A complication of double lumen hemocatheter guide wire entrapment in a hemodialysis patient

Double lumen hemocatheter is commonly used for temporary hemodialysis patient and various complications have been documented but few reports of guide wire‐related complications. We report a complication of double lumen hemocatheter guide wire entrapment in a 43‐year‐old female of type 1 diabetes mellitus and hemodialysis patient. She was admitted for left arteriovenous shunt dysfunction and right internal jugular vein hemocatheter chamber clotting was found while on hemodialysis, so a new hemocatheter was changed over guide wire. Guide wire was introduced without any resistance and the clotting hemocatheter was removed. During the procedure, the J‐tipped guide wire could not be withdrawn and portable chest radiography revealed the J‐tip of the guide wire was in the right ventricle near the region of tricuspid valve. Fluoroscopy was arranged and it also confirmed the J‐tip was lying in the ventricle near the tricuspid valve where it was stuck. Snare catheter kit was inserted through the 10 Fr sheath and the cardiologist untied the knot by endovascular snare and removed the guide wire smoothly. This report emphasizes the importance of awareness on guide wire entrapment while inserting double lumen hemocatheter. When a guide wire became hard to withdraw, extracting an entrapped guide wire with fluoroscopy guide and snare catheter is a preferable and minimal invasive approach.     

颈内静脉穿刺置管术术前彩色多普勒超声定位和术后超声监测的研究

目的:评估彩色多普勒超声监测颈内静脉置管术的临床价值。方法:应用彩色多普勒超声实时监测120例患者的置管过程,对临床"盲穿"不成功的25例患者及"盲穿"后出现并发症的30例患者进行超声检查分析。结果:120例经实时超声监测的患者均取得成功,没有出现严重的并发症;临床盲穿不成功的原因有误穿颈总动脉、颈内静脉瓣膜过长、误穿颈外静脉、穿入颈内静脉或锁骨下静脉的对侧壁致使导丝不能下移;"盲穿"后出现的并发症主要为血肿、导管堵塞、胸锁乳突肌肿胀、静脉血栓形成、胸腔积血、误穿动脉、假性动脉瘤形成、导管周围纤维鞘膜形成等。结论:超声定位有助于顺利完成颈内静脉穿刺置管,并且对颈内静脉穿刺的各种并发症能够作出准确的诊断。     

Optimizing the beam pattern of a forward-viewing ring-annular ultrasound array for intravascular imaging

Intravascular ultrasound (IVUS) imaging systems using circumferential arrays mounted on cardiac catheter tips fire beams orthogonal to the principal axis of the catheter. The system produces high resolution cross-sectional images but must be guided by conventional angioscopy. A real-time forward-viewing array, integrated into the same catheter, could greatly reduce radiation exposure by decreasing angiographic guidance. Unfortunately, the mounting requirement of a catheter guide wire prohibits a full-disk imaging aperture. Given only an annulus of array elements, prior theoretical investigations have only considered a circular ring of point transceivers and focusing strategies using all elements in the highly dense array, both impractical assumptions. In this paper, we consider a practical array geometry and signal processing architecture for a forward-viewing IVUS system. Our specific design uses a total of 210 transceiver firings with synthetic reconstruction for a given 3-D image frame. Simulation results demonstrate this design can achieve side-lobes under -40 dB for on-axis situations and under -30 dB for steering to the edge of a 60/spl deg/ cone.     

Inability to start hemodialysis after a smooth temporary hemodialysis catheter insertion procedure

Cannulation of the central vein for placement of the temporary dual-lumen catheter for hemodialysis can usually be safely and reliably performed under ultrasonographic guidance. Here, we report a case of aberrant catheter entry into the internal thoracic vein during an apparently smooth procedure. The value of sonographic guidance, together with fluoroscopy with or without venography, will be discussed.     

Maintenance of blood flow rate on dialysis with self‐centering CentrosFLO catheter: A multicenter prospective study

Introduction Chronic central venous catheters (CVC) for dialysis lose patency and deliver lower blood flow over time, often due to fibrous sheathing that covers the lumen tips. The CentrosFLO central venous catheter has a shape that directs the arterial and venous tips away from the walls of the vena cava and right atrium, making sheathing of the tips less likely. Methods A prospective, multicenter, single arm, non‐controlled, observational study was conducted at eight sites in the United States. All consenting dialysis patients receiving CentrosFLO catheters through the right or left internal jugular veins were accepted in the study, as long as the catheter was expected to be used for 45 days and was not an over‐the‐wire replacement for a previous CVC. Data were automatically collected on initial and average dialysis blood flow rate and initial arterial and venous pressures, for up to 26 weeks of dialysis therapy. Findings 75 patients were enrolled. Kaplan‐Meier analysis indicated that 87% of patients maintained blood flow rate over 300 mL/min throughout 26 weeks of follow‐up. There was no decline in average dialysis blood flow rate and no significant change in hydraulic resistance of the arterial or venous lumens of the catheters during the study. Discussion The CentrosFLO catheter demonstrates long term patency with good flow rates on dialysis, which, by comparison with previous studies, shows a clinically significant improvement in blood flow rate vs. other catheters. Stable hydraulic resistance of the catheter lumens showed no evidence of tip encroachment by fibrous sheaths.     

One patient,two malpositioned hemodialysis catheters, (hepatic vein and ascending lumbar vein), no fluoroscopy

Cuffed-tunneled hemodialysis catheter (CTHC) application via the femoral vein is a safe and effective alternative when peripheral vascular routes are exhausted for hemodialysis in patients with end-stage renal disease. Also, imaging methods have become more important for the diagnosis or prevention of the possible complications that may develop during or after catheter placements. Here, we present a case of hemodialysis catheter dysfunction due to the insertion of a CTHC tip into the hepatic vein, and into the left ascending lumbar vein at the next attempt. We think that the use of fluoroscopy, whether in the first catheter intervention or catheter change, is extremely important in preventing possible complications that may develop, or detecting them as soon as possible.     

绳锯线弓角静态测量方法的研究

金刚石绳锯在切割圆弧板材时,受到进给方向的阻力,形成"线弓角",使板材中部产生"过切",严重时导致材料报废.为解决这一问题,提出了线弓角的概念,从理论上提出了一种基于悬臂式力传感器的绳锯线弓角的静态测量方法,通过轴力传感器输出的电压值计算出线弓角度.试验在自行设计和搭建的绳锯线弓角测量平台上进行,用钢丝绳模拟串珠绳产生线弓角,并进行导轮受力与线弓角关系的静态测量试验分析,以验证该方法测量线弓角的可行性.试验结果表明:在一定范围内,串珠绳初始张紧力越大,线弓角的计算值越接近理论值.因此,采用所提出的测量方法,当装有轴力传感器的导轮处在刚好与钢丝绳接触的状态下,选择合适的初始张紧力,可以测得较准确的角度值.     

Preliminary assessment of the dose to the interventional radiologist in fluoro-CT-guided procedures

A preliminary assessment of the occupational dose to the intervention radiologist received in fluoroscopy computerised tomography (CT) used to guide the collection of lung and bone biopsies is presented. The main aim of this work was to evaluate the capability of the reading system as well as of the available whole-body (WB) and extremity dosemeters used in routine monthly monitoring periods to measure per procedure dose values. The intervention radiologist was allocated 10 WB detectors (LiF: Mg, Ti, TLD-100) placed at chest and abdomen levels above and below the lead apron, and at both right and left arms, knees and feet. A special glove was developed with casings for the insertion of 11 extremity detectors (LiF:Mg, Cu, P, TLD-100H) for the identification of the most highly exposed fingers. The H(p)(10) dose values received above the lead apron (ranged 0.20-0.02 mSv) depend mainly on the duration of the examination and on the placement of physician relative to the beam, while values below the apron are relatively low. The left arm seems to receive a higher dose value. H(p)(0.07) values to the hand (ranged 36.30-0.06 mSv) show that the index, middle and ring fingers are the most highly exposed. In this study, the wrist dose was negligible compared with the finger dose. These results are preliminary and further studies are needed to better characterise the dose assessment in CT fluoroscopy.     

Radiation exposure of the operator during cardiac catheter ablation procedures

Radiation exposure of the operator during cardiac catheter ablation procedures was assessed for an experienced cardiologist adopting various measures of radiation protection and utilised electroanatomic navigation. Chip thermoluminescent dosemeters were placed at the eyes, chest, wrists and legs of the operator. The ranges of fluoroscopy time and air kerma area product values associated with cardiac ablation procedures were wide (6.3-48.3 min and 1.7-80.3 Gy cm(2), respectively). The measured median radiation doses per procedure for each monitored position were 23.6 and 21.3 μSv to the left and right wrists, respectively, 25.3 and 30.4 μSv to the left and right legs, respectively. The doses to the eyes were below the minimum detectable dose of 9 μSv. The estimated median effective dose was 22.5 μSv. Considering the actual workload of the operator, the calculated annual doses to the hands, legs and eyes, as well as the annual effective dose, were all below the corresponding limits. The findings of this study indicate that cardiac ablation procedures performed at a modern laboratory do not impose a high radiation hazard to the operator when radiation protection measures are routinely adopted.     

An integrated compliant balloon ultrasound catheter for intravascular strain imaging

An integrated compliant balloon ultrasound catheter was developed to allow greater deformations in strain imaging with intravascular ultrasound. A 64-element circumferential array was placed inside a compliant silicone balloon catheter to capture real-time, phase-sensitive radio frequency (RF) data during deformation experiments. Strains over 40% could be applied to normal arterial wall tissue with intracatheter pressures as low as 200 kPa (2 atm). Strain images of a hard-soft rubber phantom, thrombus, and fibrotic plaque were produced using the integrated balloon ultrasound catheter. Results show that this catheter can apply large deformations at low pressures and image various vascular pathologies ex vivo. Potentially, it can serve as a multifunctional, intravascular therapeutic device to guide angioplasty and stent deployment.     

应用TRIZ理论对钢丝绳电动葫芦导绳器的改进设计

 TRIZ(发明问题解决理论)的发明原理数据库可以为设计人员提供设计案例进行结构的类比创新.钢丝绳电动葫芦导绳器发生损坏以后,其原有弧形压板更换时安装拆卸麻烦.针对这一问题,利用TRIZ中的冲突分析解决方法对其进行详细分析,并利用基于TRIZ构建的软件系统获得相应的发明原理.根据所得到的发明原理对钢丝绳电动葫芦导绳器进行改进设计,所提出设计方案一方面可提高钢丝绳电动葫芦的性能,为钢丝绳电动葫芦的使用带来社会效益,也可以进一步补充TRIZ发明原理案例数据库,给其他应用该系统中发明原理的设计者以启发．     

Femoral arteriovenous fistula 3 months after removal of catheter for hemodialysis

A 56‐year‐old Asian woman was admitted to hospital for the consideration of hemodialysis (HD). A right femoral dialysis catheter was inserted for HD. Three months after removal of catheter, she was admitted because of right inguinal swelling. A thrill and bruit were felt and heard at the inguinal area. Color Doppler detected a fistula between right superficial femoral artery and right common femoral vein and subsequently confirmed by contrast enhanced computed tomography scan and 3‐dimensional reconstruction with computed tomography. At surgery, a 4‐mm–diameter fistula was found between the right superficial femoral artery and right common femoral vein. A primary closure of both defects in the artery and vein was then carried out. A follow‐up digital vascular study 3 months after surgical repair was normal. In conclusion, nephrologist should have a heightened awareness to the potential of this complication and should at least document a normal exam following the removal of femoral catheters.     

Accidental extravascular insertion of a subclavian hemodialysis catheter is signaled by nonvisualization of catheter tip

Subclavian hemodialysis (HD) catheter placement under fluoroscopy with perforation of the superior vena cava (SVC) is a rare complication that needs to be recognized and treated appropriately. We report the case of a 47-year-old black woman under treatment for end-stage renal disease secondary to HIV-associated nephropathy who sustained an extravascular insertion of fluoroscopy-guided subclavian catheterization for HD. Subsequent successful removal of the extravascularly placed catheter along with repair of the lacerated SVC were effected by open thoracic surgery.     

Remove or not,that is the question: A case report on carotid artery cannulation during indwelling venous hemodialysis catheter

A 58‐year‐old woman visited the emergency department for acute occlusion of arteriovenous fistula. One session of hemodialysis was scheduled via temporary venous hemodialysis catheter before thrombectomy. Unfortunately, neck arterial cannulation was discovered after complete placement of catheter. The catheter was removed immediately but bleeding could not be stopped. Pseudoaneurysm over the right carotid artery was proved by angiography and repaired by graft stent. Arterial cannulation during venous hemodialysis catheter insertion is a rare but serious complication and there is no standard response recommended. Immediate removal of the misplaced hemodialysis catheter might not be the best choice. We suggest to leave the misplaced catheter in artery until further intervention in consideration of complications and repair access. Every hemodialysis center should standardize responses to arterial cannulation during venous hemodialysis catheter indwelling, especially carotid puncture happens, according to the medical facility.     

Catheter tip malposition after percutaneous placement of tunneled hemodialysis catheters

The percutaneous catheterization of central veins is increasingly used in nephrological practice as a temporary or permanent vascular access. The aim of our study was to present and to analyze episodes of catheter tip malposition during percutaneous tunneled hemodialysis catheter insertion in the large, unselected group of patients. All patients who underwent the procedure of catheter insertion in our department during year 2012 were analyzed retrospectively. One hundred four tunneled hemodialysis catheters were inserted in 101 patients. In 58 patients, the catheter was inserted at the initiation of hemodialysis therapy as the first access and in 46 the catheter was placed because of the failure of the existing one. In 68 patients, the catheter was inserted into the right internal jugular vein and in 20 patients into the left internal jugular vein (LIJV). Subclavian veins were used in five cases and femoral veins in 11 cases. Malposition of the catheter tips occurred in six patients. In all cases, the LIJV was cannulated. In two cases, the catheter tip malposition was in the right innominate vein and in four cases in the azygos vein. Our data demonstrate that with the blind insertion of tunneled hemodialysis catheters, the risk of catheter tip malposition is significantly higher with the left side insertion. As catheter insertion through the LIJV holds very high (30%) risk of the tip malposition, it should always be performed under the fluoroscopic control.     

The permanent catheter

An elderly woman receiving hemodialysis via a right brachiocephalic arteriovenous fistula presented to the clinic for elective removal of a tunneled hemodialysis catheter inserted 5 years ago. The catheter had not been removed earlier at the patient's request. Removal was now unsuccessful in the clinic. Exploration in the operating room revealed the innominate vein had fibrosed around the length of the catheter. The procedure was abandoned, catheter cut short and the remnant left in situ. This case serves as a reminder to exercise caution if there is difficulty in removing the catheter even after the cuff is dissected free, and to remove them once a working fistula or graft is available. Failing which, the patient bears an unnecessary risk of line infection, or as in this case, the catheter may unintentionally end up what its common misnomer “perm‐cath” alludes to – becoming truly “permanent.”     

Right atrial thrombus due to internal jugular vein catheter

Right atrial thrombus is rare complication of hemodialysis central venous catheter. Literature survey revealed 49 documentations of right atrial thrombus due to a central venous catheter. We report a 58-year-old type 2 diabetic, hypertensive, end-stage renal disease patient, who 2 months after initiation of hemodialysis through a right internal jugular vein catheter, developed clinical features suggestive of pulmonary thromboembolism. An echocardiography revealed presence of a serpentine thrombus in right atrium. The internal jugular vein catheter was removed and unfractionated heparin was initiated. At the end of 6 weeks he was symptom free. We compared conservative treatment with surgery for RAT. Conservative management with central venous catheter removal and anticoagulation therapy is not inferior to the surgery.     

3-D ultrasound guidance of surgical robotics using catheter transducers: feasibility study

The goal of this study was to test the feasibility of using a real-time 3-D (RT3D) ultrasound scanner with matrix array catheter probes to guide a surgical robot. We tested the accuracy of using 3-D catheter transducers with the 3-D measurement software of the scanner to direct automatically a robot arm that touched two needle tips together within a water tank and inside a vascular graft. RMS measurement error ranged from 2.4 to 3.4 mm for two catheter designs.     

包装机送丝导路结构分析与设计

介绍了冶金厂矿高温线材(小盘卷)在线快速包装中送丝导路的方案形成和工作原理,并从包装机送丝导路的理论探导入手,设计了相关参数,分析了导路结构,经样机试验和现场使用,该导路结构能满足打捆要求,达到了设计目的.     

全自动引线键合机送丝系统受力模型及实验

丝线传输的阻力控制和张紧力控制是引线键合机送丝系统的关键技术之一,对键合质量有着重要的影响．为了解决当前全自动引线键合机送丝系统中的传输阻力大、传输张力不稳定等问题,根据引线键合工艺过程和系统的技术要求,设计了由气体导轨和真空张紧装置组成的低摩擦送丝系统,来实现金丝的低阻传输．建立了金线在气体导轨和真空张紧装置内的受力模型,得出了二者的控制参数与金线作用力的关系;分别对金丝在气体导轨和真空张紧装置内的受力模型进行了实验验证,实验结果表明达到了所要求的低摩擦力要求．