Research Progress of Bowel Preparation for Colonoscopy

Colorectal cancer ranks third in the global cancer data in 2020. Colorectal scope is the most effective method to diagnose colorectal diseases such as benign and malignant colorectal tumors. The poor quality of intestinal preparation causes an increased rate of missed diagnosis of colorectal tumors, reduces the rate of cecal intubation for colorectal examination, increases the discomfort, and reduces the compliance of re-examination. Therefore, we should try our best to improve the quality of intestinal preparation. This study reviewed the latest advances related to the preoperative preparation for colonoscopy. Recent research shows that smartphone apps can provide more detailed education and guidance on bowel preparation;Pre-packaged foods are more suitable as a way to eat before colonoscopy. The use of smaller doses, better taste of cathartic agents, and some auxiliary measures, combined with the patient’s situation to provide personalized intestinal preparation measures to improve the quality of intestinal preparation. Starting from the quality of colonoscopy bowel preparation, continuous improvement of patients’ tolerance to bowel preparation, continuous improvement of bowel preparation plan based on individual factors’ needs, and better communication with examined subjects by using existing scientific information technology, may be the hot spot of colonoscopy bowel preparation research in the next few years.

Evaluating bacterial contamination and surgical site infection risks in intracorporeal anastomosis: Role of bowel preparation

We recently read the study by Kayano et al on intracorporeal anastomosis(IA)for colon cancer,which assessed bacterial contamination and medium-term onco-logical outcomes and affirmed that IA is analogous to extracorporeal anastomosis in reducing intraperitoneal bacterial risk and achieving similar oncological results.Our commentary addresses gaps,particularly concerning bowel preparation and surgical site infections(SSIs),and highlights the need for comprehensive details on the bowel preparation methods that are currently employed,including mecha-nical bowel preparation,oral antibiotics(OA),their combination,and specific OA types.We emphasize the necessity for further analyses that investigate these me-thods and their correlation with SSI rates,to enhance clinical protocol guidance and optimize surgical outcomes.Such meticulous analyses are essential for refi-ning strategies to effectively mitigate SSI risk in colorectal surgeries.

Research Progress of Bowel Preparation for Colonoscopy

Colorectal cancer ranks third in the global cancer data in 2020.Colorectal scope is the most effective method to diagnose colorectal diseases such as benign and malignant colorectal tumors.The poor quality of intestinal preparation causes an increased rate of missed diagnosis of colorectal tumors,reduces the rate of cecal intubation for colorectal examination,increases the discomfort,and reduces the compliance of re-examination.Therefore,we should try our best to improve the quality of intestinal preparation.This study reviewed the latest advances related to the preoperative preparation for colonoscopy.Recent research shows that smartphone apps can provide more detailed education and guidance on bowel preparation;Pre-packaged foods are more suitable as a way to eat before colonoscopy.The use of smaller doses,better taste of cathartic agents,and some auxiliary measures,combined with the patient’s situation to provide personalized intestinal preparation measures to improve the quality of intestinal preparation.Starting from the quality of colonoscopy bowel preparation,continuous improvement of patients’tolerance to bowel preparation,continuous improvement of bowel preparation plan based on individual factors’needs,and better communication with examined subjects by using existing scientific information technology,may be the hot spot of colonoscopy bowel preparation research in the next few years.

Factors affecting the quality of bowel preparation for colonoscopy in hard-to-prepare patients:Evidence from the literature

Adequate bowel cleansing is critical for a high-quality colonoscopy because it affects diagnostic accuracy and adenoma detection.Nevertheless,almost a quarter of procedures are still carried out with suboptimal preparation,resulting in longer procedure times,higher risk of complications,and higher likelihood of missing lesions.Current guidelines recommend high-volume or low-volume polyethylene glycol(PEG)/non-PEG-based split-dose regimens.In patients who have had insufficient bowel cleansing,the colonoscopy should be repeated the same day or the next day with additional bowel cleansing as a salvage option.A strategy that includes a prolonged low-fiber diet,a split preparation regimen,and a colonoscopy within 5 h of the end of preparation may increase cleansing success rates in the elderly.Furthermore,even though no specific product is specifically recommended in the other cases for difficult-to-prepare patients,clinical evidence suggests that 1-L PEG plus ascorbic acid preparation are associated with higher cleansing success in hospitalized and inflammatory bowel disease patients.Patients with severe renal insufficiency(creatinine clearance<30 mL/min)should be prepared with isotonic high volume PEG solutions.Few data on cirrhotic patients are currently available,and no trials have been conducted in this population.An accurate characterization of procedural and patient variables may lead to a more personalized approach to bowel preparation,especially in patients undergoing resection of left colon lesions,where intestinal preparation has a poor outcome.The purpose of this review was to summarize the evidence on the risk factors influencing the quality of bowel cleansing in difficult-to-prepare patients,as well as strategies to improve colonoscopy preparation in these patients.

Bowel preparation experiences and needs before follow-up colonoscopy in older adult postoperative colorectal cancer patients: A qualitative study

BACKGROUND The bowel preparation process prior to colonoscopy determines the quality of the bowel preparation,which in turn affects the quality of the colonoscopy.Colono-scopy is an essential procedure for postoperative follow-up monitoring of colorec-tal cancer(CRC)patients.Previous studies have shown that advanced age and a history of colorectal resection are both risk factors for inadequate bowel prepara-tion.However,little attention has been paid to the bowel preparation experiences and needs of predominantly older adult postoperative CRC patients.AIM To explore the experiences and needs of older adult postoperative CRC patients during bowel preparation for follow-up colonoscopy.METHODS Fifteen older adult postoperative CRC patients who underwent follow-up colonoscopy at a tertiary hospital in Shanghai were selected using purposive sampling from August 2023 to November 2023.The phenomenological method in qualitative research was employed to construct an interview outline and conduct semi-structured interviews with the patients.Colaizzi's seven-step analysis was utilized to organize,code,categorize,summarize,and verify the interview data.RESULTS The results of this study were summarized into four themes and eight sub-themes:(1)Inadequate knowledge about bowel preparation;(2)Decreased physiological comfort during bowel preparation(gastrointestinal discomfort and sleep deprivation caused by bowel cleansing agents,and hunger caused by dietary restrictions);(3)Psychological changes during different stages of bowel preparation(pre-preparation:Fear and resistance due to previous experiences;during preparation:Irritation and helplessness caused by taking bowel cleansing agents,and post-preparation:Anxiety and worry while waiting for the colonoscopy);and(4)Needs related to bowel preparation(detailed instructions from healthcare professionals;more ideal bowel cleansing agents;and shortened waiting times for colonoscopy).CONCLUSION Older adult postoperative CRC patients'knowledge of bowel preparation is not adequate,and they may encounter numerous difficulties and challenges during the process.Healthcare professionals should place great emphasis on providing instruction for their bowel preparation.

Quality of bowel preparation in patients with inflammatory bowel disease undergoing colonoscopy:What factors to consider?

An adequate bowel preparation in patients with inflammatory bowel disease(IBD)is a prerequisite for successful colonoscopy for screening,diagnosis,and surveillance.Several bowel preparation formulations are available,both high-and low-volume based on polyethylene glycol.Generally,low-volume formulations are also based on several compounds such as magnesium citrate preparations with sodium picosulphate,oral sulphate solution,and oral sodium phosphatebased solutions.Targeted studies on the quality of bowel preparation prior to colonoscopy in the IBD population are still required,with current evidence from existing studies being inconclusive.New frontiers are also moving towards the use of alternatives to anterograde ones,using preparations based on retrograde colonic lavage.

Emerging space for non-polyethene-glycol bowel preparations in inflammatory bowel disease-related colonoscopy:Veering toward better adherence and palatability

Patients with inflammatory bowel diseases(IBDs)require repeated endoscopic evaluations over time by colonoscopy to weigh disease activity but also for different and additional indications(e.g.,evaluation of postoperative recurrence,colorectal cancer surveillance).Colonoscopy,however,requires adequate bowel preparation to be of quality.The latter is achieved as long as the patient takes a certain amount of product to have a number of bowel movements suitable to clean the colon and allow optimal visualization of the mucosa during endoscopy.However,significant guidelines recommend preparations for patients with IBD not excelling in palatability.This recommendation originates from the fact that most of the studies conducted on bowel preparations in patients with IBD have been done with isosmolar preparations based on polyethylene glycol(PEG),for which,therefore,more safety data exist.As a result,the low-volume non-PEG preparations(e.g.,magnesium citrate plus picosulphate,oral sulphate solutions)have been set aside for the whole range of warnings to be heeded because of their hyperosmolarity.New studies,however,are emerging,leaning in overall for a paradigm shift in this matter.Indeed,such non-PEG preparations seem to show a particularly encouraging and engaging safety profile when considering their broad potential for tolerability and patient preference.Indeed,such evidence is insufficient to indicate such preparations in all patients with IBD but may pave the way for those with remission or well-controlled disease.This article summarizes the central studies conducted in IBD settings using non-PEG preparations by discussing their results.

Impact of mechanical bowel preparation in elective colorectal surgery:A meta-analysis

AIM To analyse the effect of mechanical bowel preparation vs no mechanical bowel preparation on outcome in patients undergoing elective colorectal surgery.METHODS Meta-analysis of randomised controlled trials and observational studies comparing adult patients receiving mechanical bowel preparation with those receiving no mechanical bowel preparation, subdivided into those receiving a single rectal enema and those who received no preparation at all prior to elective colorectal surgery. RESULTS A total of 36 studies(23 randomised controlled trials and 13 observational studies) including 21568 patients undergoing elective colorectal surgery were included. When all studies were considered, mechanical bowel preparation was not associated with any significant difference in anastomotic leak rates(OR = 0.90, 95%CI: 0.74 to 1.10, P = 0.32), surgical site infection(OR = 0.99, 95%CI: 0.80 to 1.24, P = 0.96), intraabdominal collection(OR = 0.86, 95%CI: 0.63 to 1.17, P = 0.34), mortality(OR = 0.85, 95%CI: 0.57 to 1.27, P = 0.43), reoperation(OR = 0.91, 95%CI: 0.75 to 1.12, P = 0.38) or hospital length of stay(overall mean difference 0.11 d, 95%CI:-0.51 to 0.73, P = 0.72), when compared with no mechanical bowel preparation, nor when evidence from just randomized controlledtrials was analysed. A sub-analysis of mechanical bowel preparation vs absolutely no preparation or a single rectal enema similarly revealed no differences in clinical outcome measures. CONCLUSION In the most comprehensive meta-analysis of mechanical bowel preparation in elective colorectal surgery to date, this study has suggested that the use of mechanical bowel preparation does not affect the incidence of postoperative complications when compared with no preparation. Hence, mechanical bowel preparation should not be administered routinely prior to elective colorectal surgery.

Bisacodyl plus split 2-L polyethylene glycol-citrate-simethicone improves quality of bowel preparation before screening colonoscopy

AIM:To compare the bowel cleansing efficacy,tolerability and acceptability of split 2-L polyethylene glycol(PEG)-citrate-simethicone(PEG-CS)plus bisacodyl(BIS)vs 4-L PEG for fecal occult blood test-positive screening colonoscopy.METHODS:This was a randomised,observer-blind comparative study.Two hundred and sixty-four subjects underwent screening colonoscopy(mean age 62.5±7.4years,male 61.7%).The primary objective of the study was to compare the bowel cleansing efficacy of the two preparations.Interventions:BIS plus PEG-CS:3 tablets of 5-mg BIS at 16:00,PEG-CS 1-L at 19:00 and 1-L at7:00,4-L PEG:3-L at 17:00,and 1-L at 7:00.Colonoscopy was carried out after 11:00,at least 3 h after the completion of bowel preparation.Bowel cleansing was evaluated using the Harefield Cleansing Scale.RESULTS:Bowel preparation was successful for 92.8%of subjects in the PEG-CS group and for 92.1%of subjects in the 4-L PEG(RR=1.01;95%CI:0.94-1.08).BIS+PEG-CS was better tolerated than 4-L PEG.A greater rate of patients in the BIS+PEG-CS group had no difficulty and/or were willing to repeat the same preparation compared to split-dose 4-L PEG group.Subjects in the BIS+PEG-CS group rated the prep as good or satisfactory in 90.6%as compared to 77%in the 4-L PEG(P=0.003).Subjects receiving BIS+PEGCS stated they fully adhered to instructions drinking all the 2-L solution in 97.1%compared with 87.3%in the4-L PEG(P=0.003).CONCLUSION:BIS plus split 2-L PEG-CS was as effective as but better tolerated and accepted than split4-L PEG for screening colonoscopy.This new procedure may increase the positive attitude and participation to colorectal cancer screening colonoscopy.

Comparison of split-dosing vs non-split(morning) dosing regimen for assessment of quality of bowel preparation for colonoscopy

AIM: To compare(using the Ottawa Bowel Preparation Scale) the efficacy of split-dose vs morning administration of polyethylene glycol solution for colon cleansing in patients undergoing colonoscopy, and to assess the optimal preparation-to-colonoscopy interval.METHODS: Single-centre, prospective, randomized, investigator-blind stud in an academic tertiarycare centre. Two hundred patients requiring elective colonoscopy were assigned to receive one of the two preparation regimens(split vs morning) prior to colonoscopy. Main outcome measurements were bowel preparation quality and patient tolerability.RESULTS: Split-dose regimen resulted in better bowel preparation compared to morning regimen [Ottawascore mean 5.52(SD 1.23) vs 6.02(1.34); P = 0.017]. On subgroup analysis, for afternoon procedures, both the preparations were equally effective(P = 0.756). There was no difference in tolerability and compliance between the two regimens.CONCLUSION: Overall, previous evening- same morning split-dosing regimen results in better bowel cleansing for colonoscopy compared to morning preparation. For afternoon procedures, both schedules are equally effective; morning preparation may be more convenient to the patient.

Factors influencing quality of bowel preparation for colonoscopy

Recent technological advances in colonoscopy have led to improvements in both image enhancement and procedural performance.However,the utility of these technological advancements remain dependent on the quality of bowel preparation during colonoscopy.Poor bowel preparation has been shown to be associated with lower quality indicators of colonoscopy performance,such as reduced cecal intubation rates,increased patient discomfort and lower adenoma detection.The most popular bowel preparation regimes currently used are based on either Polyethylene glycol-electrolyte,a non-absorbable solution,or aqueous sodium phosphate,a lowvolume hyperosmotic solution.Statements from various international societies and several reviews have suggested that the efficacy of bowel preparation regimes based on both purgatives are similar,although patients' compliance with these regimes may differ somewhat.Many studies have now shown that factors other than the type of bowel preparation regime used,can influence the quality of bowel preparation among adult patients undergoing colonoscopy.These factors can be broadly categorized as either patient-related or procedure-related.Studies from both Asia and the West have identified patient-related factors such as an increased age,male gender,presence of co-morbidity and socioeconomic status of patients to be associated with poor bowel preparation among adults undergoing routine out-patient colonoscopy.Additionally,procedure-related factors such as adherence to bowel preparation instructions,timing of bowel purgative administration and appointment waiting times for colonoscopy are recognized to influence the quality of colon cleansing.Knowledge of these factors should aid clinicians in modifying bowel preparation regimes accordingly,such that the quality of colonoscopy performance and delivery of service to patients can be optimised.

Improving quality of colonoscopy by adding simethicone to sodium phosphate bowel preparation

AIM： To evaluate the effectiveness of simethicone in enhancing visibility and efficacy during colonoscopy.METHODS： A prospective, double-blind, randomized, placebo-controlled study was conducted. One hundred and twenty-four patients were allocated to receive 2 doses of sodium phosphate plus 240 mg of tablet simethicone or placebo as bowel preparation. Visibility was blindly assessed for the amount of air bubbles and adequacy of colon preparation. Total colonoscopic time, side effects of the medication, endoscopist and patient satisfaction were also compared.RESULTS： Sodium phosphate plus simethicone, compared to sodium phosphate plus placebo, improved visibility by diminishing air bubbles （100.00% vs 42.37%, P 〈 0.0002） but simethicone failed to demonstrate improvement in adequacy of colon preparation （90.16% vs 81.36%, P = 0.17）. Endoscopist and patient satisfaction were increased significantly in the simethicone group. However, there was no difference in the total duration of colonoscopy and side effects of the medication.CONCLUSION： The addition of simethicone is of benefit for colonoscopic bowel preparation by diminishing air bubbles, which results in enhanced visibility. Endoscopist and patient satisfaction is also increased.

Split-dose bowel preparation improves adequacy of bowel preparation and gastroenterologists' adherence to National Colorectal Cancer Screening and Surveillance Guidelines

AIM To quantify the impact of split-dose regimen on endoscopists' compliance with guideline recommendations for timing of repeat colonoscopy in patients with normal colonoscopy or 1-2 small polyps(< 10 mm).METHODS A retrospective chart review of all endoscopy reports was undertaken in average-risk individuals > 50 years old with a normal screening colonoscopy and 1-2 small polyps. Data were abstracted from two time periods, pre and post-split-dose bowel preparation institution. Main outcome measurements were recommendation for timing of repeat colonoscopy and bowel preparation quality. Bivariate analysis by χ~2 tests and Student's t-tests were performed to assess differences between the two cohorts. Multivariable logistic regression was used with guideline consistent recommendations as the dependent variables and an indicator for 2011 cohort as the primary predictor. RESULTS Four thousand two hundred and twenty-five patients were included in the study; 47.0%(1987) prior to the institution of split dose bowel preparation, and 53.0%(2238) after the institution of split dose bowel preparation. Overall, 82.2%(n = 3472) of the colonoscopies were compliant with guideline recommendations, with a small but significantly increased compliance rate in year 2011(83.7%) compared to year 2009(80.4%, P = 0.005), corresponding to an unadjusted odds ratio of 1.25(95%CI: 1.07-1.47; P = 0.005). Colonoscopies with either "Adequate" or "Excellent" had increased from 30.6% in year 2009 to 39.6% in year 2011(P < 0.001). However, there was no significant difference in poor/inadequate category of bowel preparation as there was a mild increase from 4.6% in year 2009 to 5.1% in year 2011(P = 0.50). CONCLUSION Split-dose bowel regimen increases endoscopists' compliance to guidelines in average-risk patients with normal colonoscopy or 1-2 small polyps.

Efficacy of 1.2L polyethylene glycol plus ascorbic acid for bowel preparations

BACKGROUND A low-volume polyethylene glycol(PEG) solution that combines ascorbic acid with PEG-based electrolyte solution(PEG-ASC) is gaining mainstream acceptance for bowel preparation due to reduced volume and improved taste.Although several reports showed that bowel preparation with PEG-ASC volume lower than 2.0 L with laxative agents could be an alternative to traditional preparation regimen, the cleansing protocols have not been fully investigated.AIM To evaluate the cleansing efficacy of 1.2 L PEG-ASC solution comparing with 2.0 L PEG electrolyte(PEG-ELS) for bowel preparations.METHODS A randomized, single-blinded, open-label, single-center, non-inferiority study was conducted. In total, 312 Japanese adult patients(aged > 18 years) who underwent colonoscopy were enrolled. Patients were randomly allocated to bowel lavage with either 1.2 L of PEG-ASC solution with at least 0.6 L of an additional clear fluid(1.2 L PEG-ASC group) or 2.0 L of PEG-ELS(PEG-ELS group). Then, 48 mg of sennoside was administered at bedtime on the day before colonoscopy, and the designated drug solution was administered at the hospital on the day of colonoscopy. Bowel cleansing was evaluated using the Boston Bowel Preparation Scale(BBPS). The volume of fluid intake and required time for bowel preparation were evaluated. Furthermore, compliance, patient tolerance,and overall acceptability were evaluated using a patient questionnaire, which was assessed using a visual analog scale.RESULTS In total, 291 patients(1.2 L PEG-ASC group, 148; PEG-ELS group, 143) completed the study. There was no significant difference in successful cleansing, defined as a BBPS score ≥ 2 in each segment, between the two groups(1.2 L PEG-ASC group, 91.9%; PEG-ELS group, 90.2%; 95%CI:-0.03-0.09). The required time for bowel preparation was significantly shorter(164.95 min ± 68.95 min vs 202.16 min± 68.69 min, P < 0.001) and the total fluid intake volume was significantly lower(2.23 L ± 0.55 L vs 2.47 L ± 0.56 L, P < 0.001) in the 1.2 L PEG-ASC group than in the PEG-ELS group. Palatability, acceptability of the volume of solution, and overall acceptability evaluated using a patient questionnaire, which was assessed by the visual analog scale, were significantly better in the 1.2 L PEG-ASC group than in the PEG-ELS group(7.70 cm ± 2.57 cm vs 5.80 cm ± 3.24 cm, P < 0.001). No severe adverse event was observed in each group.CONCLUSION The 1.2 L PEG-ASC solution was non-inferior to the 2.0 L PEG-ELS solution in terms of cleansing efficacy and had better acceptability among Japanese patients.

Magnesium citrate with a single dose of sodium phosphate for colonoscopy bowel preparation

AIM:To evaluate the efficacy and acceptability of magnesium citrate and a single dose of oral sodium phosphate(45 mL) solution for morning colonoscopy bowel preparation. METHODS:A total of 159 patients were randomly assigned to receive two split doses of 90 mg of sodium phosphate(GroupⅠ,n=79) or magnesium citrate(250 mL,the day before the procedure) followed by 45 mL of sodium phosphate(the day of procedure,GroupⅡ,n= 80) .The quality of bowel cleansing and the acceptability of each regimen were compared,including the satisfaction,taste,willing to repeat and adverse effects of each regimen. RESULTS:The quality of bowel cleansing of GroupⅡ was as good as that of GroupⅠ(An Aronchick scale score of good or excellent:70.9%vs 81.0%,respectively,P=0.34;the Ottawa system score:4.4±2.6 vs 3.8 ±3.0,respectively,P=0.76) .There was no statisticallysignificant difference between both groups with regard to acceptability,including the satisfaction,taste and willingness to repeat the regimen.A significantly greater number of older patients(over 65 years old) in Group Ⅱgraded the overall satisfaction as satisfactory(48.1% vs 78.1%,respectively;GroupⅠvs GroupⅡ,P=0.01) . There were no significant adverse reactions. CONCLUSION:Magnesium citrate and a single dose of sodium phosphate was as effective and tolerable as the conventional sodium phosphate regimen and is a satisfactory option.

Bowel preparation for colonoscopy using standard vs reduced doses of sodium phosphate: A single-blind randomized controlled study

AIM: To evaluate the efficacy of a colonoscopy prepa-ration that utilizes a reduced dose of sodium phosphate(NaP) and an adjunct.METHODS: Sixty-two patients requiring screening colonoscopies were studied. Each patient was randomly allocated to receive either 50 NaP tablets(50 g) or 30 NaP tablets(30 g) with 10 mL of 0.75% sodium pico-sulfate for bowel preparation. NaP was administered at a rate of five tablets(5 g) or three tablets(3 g) every 15 min with 200 mL of water, beginning five to six hours before colonoscopy. The sodium picosulfate was administered with 200 mL of water on the night before the procedure. Both groups were compared in term of the efficacies of colonic cleansing, the time required for completion of the bowel preparation, and acceptability of the preparation.RESULTS: Sixty patients(n = 30 for each group) were analyzed. The cleansing efficacy tended to be higher in the 30 g NaP plus sodium picosulfate group as as-sessed by the mean total Ottawa scale score(50 g NaP6.70 ± 1. 42 vs 30 g NaP plus sodium picosulfate 6.17 ± 1.18 P = 0.072). The mean time for bowel prepara-tion tended to be shorter in the 30 g NaP plus sodium picosulfate group(50 g NaP 189.9 ± 64.0 min vs 30 g NaP plus sodium picosulfate 161.8 ± 57.6 min, P = 0.065). There were no significant differences between the two groups in the acceptability of the preparations(50 g NaP 83.3% vs 30 g NaP plus sodium picosulfate 86.7%, P = 0.500). There were no adverse events re-lated to bowel preparation in either of the groups.CONCLUSION: The colonoscopy preparation that uti-lized 30 g NaP with sodium picosulfate was comparable to that utilizing 50 g NaP. This novel bowel preparation might be useful before colonoscopy.

Prospective evaluation of small bowel preparation with bisacodyl and sodium phosphate for capsule endoscopy

AIM： To determine the effect of Prepacol, a combination of sodium phosphate and bisacodyl, on transit and quality of capsule endoscopy （CE）. METHODS： Fivety two consecutive patients were included in this prospective study. CE was performed following a 12 h fasting period. Twenty six patients were randomized for additional preparation with Prepacol. The quality of CE was assessed separately for the proximal and the distal small bowel by 3 experienced endoscopists on the basis of a graduation which was initially developed with 20 previous CE. RESULTS： Preparation with Prepacol accelerated small bowel transit time （262 ± 55 rain vs 287 ± 97 min）, but had no effect on the quality of CE. Visibility was significantly reduced in the distal compared to the proximal small bowel. CONCLUSION： The significantly reduced visibility of CE in the distal small bowel allocates the need for a good preparation. Since Prepacol has no beneficial effect on CE the modality of preparation and the ideal time of application remains unclear. Further standardized examinations are necessary to identify sufficient preparation procedures and to determine the impact of the volume of the preparation solution.

Preoperative bowel preparation does not favor the management of colorectal anastomotic leak

BACKGROUND Controversy exists regarding the impact of preoperative bowel preparation on patients undergoing colorectal surgery. This is due to previous research studies,which fail to demonstrate protective effects of mechanical bowel preparation against postoperative complications. However, in recent studies, combination therapy with oral antibiotics(OAB) and mechanical bowel preparation seems to be beneficial for patients undergoing an elective colorectal operation.AIM To determine the association between preoperative bowel preparation and postoperative anastomotic leak management(surgical vs non-surgical).METHODS Patients with anastomotic leak after colorectal surgery were identified from the 2013 and 2014 Colectomy Targeted American College of Surgeons National Surgical Quality Improvement Program(ACS-NSQIP) database and were employed for analysis. Every patient was assigned to one of three following groups based on the type of preoperative bowel preparation: first groupmechanical bowel preparation in combination with OAB, second groupmechanical bowel preparation alone, and third group-no preparation.RESULTS A total of 652 patients had anastomotic leak after a colectomy from January 1,2013 through December 31, 2014. Baseline characteristics were assessed and found that there were no statistically significant differences between the three groups in terms of age, gender, race, American Society of Anesthesiologists score,and other preoperative characteristics. A χ~2 test of homogeneity was conducted and there was no statistically/clinically significant difference between the three categories of bowel preparation in terms of reoperation.CONCLUSION The implementation of mechanical bowel preparation and antibiotic use in patients who are going to undergo a colon resection does not influence the treatment of any possible anastomotic leakage.

Efficiency of bowel preparation for capsule endoscopy examination:A meta-analysis

Good preparation before endoscopic procedures is essential for successful visualization. The small bowel is difficult to evaluate because of its length and complex configuration. A meta-analysis was conducted of studies comparing small bowel visualization by capsule endoscopy with and without preparation. Medical data bases were searched for all studies investigating the preparation for capsule endoscopy of the small bowel up to July 31, 2007. Studies that scored bowel cleanness and measured gastric and small bowel transit time and rate of cecum visualization were included. The primary endpoint was the quality of bowel visualization. The secondary endpoints were transit times and proportion of examinations that demonstrated the cecum, with and without preparation. Meta-analysis was performed with StatDirect Statistical software, version 2.6.1 (http:// statsdirect.com). Eight studies met the inclusion criteria. Bowel visualization was scored as "good" in 78% of the examinations performed with preparation and 49% performed without (P < 0.0001). There were no significant differences in transit times or in the proportion of examinations that demonstrated the cecum with and without preparation. Capsule endoscopy preparation improves the quality of small bowel visualization, but has no effect on transit times, or demonstration of the cecum.

Efficacy and tolerability of high and low-volume bowel preparation compared:A real-life single-blinded large-population study

BACKGROUND Low-volume preparations for colonoscopy have shown similar efficacy compared to high-volume ones in randomized controlled trials(RCT).However,most RCTs do not provide data about clinical outcomes including lesions detection rate.Moreover,real-life comparisons are lacking.AIM To compare efficacy(both in terms of adequate bowel preparation and detection of colorectal lesions)and tolerability of a high-volume(HV:4 L polyethylene glycol,PEG)and a low-volume(LV:2 L PEG plus bisacodyl)bowel preparation in a real-life setting.METHODS Consecutive outpatients referred for colonoscopy were prospectively enrolled between 1 December 2014 and 31 December 2016.Patients could choose either LV or HV preparation,with a day-before schedule for morning colonoscopies and a split-dose for afternoon procedures.Adequate bowel preparation according to Boston Bowel Preparation Scale(BBPS),clinical outcomes including polyp detection rate(PDR),adenoma detection rate(ADR),advanced adenoma detection rate(AADR),sessile/serrated lesion detection rate(SDR)and cancer detection rate and self-reported tolerability of HV and LV were blindly assessed.RESULTS Total 2040 patients were enrolled and 1815(mean age 60.6 years,50.2%men)finally included.LV was chosen by 52%of patients(50.8%of men,54.9%of women).Split-dose schedule was more common with HV(44.7%vs 38.2%,P=0.005).High-definition scopes were used in 33.4%of patients,without difference in the two groups(P=0.605).HV and LV preparations showed similar adequate bowel preparation rates(89.2%vs 86.6%,P=0.098),also considering the two different schedules(HV split-dose 93.8%vs LV split-dose 93.6%,P=1;HV daybefore 85.5%vs LV day-before 82.3%,P=0.182).Mean global BBPS score was higher for HV preparations(7.1±1.7 vs 6.8±1.6,P<0.001).After adjustment for sex,age and indications for colonoscopy,HV preparation resulted higher in PDR[Odds ratio(OR)1.32,95%CI:1.07-1.63,P=0.011]and ADR(OR 1.29,95%CI 1.02–1.63,P=0.038)and comparable to LV in AADR(OR 1.51,95%CI 0.97-2.35,P=0.069),SDR and cancer detection rate.The use of standard-definition colonoscopes was associated to lower PDR(adjusted OR 1.59,95%CI:1.22-2.08,P<0.001),ADR(adjusted OR 1.71,95%CI:1.26–2.30,P<0.001)and AADR(adjusted OR 1.97,95%CI:1.09-3.56,P=0.025)in patients receiving LV preparation.Mean Visual Analogue Scale tolerability scored equally(7,P=0.627)but a≥75%dose intake was more frequent with LV(94.6%vs 92.1%,P=0.003).CONCLUSION In a real-life setting,PEG-based low-volume preparation with bisacodyl showed similar efficacy and tolerability compared to standard HV preparation.However,with higher PDR and ADR,HV should still be considered as the reference standard for clinical trials and the preferred option in screening colonoscopy,especially when colonoscopy is performed with standard resolution imaging.