Predictive value of diaphragm ultrasound for mechanical ventilation outcome in patients with acute exacerbation of chronic obstructive pulmonary disease

BACKGROUND Acute exacerbation of chronic obstructive pulmonary disease(AECOPD)is often combined with respiratory failure,which increases the patient's morbidity and mortality.Diaphragm ultrasound(DUS)has developed rapidly in the field of critical care in recent years.Studies with DUS monitoring diaphragm-related rapid shallow breathing index have demonstrated important results in guiding intensive care unit patients out of the ventilator.Early prediction of the indications for withdrawal of non-invasive ventilator and early evaluation of patients to avoid or reduce disease progression are very important.AIM To explore the predictive value of DUS indexes for non-invasive ventilation outcome in patients with AECOPD.METHODS Ninety-four patients with AECOPD who received mechanical ventilation in our hospital from January 2022 to December 2023 were retrospectively analyzed,and they were divided into a successful ventilation group(68 cases)and a failed ventilation group(26 cases)according to the outcome of ventilation.The clinical data of patients with successful and failed noninvasive ventilation were compared,and the independent predictors of noninvasive ventilation outcomes in AECOPD patients were identified by multivariate logistic regression analysis.RESULTS There were no significant differences in gender,age,body mass index,complications,systolic pressure,heart rate,mean arterial pressure,respiratory rate,oxygen saturation,partial pressure of oxygen,oxygenation index,or time of inspiration between patients with successful and failed mechanical ventilation(P>0.05).The patients with successful noninvasive ventilation had shorter hospital stays and lower partial pressure of carbon dioxide(PaCO_(2))than those with failed treatment,while potential of hydrogen(pH),diaphragm thickening fraction(DTF),diaphragm activity,and diaphragm movement time were significantly higher than those with failed treatment(P<0.05).pH[odds ratio(OR)=0.005,P<0.05],PaCO_(2)(OR=0.430,P<0.05),and DTF(OR=0.570,P<0.05)were identified to be independent factors influencing the outcome of mechanical ventilation in AECOPD patients.CONCLUSION The DUS index DTF can better predict the outcome of non-invasive ventilation in AECOPD patients.

Low-temperature characteristicsof rubbers and performance testsof type 120 emergencyvalve diaphragms

Purpose–The type 120 emergency valve is an essential braking component of railway freight trains,butcorresponding diaphragms consisting of natural rubber(NR)and chloroprene rubber(CR)exhibit insufficientaging resistance and low-temperature resistance,respectively.In order to develop type 120 emergency valverubber diaphragms with long-life and high-performance,low-temperatureresistant CR and NR were processed.Design/methodology/approach–The physical properties of the low-temperature-resistant CR and NRwere tested by low-temperature stretching,dynamic mechanical analysis,differential scanning calorimetryand thermogravimetric analysis.Single-valve and single-vehicle tests of type 120 emergency valves werecarried out for emergency diaphragms consisting of NR and CR.Findings–The low-temperature-resistant CR and NR exhibited excellent physical properties.The elasticityand low-temperature resistance of NR were superior to those of CR,whereas the mechanical properties of thetwo rubbers were similar in the temperature range of 0℃–150℃.The NR and CR emergency diaphragms metthe requirements of the single-valve test.In the low-temperature single-vehicle test,only the low-temperaturesensitivity test of the NR emergency diaphragm met the requirements.Originality/value–The innovation of this study is that it provides valuable data and experience for futuredevelopment of type 120 valve rubber diaphragms.

Role of diaphragmatic ultrasound in patients with acute exacerbation of chronic obstructive pulmonary disease

Assessing diaphragm function status is vital for diagnosing and treating acute exacerbation of chronic obstructive pulmonary disease(AECOPD).Diaphrag-matic ultrasound has become increasingly important due to its non-invasive nature,absence of radiation exposure,widespread availability,prompt results,high accuracy,and repeatability at the bedside.The diaphragm is a crucial respiratory muscle.Decline or dysfunction of the diaphragm can lead to dyspnea and even respiratory failure in AECOPD patients.In this editorial,we comment on an article,retrospectively analyzed ninety-four acute exacerbations of chronic obstructive pulmonary disease patients who received mechanical ventilation from January 2022 to December 2023.The study found that the diaphragm thickening fraction,an index from diaphragm ultrasound,can better predict the outcome of non-invasive ventilation in patients with AECOPD.The value of non-invasive ventilation in treating respiratory failure caused by AECOPD has been widely acknowledged.Diaphragmatic dysfunction diagnosed with ultrasound is asso-ciated with prolonged mechanical ventilation and weaning times and higher mortality.

Theoretical and Experimental Study on the Performance of Hermetic Diaphragm Squeeze Film Dampers for Gas-Lubricated Bearings

Low damping characteristics have always been a key sticking points in the development of gas bearings.The application of squeeze film dampers can significantly improve the damping performance of gas lubricated bearings.This paper proposed a novel hermetic diaphragm squeeze film damper(HDSFD)for oil-free turbomachinery supported by gas lubricated bearings.Several types of HDSFDs with symmetrical structure were proposed for good damping performance.By considering the compressibility of the damper fluid,based on hydraulic fluid mechanics theory,a dynamic model of HDSFDs under medium is proposed,which successfully reflects the frequency dependence of force coefficients.Based on the dynamic model,the effects of damper fluid viscosity,bulk modulus of damper fluid,thickness of damper fluid film and plunger thickness on the dynamic stiffness and damping of HDSFDs were analyzed.An experimental test rig was assembled and series of experimental studies on HDSFDs were conducted.The damper fluid transverse flow is added to the existing HDSFD concept,which aims to make the dynamic force coefficients independent of frequency.Although the force coefficient is still frequency dependent,the damping coefficient at high frequency excitation with damper fluid supply twice as that without damper fluid supply.The results serve as a benchmark for the calibration of analytical tools under development.

Traumatic Diaphragmatic Hernia in Children: A Case Report

Introduction: Traumatic diaphragmatic hernia is a rare condition in children complicating closed or penetrating trauma to the abdomen and thorax. We report the case of an 11-year-old girl with a traumatic diaphragmatic hernia. Case Presentation: An 11-year-old girl was seen in the paediatric surgery department for a thoracolumbar spine deformity and intermittent chest pain. These symptoms occurred after a domestic accident involving a fall from a low wall onto the thoracolumbar spine 5 months previously. The diagnosis was suggested by the presence of a left hemithoracic hydroaera and confirmed by a thoraco-abdominal CT scan. Surgical exploration revealed a linear rupture of the entire left hemi-diaphragm with herniation of the stomach, small intestine, cecum, transverse colon and omentum. We performed a double-layer suture of the diaphragmatic rupture with a non-absorbable suture without edge rejuvenation after the reduction of the hernia. The outcome was favourable with normal postoperative radiographs at one year follow-up. Conclusion: Traumatic diaphragmatic hernia, although uncommon and difficult to diagnose, is a condition that is relatively easy to manage surgically, even if it is discovered late. In all cases of trauma to the thoracolumbar spine, regular follow-up and repeat X-rays are necessary if pain persists.

Hepatic ectopic pregnancy with hemorrhage secondary diaphragmatic adhesion:A case report

BACKGROUND Primary abdominal pregnancy is an extremely rare form of ectopic pregnancy.Ectopic pregnancies that occur in the liver and diaphragm are even rarer,limited case reports are available in the literature.CASE SUMMARY A woman of childbearing age was transferred to the emergency department due to lumbar and abdominal pain radiating to the back toward the lower right.After a series of physical and auxiliary examinations,she was clinically diagnosed with hepatic ectopic pregnancy.Laparoscopic surgery was performed to remove the pregnancy tissue and achieve hemostasis.After a period of follow-up,the patient was successfully cured.CONCLUSION Paying attention to the patient's signs and utilizing imaging examination methods can help avoid missed diagnoses of liver pregnancy.

Application Effect of External Diaphragm Pacemaker Combined with Active Respiratory Circulation Technology in Pulmonary Rehabilitation of Perioperative Lung Cancer Patients

Aim: To explore the application effect of external diaphragm pacemaker combined with active respiratory circulation technology in pulmonary rehabilitation of perioperative lung cancer patients. Methods: A total of 98 lung cancer patients admitted to our hospital from April 2020 to November 2021 were selected as the observation objects, and then divided into a control group and an observation group using the random number table method, with 49 cases in each group. The control group received routine admission guidance and active respiratory circulation training, while the observation group was supplemented with external diaphragm pacemaker on the basis of the control group. The intervention effect was evaluated by blood gas indicators, pulmonary function indicators, diaphragm function indicators, sputum comfort degree, and activity tolerance indicators before and after intervention. Results: Before intervention, there were no significant differences in blood gas analysis indicators, pulmonary function indicators, diaphragm function indicators, sputum comfort degree, and activity tolerance indicators between the two groups (P > 0.05). After intervention, the improvement degree of the above indicators in the observation group was higher than that in the control group (P < 0.05). Conclusions: The application of external diaphragm pacemaker combined with active respiratory circulation technology in pulmonary rehabilitation of perioperative lung cancer patients is significant, which can effectively improve the pulmonary function, blood gas function, and diaphragm function of lung cancer patients after surgery, and improve the activities of daily living and quality of life of patients.

Numerical analysis of flow and heat transfer behavior in fin-tube flat-plate solar collector

Temperature distribution over the absorber plate of a parallel flow flat-plate solar collector is numerically analyzed. The governing differential equations with boundary conditions are solved numerically using fluent software. Effects of the inlet mass flux, inlet temperature and tube spacing on velocity and temperature distributions are discussed. Numerical results show that the distributions of velocity and temperature of fluid is unsymmetrical inside pipe.

南京仙新路长江大桥主桥结构设计

南京仙新路长江大桥主桥为跨径1760 m的单跨钢箱梁悬索桥,主缆垂跨比1/9,边跨跨径580 m,边中跨比0.33。该桥上、下游各设1根主缆,单根主缆由169股127∅5.4 mm镀锌铝高强钢丝索股组成,采用PPWS法施工,钢丝标准抗拉强度2100 MPa。吊索与索夹采用销接式结构,跨中设置柔性中央扣索,短吊索设置关节轴承。主索鞍采用宽鞍槽单纵肋铸焊结合构造,散索鞍采用底座式全铸结构。加劲梁采用扁平流线型封闭整体钢箱梁,总宽31.5 m,梁高4 m,顶板与U肋之间采用双面埋弧全熔透焊接。桥塔采用门形混凝土结构,总高277.3 m,其上横梁为预应力混凝土结构,外包N字造型钢结构;桥塔基础采用直径2.8 m钻孔灌注桩。南锚碇采用外径65 m圆形地下连续墙基础;北锚碇采用沉井基础,平面尺寸70 m×50 m,高50 m。对结构进行静力分析及抗风性能理论和试验研究,结果表明:结构强度、刚度均满足规范要求;在加劲梁上设置0.67 m高中央稳定板、两侧风嘴处设置1 m宽水平稳定板后,大桥的颤振、涡振等抗风性能均满足要求,且具备一定的阻尼储备。

超声在膈肌功能评估中的信度研究

目的:分析超声用于膈肌功能评估的一致性及可重复性。方法:采用PA12A型便携式彩色多普勒超声诊断系统。记录60例健康受试者平静呼吸和深呼吸时的膈肌数据,包括平静呼吸和深呼吸时的膈肌移动度、平静呼气和平静吸气时的膈肌厚度、最大呼气和最大吸气时的膈肌厚度,对以上指标的测试内信度、测试者间信度和重测信度分别进行分析。结果:测试内信度:平静呼吸时膈肌移动度、深呼吸时膈肌移动度、平静呼气时膈肌厚度、平静吸气时膈肌厚度、最大呼气时膈肌厚度和最大吸气时膈肌厚度的组内相关系数(intra-class correlation coefficient,ICC)值分别为0.99、0.99、0.99、0.99、0.99、0.99;测试者间信度方面6个指标的ICC值分别为0.84、0.80、0.82、0.82、0.83、0.77;重测信度:6个指标的相对信度ICC值分别为0.98、0.86、0.98、0.97、0.94、0.86;绝对信度6个指标的测量标准误(standard error of measurement,SEM)分别为0.09、0.39、0.01、0.02、0.02、0.03,SEM%分别为5.23%、8.40%、5.38%、5.7%、8.17%、8.77%,最小真正改变量(minimal detectable change,MDC)分别为0.26、1.08、0.03、0.04、0.04、0.09,MDC%分别为14.48%、23.28%、14.9%、15.8%、22.64%、24.31%;Bland-Altman图形分析显示无系统性误差。结论:超声在膈肌功能评估中具有良好信度。

基于组织多普勒成像校正膈肌超声参数评估无创机械通气呼吸困难患者膈肌功能

目的观察组织多普勒成像(TDI)校正膈肌超声参数用于评估无创机械通气呼吸困难患者膈肌功能的价值。方法前瞻性对31例因突发呼吸困难而接受无创机械通气<1 h患者(无创通气组)及31名健康体检者(对照组)行膈肌超声检查,测算膈肌移动度(DD)、呼气末期膈肌厚度(DTee)、吸气末期膈肌厚度(DTei)及膈肌增厚率(DTF),并以TDI模式测量膈肌收缩期(DPSV)及舒张期峰值速度(DPDV);计算以浅快呼吸指数(RSBI)校正后的DD及DTF(DD-RSBI、DTF-RSBI),根据DPSV及DPDV与呼吸频率乘积获得DPSV-RSBI及DPDV-RSBI,以DPSV及DPDV校正DD及DTF,获得膈肌收缩期(DD/DPSV及DTF/DPSV)及舒张期(DD/DPDV及DTF/DPDV)代偿做功指数。对上述超声参数进行组间比较;绘制受试者工作特征曲线,计算曲线下面积(AUC),分析各参数评估无创机械通气呼吸困难患者膈肌功能的效能。结果无创通气组DPSV、DPDV、DD-RSBI、DTF-RSBI、DPSV-RSBI及DPDV-RSBI均高于,而DD/DPSV、DD/DPDV、DTF/DPSV及DTF/DPDV均低于对照组(P均<0.05);组间DD、DTee、DTei及DTF差异均无统计学意义(P均>0.05)。DPSV-RSBI及DPDV-RSBI用于评估无创通气呼吸困难患者膈肌功能效能优异(AUC=0.974、0.919),DPSV、DD-RSBI、DTF-RSBI、DD/DPSV及DTF/DPSV效能尚好(AUC为0.760~0.881),而DD、DPDV、DTee、DTei、DTF、DD/DPDV及DTF/DPDV效能差或一般(AUC为0.467~0.698)。结论TDI校正膈肌超声参数可有效评估无创通气呼吸困难患者膈肌功能。

床旁膈肌超声在预测胸腔镜肺叶切除术后肺部并发症中的应用价值

目的评估床旁膈肌超声在预测胸腔镜肺叶切除术后肺部并发症(PPCs)中的应用价值。方法收集河南省人民医院择期行胸腔镜肺叶切除术患者,记录一般资料、围术期相关指标;术前,术后1、3、5 d床旁超声检测膈肌活动度(DE1d、DE3d、DE5d)。根据是否发生PPCs将患者分为两组(PPCs组和非PPCs组)。将单变量分析中有统计学差异的参数纳入多变量logistic回归分析中,筛选PPCs的独立影响因素。绘制受试者工作曲线(ROC),并通过曲线下面积(AUC)评估膈肌超声预测PPCs的效能。结果共纳入患者934例,其中537例发生PPCs(57.5%)。单因素分析显示:与非PPCs组比较,PPCs组糖尿病患者占比、术后24 h活动VAS评分增加;胸管拔除时间、单肺通气时间、术后住院时间长;PPCs组患者术后DE1d、3d手术侧、健侧;DE5d手术侧DE值低(P<0.05)。多因素logistic回归分析显示:单肺通气时间延长、糖尿病、术后(DE1d、3d)手术侧、健侧和DE5d手术侧DE值降低是发生PPCs的独立危险因素。ROC曲线显示:术后DE1d、3d的手术侧、健侧预测PPCs的效能较高(AUC分别为0.797、0.821、0.933、0.929);术后DE5d手术侧、健测预测PPCs效能较弱(AUC分别为0.703、0.512)。结论术后相应时间DE降低、单肺通气时间延长、糖尿病是胸腔镜肺叶切除术后发生PPCs的独立危险因素,术后3 d应用床旁超声评价DE对PPCs具有较高的预测价值。

北京地铁薄壁地下连续墙基坑变形规律统计分析

[目的]地下连续墙(以下简称“地连墙”)厚度对基坑变形量与变形模式的影响较为明显,尤其是薄壁地连墙对于基坑开挖和坑边荷载十分敏感。因此,有必要对北京地铁不同壁厚的地连墙基坑变形规律进行研究。[方法]以北京地铁6座薄壁地连墙车站基坑工程为例,使用统计学方法对其地面竖向变形、地连墙墙顶竖向变形、地连墙水平位移及钢支撑轴力的监测数据进行统计分析。[结果及结论]薄壁地连墙基坑的地面变形可分为隆起-沉降型和沉降型两种,且地面变形中隆起变形的占比较高。土方开挖阶段,地连墙呈快速隆起趋势,开挖结束后墙顶隆起值产生小幅回落,并最终达到稳定值。根据地连墙变形特征,将其分为正常抛物线型、荷载抛物线A型、荷载抛物线B型3种类型。地连墙最大变形位置一般处于0.50H~0.85H(H为基坑深度),累计变形量集中于10~20 mm。第1道钢支撑轴力变化特征较为明显,其曲线可分为快速上升、快速下降、缓慢下降、快速上升4个阶段。

变光阑长波红外连续变焦光学系统设计

非制冷长波连续变焦光学系统由于相对孔径大导致小型化和无热化设计困难,本文采用可变光阑约束物镜尺寸压缩系统总长,实现长波640×512非制冷连续变焦光学系统轻小型化设计。通过材料合理配置及主动补偿实现5片透镜的8.5×连续变焦光学系统消热设计。该系统F#恒定1.2、工作波段为8~12μm、视场变焦范围为30°×24°~3.5°×2.8°、系统总长187.5 mm,该连续变焦光学系统重量轻、总长短、透过率高、在-40℃~+60℃温度范围全视场成像质量良好。

装配式地连墙接缝变形特性研究

为了研究接缝对装配式地连墙变形特性的影响并采取合理的改进措施,采用现场试验的方法将局部现浇地连墙替换为装配式地连墙,并对其实测的变形数据进行了对比分析;在实测数据分析的基础上,通过PLAXIS2D有限元软件模拟分析了不同深度横向接缝对装配式地连墙变形特性的影响规律;通过PLAXIS3D有限元软件对比了现浇墙与装配式地连墙水平方向及竖直方向变形形态,分析了竖向接缝对装配式地连墙变形特性的影响规律;最后,针对实测数据显示出的变形偏大问题,提出了改变冠梁刚度、围檩刚度、墙幅宽度、支撑位置4种改进措施,并通过PLAXIS3D有限元软件进行了验证。结果表明:装配式地连墙的接缝对墙体的刚度存在弱化作用,增大了其变形程度;位于坑底以上的横向接头失效时,墙体水平位移会显著增大,位于坑底以下的横向接头失效时,不会引起墙体水平位移的显著增大;竖向接头会显著减小装配式墙体的整体刚度,使其协同变形能力变差,变形更加难以控制;适当调节支撑位置可有效缓解墙幅间的错动和减小墙体变形。

MEMS电容薄膜真空计微电容检测系统的设计

为了满足空间环境探测对真空测量仪器准确度高、体积小、质量轻、功耗低的应用需求,基于微机电系统(MEMS)的小型化电容薄膜真空计应运而生。针对MEMS电容薄膜真空计微小电容测量需求,设计了一种基于CDC电容数字转换器的微电容检测系统,获得了fF级微电容检测分辨率。采用温度漂移误差自校准技术,解决了测量压力受温度扰动影响的问题。地面样机测试与验证表明,该检测系统具有宽量程、高分辨率和低功耗检测的优点,为MEMS电容薄膜真空计实现空间应用奠定了技术基础。

饱和黏性土地基中邻近圆形基坑相互影响分析

间距很小的圆形基坑后方土压力分布复杂,很难判断考虑圆拱效应的竖向弹性地基梁法和三维弹性地基板法的适用性。采用三维连续介质有限元法对位于饱和黏性土中2个间距很小的由地下连续墙组成的圆形事故应急池基坑进行整体建模分析。结果表明,对于1号池开挖到底后和2号池开挖到底后2种工况,地下连续墙的最大水平位移和最大弯矩的差异都不大。基坑位移和竖向弯矩的实测结果与计算值也较为接近。2个相邻圆形基坑在间距很小的情况下,其相互影响也是非常有限的。圆形地下连续墙支护结构对周围土体刚度参数的变化不敏感。采用三维连续介质有限元法对圆形地下连续墙支护结构进行计算分析,得到的结构内力远小于考虑圆拱效应的竖向弹性地基梁法和三维弹性地基板法,在经济性上有明显优势。

慢性阻塞性肺疾病并发膈肌疲劳的中西医研究进展

慢性阻塞性肺疾病(COPD)膈肌疲劳是常见病症,当膈肌疲劳时,其收缩力和耐力都会下降,导致呼吸困难、气短等症状。长期的膈肌的疲劳会造成膈肌的损伤从而严重影响患者生活质量。西医研究显示,COPD患者膈肌功能异常,病理改变与膈肌疲劳有关。目前治疗以药物和呼吸康复为主,效果有限。中医认为病机为肺脾肾虚弱、气血不足、痰湿阻络,治疗以补益肺脾肾、化痰通络为主。运用针灸、中药等可增强膈肌功能。本文从发病原因、发生机制和相关治疗这三个方面展开讨论COPD膈肌疲劳的研究进展,以期为加强中西医学合作,为COPD膈肌疲劳的研究治疗提供新的思路和依据。

体外膈肌起搏器联合间歇式训练在慢性阻塞性肺疾病急性加重期患者肺康复中的应用

目的探讨体外膈肌起搏器联合间歇式训练在慢性阻塞性肺疾病急性加重期(AECOPD)患者肺康复中的应用价值。方法选取2019年2月至2022年2月南京市第一医院呼吸内科门诊或急诊收治的100例AECOPD患者,采用随机数字表法将其分为对照组和试验组,各50例。对照组采用间歇式训练干预,试验组采用体外膈肌起搏器联合间歇式训练,两组均持续接受干预到出院,出院时进行效果评价。对两组膈肌功能、肺功能进行比较。结果干预后,两组膈肌活动度、膈肌增厚分数高于干预前,且试验组高于对照组,差异有统计学意义(P<0.05)。干预后,两组第1秒用力呼气量(FEV_(1))、用力肺活量(FVC)、FEV_(1)/FVC水平高于干预前,且试验组高于对照组,差异有统计学意义(P<0.05)。结论采用体外膈肌起搏器联合间歇式训练干预AECOPD患者能显著改善膈肌功能,促进肺功能康复。

开洞刚性墙后土体破坏模式运动单元上限分析

超载作用下开洞地下刚性连续墙后土体稳定性问题具有广泛的工程应用背景。考虑墙体矩形开洞宽度足够大,且刚性墙与土体完全光滑接触等条件,参考构造刚性多块体上限法思路,预设墙后土体极简破坏机构并转化为初始三角网格,提出交替循环式新增节点、单元缩减、对角互换及成层加密等网格更新措施,同步开展基于刚体平动运动单元上限方法的刚性墙后土体破坏分析,通过多层级非线性规划运算获得高精度临界超载系数σ_(s)/c上限解,界定墙后土体滑移线网破坏模式及其定量范围与扩展边界。进一步依前述流程计算获得多参数影响下的临界超载系数σ_(s)/c上限解图表,结果表明:1)刚性墙后土体典型破坏特征表现为土体上方和开洞处的整体下沉刚性区域,开洞前方核心区域以密集滑移线网区隔的刚性滑块群,以及外围主要滑动面;2)临界超载系数σ_(s)/c随土体内摩擦角ϕ增大而增大,且后续增幅显著增加;3)σ_(s)/c随开洞深度比C/D的增大呈现出近似线性增大的趋势;4)相较于ϕ和C/D,土体重度参数γD/c的变化对于σ_(s)/c的影响不甚明显,σ_(s)/c随γD/c增大呈现近似线性减小的趋势;5)σ_(s)/c受剪胀角参数ψ/ϕ的影响与ϕ的增大程度密切相关。本研究结果可为开洞地下刚性连续墙后土体失稳破坏模式定量分析、破坏机理研究及工程措施制定等工作提供有力的数据支持。