUSION

Several patient characteristics were identified that may predict difficulty of cecal intubation in colonoscopy trainees. Particularly, low BMI, inadequate bowel cleansing, and previous stomach operation were predictors of cecal intubation failure before the trainees have reached technical competency. The results could be informative so that trainees enhance the success rate regarding better colonoscopy training programs.

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

BACKGROUND

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

OBJECTIVE

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

DESIGN

Randomized, controlled, double-blinded study.

SETTING

Outpatient endoscopy unit at an academic medical center.

PATIENTS

A total of 175 adults.

INTERVENTION

Elective outpatient sedated screening colonoscopies.

MAIN OUTCOME MEASUREMENTS

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

RESULTS

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

LIMITATIONS

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

CONCLUSION

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

Segmental increases in force application during colonoscope insertion: quantitative analysis using force monitoring technology

BACKGROUND

Colonoscopy is a frequently performed procedure that requires extensive training and a high skill level.

OBJECTIVE

Quantification of forces applied to the external portion of the colonoscope insertion tube during the insertion phase of colonoscopy.

DESIGN

Observational cohort study of 7 expert and 9 trainee endoscopists for analysis of colonic segment force application in 49 patients. Forces were measured by using the colonoscopy force monitor, which is a wireless, handheld device that attaches to the insertion tube of the colonoscope.

SETTING

Academic gastroenterology training programs.

PATIENTS

Patients undergoing routine screening or diagnostic colonoscopy with complete segment force recordings.

MAIN OUTCOME MEASUREMENTS

Axial and radial force and examination time.

RESULTS

Both axial and radial force increased significantly as the colonoscope was advanced from the rectum to the cecum. Analysis of variance demonstrated highly significant operator-independent differences between segments of the colon (zones) in all axial and radial forces except average torque. Expert and trainee endoscopists differed only in the magnitude of counterclockwise force, average push/pull force rate used, and examination time.

LIMITATIONS

Small study, observational design, effect of prototype device on insertion tube manipulation.

CONCLUSION

Axial and radial forces used to advance the colonoscope increase through the segments of the colon and are operator independent.

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

BACKGROUND

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

OBJECTIVE

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

DESIGN

Retrospective cohort study.

SETTING

Tertiary academic center.

PATIENTS

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

INTERVENTIONS

Colonoscopy with or without water immersion insertion.

MAIN OUTCOME MEASUREMENTS

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

RESULTS

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

LIMITATIONS

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

CONCLUSION

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

Water-aided colonoscopy: a systematic review

BACKGROUND

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

OBJECTIVE

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

DESIGN

Systematic review.

SETTING

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

PATIENTS

Patients undergoing colonoscopy.

INTERVENTION

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

MAIN OUTCOME MEASUREMENTS

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

RESULTS

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

LIMITATIONS

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

CONCLUSION

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

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

BACKGROUND

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

OBJECTIVE

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

DESIGN

Observational, performance improvement.

SETTING

Veterans Affairs outpatient endoscopy.

PATIENTS

Routine colonoscopy cases.

INTERVENTIONS

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

MAIN OUTCOME MEASURES

Loop formation based on a visual guide provided by Olympus.

RESULTS

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

LIMITATIONS

Colonoscopy method was not blinded and non randomized.

CONCLUSION

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

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

PURPOSE

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

HYPOTHESIS

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

METHODS

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

STATISTICS

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

RESULTS

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

CONCLUSION

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

The water exchange method for colonoscopy-effect of coaching

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

Unsedated colonoscopy: A neverending story

Although sedation and analgesia for patients undergoing colonoscopy is the standard practice in Western countries, unsedated colonoscopy is still routinely provided in Europe and the Far East. This variation in sedation practice relies on the different cultural attitudes of both patients and endoscopists across these countries. Data from the literature consistently report that, in unsedated patients, the use of alternative techniques, such as warm water irrigation or carbon dioxide insufflation, can allow a high quality and well tolerated examination.

A randomized comparison of ultrathin and standard colonoscope in cecal intubation rate and patient tolerance

BACKGROUND

Complete colonoscopy examination cannot be performed in as many as 10% of cases. The new 9.2-mm ultrathin colonoscope (UTC) with an extra bending section may improve procedure tolerance and allow improvement in colonoscopy completion rate compared with a 12.9-mm standard colonoscope (SC).

OBJECTIVE

To compare the performance of the 9.2-mm UTC with that of the 12.9-mm SC.

DESIGN

Prospective, randomized, controlled trial.

SETTING

Academic endoscopic unit.

PATIENTS

Subjects 18 years and older undergoing their first colonoscopy.

INTERVENTION

Subjects were randomized to either the UTC or SC group.

MAIN OUTCOME MEASUREMENTS

First and rescue successful cecal intubation rates, subject satisfaction scores, and sedation requirements were compared.

RESULTS

A total of 1121 patients (56% women, mean age 53.6 years) were randomized to the UTC group (n = 551) or the SC group (n = 570). There was no statistically significant difference in the first successful cecal intubation rate between the UTC and SC groups (98.9% vs 97.4%, P = .057). The mean (standard deviation) dose of midazolam and pethidine used was significantly lower in the UTC group (2.65 [0.65] mg vs 2.82 [0.85] mg, P < .001 and 27.6 [7.4] mg vs 29.7 [9.6] mg, P < .001, respectively). The mean (standard deviation) patient satisfaction score was similar between groups (6.99 [2.89] vs 7.04 [3.06], P = .762). Of the 21 patients (1.9%) with an incomplete initial colonoscopy (6 in the UTC group and 15 in the SC group), all 6 in the UTC group had their procedure completed with an SC. Eleven of 15 patients in the SC group had their procedures completed with a UTC in the same session.

LIMITATIONS

Low failure rate may mask any difference between the 2 colonoscopes as a rescue instrument.

CONCLUSIONS

The 9.2-mm UTC has performance characteristics similar to those of an SC in Chinese subjects undergoing their first colonoscopy performed by experienced and trainee endoscopists. (

CLINICAL TRIAL REGISTRATION NUMBER

NCT01142167.).

An effective instillation method for water-assisted colonoscopy as performed by in-training endoscopists in terms of volume and temperature

BACKGROUND AND STUDY AIMS

There is general consensus that water instillation helps insert a colonoscope. However, the most effective method for water instillation has not yet been established, especially for endoscopists-in-training. The aim of this study was to determine volume and temperature for effective water instillation colonoscopy.

PATIENTS AND METHODS

This is a prospective, randomized, controlled trial that was carried out at a single center, and a total of 207 consecutive subjects who underwent colonoscopic examination for health checkup were included in the study. Water instillation of supplied water was conducted under four different conditions: 100 and 300 ml at room temperature, 300 ml at 30 °C and no use of water instillation. The following parameters were recorded and analyzed: intubation success rate, independent predictors of successful intubation and intubation time to reach the cecum.

RESULTS

The intubation success rate was not significantly different between individual groups. Independent predictors of successful intubation were younger age (P = 0.004) and later examined subjects (P = 0.016). The 300-ml warm water instillation during colonoscopy significantly reduced intubation time over the conventional method without water instillation (P = 0.034).

CONCLUSIONS

Instillation of 300-ml warm (30 °C) water during colonoscopy can reduce cecal intubation time for in-training endoscopists without improving the intubation success rate.

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

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

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

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

Water infusion for cecal intubation increases patient tolerance, but does not improve intubation of unsedated colonoscopies

BACKGROUND & AIMS

Several studies have indicated that water infusion, instead of air insufflation, enhances cecal intubation in selected patients undergoing unsedated colonoscopy. We performed a prospective, randomized, controlled trial to investigate whether the water technique increases the proportion of patients that are able to complete unsedated colonoscopy.

METHODS

We analyzed data from 116 consecutive outpatients who were willing to start colonoscopy without sedation; 58 were each randomly assigned to groups given water infusion or air insufflation during the insertion phase. Sedation and analgesia were administered on demand.

RESULTS

Fewer patients requested sedation in the water group (8.6%) than in the air group (34.5%; P = .003) and their maximum pain scores were lower (2.8 ± 1.9 vs 4.2 ± 2.3 in the air group; P = .011). However, differences in percentages of patients who received complete, unsedated colonoscopy between the water group (74.1%) and air group (62.1%) did not reach statistical significance (P = .23); the percentage of successful cecal intubations was lower in the water group (82.8%) than in the air group (96.5%; P = .03) because of poor visibility. Failed procedures in the water group were completed successfully after air insufflation. The cecal intubation time was shorter in the air group (6.2 ± 3.4 min) than in the water group (8.1 ± 3.0 min; P = .01).

CONCLUSIONS

In patients willing to undergo unsedated colonoscopy, water infusion improves patient tolerance for cecal intubation, compared with air insufflation. However, it does not increase the overall percentage of successful cecal intubations because suboptimal bowel preparation interferes with visibility.