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

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.

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.

WASh multicentre randomised controlled trial: water-assisted sigmoidoscopy in English NHS bowel scope screening

OBJECTIVES

The English Bowel Cancer Screening Programme invites 55 year olds for a sigmoidoscopy (Bowel Scope Screening (BSS)), aiming to resect premalignant polyps, thus reducing cancer incidence. A national patient survey indicated higher procedural pain than anticipated, potentially impacting on screening compliance and effectiveness. We aimed to assess whether water-assisted sigmoidoscopy (WAS), as opposed to standard CO₂ technique, improved procedural pain and detection of adenomatous polyps.

DESIGN

The WASh (Water-Assisted Sigmoidoscopy) trial was a multicentre, single-blind, randomised control trial for people undergoing BSS. Participants were randomised to either receive WAS or CO₂ from five sites across England. The primary outcome measure was patient-reported moderate/severe pain, as assessed by patients on a standard Likert scale post procedure prior to discharge. The key secondary outcome was adenoma detection rate (ADR). The costs of each technique were also measured.

RESULTS

1123 participants (50% women, mean age 55) were randomised (561 WAS, 562 CO₂). We found no difference in patient-reported moderate/severe pain between WAS and CO₂ (14% in WAS, 15% in CO2; p=0.47). ADR was 15% in the CO₂ arm and 11% in the WAS arm (p=0.03); however, it remained above the minimum national performance standard in both arms. There was no statistical difference in mean number of adenomas nor overall polyp detection rate. There was negligible cost difference between the two techniques.

CONCLUSION

In the context of enema-prepared unsedated screening sigmoidoscopies performed by screening-accredited endoscopists, no difference in patient-reported pain was seen when using either a CO₂ or WAS intubation technique.

TRIAL REGISTRATION NUMBER

ISRCTN81466870.

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.

Comparison of Detection Methods for Tracheoesophageal Fistulae With a Novel Method: Capnography With CO2 Insufflation

BACKGROUND

Tracheoesophageal fistulae (TEF) are difficult to detect and require a high index of suspicion. We hypothesized that capnography to identify a spike in end-tidal carbon dioxide (etCO2) during esophagoscopy with carbon dioxide (CO2) insufflation would facilitate TEF diagnosis because of gas passage from the esophagus to the trachea.

METHODS

Medical records of 42 consecutive cases of recurrent, acquired, or missed congenital TEF diagnosed between January 2015 and November 2019 that underwent esophagoscopy with CO2 insufflation were reviewed. A control cohort of 97 similarly endoscopically evaluated patients with surgical confirmation of absence of recurrent TEF (eg, patients undergoing posterior tracheopexy) was also collected. All patients underwent pre-operative esophagoscopy, bronchoscopy, and capnography; diagnostic abilities of various combinations of modalities for TEF identification were calculated.

RESULTS

Statistical analysis identified a maximum intra-esophagoscopy end-tidal CO2 level of 68 mmHg as the optimal discriminator between cases and controls, though in practice, we anecdotally find that recurrent TEFs typically permit rapid rise ≥90 mmHg. Increasing numbers of diagnostic modalities increased diagnostic sensitivity to detect recurrent TEF; the highest diagnostic sensitivity for TEF identification was achieved by the combination of intra-esophagoscopy fluoroscopy with bronchoscopy and capnography ≥68 mmHg (sensitivity = 88.1%). There were multiple cases of TEF (N = 7 for etCO2 ≥68 mmHg, N = 3 for etCO2 ≥90 mmHg) identified by capnography that were missed by esophagoscopy. There were 5 (for etCO2 ≥68 mmHg) or 6 (for etCO2 ≥90 mmHg) cases of recurrent TEF that were missed by all nonsurgical methods.

CONCLUSION

Attention to etCO2 during esophagoscopy with CO2 insufflation represents a simple, novel way to detect TEF. Identification of TEF remains challenging, though combinations of diagnostic modalities improve diagnostic sensitivity.

A meta-analysis of carbon dioxide versus room air insufflation on patient comfort and key performance indicators at colonoscopy

BACKGROUND

Carbon dioxide (CO₂) has been used as an alternative to air insufflation at endoscopy with good results; however, uptake of the technique has been poor, possibly due to perceived lack of outcome equivalency. This meta-analysis evaluates the effectiveness of CO₂ versus air in reducing pain post-colonoscopy and furthermore examines other key performance indicators (KPIs) such as sedative use, procedure times and polyp detection rates.

METHODS

This meta-analysis was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Pubmed, Pubmed Central, Embase and Cochrane Library were searched for randomized studies from 2004 to 2019, reporting outcomes for patients undergoing colonoscopy with air or CO₂ insufflation, who reported pain on a numerical or visual analogue scale (VAS). Results were reported as mean differences (MD) or pooled odds ratios (OR) with 95% confidence intervals (95% CI).

RESULTS

Of 3586 citations, 23 studies comprising 3217 patients were analysed. Patients undergoing colonoscopy with air insufflation had 30% higher intraprocedural pain scores than those receiving CO₂ (VAS 3.4 versus 2.6, MD -0.7, 95% CI - 1.4-0.0, p = 0.05), with a sustained beneficial effect amongst those in the CO₂ group at 30 min, 1-2-h and 6-h post procedure (MD - 0.8, - 0.6 and - 0.2, respectively, p < 0.001 for all), as well as less distension, bloating and flatulence (p < 0.01 for all). There were no differences between the two groups in KPIs such as the sedation required, procedure time, caecal intubation or polyp detection rates.

CONCLUSIONS

CO₂ insufflation improves patient comfort without compromising colonoscopic performance.

ASGE review of adverse events in colonoscopy

Colonoscopy is the most commonly performed endoscopic procedure and overall is considered a low-risk procedure. However, adverse events (AEs) related to this routinely performed procedure for screening, diagnostic, or therapeutic purposes are an important clinical consideration. The purpose of this document from the American Society for Gastrointestinal Endoscopy's Standards of Practice Committee is to provide an update on estimates of AEs related to colonoscopy in an evidence-based fashion. A systematic review and meta-analysis of population-based studies was conducted for the 3 most common and important serious AEs (bleeding, perforation, and mortality). In addition, this document includes an updated systematic review and meta-analysis of serious AEs (bleeding and perforation) related to EMR and endoscopic submucosal dissection for large colon polyps. Finally, a narrative review of other colonoscopy-related serious AEs and those related to specific colonic interventions is included.

The WASh Trial: water-assisted sigmoidoscopy in the English Bowel Scope Screening Programme: study protocol for a randomized multicenter trial

Background and study aims  The English National Bowel Scope Screening Programme (BSSP) invites 55-year-olds for a one-off, unsedated flexible sigmoidoscopy (FSIG). Data from BSSP participant-reported experience studies shows 1 in 3 participants report moderate or severe discomfort. Water-assisted colonoscopy (WAS) may improve participants' comfort. The primary objective of this study is to ascertain if post-procedural participant-assessed pain is reduced in WAS compared with carbon dioxide (CO 2 ) insufflation, in invitees undergoing FSIG in BSSP. Patients and methods  This is a multicenter, prospective, randomized, two-arm, single-blinded trial designed to evaluate the performance of WAS versus CO 2 insufflation in BSSP. Participants will be randomized to either CO 2 or WAS and will be asked to rate pain post-procedure. Key procedure-related data will be analyzed, including adenoma detection rates (ADR) and degree of sigmoid looping. A cost-effectiveness analysis of WAS versus CO 2 and a discrete choice experiment exploring preferences of participants for attributes of sigmoidoscopy will also be performed. Discussion  This is the first trial in the United Kingdom (UK) to investigate the effects of WAS in a screening setting. If the trial shows WAS either reduces pain or increases ADR, this may result in a practice change to implement WAS in screening and non-screening endoscopic practice directly impacting on 256,000 people a year who will undergo BSSP FSIG by 2020. Trial funding came from National Institute for Health Research (NIHR) Research for Patient Benefit (RfPB) supported by the NIHR Clinical Research Network. The trial is actively recruiting. ID: 35866 ISRCTN: 81466870.

Compared Abilities of Endoscopic Techniques to Increase Colon Adenoma Detection Rates: A Network Meta-analysis

BACKGROUND AND AIMS

Adenoma detection rate (ADR) is a quality metric for colorectal cancer screening. We performed a systematic review and network meta-analysis to assess the overall and comparative efficacies of different endoscopic techniques in adenoma detection.

METHODS

We performed a systematic review of published articles and abstracts, through March 15, 2018, to identify randomized controlled trials of adults undergoing colonoscopy that compared the efficacy of different devices in detection of adenomas. Our final analysis included 74 2-arm trials that comprised 44948 patients. These studies compared efficacies of add-on devices (cap, endocuff, endo-rings, G-EYE), enhanced imaging techniques (chromoendoscopy, narrow-band imaging, flexible spectral imaging color enhancement, blue laser imaging), new scopes (full-spectrum endoscopy, extra-wide-angle-view colonoscopy, dual focus), and low-cost optimizing existing resources (water-aided colonoscopy, second observer, dynamic position change), alone or in combination with high-definition colonoscopy or each other. Primary outcome was increase in ADR. We performed pairwise and network meta-analyses, and appraised quality of evidence using GRADE.

RESULTS

Low-cost optimizing existing resources (odds ratio [OR], 1.29; 95% CI,1.17-1.43), enhanced imaging techniques (OR,1.21; 95% CI, 1.09-1.35), and add-on devices (OR,1.18; 95% CI, 1.07-1.29) were associated with a moderate increase in ADR compared with high-definition colonoscopy; there was low to moderate confidence in estimates. Use of newer scopes was not associated with significant increases in ADR compared with high-definition colonoscopy (OR, 0.98; 95% CI, 0.79-1.21). In our comparative efficacy analysis, no specific technology for increasing ADR was superior to others. We did not find significant differences between technologies in detection of advanced ADR, polyp detection rate, or mean number of adenomas/patient.

CONCLUSIONS

In a network meta-analysis of published trials, we found that low-cost optimization of existing resources to be as effective as enhanced endoscopic imaging, or add-on devices, in increasing ADR during high-definition colonoscopy.

Inhibitory effect of lidocaine on colonic spasm during colonoscopy: A multicenter double-blind, randomized controlled trial

OBJECTIVES

Colonic spasm can interfere with colonoscopy, but antispasmodic agents can cause complications. This study aimed to assess the inhibitory effect of topical lidocaine compared with a placebo control.

METHODS

In five tertiary-care hospitals in Japan, 128 patients requiring endoscopic resection of a colorectal lesion were enrolled and randomly and double-blindly allocated to colonoscopy with topical administration of 2% lidocaine solution 20mL (LID, n = 64) or normal saline 20mL (control, n = 64). During colonoscopy, the assigned solution was applied with a spray catheter near the lesion and the area was observed for three minutes. primary endpoint was the inhibitory effect at three time-points (1, 2 and 3 minutes after dispersion), using a three-point scale (excellent, fair, poor). Secondary endpoints were rebound spasm and adverse events. All endpoints were scored in real time. Serum lidocaine levels were measured in 32 patients (LID 16, control 16).

RESULTS

There were no significant differences between groups in patient demographics. At all time-points, the proportion of patients with "excellent" scores was greater in LID group than control group, with significant differences observed at 2 minutes (p = 0.02) and 3 minutes (p = 0.02). In LID group, the rate of "excellent" scores increased by 12.5% at 2 minutes and was maintained at 3 minutes. Rebound spasm did not occur in LID group, compared with 15.6% of control group (p = 0.001). There were no adverse events in LID group. All serum lidocaine levels were below detectable levels.

CONCLUSIONS

Topical lidocaine is an effective and safe method for suppressing colorectal spasm during colonoscopy (UMIN000024733).

Carbon dioxide versus room air for colonoscopy in deeply sedated pediatric patients: a randomized controlled trial

Background and study aims  Use of carbon dioxide (CO ₂ ) instead of room air (RA) during colonoscopy in adults revealed significantly less flatulence and abdominal pain in several studies. The objectives of this study were to investigate the effects of CO ₂ usage on post-interventional pain, abdominal discomfort, abdominal girth, pCO ₂ levels, and narcotic requirement in deeply sedated pediatric patients. Patients and methods  A total of 97 children and adolescents aged 4 years to 17 years undergoing colonoscopy were randomized to RA or CO ₂ in a prospective, randomized, controlled trial. Age-appropriate pain scales assessed abdominal pain as primary outcome. In addition, abdominal girth, abdominal bloating, transcutaneous pCO ₂ , narcotic requirement to achieve deeply sedation, and post-procedural analgesic demand was analyzed in 73 patients. Results  Overall, significantly fewer patients reported bloating in the CO ₂ group ( P  = 0.0012). However, we observed only a trend to lower post-interventional pain ( P  = 0.15) and a lower pain score. There was no significant difference in transcutaneous pCO ₂ level and no adverse events occurred. Although there was no difference in the dosage of propofol and midazolam, we observed a significant increased necessity for use of synthetic opioids in the RA group to achieve optimal examination conditions ( P  = 0.023). Conclusions  The benefits using CO ₂ in colonoscopy of deeply sedated children predominate. In particular, CO ₂ insufflation may allow a less painful post-interventional time and it significantly reduces abdominal bloating. Moreover, with CO ₂ , significantly less additional opioids were used. Thus, CO ₂ insufflation can be considered as safe in deeply sedated patients as there was no relevant pulmonary CO ₂ retention observed. (DRKS00013914).

Water exchange colonoscopy increases adenoma detection rate: a systematic review with network meta-analysis of randomized controlled studies

BACKGROUND AND AIMS

Water-aided colonoscopy techniques, such as water immersion (WI) and water exchange (WE), have shown different results regarding adenoma detection rate (ADR). We determined the impact of WI and WE on ADR and other procedural outcomes versus gas (air, AI; CO₂) insufflation colonoscopy.

METHODS

A systematic search of multiple databases for randomized controlled trials comparing WI and/or WE with AI and/or CO₂ and reporting ADR was conducted. A network meta-analysis with mixed comparisons was performed. Primary outcome was ADR (overall, in the right side of the colon and by colonoscopy indication).

RESULTS

Seventeen randomized controlled trials (10,350 patients) were included. WE showed a significantly higher overall ADR versus WI (odds ratio [OR], 1.31; 95% credible interval [CrI], 1.12-1.55) versus AI (OR, 1.40; CrI, 1.22-1.62) versus CO₂ (OR, 1.48; 95% CrI, 1.15-1.86). WE achieved the highest ADR also in the right side of the colon and in colorectal cancer screening cases (both significant vs AI and WI) as well as in patients taking a split-dose preparation (significant vs all the other techniques). The Boston Bowel Preparation Scale cleanliness score (vs AI and WI) was significantly higher for WE. Both WI and WE showed increased proportion of unsedated examinations and decreased real-time insertion pain, with WE being the least-painful insertion technique. Withdrawal time was comparable across techniques, but WE showed the longest insertion time (3-5 additional minutes).

CONCLUSIONS

WE significantly increases overall ADR, ADR in screening cases, and in the right side of the colon; it also improves colon cleanliness but requires a longer insertion time.

Is water exchange superior to water immersion in detecting adenomas during colonoscopies? Results from a Bayesian network meta-analysis

AIM

Water-assisted colonoscopy (water exchange [WE] and water immersion [WI]) has been shown to improve the adenoma detection rate. However, few studies have compared these two methods head-to-head. Thus, we conducted a network meta-analysis to integrate both direct and indirect evidence comparing the effectiveness of these two procedures.

METHOD

We searched PubMed, Web of Science, and the Cochrane Central Register of Controlled Trials for original papers and abstracts published up to March 2018. Randomized controlled trials (RCTs) reporting data in accordance with the eligibility criteria were included in this study. We performed a Bayesian random effects network meta-analysis with mixed comparisons.

RESULTS

Twenty-nine studies (n = 11464 patients) including 6 direct and 23 indirect comparisons were included in this network meta-analysis. There was a statistically significant difference in the efficacy of adenoma detection when WE was compared with WI (risk ratio [RR]: 1.2, 95% credible interval [CrI]: 1.1-1.3), air insufflation (AI; RR: 1.3, 95% CrI: 1.1-1.4), and carbon dioxide (CO2) insufflation (RR: 1.2, 95% CrI: 1.1-1.5). The different methods were ranked in order from the most to least effective in adenoma detection as follows: WE, WI, AI, and CO2. Moreover, although there were no significant differences in pain scores, willingness to repeat, caecal intubation rate, or total procedure time between WI and WE colonoscopy, WE required a longer caecal intubation time than WI.

CONCLUSION

This network meta-analysis supposes that WE may be superior to WI in detecting adenomas during colonoscopies without affecting other technical features or patient acceptance.

Bayesian network meta-analysis: Efficacy of air insufflation, CO2 insufflation, water exchange, and water immersion in colonoscopy

BACKGROUND AND AIM

Colonoscopy is an excellent screening tool for colorectal cancer. There are four colonoscopy techniques: air insufflation, CO₂ insufflation, water exchange, and water immersion. Some studies reported that the latter three methods are better than the criterion standard (air insufflation), whereas some studies did not. In order to evaluate the efficacy of the four colonoscopy techniques, a network meta-analysis was carried out.

METHODS

We searched randomized controlled trials (RCT) published up to September 2017 from PubMed, Embase, Cochrane library, and Web of Science. Studies referencing the comparison between at least two of air insufflation, CO₂ insufflation, water exchange, and water immersion were selected. Primary outcomes included pain score during insertion, polyp detection rate, and adenoma detection rate, and secondary outcomes included cecal intubation time and cecal intubation rate. Mean differences or odds ratios and their corresponding 95% credible intervals were pooled with Bayesian modeling.

RESULTS

Forty RCT with 13 734 patients were included in this network meta-analysis. Our analysis showed that air insufflation had the highest pain score (surface under the cumulative ranking curve [SUCRA]: 98.8%) and the lowest detection rate of adenoma (SUCRA: 21.3%) and polyp (SUCRA: 16.8%). Water exchange had the lowest pain score (SUCRA: 1.1%) and highest detection rate of adenoma (SUCRA: 96.0%) and polyp (SUCRA: 98.9%), although it led to the longest cecal intubation time (SUCRA: 86.9%).

CONCLUSIONS

Air insufflation might be the most unsatisfactory colonoscopy. Meanwhile, water exchange might be the most efficient colonoscopy.

Use of warm carbon dioxide insufflators does not affect intra-colonic gas temperature and has no effect on polyp detection rate during colonoscopy - a randomized controlled trial

BACKGROUND AND STUDY AIMS

Methods to improve polyp detection during colonoscopy have been investigated, with conflicting results for warm water irrigation. Carbon Dioxide (CO ₂₎ warmed to 37 °C may have similar or more pronounced effects on bowel motility. This study aimed to assess whether warmed CO ₂ would improve polyp detection compared to room temperature air insufflation.

PATIENTS AND METHODS

 This was a double-blind, randomized controlled trial that enrolled 204 patients undergoing screening or surveillance outpatient colonoscopy. The primary outcome was polyp per patient detection rate. Secondary outcomes included adenoma per patient detection rates, bowel spasm, and patient comfort.

RESULTS

 The trial was terminated after an interim analysis determined futility. Between the warmed CO ₂ and room air groups, no significant differences were found in the per-colonoscopy polyp detection rate ( P  = 0.57); overall polyp detection rate ( P  = 0.69); or adenoma detection rates ( P  = 0.74). More patients in the room temperature group had lower spasm scores (p = 0.02); however, there was a trend towards greater patient comfort in the warmed CO ₂ group ( P  = 0.054). An ex-vivo study showed a significant difference between exiting CO ₂ temperature at the insufflator end vs. delivered CO ₂ temperature at the colonoscope tip end. The temperature of insufflation at the tip of the colonoscope was not different when using warmed vs. unwarmed insufflation ( P  = 0.62).

CONCLUSION

 When compared with room air insufflation, warmed CO ₂ insufflation did not affect polyp detection rates.

Comparison of carbon dioxide and air insufflation during consecutive EGD and colonoscopy in moderate-sedation patients: a prospective, double-blind, randomized controlled trial

BACKGROUND AND AIMS

Endoscopy is performed with air insufflation and is usually associated with abdominal pain. It is well recognized that carbon dioxide (CO₂) is absorbed more quickly into the body than air; however, to date, few studies have investigated the use of CO₂ insufflation during consecutive EGD and colonoscopy (CEC). Thus, this study evaluated the efficacy of CO₂ insufflation compared with air insufflation in CEC.

METHODS

From March 2014 to April 2016, a total of 215 consecutive patients were randomly assigned to receive CO₂ insufflation (CO₂ group, n = 108) or air insufflation (air group, n = 107). Abdominal pain after CEC was recorded on a visual analogue scale (VAS). The amount of sedatives administered, use of analgesics, polyp detection rate (PDR), adenoma detection rate (ADR), abdominal circumference, and adverse events were also analyzed.

RESULTS

Baseline patient characteristics were not significantly different between the groups. Abdominal pain on the VAS in the CO₂ group and air group 1 hour after CEC was, respectively, 13.8 and 20.1 (P = .010), 3 hours after CEC was 8.3 and 12.5 (P = .056), 6 hours after CEC was 3.5 and 5.3 (P = .246), and 1 day after CEC was 1.8 and 3.4 (P = .192). The dose of sedative administered, analgesic usage, PDR, ADR, and adverse events were not statistically different between the groups. However, the increase in abdominal circumference was significantly higher in the air group than in the CO₂ group.

CONCLUSIONS

CO₂ insufflation was superior to air insufflation with regard to the pain score on the VAS in the hour after CEC. (Clinical trial registration number: KCT0001491.).

Colonoscopy: Advanced and Emerging Techniques-A Review of Colonoscopic Approaches to Colorectal Conditions

A complete colonoscopy is key in the diagnostic and therapeutic approaches to a variety of colorectal diseases. Major challenges are incomplete polyp removal and missed polyps, particularly in the setting of a difficult colonoscopy. There are a variety of both well-established and newer techniques that have been developed to optimize polyp detection, perform complete polypectomy, and endoscopically treat various complications and conditions such as strictures and perforations. The objective of this article is to familiarize the colorectal surgeon with techniques utilized by advanced endoscopists.

Carbon Dioxide Versus Air Insufflation for Elective Colonoscopy: A Meta-Analysis and Systematic Review of Randomized Controlled Trials

AIMS AND OBJECTIVE

The aim of this study was to conduct a meta-analysis and systematic review of randomized controlled trials (RCTs) comparing 2 methods of colonic insufflation for elective colonoscopy, that is, carbon dioxide (CO2) or air, and to evaluate their efficiency, safety, and side effects.

MATERIALS AND METHODS

Prospective RCTs comparing CO2 versus air insufflation for colonic distension during colonoscopy were selected by searching PubMed, Medline, Embase, Science Citation Index, Current Contents, and the Cochrane Central Register of Controlled Trials published between January 1980 and October 2014. The outcome variables analyzed included procedural and immediate postprocedural pain (during, end, or within 15 min after procedure), early postprocedural pain (between 30 and 120 min), intermediate postprocedural pain (360 min) and late postprocedural pain (720 to 1140 min), cecal/ileal intubation rate, cecal/ileal intubation time, and total colonoscopy examination time. These outcomes were unanimously decided to be important as they influence the practical approach toward patient management within and outside of hospital. Random effects model was used to calculate the effect size of both binary and continuous data. Heterogeneity among the outcome variables of these trials was determined by the Cochran Q statistic and I2 index. The meta-analysis was prepared in accordance with PRISMA guidelines.

RESULTS

Twenty-four RCTs totaling 3996 patients (CO2=2017, Air=1979) were analyzed. Statistically significant differences for the pooled effect size were observed for procedural and immediate postprocedural pain [weighted mean difference (WMD)=0.49; 95% confidence interval (CI), 0.32, 0.73; P=0.0005], early postprocedural pain between 30 and 120 minutes (WMD=0.25; 95% CI, 0.12, 0.49; P<0.0001), intermediate postprocedural pain, that is, 360 minutes after completion (WMD=0.35; 95% CI, 0.23, 0.52; P<0.0001), and late postprocedural pain between 720 and 1440 minutes (WMD=0.53; 95% CI, 0.34, 0.84; P=0.0061). Comparable effects were noted for cecal/ileal intubation rate (WMD=0.86; 95% CI, 0.61, 1.22; P=0.3975), cecal/ileal intubation time (WMD=-0.64; 95% CI, -1.38, 0.09; P=0.0860), and total examination time (WMD=-0.20; 95% CI, -0.96, 0.57; P=0.6133).

CONCLUSIONS

On the basis of our meta-analysis and systematic review, we conclude that CO2 insufflation significantly reduces abdominal pain during and following the procedure lasting up to 24 hours. There is no difference in the cecal/ileal intubation rate and time and total examination time between the 2 methods. CO2 retention with CO2 insufflation during and after the colonoscopy shows inconsequential variation compared with air insufflation and has no adverse effect on patients. CO2 instead of air should be routinely utilized for colonoscopy.

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.

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

BACKGROUND & AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

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

BACKGROUND

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

OBJECTIVE

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

DESIGN

Patient-blinded, prospective, randomized, controlled trials.

SETTING

Two community hospitals in Italy.

PATIENTS

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

INTERVENTION

Colonoscopy with AI, WI, or WE.

MAIN OUTCOME MEASUREMENTS

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

RESULTS

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

LIMITATIONS

Unblinded colonoscopists.

CONCLUSION

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

Carbon dioxide insufflation vs conventional air insufflation for colonoscopy: a systematic review and meta-analysis of published randomized controlled trials

AIM

Conventional air insufflation (AI) may cause prolonged abdominal bloating, excessive abdominal pain and discomfort during colonoscopy. Carbon dioxide may be an acceptable alternative to avoid these complications. The object of this study was to evaluate systematically the effectiveness of carbon dioxide insufflation (CI) for colonoscopy compared with AI.

METHOD

Randomized controlled trials (RCTs) comparing the effectiveness of CI with that of AI during colonoscopy were retrieved from medical electronic databases and combined analysis was performed using the RevMan statistical package. The combined outcome of dichotomous and continuous variables was expressed as an odds ratio (OR) and standardized mean difference (SMD).

RESULTS

Twenty-one RCTs comprising 3607 patients were included in the study. There was statistically significant heterogeneity among included studies. CI showed a significant trend towards reduced procedural pain [SMD -1.34; 95% confidence interval (95% CI) -2.23 to -0.45; z = 2.96; P < 0.003] and also postprocedural pain at 1 h (SMD -1.11; 95% CI -1.83 to -0.38; z = 2.97; P < 0.003), 6 and 24 h (OR 0.44; 95% CI 0.23-0.85; z = 2.44; P < 0.01). CI was associated with faster caecal intubation (SMD -0.20; 95% CI -0.37 to -0.02; z = 2.23; P < 0.03) but the caecal intubation rate was similar (P = 0.59) in both colonic insufflation techniques .

CONCLUSION

CI seems to have clinical advantages over AI for colonoscopy with regard to pain during and after the procedure.

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.

Advances in colonoscopy

Colonoscopy with polypectomy has been established as the major prevention and detection strategy for colorectal cancer for over a decade. Over this period advances in colonoscopic imaging, polyp detection, prediction of histopathology and polypectomy techniques have all been seen; however, the true magnitude of the limitations of colonoscopy has only recently been widely recognized. The rate and location of missed or interval cancers after complete colonoscopy appears to be influenced by the operator-dependency of colonoscopy and failure of conventional practices to detect and treat adenomatous, and possibly more importantly, non-adenomatous colorectal cancer precursors. Consequently, studies that expand our understanding of these factors and advances that aim to improve colonoscopy, polypectomy, and cancer protection are of critical importance.

Endoscopic innovations to increase the adenoma detection rate during colonoscopy

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

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.

Comfort and safety of carbon dioxide-insufflating colonoscopy in patients with irritable bowel syndrome

AIM: To investigate the comfort and safety of carbon dioxide-insufflating colonoscopy in patients with irritable bowel syndrome (IBS).

METHODS: One hundred and twenty-eight IBS patients were included in this study. One hundred and thirty healthy volunteers who underwent physical examination in the outpatient department in the same period were used as controls. Both IBS patients and healthy controls were randomized into two groups to receive air and CO₂ insufflation, respectively. Patients' symptoms such as distension and pain were scored and compared using a 10-cm visual analog scale (VAS). P_ETCO₂ was measured immediately before the examination, when the endoscope reached the cecum, immediately, 5 and 15 min after the examination.

RESULTS: The mean severity of pain before the examination was higher in the IBS group than in the control group. For patients with IBS, the severity of symptoms was reduced earlier in the CO₂ group. There was no rise in the mean P_ETCO₂during and after colonoscopy in both groups.

CONCLUSION: CO₂ insufflation in colonoscopy is safe and effective for IBS patients.