A pilot study on using chlorine dioxide gas for disinfection of gastrointestinal endoscopes

Objectives： This pilot study of employing chlorine dioxide （CD） gas to disinfect gastrointestinal endoscopes was conducted to meet the expectations of many endoscopy units in China for a high-efficiency and low-cost disin- fectant. Methods： An experimental prototype with an active circulation mode was designed to use CD gas to disinfect gastrointestinal endoscopes. One type of testing device composed of polytetrafluoroethylene （PTFE） tubes （2 m long, inner diameter 1 mm） and bacterial carrier containers was used to simulate the channel of the endoscope. PTFE bacterial carriers inoculated with Bacillus atrophaeus with or without organic burden were used to evaluate the spor- icidal activity of CD gas. Factors including exposure dosage, relative humidity （RH）, and flow rate （FR） influencing the disinfection effect of CD gas were investigated. Moreover, an autoptic disinfecting test on eight real gastrointestinal endoscopes after clinical use was performed using the experimental prototype. Results： IRH, exposure dosage, or- ganic burden, and the FIR through the channel significantly （P〈0.05） affected the disinfection efficacy of CD gas for a long and narrow lumen. The log reduction increased as FR decreased. Treatment with 4 mg/L CD gas for 30 min at 0.8 L/min FR and 75% IRH, resulted in complete inactivation of spores. Furthermore, all eight endoscopes with a maximum colony-forming unit of 915 were completely disinfected. The cost was only 3 CNY （0.46 USD） for each endoscope. Conclusions： The methods and results reported in this study could provide a basis for further studies on using CD gas for the disinfection of endoscopes.

Early esophagus cancer segmentation from gastrointestinal endoscopic images based on U-Net++model

Automatic segmentation of early esophagus cancer(EEC)in gastrointestinal endoscopy(GIE)images is a critical and challenging task in clinical settings,which relies primarily on labor-intensive and time-consuming routines.EEC has often been diagnosed at the late stage since early signs of cancer are not obvious,resulting in low survival rates.This work proposes a deep learning approach based on the U-Net++method to segment EEC in GIE images.A total of 2690 GIE images collected from 617 patients at the Digestive Endoscopy Center,West China Hospital of Sichuan University,China,have been utilized.The experimental result shows that our proposed method achieved promising results.Furthermore,the comparison has been made between the proposed and other U-Net-related methods using the same dataset.The mean and standard deviation(SD)of the dice similarity coefficient(DSC),intersection over union(IoU),precision(Pre),and recall(Rec)achieved by the proposed framework were DSC(%)=94.62±0.02,IoU(%)=90.99±0.04,Pre(%)=94.61±0.04,and Rec(%)=95.00±0.02,respectively,outperforming the others.The proposed method has the potential to be applied in EEC automatic diagnoses.

Endotracheal intubation in patients with COVID-19 using an ultrathin flexible gastrointestinal endoscope

Pneumonia caused by severe acute respiratory syndrome coronavirus 2 occasionally becomes severe and requires endotracheal intubation.Endotracheal intubation is usually performed using a laryngoscope;however,the operator needs to be in close proximity to the patient’s face during the procedure,which increases the risk of droplet exposure.Therefore,we simulated fiberoptic endotracheal intubation on a mannequin representing the patient,using an ultrathin flexible gastrointestinal endoscope as an alternative to the bronchoscope,in order to maintain distance from the patient during the procedure.We performed this procedure 10 times and measured the time required;the median procedure time was 6.4 s(interquartile range,5.7-8.1 s).The advantage of this method is the short procedure time and distance maintained from the patients.The flexible tip-steerable control and length of the gastrointestinal endoscope contributed to shortening the procedure time and maintaining distance from the patients.In addition,this method can handle difficult airways without risk of misplacement of the endotracheal tube.However,it is necessary to consider the risk of aerosol generation associated with this procedure.In the pandemic setting of coronavirus disease 2019,this approach may be useful when a gastrointestinal endoscopist is in charge of endotracheal intubation of patients with coronavirus disease 2019.

Comparison between air and carbon dioxide insufflation in the endoscopic submucosal excavation of gastrointestinal stromal tumors

AIM:To evaluate the safety and efficacy of CO2 insufflation compared with air insufflation in the endoscopic submucosal excavation(ESE) of gastrointestinal stromal tumors.METHODS:Sixty patients were randomized to undergo endoscopic submucosal excavation,with the CO2 group(n = 30) and the air group(n = 30) undergoingCO2 insufflation and air insufflation in the ESE,respectively.The end-tidal CO2 level(pETCO2) was observed at 4 time points:at the beginning of ESE,at total removal of the tumors,at completed wound management,and 10 min after ESE.Additionally,the patients' experience of pain at 1,3,6 and 24 h after the examination was registered using a visual analog scale(VAS).RESULTS:Both the CO2 group and air group were similar in mean age,sex,body mass index(all P > 0.05).There were no significant differences in PetCO2 values before and after the procedure(P > 0.05).However,the pain scores after the ESE at different time points in the CO2 group decreased significantly compared with the air group(1 h:21.2 ± 3.4 vs 61.5 ± 1.7;3 h:8.5 ± 0.7 vs 42.9 ± 1.3;6 h:4.4 ± 1.6 vs 27.6 ± 1.2;24 h:2.3 ± 0.4 vs 21.4 ± 0.7,P < 0.05).Meanwhile,the percentage of VAS scores of 0 in the CO2 group after 1,3,6 and 24 h was significantly higher than that in the air group(60.7 ± 1.4 vs 18.9 ± 1.5,81.5 ± 2.3 vs 20.6 ± 1.2,89.2 ± 0.7 vs 36.8 ± 0.9,91.3 ± 0.8 vs 63.8 ± 1.3,respectively,P < 0.05).Moreover,the condition of the CO2 group was better than that of the air group with respect to anal exsufflation.CONCLUSION:Insufflation of CO2 in the ESE of gastrointestinal stromal tumors will not cause CO2 retention and it may significantly reduce the level of pain,thus it is safe and effective.

Endoscopic ultrasonography: an advancing option with duality in both diagnosis and treatment of gastrointestinal oncology

Since their introduction into the clinical practices in 1980s, techniques of endoscopic ultrasonography（EUS） have been rapidly developing and are now in widespread use in gastrointestinal oncology. Evolving from the classical option, EUS today has been much innovated with addition of a variety of novel ideation which makes it a powerful tool with encouraging duality for both diagnostic and therapeutic purposes. There is a dire need for physicians in this field to understand the status quo of EUS as related to the management and detection of gastrointestinal tumors, which is globally reviewed in this paper.

Clinical impact of gastrointestinal endoscopy on the early detection of pharyngeal squamous cell carcinoma: A retrospective cohort study

BACKGROUND In recent years,with the growing availability of image-enhanced gastrointestinal endoscopy,gastroenterologists have contributed to the early detection of pharyngeal squamous cell carcinomas(SCC).AIM To clarify the clinical characteristics of pharyngeal SCCs detected by gastrointestinal endoscopy.METHODS This is a retrospective cohort study conducted in a single-center,a university hospital in Japan.We retrospectively assessed the clinical records of 522 consecutive patients with oropharyngeal or hypopharyngeal SCC who were examined in our hospital between 2011 and 2018.The lesions were classified into two groups:Group GE(detected by gastrointestinal endoscopy)and Group non-GE(detected by means other than gastrointestinal endoscopy).The clinical characteristics were compared between the two groups.Continuous data were compared using the Mann–Whitney U test.Pearson’sχ2 test or Fisher's exact test was used to analyze the categorical data and compare proportions.The Kaplan–Meier method was used to estimate the cumulative patient survival rates.RESULTS In our study group,the median age was 65 years and 474 patients(90.8%)were male.One hundred and ninety-six cases(37.5%)involved the oropharynx and 326 cases(62.5%)involved the hypopharynx.Three hundred and ninety-five cases(75.7%)had some symptoms at the time of diagnosis.One hundred and forty-five(27.8%)cases had concurrent ESCC or a history of ESCC.One hundred and sixtyfour(31.4%)cases were detected by gastrointestinal endoscopy and classified as Group GE.The proportions of asymptomatic cases,cTis-1 cases and cases with no lymph node metastasis were significantly higher in Group GE than Group non-GE(61.6%vs 7.3%,P<0.001,32.9%vs 12.0%,P<0.001 and 69.5%vs 19.0%,P<0.001).Endoscopic laryngo-pharyngeal surgery or endoscopic submucosal dissection were performed in only 0.6%of the lesions in Group non-GE but in 21.3%of the lesions in Group GE(P<0.001).Overall survival was significantly longer in Group GE than in Group non-GE(P=0.018).The 2-year and 4-year survival rates were 82.5%and 70.7%in Group GE,and 71.5%and 59.0%in Group non-GE,respectively.CONCLUSION Gastrointestinal endoscopy plays an important role in the early detection and improving the prognosis of pharyngeal SCCs.

Feasibility of cold snare polypectomy in Japan: A pilot study

AIM: To investigate the feasibility of cold snare polypectomy(CSP) in Japan.METHODS: The outcomes of 234 non-pedunculated polyps smaller than 10 mm in 61 patients who underwent CSP in a Japanese referral center were retrospectively analyzed. The cold snare polypectomies were performed by nine endoscopists with no prior experience in CSP using an electrosurgical snare without electrocautery.RESULTS: CSPs were completed for 232 of the 234 polyps. Two(0.9%) polyps could not be removed without electrocautery. Immediate postpolypectomy bleeding requiring endoscopic hemostasis occurred in eight lesions(3.4%; 95%CI: 1.1%-5.8%), but all were easily managed. The incidence of immediate bleeding after CSP for small polyps(6-9 mm) was significantly higher than that of diminutive polyps(≤ 5 mm; 15% vs 1%, respectively). Three(5%) patients complained of minor bleeding after the procedure but required no intervention. The incidence of delayed bleeding requiringendoscopic intervention was 0.0%(95%CI: 0.0%-1.7%). In total, 12% of the resected lesions could not be retrieved for pathological examination. Tumor involvement in the lateral margin could not be histologically assessed in 70(40%) lesions.CONCLUSION: CSP is feasible in Japan. However, immediate bleeding, retrieval failure and uncertain assessment of the lateral tumor margin should not be underestimated. Careful endoscopic diagnosis before and evaluation of the tumor residue after CSP are recommended when implementing CSP in Japan.

Clinical outcomes of self-expandable metal stents in palliation of malignant anastomotic strictures caused by recurrent gastric cancer

AIM： To examine the technical feasibility and clinical outcomes of the endoscopic insertion of a selfexpandable metal stent （SEMS） for the palliation of a malignant anastomotic stricture caused by recurrent gastric cancer. METHODS： The medical records of patients, who had obstructive symptoms caused by a malignant anastomotic stricture after gastric surgery and underwent endoscopic insertion of a SEMS from January 2001 to December 2007 at Kangnam St Mary＇s Hospital, were reviewed retrospectively. RESULTS： Twenty patients （15 male, mean age 63 years） were included. The operations were a total gastrectomy with esophagojejunostomy （n = 12）, subtotal gastrectomy with Billroth-Ⅰ reconstruction （n = 2） and subtotal gastrectomy with Billroth- Ⅱ reconstruction （n = 8）. The technical and clinical success rates were 100% and 70%, respectively. A small bowel or colon stricture was the reason for a lack of improvement in symptoms in 4 patients. Two of these patients showed improvement in symptoms after another stent was placed. Stent reobstruction caused by tumor ingrowth or overgrowth occurred in 3 patients （15%） within 1 mo after stenting. Stent migration occurred with a covered stent in 3 patients who underwent a subtotal gastrectomy with Billroth-Ⅱ reconstruction. Two cases of partial stent migration were easily treated with a second stent or stent repositioning. The median stent patency was 56 d （range, 5-439 d）. The median survival was 83 d （range, 12-439 d）. CONCLUSION： Endoscopic insertion of a SEMS provides safe and effective palliation of a recurrent anastomotic stricture caused by gastric cancer, A meticulous evaluation of the presence of other strictures before inserting the stent is essential for symptom improvement.

Is it possible to differentiate gastric GISTs from gastric leiomyomas by EUS?

AIM: To evaluate the ultrasonog raphy (EUS) features of gastric gastrointestinal stromal tumors (GISTs) as compared with gastric leiomyomas and then to determine the EUS features that could predict malignant GISTs.METHODS: We evaluated the endoscopic EUS features in 53 patients with gastric mesenchymal tumors conf irmed by histopathologic diagnosis. The GISTs were classif ied into benign and malignant groups according to the histological risk classif ication.RESULTS: Immunohistochemical analyses demon-strated 7 leiomyomas and 46 GISTs. Inhomogenicity, hyperechogenic spots, a marginal halo and higher echogenicity as compared with the surrounding muscle layer appeared more frequently in the GISTs than in the leiomyomas (P < 0.05). The presence of at least two of these four features had a sensitivity of 89.1% and a specifi city of 85.7% for predicting GISTs. Except for tumor size and irregularity of the border, most of the EUS features were not helpful for predicting the malignant potential of GISTs. On multivariate analysis, only the maximal diameter of the GISTs was an independent predictor. The optimal size for predicting malignant GISTs was 35 mm. The sensitivity and specificity using this value were 92.3% and 78.8%, respectively.CONCLUSION: EUS may help to differentiate gastric GISTs from gastric leiomyomas. Once GISTs are suspected, surgery should be considered if the size is greater than 3.5 cm.

Endoscopic identification of Peyer's patches of the terminal ileum in a patient with Crohn's disease

We presented a 20-year-old patient with Crohn's disease (CD).Colonoscopy revealed longitudinal ulceration in the terminal ileum and rectal aphtoid ulcers.After treatment with mesalamine and total parenteral nutrition,repeat colonoscopy revealed a granular elevated area in the terminal ileum,which appeared as an irregular dome-like elevation with irregularly arranged villi on magnifying endoscopy.Biopsy specimens taken from the region showed microgranulomas and lymphoid hyperplasia,Scanning electron microscopy revealed the presence of M cells,confirming that the area corresponded to Peyer's patches.Peyer's patches by magnifying endoscopy and electron microscopy may provide insights into the pathogenesis of CD.

Histologyassessmentofbipolarcoagulationandargonplasmacoagulationon digestivetract

AIM: To analyze the effect of bipolar electrocoagula-tion and argon plasma coagulation on fresh specimens of gastrointestinal tract. METHODS: An experimental evaluation was performed at Hospital das Clinicas of the University of So Paulo, on 31 fresh surgical specimens using argon plasma coagulation and bipolar electrocoagulation at different time intervals. The depth of tissue damage was his-topathologically analyzed by single senior pathologist unaware of the coagulation method and power setting applied. To analyze the results, the mucosa was divided in superficial mucosa (epithelial layer of the esophagus and superficial portion of the glandular layer of the stomach and colon) intermediate mucosa (until thelamina propria of the esophagus and until the bottom of the glandular layer of the stomach and colon) and muscularis mucosa. Necrosis involvement of the layers was compared in several combinations of power and time interval. RESULTS: Involvement of the intermediate mucosa of the stomach and of the muscularis mucosa of the three organs was more frequent when higher amounts of en-ergy were used with argon plasma. In the esophagus and in the colon, injury of the intermediate mucosa was frequent, even when small amounts of energy were used. The use of bipolar electrocoagulation resulted in more frequent involvement of the intermediate mucosa and of the muscularis mucosa of the esophagus and of the colon when higher amounts of energy were used. In the stomach, these involvements were rare. The risk of injury of the muscularis propria was significant only in the colon when argon plasma coagulation was em-ployed.CONCLUSION: Tissue damage after argon plasma coagulation is deeper than bipolar electrocoagulation. Both of them depend on the amount of energy used.