AI-assisted capsule endoscopy reading in suspected small bowel bleeding: a multicentre prospective study.

BACKGROUND: Capsule endoscopy reading is time consuming, and readers are required to maintain attention so as not to miss significant findings. Deep convolutional neural networks can recognise relevant findings, possibly exceeding human performances and reducing the reading time of capsule endoscopy. Our primary aim was to assess the non-inferiority of artificial intelligence (AI)-assisted reading versus standard reading for potentially small bowel bleeding lesions (high P2, moderate P1; Saurin classification) at per-patient analysis. The mean reading time in both reading modalities was evaluated among the secondary endpoints. METHODS: Patients aged 18 years or older with suspected small bowel bleeding (with anaemia with or without melena or haematochezia, and negative bidirectional endoscopy) were prospectively enrolled at 14 European centres. Patients underwent small bowel capsule endoscopy with the Navicam SB system (Ankon, China), which is provided with a deep neural network-based AI system (ProScan) for automatic detection of lesions. Initial reading was performed in standard reading mode. Second blinded reading was performed with AI assistance (the AI operated a first-automated reading, and only AI-selected images were assessed by human readers). The primary endpoint was to assess the non-inferiority of AI-assisted reading versus standard reading in the detection (diagnostic yield) of potentially small bowel bleeding P1 and P2 lesions in a per-patient analysis. This study is registered with ClinicalTrials.gov, NCT04821349. FINDINGS: From Feb 17, 2021 to Dec 29, 2021, 137 patients were prospectively enrolled. 133 patients were included in the final analysis (73 [55%] female, mean age 66·5 years [SD 14·4]; 112 [84%] completed capsule endoscopy). At per-patient analysis, the diagnostic yield of P1 and P2 lesions in AI-assisted reading (98 [73·7%] of 133 lesions) was non-inferior (p<0·0001) and superior (p=0·0213) to standard reading (82 [62·4%] of 133; 95% CI 3·6-19·0). Mean small bowel reading time was 33·7 min (SD 22·9) in standard reading and 3·8 min (3·3) in AI-assisted reading (p<0·0001). INTERPRETATION: AI-assisted reading might provide more accurate and faster detection of clinically relevant small bowel bleeding lesions than standard reading. FUNDING: ANKON Technologies, China and AnX Robotica, USA provided the NaviCam SB system.

Pilot study on cultural and metagenomic analysis of bile and biliary stentslead to unveiling the key players in stent occlusion.

Endoscopic Retrograde Cholangio-Pancreatography (ERCP) with biliary stenting is a minimally invasive medical procedure employed to address both malignant and benign obstructions within the biliary tract. Benign biliary strictures (BBSs), typically arising from surgical interventions such as liver transplants and cholecystectomy, as well as chronic inflammatory conditions, present a common clinical challenge. The current gold standard for treating BBSs involves the periodic insertion of plastic stents at intervals of 3-4 months, spanning a course of approximately one year. Unfortunately, stent occlusion emerges as a prevalent issue within this treatment paradigm, leading to the recurrence of symptoms and necessitating repeated ERCPs. In response to this clinical concern, we initiated a pilot study, delving into the microbial composition present in bile and on the inner surfaces of plastic stents. This investigation encompassed 22 patients afflicted by BBSs who had previously undergone ERCP with plastic stent placement. Our preliminary findings offered promising insights into the microbial culprits behind stent occlusion, with Enterobacter and Lactobacillus spp. standing out as prominent bacterial species known for their biofilm-forming tendencies on stent surfaces. These revelations hold promise for potential interventions, including targeted antimicrobial therapies aimed at curtailing bacterial growth on stents and the development of advanced stent materials boasting anti-biofilm properties.

Endoscopic full-thickness resection vs. endoscopic submucosal dissection of residual/recurrent colonic lesions on scars: a retrospective Italian and Japanese comparative study.

BACKGROUND AND AIMS: Endoscopic treatment of recurrent/residual colonic lesions on scars is a challenging procedure. In this setting, endoscopic submucosal dissection (ESD) is considered the first choice, despite a significant rate of complications. Endoscopic full-thickness resection (eFTR) has been shown to be well-tolerated and effective for these lesions. The aim of this study is to conduct a comparison of outcomes for resection of such lesions between ESD and eFTR in an Italian and a Japanese referral center. METHODS: From January 2018 to July 2020, we retrospectively enrolled patients with residual/recurrent colonic lesions, 20 treated by eFTR in Italy and 43 treated by ESD in Japan. The primary outcome was to compare the two techniques in terms of en-bloc and R0-resection rates, whereas complications, time of procedure, and outcomes at 3-month follow-up were evaluated as secondary outcomes. RESULTS: R0 resection rate was not significantly different between the two groups [18/20 (90%) and 41/43 (95%); P= 0.66]. En-bloc resection was 100% in both groups. No significant difference was found in the procedure time (54 min vs. 61 min; P= 0.9). There was a higher perforation rate in the ESD group [11/43 (26%) vs. 0/20 (0%); P= 0.01]. At the 3-month follow-up, two lesions relapsed in the eFTR cohort and none in the ESD cohort (P= 0.1). CONCLUSION: eFTR is a safer, as effective and equally time-consuming technique compared with ESD for the treatment of residual/recurrent colonic lesions on scars and could become an alternative therapeutic option for such lesions.

Endoscopic powered resection device for residual colonic lesions: the first multicenter, prospective, international clinical study.

BACKGROUND AND AIMS: Endoscopic resection is standard treatment for adenomatous colorectal lesions. Depending on lesion morphology and resection technique, recurrence can occur. Scarred adenomas are challenging to resect and may require surgical management. This study evaluated the safety and effectiveness of an endoscopic powered resection (EPR) system for scarred adenomatous colorectal lesions. METHODS: This single-arm, prospective, multicenter study was conducted from January 2018 to January 2021 at 12 sites. Patients with persistent flat or sessile colorectal lesions were enrolled. Primary end points were technical success (the ability of the device to resect the lesion[s] without use of other resection devices without device-related serious adverse events [AEs]) and safety (the occurrence of AEs through 90 days). Secondary end points included endoscopic confirmation of resection completeness, occurrence of colon stenosis, disease persistence, and diagnostic value of resected specimens. RESULTS: Sixty-five patients were in the intention-to-treat/safety analysis population. Primary analysis was performed on 45 per-protocol (PP) patients with 48 lesions. All PP patients were solely treated by using the EPR device. Technical success was achieved in 44 (98%) patients. Three (5%) serious AEs occurred: 2 delayed self-limited bleeds and 1 perforation. Nonserious AEs included 4 (6%) cases of mild intraprocedural bleeding. Completeness of resection and histopathologic diagnosis of tissue specimens were achieved in all patients. Twenty-one (46.7%) patients had disease persistence after the first treatment, and there was no colon stenosis. CONCLUSIONS: EPR is safe and effective for benign, persistent, large (>20 mm), scarred colorectal adenomas and should be considered as an alternative treatment in lieu of surgery. A persistence rate of 46.7% indicates that >1 treatment is necessary for effective endoscopic treatment. (Clinical trial registration number: NCT04203667.).

Diagnostic accuracy and interobserver agreement of cholangioscopy for indeterminate biliary strictures: A single-center experience.

BACKGROUND AND STUDY AIMS: Characterization of indeterminate biliary strictures (IDBS) still represents a major challenge. Digital single-operator cholangioscopy (DSOC) could potentially overcome limits of conventional biopsy and brush sampling. The aim of this study was to compare diagnostic accuracy of visual evaluation and DSOC-guided biopsies to conventional trans-papillary sampling techniques and to evaluate the inter-observer agreement (IOA) on visual diagnosis. PATIENTS AND METHODS: All consecutive patients undergoing DSOC-guided biopsy after conventional sampling techniques for IDBS during a six-year period were retrospectively evaluated. Final diagnosis was based on histological evaluation of the surgical specimen if available or a clinical follow-up of at least 6 months. For IOA, 20-second DSOC clips were retrospectively reviewed by 6 experts and 6 trainees and classified according to the Monaco Classification. RESULTS: Thirty-five patients underwent DSOC for IDBS in the study period; 14 patients (F = 9) with a median age of 64 years (range 53-76) met the study aim. After DSOC, strictures location was changed in three patients (additional yield of 21.4 %). Intraductal DSOC-guided biopsy were technically successful in all cases, with an adequacy of 92.8 %. No adverse events were recorded. Final diagnosis was benign disease in five cases and cholangiocarcinoma in the others. For IOA, 29 videos were evaluated with almost perfect agreement for final diagnosis (kappa 0.871; agreement 93.1, p <0.001), although overall accuracy of DSOC visual finding was 73.6 % and 64.4 % for experts and trainees, respectively. CONCLUSIONS: DSOC could improve diagnostic accuracy for IDBS, since it showed high sensitivity for visual finding and high specificity for DSOC guided-biopsy. Visual diagnosis seems reliable for diagnosis using the Monaco Classification.

Management of Benign Biliary Stricture in Chronic Pancreatitis.

Endoscopic therapy is the first line of management for chronic pancreatitis (CP)-related benign biliary strictures. Multiple plastic stents (MPS) exchanged at regular intervals and temporary placement of fully covered self-expanding metal stents (FCSEMS) are preferred modalities of endotherapy. FCSEMS placement is non-inferior to MPS and requires fewer sessions of endoscopic retrograde cholangiopancreatography than MPS placement. The presence of head calcifications, severe CP, and length of stricture are predictors of failure or recurrence after endotherapy. Failure of endotherapy should be considered after 1 year when surgery should be considered.

Impact of Pregnancy on Weight Loss After Endoscopic Sleeve Gastroplasty.

PURPOSE: Obesity and pregnancy are strictly related: on the one hand, obesity-one of the most common comorbidities in women of reproductive age-contributes to infertility and obesity-related pregnancy complications, whereas pregnancy is a condition in which, physiologically, the pregnant woman undergoes weight gain. Endoscopic sleeve gastroplasty (ESG) may be used for the treatment of obesity in women of childbearing age. MATERIALS AND METHODS: A retrospective analysis was conducted to evaluate weight trajectories, the evolution of obesity-related comorbidities, and lifestyle modification in women who became pregnant after ESG. A comparison was made between childbearing-age women who became pregnant after ESG and non-pregnant women. RESULTS: A total of 150 childbearing-age women underwent ESG at a large tertiary medical center. Of these, 11 patients (33.4 ± 6.2 years) became pregnant after the procedure, following a mean time interval of 5.5 ± 3.9 months. Three women (two affected by polycystic ovary syndrome) reported difficulty getting pregnant before undergoing ESG. The mean preconception BMI was 31.9±4.0 kg/m2 (-7.24 ± 4.0 kg/m2 after ESG). Total body weight loss (TBWL, %) was 18.08 ± 8.00, 11.00 ± 11.08, and 12.08 ± 8.49, at the beginning of pregnancy, at the delivery, and at the first follow-up (19.6 ± 7.8 months after ESG). TBWL of at least 5% was achieved before pregnancy in all patients (73% reached a TBWL ≥ 10%). No significant differences in weight loss and QoL were found between the pregnancy and non-pregnancy groups up to 24 months after ESG. CONCLUSIONS: Endoscopic sleeve gastroplasty allows for adequate weight loss before and after pregnancy in patients with obesity.

Texture and color enhancement imaging versus high definition white-light endoscopy for detection of colorectal neoplasia: a randomized trial.

BACKGROUND: Texture and color enhancement imaging (TXI) was recently proposed as a substitute for standard high definition white-light imaging (WLI) to increase lesion detection during colonoscopy. This international, multicenter randomized trial assessed the efficacy of TXI in detection of colorectal neoplasia. METHODS: Consecutive patients aged ≥ 40 years undergoing screening, surveillance, or diagnostic colonoscopies at five centers (Italy, Germany, Japan) between September 2021 and May 2022 were enrolled. Patients were randomly assigned (1:1) to TXI or WLI. Primary outcome was adenoma detection rate (ADR). Secondary outcomes were adenomas per colonoscopy (APC) and withdrawal time. Relative risks (RRs) adjusted for age, sex, and colonoscopy indication were calculated. RESULTS: We enrolled 747 patients (mean age 62.3 [SD 9.5] years, 50.2 % male). ADR was significantly higher with TXI (221/375, 58.9 %) vs. WLI (159/372, 42.7 %; adjusted RR 1.38 [95 %CI 1.20-1.59]). This was significant for ≤ 5 mm (RR 1.42 [1.16-1.73]) and 6-9 mm (RR 1.36 [1.01-1.83]) adenomas. A higher proportion of polypoid (151/375 [40.3 %] vs. 104/372 [28.0 %]; RR 1.43 [1.17-1.75]) and nonpolypoid (136/375 [36.3 %] vs. 102/372 [27.4 %]; RR 1.30 [1.05-1.61]) adenomas, and proximal (143/375 [38.1 %] vs. 111/372 [29.8 %]; RR 1.28 [1.05-1.57]) and distal (144/375 [38.4 %] vs. 98/372 [26.3 %]; RR 1.46 [1.18-1.80]) lesions were found with TXI. APC was higher with TXI (1.36 [SD 1.79] vs. 0.89 [SD 1.35]; incident rate ratio 1.53 [1.25-1.88]). CONCLUSIONS: TXI increased ADR and APC among patients undergoing colonoscopy for various indications. TXI increased detection of polyps < 10 mm, both in the proximal and distal colon, and may help to improve colonoscopy quality indicators.

Global prospective case series of ERCPs using a single-use duodenoscope.

BACKGROUND: The first commercialized single-use duodenoscope was cleared by the US Food and Drug Administration in December 2019. Data regarding endoscopic retrograde cholangiopancreatography (ERCP) using a single-use duodenoscope are needed on a broader range of cases conducted by endoscopists with varying levels of experience in a wide range of geographic areas. METHODS: 61 endoscopists at 22 academic centers in 11 countries performed ERCP procedures in adult patients aged ≥ 18. Outcomes included ERCP completion for the intended indication, rate of crossover to a reusable endoscope, device performance ratings, and serious adverse events (SAEs). RESULTS: Among 551 patients, 236 (42.8 %) were aged > 65, 281 (51.0 %) were men, and 256 (46.5 %) had their procedure as an inpatient. ERCPs included 196 (35.6 %) with American Society for Gastrointestinal Endoscopy complexity of grades 3-4. A total of 529 ERCPs (96.0 %) were completed: 503 (91.3 %) using only the single-use duodenoscope, and 26 (4.7 %) with crossover to a reusable endoscope. There were 22 ERCPs (4.0 %) that were not completed, of which 11 (2.0 %) included a crossover and 11 (2.0 %) were aborted cases (no crossover). Median ERCP completion time was 24.0 minutes. Median overall satisfaction with the single-use duodenoscope was 8.0 (scale of 1 to 10 [best]). SAEs were reported in 43 patients (7.8 %), including 17 (3.1 %) who developed post-ERCP pancreatitis. CONCLUSIONS: In academic medical centers over a wide geographic distribution, endoscopists with varying levels of experience using the first marketed single-use duodenoscope had good ERCP procedural success and reported high performance ratings for this device.

Clinical outcomes of endoscopic submucosal dissection for giant rectal tumors larger than 8 cm: A European referral center experience.

BACKGROUND AND AIMS: To date, western data on colorectal ESD are limited. This study aimed to assess the efficacy and safety of rectal ESD for superficial lesions ≥ 8 cm. METHODS: A total of 138 superficial rectal neoplasms treated by ESD were allocated in two groups: 25 in the "giant" ESD group and 113 in the control group. RESULTS: En bloc resection was achieved in 96% of cases in both groups. En bloc R0 resection rate was similar between the "giant" ESD group and the control group (84% vs 86%; p: 0.5) and curative resection was higher in the control group (81%) than in "giant" ESD group (68%) without reaching statistical significance (p: 0.2). Dissection time was significantly longer in the "giant" ESD group (251 vs 108 min; p <0.001), however, dissection speed was significantly higher (0.35 vs 0.17 cm2/min; p: 0.02).). Post-ESD stenosis was observed in 2 patients from the "giant" ESD group (8% vs 0% of control group, p: 0.03). No significant differences were found in delayed bleeding, perforation, local recurrences, and need for additional surgery. CONCLUSIONS: ESD for superficial rectal tumors ≥ 8 cm is a feasible, safe, and effective therapeutic option.

Face and content validity of a biological papilla designed for the Boskoski-Costamagna ERCP simulator.

BACKGROUND AND AIMS: A biological papilla made of chicken heart tissue, incorporated into the Boskoski-Costamagna ERCP Trainer simulator, was recently designed to allow training in sphincterotomy. This study aimed to evaluate the face and content validity of this tool. METHOD: Participants from 2 groups (nonexperienced and experienced [<600 or >600 lifetime ERCPs, respectively]) were invited to perform standardized assignments on the model: sphincterotomy and precut for both groups and papillectomy for the experienced group. Following these assignments, all participants filled out a questionnaire to rate their appreciation of the realism of the model, and experienced endoscopists were also asked to evaluate its didactic value using a 5-point Likert scale. RESULTS: A total of 19 participants were included (nonexperienced, n = 10; experienced, n = 9). Parameters regarding the realism of the tool in terms of general appearance, sphincterotomy, precut, and papillectomy were overall considered realistic (4 of 5), with good agreement rates in terms of overall realism between groups. Experienced operators reported the highest realism for "positioning the scope and needle-knife in the field of view" and "during precut," "cutting in small increments during precut," and "controlling the scope during papillectomy," and they highly agreed that this papilla should be included for training novice and intermediate trainees in sphincterotomy, precut, and papillectomy. CONCLUSIONS: Our results show good face validity and excellent content validity of this biological papilla combined with the Boskoski-Costamagna ERCP Trainer. This new tool provides a useful, inexpensive, versatile, and easy tool for training regarding sphincterotomy, precut, and papillectomy. Future studies should explore whether including this model in real-life training improves the learning curve of endoscopy trainees.

Safety and efficacy of endoscopic ultrasound-guided radiofrequency ablation for pancreatic insulinoma: A single-center experience.

BACKGROUND/OBJECTIVES: Insulinomas are rare, functioning pancreatic neuroendocrine neoplasms (pNEN), whose gold standard therapy is surgical resection. Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) is a recent technique that has emerged as a minimally invasive therapeutic option for patients with pancreatic lesions not eligible for surgery. In this study, we aimed to describe a series of patients with unresectable pancreatic insulinoma treated with EUS-RFA. METHODS: This is a single-center, retrospective study including all consecutive patients with functioning pancreatic insulinoma undergoing EUS-RFA for surgical unfitness or surgery refusal, between March 2017 and September 2021. Technical success (i.e., complete mass ablation), adverse event rate and severity, clinical and radiologic outcomes (i.e., symptom remission with a normal concentration of blood glucose, and the presence of intralesional necrosis), and post-procedural follow-up were assessed. RESULTS: A total of 10 patients (mean age: 67.1 ± 10.1years; F:M 7:3) were included. The mean size of insulinoma was 11.9 ± 3.3 mm. Technical success and clinical remission were achieved in 100% of patients. Only one (10%) patient was successfully treated with two RFA sessions. Two procedure-related early adverse events occurred, including two (20%) cases of mild abdominal pain. No major complications were observed. The complete radiologic response within 3 months after EUS-RFA was observed in all patients (100%). After a median follow-up of 19.5 (range12-59) months, symptom remission and persistent euglycemia were assessed in all the patients. CONCLUSIONS: Data from this case series suggest that EUS-RFA is a feasible and safe therapeutic approach for pancreatic insulinomas in patients unwilling or unable to undergo surgery with medium-term efficacy.

Cost-effectiveness Analysis of Radiofrequency Ablation in Patients With Barrett Esophagus and High-grade Dysplasia or Low-grade Dysplasia.

PURPOSE: Clinical guidelines recommend radiofrequency ablation (RFA) for eradication of Barrett esophagus in patients with low-grade dysplasia (LGD) and high-grade dysplasia (HGD), but evidence on whether RFA provides good value for money is still sparse. This study evaluates the cost-effectiveness of RFA in Italy. METHODS: A Markov model was used to estimate lifelong costs and consequences of disease progression with different treatments. RFA was compared with esophagectomy in the HGD group or endoscopic surveillance in the LGD group. Clinical and quality-of-life parameters were derived from a review of the literature and expert opinions, whereas Italian national tariffs were used as a proxy for costs. FINDINGS: RFA dominated esophagectomy in patients with HGD with a probability of 83%. For patients with LGD, RFA was more effective and more costly than active surveillance (incremental cost-effectiveness ratio, €6276 per quality-adjusted life-year). At a cost-effectiveness threshold of €15,272, the probability of RFA being the optimal strategy in this population was close to 100%. Model results were sensitive to the cost of the interventions and utility weights used in the different disease states. IMPLICATIONS: RFA is likely to be the optimal choice for patients with LGD and HGD in Italy. Italy is discussing the implementation of a national program for the health technology assessment of medical devices, requiring more studies to prove value for money of emerging technologies.

Long versus short peroral endoscopic myotomy for the treatment of achalasia: results of a non-inferiority randomised controlled trial.

OBJECTIVE: Peroral endoscopic myotomy (POEM) has become standard treatment for achalasia with comparable efficacy to surgery. In most of published series, the length of myotomy is 12-13 cm. Shorter cuts could have the advantage of shorter procedure time and possibly reduced gastro-oesophageal reflux disease (GORD) rate. DESIGN: This single-centre, patient-blinded, randomised, non-inferiority clinical trial included 200 patients, who were randomly allocated, to receive either a long-POEM (13 cm; 101 patients) or a short-POEM (8 cm; 99 patients). Primary outcome was defined as an Eckardt symptom score of ≤3 at 24 months after the procedure; a non-inferiority design was chosen with an accepted success range of 6% between the two treatments. Secondary outcomes included operating time, complication rate, postoperative manometry, GORD rate and quality of life. RESULTS: In the intention-to-treat analysis, clinical success rates were 89.1% in the long-POEM and 98.0% in the short-POEM group, resulting in an absolute between-group difference of -8.9% (90% CI -14.5 to -3.3).Procedure time was significantly reduced in the short-POEM as compared with the long-POEM group (40 vs 50 min, p<0.0001). Severe adverse events occurred in one patient in both groups.No differences were observed in postoperative GORD: acid exposure >6% on pH monitoring study at 6 months was seen in 34.3% (long-POEM) vs 31.1% (short-POEM), while endoscopic oesophagitis was diagnosed in 37.6% vs 51.5% at 6 months and in 21% vs 24.5% at 24 months. Regular proton pump inhibitor use was not different either (36.8% vs 37.5%). CONCLUSIONS: Our study demonstrates non-inferiority of a shorter cut length of POEM as compared with the standard treatment, which saved some procedural time. GORD rate was not reduced by reducing cutting length. TRIAL REGISTRATION NUMBER: NCT03450928.

Prevention of post-ERCP pancreatitis: current strategies and novel perspectives.

Endoscopic retrograde cholangiopancreatography (ERCP) is an advanced endoscopic procedure that might lead to severe adverse events. Post-ERCP pancreatitis (PEP) is the most common post-procedural complication, which is related to significant mortality and increasing healthcare costs. Up to now, the prevalent approach to prevent PEP consisted of employing pharmacological and technical expedients that have been shown to improve post-ERCP outcomes, such as the administration of rectal nonsteroidal anti-inflammatory drugs, aggressive intravenous hydration, and the placement of a pancreatic stent. However, it has been reported that PEP originates from a more complex interaction of procedural and patient-related factors. Appropriate ERCP training has a pivotal role in PEP prevention strategy, and it is not a chance that a low PEP rate is universally considered one of the most relevant indicators of proficiency in ERCP. Scant data on the acquisition of skills during the ERCP training are currently available, although some efforts have been recently done to shorten the learning curve by way of simulation-based training and demonstrate competency by meeting technical requirements as well as adopting skill evaluation scales. Besides, the identification of adequate indications for ERCP and accurate pre-procedural risk stratification of patients might help to reduce PEP occurrence regardless of the endoscopist's technical abilities, and generally preserve safety in ERCP. This review aims at delineating current preventive strategies and highlighting novel perspectives for a safer ERCP focusing on the prevention of PEP.

Factors influencing the presence of potentially explosive gases during colonoscopy: Results of the SATISFACTION study.

This study tested the hypothesis that bowel preparation with mannitol should not affect the colonic concentration of H2 and CH4 . Therefore, the SATISFACTION study, an international, multicenter, randomized, parallel-group phase II-III study investigated this issue. The phase II dose-finding part of the study evaluated H2 , CH4 , and O2 concentrations in 179 patients randomized to treatment with 50 g, 100 g, or 150 g mannitol. Phase III of the study compared the presence of intestinal gases in 680 patients randomized (1:1) to receive mannitol 100 g in single dose or a standard split-dose 2 L polyethylene glycol (PEG)-Asc preparation (2 L PEG-Asc). Phase II results showed that mannitol did not influence the concentration of intestinal gases. During phase III, no patient in either group had H2 or CH4 concentrations above the critical thresholds. In patients with H2 and/or CH4 levels above detectable concentrations, the mean values were below the risk thresholds by at least one order of magnitude. The results also highlighted the effectiveness of standard washing and insufflation maneuvers in removing residual intestinal gases. In conclusion, bowel cleansing with mannitol was safe as the concentrations of H2 and CH4 were the same as those found in patients prepared with 2 L PEG-Asc. In both groups, the concentrations of gases were influenced more by the degree of cleansing achieved and the insufflation and washing maneuvers performed than by the preparation used for bowel cleansing. The trial protocol was registered with ClinicalTrials.gov (https://clinicaltrials.gov/ct2/show/NCT04759885) and with EudraCT (eudract_number: 2019-002856-18).