Objective To evaluate the ventilation modes and factors influencing the tidal volume(VT)in the nonventilated lung during one-lung ventilation(OLV)in patients undergoing thorascopic surgery using electrical impedance tomography.Methods Thirteen American Society of Anesthesiologists physical statusⅠ or Ⅱ patients of both sexes,aged 45-64 yr,weighing 45-80 kg,undergoing elective pulmonary surgery performed via video-assisted thoracoscope,were enrolled in the study.After anesthesia induction,a double lumen tube was placed,and correct tube placement was confirmed with a fiberoptic bronchoscope.Two-lung ventilation and OLV were performed sequentially when in supine position with a fixed VT of 8 ml/kg and respiratory rate(RR)of 12 breaths/min.When the patients were turned to lateral position(with the operated lung on the upper side),correct placement of the tube was reconfirmed with a fiberoptic bronchoscope.Bilateral lungs were ventilated with VT of 8 ml/kg and RR of 12 breaths/min,and unilateral lungs were then ventilated in the following modes in sequence:VT 8 ml/kg and RR 12 breaths/min for the lung on the upper side;VT 8 ml/kg and RR 12 breaths/min for the lung on the lower side;VT 8 ml/kg,RR 12 breaths/min and positive end-expiratory pressure(PEEP)4 cmH2O for the lung on the lower side;VT 6 ml/kg and RR 16 breaths/min for the lung on the lower side;VT 4 ml/kg and RR 24 breaths/min for the lung on the lower side.Each ventilation mode stabilized for 2 min.At 2 min of OLV in each mode,electrical impedance tomography was used to record the ventilation mode in the nonventilated lung,anesthesia machine was used to record VT in the nonventilated lung,and the percentage of VT on nonventilated side in VT on ventilated side(VT-non/VT-ven%)was calculated.When the unilateral lung on the lower side was ventilated in lateral position,logistic regression analysis was used to analyze the correlation between VT on ventilated side(no PEEP)and that on nonventilated side.Results Opposite ventilation was found in the nonventilated lung during OLV.VT-non/VT-ven% was significantly higher in lateral position than in supine position(P<0.05).VT-non/VT-ven% was significantly higher when the lung on the lower side was ventilated than that when the lung on the upper side was ventilated(P<0.05).Four cmH2O PEEP exerted no effect on VT-non/VT-ven%.When the lung on the lower side was ventilated in lateral position,there was a linear positive correlation between VT on ventilated side(no PEEP)and that on nonventilated side(r=0.899,P<0.05).Conclusion During OLV in patients undergoing thorascopic surgery,there is opposite ventilation in the nonventilated lung,and VT is influenced by body positions and VT in contralateral lungs.

Objective To estimate the prevalence and risk factors for irritable bowel syndrome (IBS) in China.Methods Cross-sectional studies relevant to IBS conducted among Chinese were identified through the databases including PubMed,Web of Science,the Cochrane Library,CBM,CNKI,Wanfang data and VIP.Quality of studies was assessed according to the criteria for cross-sectional studies recommended by Agency for Healthcare Research and Quality(AHRQ).Analysis of data,publication bias and sensitivity were performed with Stata (Version 12.0).Results A total of twenty-three studies were extracted.No obvious publication bias was detected in all analysis except the effect of depression on IBS prevalence.Pooled prevalence of IBS in China was 6.5％.IBS was more common in women than in men (8.1％ vs 6.8％;OR=1.23,95％CI 1.09-1.38) and high rate in age group between 30 to 59 years (6.9％ ; OR =1.22,95％ CI 1.12-1.32).Intestinal infection history(OR =2.39,95％ CI 1.69-3.38),anxiety (OR =2.95,95 ％ CI 1.94-4.49),depression (OR =1.85,95 ％ CI 1.11-3.09),food allergy (OR =2.80,95％ CI 2.12-3.67) and alcohol consumption (OR =1.15,95％ CI 1.07-1.24) might increase the risk for IBS.There were no significant difference of IBS prevalence between urban and rural areas (OR =0.97,95％ CI 0.72-1.29),neither in different education classes (OR =0.85,95％ CI 0.70-1.03).Sub-group analysis showed IBS prevalence varied apparently with different diagnostic criteria:prevalence defined by Manning was 11.8％ and by Rome Ⅱ and Rome Ⅲ prevalence values were 4.4％ and 8.9％ respectively.Conclusions Pooled prevalence of IBS in China was 6.5％.IBS is more common in age group between 30 to 59 years.Female,history of intestinal infection,anxiety,depression,food allergy and alcohol consumption were risk factors for IBS in Chinese population.

Objective:To evaluate the diagnostic value of hydrogen sulfide breath test(SBT) for small intestinal bacterial overgrowth (SIBO).Methods:College students were enrolled to complete gastrointestinal symptom scale, food frequency questionnaire, lactulose hydrogen- methane breath test (LHMBT) and SBT. Based on the correlation between hydrogen sulfide(H 2S) and hydrogen or methane gas,the receiver operating characteristic (ROC) curve of H 2S was drawn and diagnostic criteria of SBT was defined. Results:A total of 300 subjects including 84 males and 216 females with age 17-32 (21.6±2.4) years were enrolled from April 2019 to December 2019 and divided into two groups.Two hundred and three patients reported SIBO discomforts with 99 (48.8%) LHMBT positive, while 38 (39.2%) were LHMBT positive in 97 health controls. Rise of H 2S at 90 min was positively related with that of hydrogen ( r=0.516, P<0.01), and H 2S levels at 90 min were positively correlated with methane ( r=0.632, P<0.01). A rise in H 2S of ≥25.0 ppb or H 2S levels ≥62.5 ppb at 90 min during lactulose breath test was considered positive for SIBO, that sensitivity, specificity and accuracy were 66.4%,79.1% and 73.3% respectively. H 2S levels were significantly related to the amount of Vitamin B 12 intake ( P=0.011). H 2S-positive subjects exhibited a constipation-predominant pattern. Conclusion:SBT is consistent with LHMBT, especially in constipation-predominant patients, which may provide a reference to the diagnosis of SIBO.

Dysregulation of the gut microbiota/gut hormone axis contributes to the pathogenesis of irritable bowel syndrome (IBS). Melatonin plays a beneficial role in gut motility and immunity. However, altered expression of local mucosal melatonin in IBS and its relationship with the gut microbiota remain unclear. Therefore, we aimed to detect the colonic melatonin levels and microbiota profiles in patients with diarrhea-predominant IBS (IBS-D) and explore their relationship in germ-free (GF) rats and BON-1 cel s. Thirty-two IBS-D patients and twenty-eight healthy controls (HCs) were recruited. Fecal specimens from IBS-D patients and HCs were separately transplanted into GF rats by gavage. The levels of colon mucosal melatonin were assessed by immunohistochemical methods, and fecal microbiota communities were ana-lyzed using 16S rDNA sequencing. The effect of butyrate on melatonin synthesis in BON-1 cel s was eval-uated by ELISA. Melatonin levels were significantly increased and negatively correlated with visceral hypersensitivity in IBS-D patients. GF rats inoculated with fecal microbiota from IBS-D patients had high colonic melatonin levels. Butyrate-producing Clostridium cluster XIVa species, such as Roseburia species and Lachnospira species, were positively related to colonic mucosal melatonin expression. Butyrate signif-icantly increased melatonin secretion in BON-1 cel s. Increased melatonin expression may be an adaptive protective mechanism in the development of IBS-D. Moreover, some Clostridium cluster XIVa species could increase melatonin expression via butyrate production. Modulation of the gut hormone/gut micro-biota axis offers a promising target of interest for IBS in the future.

Background::As a non-invasive and effective diagnostic method for small intestinal bacterial overgrowth (SIBO), wild-use of breath test (BT) has demonstrated a high comorbidity rate in patients with diarrhea-predominant irritable bowel syndrome (IBS-D) and SIBO. Patients overlapping with SIBO respond better to rifaximin therapy than those with IBS-D only. Gut microbiota plays a critical role in both of these two diseases. We aimed to determine the microbial difference between IBS-D overlapping with/without SIBO, and to study the underlying mechanism of its sensitivity to rifaximin.Methods::Patients with IBS-D were categorized as BT-negative (IBSN) and BT-positive (IBSP). Healthy volunteers (BT-negative) were enrolled as healthy control. The patients were clinically evaluated before and after rifaximin treatment (0.4 g bid, 4 weeks). Blood, intestine, and stool samples were collected for cytokine assessment and gut microbial analyses.Results::Clinical complaints and microbial abundance were significantly higher in IBSP than in IBSN. In contrast, severe systemic inflammation and more active bacterial invasion function that were associated with enrichment of opportunistic pathogens were seen in IBSN. The symptoms of IBSP patients were relieved in different degrees after therapy, but the symptoms of IBSN rarely changed. We also found that the presence of IBSN-enriched genera ( Enterobacter and Enterococcus) are unaffected by rifaximin therapy. Conclusions::IBS-D patients overlapping with SIBO showed noticeably different fecal microbial composition and function compared with IBS-D only. The better response to rifaximin in those comorbid patients might associate with their different gut microbiota, which suggests that BT is necessary before IBS-D diagnosis and use of rifaximin.Registration::Chinese Clinical Trial Registry, ChiCTR1800017911.