Research On Hydrogen Breath Test To Predict The Quality Of Bowel Preparation For Colonoscopy

BackgroundAdequate bowel preparation is essential to high-quality colonoscopy.However,up to20%-25%of all colonoscopies have inadequate bowel preparation in patients undergoing colonoscopy.Inadequate bowel preparation can lead to increased difficulty in colonoscopy,prolonged procedural time,and even missed colorectal lesions.In clinical practice,we often ask patients to describe the appearance of their last rectal effluents as a means of predicting bowel preparation before colonoscopy,but previous studies have suggested that patient self-assessment of bowel preparation is not reliable.Hydrogen breath test?HBT?has been used as noninvasive and inexpensive indicators of orocecal transit time?OCTT?,small intestinal bacterial overgrowth?SIBO?,and carbohydrate malabsorption.Due to bowel preparation,the increased volume of fluids flushes out the luminal bacteria,and depletes the substrates fermentable by hydrogen?H₂?-producing colonic microbiota,resulting in a decrease of the hydrogen concentration in exhaled air.Inulin,a well-known prebiotic,can not be absorbed in the intestine,but can be decomposed by bacteria in the colon.Its osmotic pressure is low,so it has no obvious effect on intestinal motility and does not affect OCTT.Thus,inulin has recently been suggested as substrate for the HBT.ObjectiveTo compare H₂ concentration in breath of patients with different bowel preparation quality,and additionally,to evaluate the clinical value of hydrogen breath test in predicting the quality of bowel preparation for colonoscopy with oral supplementation of inulin.MethodsBetween December 2015 and January 2016,patients undergoing colonoscopy at Endoscopy Center of the Department of Gastroenterology,Nanjing General Hospital of Nanjing Military Region,were included in this study.Inclusion criteria:?1?18 to 65 years old,male or female;?2?patients scheduled for selective colonoscopy;?3?patients providing written informed consent.Exclusion criteria:?1?had undergone colonoscopy in 4 weeks;?2?had been under treatments with drugs known to influence intestinal microbiota or gastrointestinal motility such as antibiotics,probiotics,laxatives,prokinetic agents;?3?renal insufficiency?creatinine clearance<60 mL/min/1.73 m²?,congestive heart failure?New York heart Association functional class,III or IV?,cirrhosis,patients with peritoneal fluid and electrolyte disorders,inflammatory bowel disease and other diseases;?4?suspected obstruction or stenosis of the intestine,intestinal perforation;?5?history of gastrointestinal surgery;?6?mental illness or cognitive impairment;?7?diabetes mellitus,thyroid diseases;?8?pregnant and lactating women;?9?known to the hypersensitivity to any component of drug used in this study;?10?be participating in other clinical trials or observation in 60days.All patients,limited to low-residue foods the day before colonoscopy,drank 90ml?2bottles?NaP solution with split-dose as bowel preparation for colonoscopy,also ingested10g inulin?dissolved in 50 ml of water?as an additional substrate and 30ml simethicone with the second dose.Measurements of H₂ breath levels,of the gas exhaled by the patient,were performed at the time of appointment for colonoscopy and 5 minutes before colonoscopy.The Rome Consensus Guidelines for gastrointestinal diseases were used to perform the H2 breath testing.The subjects were asked to stop the treatment with drugs known to influence intestinal microbiota or gastrointestinal motility such as antibiotics,laxatives,prokinetic agents,probiotics 4 weeks before the breath test,and sedative hypnotics 24 hours before the test.The ingestion of foods with non-absorbable carbohydrate such as soy,potatoes,oats,wheat bran products,corn,fruit,milk and dairy products,coffee,tea,jam and other food should be avoided.Hence,a restricted diet,containing only rice and meat is suggested.Smoking,physical exercise,and eating were not allowed 2 h before and during breath samplings,and a thorough mouthwash was performed before the breath test to prevent oropharyngeal fermentation of sugars by local microflora.The subjects were required to avoid deep inspiration or hyperventilation before exhalation so alveolar air could be collected by the two-bag system.All colonoscopies were performed at 2:00 PM.As the main outcome measure,the quality of the colonic preparation was defined according to Boston Bowel Preparation Scale?BBPS?.ResultsA total of 84 patients were included in the study,and adequate bowel preparation was found in 77.4%patients.The patients were classified into two groups based on the quality of bowel preparation:adequate bowel preparation and inadequate bowel preparation.The Boston Scale?BBPS?total scores were 7.26?0.91 in patients with adequate bowel preparation and 4.63?0.76 in patients with inadequate bowel preparation.The baseline of breath H₂ levels were similar between the two groups?6.46?2.38ppm vs 6.37?2.69ppm,P=0.89?.However,the H₂ concentrations after NaP ingestion were significantly lower?P<0.001?in the patients with adequate bowel preparation?3.54?1.74ppm?compared to patients with poor preparation?8.26?2.35ppm?.According to the ROC curve analysis based on predictive value section,the cut-off H₂ breath test level of 4.5ppm was found to be a marker to predict the quality of bowel preparation for colonoscopy,with a sensitivity of 89.5%and a specificity of 80.0%?the area under the ROC curve was 0.94?.ConclusionsInulin hydrogen breath test can be used as a simple,reliable,non-invasive method to predict the quality of bowel preparation for colonoscopy.The test is particularly suitable for the patients with a history of poor bowel preparation for prior procedures and for those with chronic constipation.Inulin hydrogen breath test can be used to predict the quality of bowel preparation prior to the procedure,and to identify patients who require further preparation,in an effort to avoid aborted colonoscopies due to inadequate colonic preparation.