Construction and validation of a risk-prediction model for anastomotic leakage after radical gastrectomy: A cohort study in China

Objectives:Anastomotic leakage(AL)stands out as a prevalent and severe complication following gastric cancer surgery.It frequently precipitates additional serious complications,significantly influencing the overall survival time of patients.This study aims to enhance the risk-assessment strategy for AL following gastrectomy for gastric cancer.Methods:This study included a derivation cohort and validation cohort.The derivation cohort included patients who underwent radical gastrectomy at Sir Run Run Shaw Hospital,Zhejiang University School of Medicine,from January 1,2015 to December 31,2020.An evidence-based predictor questionnaire was crafted through extensive literature review and panel discussions.Based on the questionnaire,inpatient data were collected to form a model-derivation cohort.This cohort underwent both univariate and multivariate analyses to identify factors associated with AL events,and a logistic regression model with stepwise regression was developed.A 5-fold cross-validation ensured model reliability.The validation cohort included patients from August 1,2021 to December 31,2021 at the same hospital.Using the same imputation method,we organized the validation-queue data.We then employed the risk-prediction model constructed in the earlier phase of the study to predict the risk of AL in the subjects included in the validation queue.We compared the predictions with the actual occurrence,and evaluated the external validation performance of the model using model-evaluation indicators such as the area under the receiver operating characteristic curve(AUROC),Brier score,and calibration curve.Results:The derivation cohort included 1377 patients,and the validation cohort included 131 patients.The independent predictors of AL after radical gastrectomy included age65 y,preoperative albumin<35 g/L,resection extent,operative time240 min,and intraoperative blood loss90 mL.The predictive model exhibited a solid AUROC of 0.750(95%CI:0.694e0.806;p<0.001)with a Brier score of 0.049.The 5-fold cross-validation confirmed these findings with a calibrated C-index of 0.749 and an average Brier score of 0.052.External validation showed an AUROC of 0.723(95%CI:0.564e0.882;p?0.006)and a Brier score of 0.055,confirming reliability in different clinical settings.Conclusions:We successfully developed a risk-prediction model for AL following radical gastrectomy.This tool will aid healthcare professionals in anticipating AL,potentially reducing unnecessary interventions.

Endoscopic ultrasound-guided tissue sampling induced pancreatic duct leak resolved by the placement of a pancreatic stent:A case report

BACKGROUND Pancreatic ductal leaks complicated by endoscopic ultrasonography-guided tissue sampling(EUS-TS)can manifest as acute pancreatitis.CASE SUMMARY A 63-year-old man presented with persistent abdominal pain and weight loss.Diagnosis:Laboratory findings revealed elevated carbohydrate antigen 19-9(5920 U/mL)and carcinoembryonic antigen(23.7 ng/mL)levels.Magnetic resonance imaging of the pancreas revealed an approximately 3 cm ill-defined space-occupying lesion in the inferior aspect of the head,with severe encasement of the superior mesenteric artery.Pancreatic ductal adenocarcinoma was confirmed after pathological examination of specimens obtained by EUS-TS using the fanning method.Interventions and outcomes:The following day,the patient experienced severe abdominal pain with high amylase(265 U/L)and lipase(1173 U/L)levels.Computed tomography of the abdomen revealed edematous wall thickening of the second portion of the duodenum with adjacent fluid collections and a suspicious leak from either the distal common bile duct or the main pancreatic duct in the head.Endoscopic retrograde cholangiopancreatography revealed dye leakage in the head of the main pancreatic duct.Therefore,a 5F 7 cm linear plastic stent was deployed into the pancreatic duct to divert the pancreatic juice.The patient’s abdominal pain improved immediately after pancreatic stent insertion,and amylase and lipase levels normalized within a week.Neoadjuvant chemotherapy was then initiated.CONCLUSION Using the fanning method in EUS-TS can inadvertently cause damage to the pancreatic duct and may lead to clinically significant pancreatitis.Placing a pancreatic stent may immediately resolve acute pancreatitis and shorten the waiting time for curative therapy.When using the fanning method during EUSTS,ductal structures should be excluded to prevent pancreatic ductal leakage.

Impact of open hepatectomy on postoperative bile leakage in patients with biliary tract cancer

BACKGROUND Bile leakage is a common and serious complication of open hepatectomy for the treatment of biliary tract cancer.AIM To evaluate the incidence,risk factors,and management of bile leakage after open hepatectomy in patients with biliary tract cancer.METHODS We retrospectively analyzed 120 patients who underwent open hepatectomy for biliary tract cancer from February 2018 to February 2023.Bile leak was defined as bile drainage from the surgical site or drain or the presence of a biloma on imaging.The incidence,severity,timing,location,and treatment of the bile leaks were recorded.The risk factors for bile leakage were analyzed using univariate and multivariate logistic regression analyses.RESULTS The incidence of bile leak was 16.7%(20/120),and most cases were grade A(75%,15/20)according to the International Study Group of Liver Surgery classification.The median time of onset was 5 d(range,1-14 d),and the median duration was 7 d(range,2-28 d).The most common location of bile leakage was the cut surface of the liver(70%,14/20),followed by the anastomosis site(25%,5/20)and the cystic duct stump(5%,1/20).Most bile leaks were treated conservatively with drainage,antibiotics,and nutritional support(85%,17/20),whereas some required endoscopic retrograde cholangiopancreatography with stenting(10%,2/20)or percutaneous transhepatic cholangiography with drainage(5%,1/20).Risk factors for bile leakage include male sex,hepatocellular carcinoma,major hepatectomy,blood loss,and blood transfusion.CONCLUSION Bile leakage is a frequent complication of open hepatectomy for biliary tract cancer.However,most cases are mild and can be conservatively managed.Male sex,hepatocellular carcinoma,major hepatectomy,blood loss,and blood transfusion were associated with an increased risk of bile leak.

Preoperative neutrophil-to-lymphocyte ratio predicts symptomatic anastomotic leakage in elderly colon cancer patients: Multicenter propensity score-matched analysis

BACKGROUND The neutrophil-to-lymphocyte ratio(NLR),a composite inflammatory biomarker,is associated with the prognosis in patients with colorectal tumors.However,whether the NLR can be used as a predictor of symptomatic postoperative ana-stomotic leakage(AL)in elderly patients with colon cancer is unclear.AIM To assess the role of the NLR in predicting the occurrence of symptomatic AL after surgery in elderly patients with colon cancer.METHODS Data from elderly colon cancer patients who underwent elective radical colectomy with anastomosis at three centers between 2018 and 2022 were retrospectively analyzed.Receiver operating characteristic curve analysis was performed to determine the best predictive cutoff value for the NLR.Twenty-two covariates were matched using a 1:1 propensity score matching method,and univariate and multivariate logistic regression analyses were used to determine risk factors for the development of postoperative AL.RESULTS Of the 577 patients included,36(6.2%)had symptomatic AL.The optimal cutoff value of the NLR for predicting AL was 2.66.After propensity score matching,the incidence of AL was significantly greater in the≥2.66 NLR subgroup than in the<2.66 NLR subgroup(11.5%vs 2.5%;P=0.012).Univariate logistic regression analysis revealed statistically significant correlations between blood transfusion intraoperatively and within 2 d postoper-atively,preoperative albumin concentration,preoperative prognostic nutritional index,and preoperative NLR and AL occurrence(P<0.05);multivariate logistic regression analysis revealed that an NLR≥2.66[odds ratio(OR)=5.51;95%confidence interval(CI):1.50-20.26;P=0.010]and blood transfusion intraoperatively and within 2 d postoperatively(OR=2.52;95%CI:0.88-7.25;P=0.049)were risk factors for the occurrence of symptomatic AL.CONCLUSION A preoperative NLR≥2.66 and blood transfusion intraoperatively and within 2 d postoperatively are associated with a higher incidence of postoperative symptomatic AL in elderly patients with colon cancer.The preoperative NLR has predictive value for postoperative symptomatic AL after elective surgery in elderly patients with colon cancer.

Research on Leak Location Method of Water Supply Pipeline Based on MVMD

At present,the leakage rate of the water distribution network in China is still high,and the waste of water resources caused by water distribution network leakage is quite serious every year.Therefore,the location of pipeline leakage is of great significance for saving water resources and reducing economic losses.Acoustic emission technology is the most widely used pipeline leak location technology.The traditional non-stationary random signal de-noising method mainly relies on the estimation of noise parameters,ignoring periodic noise and components unrelated to pipeline leakage.Aiming at the above problems,this paper proposes a leak location method for water supply pipelines based on a multivariate variational mode decomposition algorithm.This method combines the two parameters of the energy loss coefficient and the correlation coefficient between adjacent modes,and adaptively determines the decomposition mode number K according to the characteristics of the signal itself.According to the correlation coefficient,the effective component is selected to reconstruct the signal and the cross-correlation time delay is estimated to determine the location of the pipeline leakage point.The experimental results show that this method has higher accuracy than the cross-correlation method based on VMD and the cross-correlation method based on EMD,and the average relative positioning error is less than 2.2%.

Choosing the best endoscopic approach for post-bariatric surgical leaks and fistulas:Basic principles and recommendations

Post-surgical leaks and fistulas are the most feared complication of bariatric surgery.They have become more common in clinical practice given the increasing number of these procedures and can be very difficult to treat.These two related conditions must be distinguished and characterized to guide the appropriate treatment.Leak is defined as a transmural defect with communication between the intra and extraluminal compartments,while fistula is defined as an abnormal communication between two epithelialized surfaces.Traditionally,surgical treatment was the preferred approach for leaks and fistulas and was associated with high morbidity with significant mortality rates.However,with the development of novel devices and techniques,endoscopic therapy plays an increasingly essential role in managing these conditions.Early diagnosis and endoscopic therapy initiation after clinical stabilization are crucial to success since clinical success rates are higher for acute leaks and fistulas when compared to late and chronic leaks and fistulas.Several endoscopic techniques are available with different mechanisms of action,including direct closure,covering/diverting or draining.The treatment should be individualized by considering the characteristics of both the patient and the defect.Although there is a lack of high-quality studies to provide standardized treatment algorithms,this narrative review aims to provide a summary of the current scientific evidence and,based on this data and our extensive experience,make recommendations to help choose the best endoscopic approach for the management of post-bariatric surgical leaks and fistulas.

A reliability-oriented genetic algorithm-levenberg marquardt model for leak risk assessment based on time-frequency features

Since leaks in high-pressure pipelines transporting crude oil can cause severe economic losses,a reliable leak risk assessment can assist in developing an effective pipeline maintenance plan and avoiding unexpected incidents.The fast and accurate leak detection methods are essential for maintaining pipeline safety in pipeline reliability engineering.Current oil pipeline leakage signals are insufficient for feature extraction,while the training time for traditional leakage prediction models is too long.A new leak detection method is proposed based on time-frequency features and the Genetic Algorithm-Levenberg Marquardt(GA-LM)classification model for predicting the leakage status of oil pipelines.The signal that has been processed is transformed to the time and frequency domain,allowing full expression of the original signal.The traditional Back Propagation(BP)neural network is optimized by the Genetic Algorithm(GA)and Levenberg Marquardt(LM)algorithms.The results show that the recognition effect of a combined feature parameter is superior to that of a single feature parameter.The Accuracy,Precision,Recall,and F1score of the GA-LM model is 95%,93.5%,96.7%,and 95.1%,respectively,which proves that the GA-LM model has a good predictive effect and excellent stability for positive and negative samples.The proposed GA-LM model can obviously reduce training time and improve recognition efficiency.In addition,considering that a large number of samples are required for model training,a wavelet threshold method is proposed to generate sample data with higher reliability.The research results can provide an effective theoretical and technical reference for the leakage risk assessment of the actual oil pipelines.

A sutureless technique for securing leaking sclerotomies with viscoelastic substances in 23-gauge microincision vitrectomy surgery

AIM:To introduce and evaluate the clinical efficacy of a new technique,the use of viscoelastic substances(VS)to close leaking sclerotomy in 23G microincision vitrectomy,and to observe its effect on the visual acuity and intraocular pressure(IOP)of patients.METHODS:Patients who underwent 23G vitrectomy in Ningbo Eye Hospital before the use of VS technique(June 2019 to September 2020)and after the use of VS technique(October 2020 to December 2021)were selected as the subjects of this study.The above cases underwent operation by the same surgeon and were retrospectively analyzed.VS technique was used as the alternative to suturing,in which a small amount of VS was injected at the leaking sclerotomy and then gently massaged to confirm leaking sclerotomy closure.RESULTS:A total of 174 eyes were covered in the study,including 84 eyes in the control group(before the use of VS technique)and 90 eyes in the VS technique group.The number of eyes that needed to be sutured decreased considerably from 42.9%in the control group to 3.3%in the VS technique group,and the proportion of subconjunctival hemorrhage at 1-2d after surgery decreased remarkably from 35.7%in the control group to 2.2%in the VS technique group.No substantial differences in the incidence of mean IOP and low IOP were found between 1-2 and 3-20d after surgery in the VS technique group.No major complications associated with VS technique were identified during the study.CONCLUSION:In 23G microincision vitrectomy,VS technique is a safe,simple,and effective method to close leaking sclerotomy.

Negligible Warming Caused by Nord Stream Methane Leaks

Unanticipated sabotage of two underwater pipelines in the Baltic Sea(Nord Stream 1 and 2)happened on 26September 2022.Massive quantities of natural gas,primarily methane,were released into the atmosphere,which lasted for about one week.As a more powerful greenhouse gas than CO_(2),the potential climatic impact of methane is a global concern.Using multiple methods and datasets,a recent study reported a relatively accurate magnitude of the leaked methane at 0.22±0.03 million tons(Mt),which was lower than the initial estimate in the immediate aftermath of the event.Under an energy conservation framework used in IPCC AR6,we derived a negligible increase in global surface air temperature of 1.8×10^(-5)℃ in a 20-year time horizon caused by the methane leaks with an upper limit of 0.25 Mt.Although the resultant warming from this methane leak incident was minor,future carbon release from additional Earth system feedbacks,such as thawing permafrost,and its impact on the methane mitigation pathways of the Paris Agreement,warrants investigation.

Progress in the study and treatment of peri-device leak after left atrial appendage closure

For patients with atrial fibrillation with an increased risk of stroke and contraindications to long-term anticoagulation,percutaneous left atrial appendage closure(LAAC)has become an important alternative to long-term oral anticoagulation.Incomplete closure of the LAAC during the procedure leads to faster blood flow in the interstitial space around the device,resulting in peri-device leak(PDL),which is not uncommon.Studies are still inconclusive in determining the incidence,long-term safety,and management of PDL.Therefore,this article reviewed the progress made in the research and treatment of PDL after LAAC.

Surgical treatment of mixed cervical spondylosis with spontaneous cerebrospinal fluid leakage: A case report

BACKGROUND Spontaneous cerebrospinal fluid(CSF)leaks associated with cervical spondylosis are rare.To our knowledge,only a few cases have been reported in which treatment is challenging and varies from case to case.Here,we review the literature and describe the surgical treatment of a 70-year-old woman who presented with a CSF leak due to a cervical spine spur.CASE SUMMARY A 70-year-old female patient who was treated for a cerebral infarction,presented with complains of weakness in the right lower extremity and a feeling of stepping on cotton.The patient underwent regular neck massage and presented with neck and right shoulder pain radiating to the right upper extremity one-month ago.Magnetic resonance imaging showed a strip of leaking cerebrospinal fluid posterior to the C1-4 vertebrae,and computed tomography showed a“sickleshaped”disc prolapse with calcification in C4/5.We chose to perform an anterior cervical discectomy.When the prolapsed C4/5 disc was scraped,clear fluid leakage was observed,and exploration revealed a 1 mm diameter rupture in the anterior aspect of the dura mater,which was compressed continuously with cotton patties,with no significant cerebrospinal fluid leakage after 1 h.CONCLUSION Three months after surgery,the patient was asymptomatic and follow-up imaging demonstrated complete resolution.

从管段走向管网:管道泄漏诊断技术研究进展

管道泄漏诊断技术在保障管道系统安全运行中起着至关重要的作用。首先,介绍了管道泄漏诊断系统的结构,并指出由单一管段向复杂管网泄漏诊断的发展趋势。进一步从基于数据驱动的传统泄漏检测方法、管道泄漏信号源定位技术和基于深度学习的复杂管网泄漏检测方法3个方面进行综述,分析了不同方法的优势、局限性和适用范围。最后指出,随着管网系统的复杂度增加,传统方法的局限性逐渐显现,基于深度学习技术的复杂管网微弱泄漏诊断、多源信号融合和管网智能化的研究将成为未来的研究趋势。

低颅压综合征合并颅内出血的诊断和治疗

目的探讨低颅压综合征合并颅内出血的病因、临床表现、影像学特点及救治方法。方法回顾性分析2015年1月—2022年12月苏州大学附属张家港医院神经外科收治的14例低颅压综合征合并颅内出血患者的临床资料,并进行定期随访,了解其预后及转归。结果14例低颅压综合征患者中,13例存在直立性头痛。4例自发性低颅压综合征合并双侧慢性硬脑膜下血肿患者,行头颅核磁共振成像(MRI)增强显示硬脑膜下出血或积液、硬脑膜强化、静脉结构充盈、垂体充血和脑组织下垂等影像学特征,钻颅引流手术治疗3例、保守治疗1例;10例创伤性低颅压综合征伴颅内出血患者保守治疗7例,钻颅引流手术治疗2例,开颅血肿清除手术治疗1例;治疗后相关症状明显好转或消失。结论对于低颅压综合征合并颅内出血的患者,临床上应根据患者的个体情况选择保守治疗或手术治疗;早期明确病因有助于临床治疗方案的优化,改善患者神经功能及预后。

LPG储罐泄漏多事故场景下社区居民疏散仿真模拟与优化

为提高社区居民在化工厂多事故场景下应急疏散效率,以大庆市某化工厂和附近社区为例,考虑当地气象环境,利用ALOHA对LPG储罐泄漏事故进行模拟,得到多种事故危害范围和社区各区域可用安全疏散时间.通过Pathfinder构建社区疏散模型,分析了步行疏散、车行疏散和人车协同疏散三种模式下的疏散时间和拥堵状况.最后,通过路网优化和安全出口均衡分配,进行疏散优化模拟.结果表明:路网优化对步行疏散下的疏散效率提升最大为14.7%,安全出口均衡分配对车行疏散下的疏散效率提升最大为10.6%.车行疏散模式下可以在可用安全疏散时间内撤离受灾区域.

室内地埋供热管道泄漏的声学监测及其信号去噪方法研究

为了更精确地对室内地埋供热管道泄漏声学监测信号进行主要特征频率提取和分析,需先对测量信号去噪。本文采用变分模态分解(variational mode decomposition,VMD),对距离漏水点5 cm和40 cm测量点的原始声信号分别进行模态分解,计算出各模态分量的排列熵并将其作为噪声信号剔除的依据,最后对信号进行重构,并与经验模态分解(empirical mode decomposition,EMD)、集合经验模态分解(ensemble empirical mode decomposition,EEMD)的处理结果进行对比。发现相比于其他两种分解降噪方法,VMD能够更好地解决模态混叠问题,能更为精确地将噪声信号去除,达到更好的去噪效果。

基于联邦学习的中心化差分隐私保护算法研究

近年来,联邦学习以独特的训练方式打破了数据“孤岛”,因此受到越来越多的关注。然而在训练全局模型时,联邦学习易受到推理攻击,可能会泄露参与训练成员的一些信息,产生严重的安全隐患。针对联邦训练过程中半诚实/恶意客户端造成的差分攻击,文章提出了基于中心化的差分隐私联邦学习算法DP-FEDAC。首先,优化联邦加速随机梯度下降算法,改进服务器的聚合方式,计算参数更新差值后采用梯度聚合方式更新全局模型,以提升稳定收敛;然后,通过对聚合参数添加中心化差分高斯噪声隐藏参与训练的成员贡献,达到保护参与方隐私信息的目的,同时还引入时刻会计(MA)计算隐私损失,进一步平衡模型收敛和隐私损失之间的关系;最后,与Fed AC、分布式MB-SGD、分布式MB-AC-SGD等算法做对比实验,评估DP-FEDAC的综合性能。实验结果表明,在通信不频繁的情况下,DP-FEDAC算法的线性加速最接近Fed AC,远优于另外两种算法,拥有较好的健壮性;此外DP-FEDAC算法在保护隐私的前提下能够达到与Fed AC算法相同的模型精度,体现了算法的优越性和可用性。

声发射法检测输气管道泄漏的研究综述

声发射法检测管道泄漏是目前的热点方法,研究涉及泄漏信号的产生与传播、信号拾取与处理、基于信号的智能识别与定位等。通过介绍声发射检测定位原理及一些基本规律,详细分析小波分析、局域均值分解、经验模态分解、变分模态分解在处理泄漏信号时的优劣,探讨人工智能在处理管道泄漏声发射信号中的应用,总结管道泄漏的模态研究、相关试验研究,来理清基于声发射的管道泄漏检测现状及展望未来发展。

炼化企业挥发性有机化合物减排的探索与实践

炼化企业加工过程有组织、无组织排放的挥发性有机化合物(VOCs)量较大,对大气环境中的颗粒物、臭氧浓度等产生重大影响。A公司自“十三五”以来对VOCs减排进行了探索与实践,通过采取油气回收、储罐浮盘高效密封改造、呼吸阀改型升级、无组织排放改为有组织回收、VOCs焚烧、常态化泄漏检测与修复工作等多种减排措施,VOCs排放量已从2015年的4230 t下降到2022年的2157 t,降低比例达到49%,取得了显著的成效。

海上某盆地胶结型防漏堵漏钻井液技术

分析了我国海上某盆地地质特征和历史井漏情况,明确了该盆地钻井防漏堵漏难点:地层裂缝发育且存在微米级至毫米级的多尺度裂缝,甚至裂缝和孔、洞并存,导致堵漏材料选配难、一次堵漏成功率低;地层发育大段风化壳、部分地层破碎严重、钻井中裂缝极易二次发育等,导致恶性漏失甚至失返性漏失等复杂情况。针对上述难点,以聚乙烯醇、聚丙烯酸以及含邻苯二酚结构的有机物为原料,合成了一种胶结型堵漏剂BFD-1。实验结果表明,人造疏松岩心在加有4%BFD-1的水溶液中浸泡后,岩心抗压强度提高率达19.34%。以BFD-1为核心,复配现场常用堵漏材料,构建了适用于不同尺寸范围漏失通道的防漏堵漏钻井液体系,具良好的防漏堵漏性、胶结性,并可有效阻止压力传递。研究成果可为该地区钻井井漏防治提供有力技术支撑。

胸腔内注射凝血酶、引流管悬吊联合治疗难治性气胸的疗效

目的探讨胸腔内注射凝血酶、引流管悬吊联合治疗难治性气胸的临床疗效,并观察该治疗方案对患者漏口闭合时间、发热发生率的影响。方法前瞻性选取2020年6月至2022年6月医院106例难治性气胸患者,依据随机数字表法将其分为对照组53例与研究组53例,对照组采用胸腔内注射凝血酶+常规胸腔闭式引流治疗,研究组采用胸腔内注射凝血酶+引流管悬吊治疗,观察2组临床疗效、留管时间、漏口闭合时间、住院时间、并发症(发热、胸膜粘连、纵隔气肿),对比2组治疗前、后肺功能指标[肺活量(VC)、残气量(RV)、肺一氧化碳弥散量(DLCO)、肺总量(TLC)]、血气分析指标[动脉血氧分压(PaO_(2))、二氧化碳分压(PCO_(2))、氧合指数(PaO_(2)/FiO_(2))、血氧饱和度(SaO_(2))]、6 min行走试验(6MWT)、Borg呼吸困难指数。结果治疗后,研究组总有效率高于对照组(P<0.05);研究组留管时间、漏口闭合时间、住院时间短于对照组(P<0.05);研究组并发症少于对照组(P<0.05);治疗后,2组VC、RV、DLCO、TLC高于治疗前,且与对照组相比,研究组更高(P<0.05);治疗后,2组PaO_(2)、PaO_(2)/FiO_(2)、SaO_(2)高于治疗前,PaCO_(2)、Borg呼吸困难指数低于治疗前,6MWT长于治疗前,且与对照组相比,研究组变化幅度更大(P<0.05)。结论胸腔内注射凝血酶联合引流管悬吊治疗难治性气胸效果显著,可改善患者肺功能指标、血气指标,减轻呼吸困难症状,提高运动耐量,缩短恢复时间,且不会增加并发症。