Intrapulmonal dislocation of a totally implantable venous access device

BACKGROUND: Totally implantable venous access devices are widely used for infusion of chemotherapy or parenteral nutrition. Device associated complications include technical operative problems, infections, paravasal infusions and catheter or punction chamber dislocation. CASE PRESENTATION: We present the case of a 49-year-old patient with the rare complication of a intrapulmonal catheter dislocation of a totally implantable venous access system. Treosulfane for chemotherapy of metastatic breast cancer was infused via the catheter causing instant coughing and dyspnoea which lead to the diagnosis of catheter dislocation. The intrapulmonal part of the catheter was removed under thoracoscopic control without further complications. CONCLUSION: Intrapulmonal catheter dislocation is a rare complication of a totally implantable venous access device which can not be avoided by any prophylactic measures. Therefore, the infusion system should be tested before each use and each new symptom, even when not obviously related to the catheter should be carefully documented and evaluated by expert physicians to avoid severe catheter-associated complications.     

Intramuscular pressures during exercise: an evaluation of a fiber optic transducer-tipped catheter system

The efficacy of a modified fibre optic transducer-tipped catheter system for measuring intramuscular pressures during exercise was determined. A microcapillary infusion technique using a catheter was employed as the standard of comparison due to its established dynamic properties. Pressures were measured in the tibialis anterior muscle of six healthy adults at rest before exercise, during isometric and concentric exercise, and at rest after exercise. The fibre optic system measured contraction pressures equal to the microcapillary infusion technique during all phases of the exercise protocols but recorded a lower relaxation pressure during isometric exercise and a lower rest pressure following 20 min of concentric exercise. Negative relaxation pressures were recorded by the fibre optic system for two subjects during continuous concentric exercise. It is hypothesized that a piston effect, due to the sliding of muscle fibres at the catheter tip following a contraction, rendered falsely low pressures during relaxation and that this artefact was reflected in the subsequent rest pressure following exercise. The larger volume (157 mm3) and area (3.49 mm2) of the fibre optic catheter in the muscle made it more prone to this effect than the conventional catheter (39 mm3 and 0.87 mm2, respectively). The fibre optic system may be preferred when recording the muscle contraction pressures during complex limb movements but should not be used when assessing the relaxation pressures or the pressure at rest following exercise.     

Robotic Ablation of Atrial Fibrillation

Background: Pulmonary vein isolation (PVI) is an established treatment for atrial fibrillation (AF). During PVI an electrical conduction block between pulmonary vein (PV) and left atrium (LA) is created. This conduction block prevents AF, which is triggered by irregular electric activity originating from the PV. However, transmural atrial lesions are required which can be challenging. Re-conduction and AF recurrence occur in 20 - 40% of the cases. Robotic catheter systems aim to improve catheter steerability. Here, a procedure with a new remote catheter system (RCS), is presented. Objective of this article is to show feasibility of robotic AF ablation with a novel system. Materials and Methods: After interatrial trans-septal puncture is performed using a long sheath and needle under fluoroscopic guidance. The needle is removed and a guide wire is placed in the left superior PV. Then an ablation catheter is positioned in the LA, using the sheath and wire as guide to the LA. LA angiography is performed over the sheath. A circular mapping catheter is positioned via the long sheath into the LA and a three-dimensional (3-D) anatomical reconstruction of the LA is performed. The handle of the ablation catheter is positioned in the robotic arm of the Amigo system and the ablation procedure begins. During the ablation procedure, the operator manipulates the ablation catheter via the robotic arm with the use of a remote control. The ablation is performed by creating point-by-point lesions around the left and right PV ostia. Contact force is measured at the catheter tip to provide feedback of catheter-tissue contact. Conduction block is confirmed by recording the PV potentials on the circular mapping catheter and by pacing maneuvers. The operator stays out of the radiationfield during ablation. Conclusion: The novel catheter system allows ablation with high stability on low operator fluoroscopy exposure.     

A surgical procedure and tethering system for chronic blood sampling, infusion, and temperature monitoring in caged nonhuman primates

A jacket and tethering system was used to maintain chronic catheters in monkeys, which provided catheter access and manipulability without further restraint. Surgical placement of catheters and a temperature probe allowed for a common cutaneous exit and interface with the jacket and tether. Monkeys were fitted in a sterile leather or denim jacket which was attached to a sterilized flexible stainless steel cable. Through this conduit, an indwelling temperature probe, as well as catheters from the internal jugular and femoral veins, were attached to a swivel unit located on the upper portion of the cage. The internal jugular catheter was used for the continuous infusion of support solution. The catheter from the femoral vein was maintained with a heparin lock and used for serial blood sampling. Using this system, it was possible to obtain frequent blood samples and body temperature readings, and to administer a continuous intravenous infusion without chemical or excessive physical restraint. To date, 367 monkeys, 322 cynomolgus (Macaca fasicularis), 16 rhesus (Macaca mulatta), and 21 African green (Cercopithecus aethiops) have been studied using this procedure.     

A new catheter for tumor targeting with radioactive microspheres in representative hepatic artery systems. Part I: impact of catheter presence on local blood flow and microsphere delivery

Building on previous studies in which the transport and targeting of (90)Y microspheres for liver tumor treatment were numerically analyzed based on medical data sets, this two-part paper discusses the influence of an anchored, radially adjustable catheter on local blood flow and microsphere delivery in an idealized hepatic artery system (Part I). In Part II a patient-inspired case study with necessary conditions for optimal targeting of radioactive microspheres (i.e., yttrium 90) onto liver tumors is presented. A new concept of optimal catheter positioning is introduced for selective targeting of two daughter-vessel exits potentially connected to liver tumors. Assuming laminar flow in rigid blood vessels with an anchored catheter in three controlled positions, the transient three-dimensional (3D) transport phenomena were simulated employing user-enhanced engineering software. The catheter position as well as injection speed and delivery function may influence fluid flow and particle transport. Although the local influences of the catheter may not be negligible, unique cross-sectional particle release zones exist, with which selectively the new controlled targeting methodology would allow optimal microsphere delivery. The insight gained from this analysis paves the way for improved design and testing of a smart microcatheter (SMC) system as well as new investigations leading to even more successful treatment with (90)Y microspheres or combined internal radiation and chemotherapy.     

Ureteral catheter system for renal function studies in conscious rabbits

To overcome the problem of obstruction of ureteral catheters with blood clots, a ureteral catheter was constructed which had a double lumen. Irrigation of blood from the catheter was accomplished by perfusion of heparinized saline through a small inner catheter. In renal function studies performed in 12 rabbits using this system, no instances of catheter obstruction occurred.     

Novel system for real-time ex vivo lactate monitoring in human whole blood

The objective of the study was to evaluate the performance of an amperometric enzyme based lactate sensor and to investigate the possibility of replacing a double lumen catheter based blood withdrawal system with a heparin coated single lumen system. The inner lumen of a double lumen catheter which was placed in a peripheral vein was perfused with heparin solution. The outer lumen was used to collect heparinized blood samples at a defined flow rate. The single lumen system was attached to a heparinized catheter which was also placed in a peripheral vein. The undiluted blood samples were collected at a specified flow rate. A sensor flow chamber incorporating an amperometric thin-film lactate microbiosensor was placed in the sampling line for real-time lactate monitoring. Plasma lactate concentrations were measured during frequently performed hyperlactatemia bicycle ergometer experiments in six healthy volunteers (age 25.8±2.8 years, BMI 22.7±1 kg/m²). Additionally, plasma lactate was measured in real-time using the lactate sensors. The first three experiments were performed with a double lumen based catheter system whereas the following three experiments were performed with a heparin coated catheter system. The correlation coefficients of sensor readings and laboratory analyzer results in all six experiments were between 0.93 and 0.99, respectively (P<0.001). The miniaturized lactate sensors showed a linear range up to 25 mmol/l lactate concentration and 95% response times <30 s in undiluted serum. During the experiments maximum lactate concentrations of 14 mmol/l were achieved. Improvements of system performance using heparin coated catheter systems could be shown. The overall SD of the sensor readings compared to laboratory results using three double lumen catheter based systems was 0.91 mmol/l whereas the SD using three heparin coated systems was 0.65 mmol/l. In summary, real-time monitoring of lactate in human whole blood is feasible with such a device and can be improved by using heparin coated catheter systems.     

Tricuspid annular PVCS: Radiofrequency ablation by subtricuspid retrograde catheter approach

Tricuspid annular PVCs constitute 8% of idiopathic PVCs and 5% of RV PVCs. Although a rare entity to encounter in routine clinical practice, it can be a prime culprit behind major arrhythmic burden in few individuals. Electroanatomic approach with sub tricuspid retrograde catheter technique can target those annular PVCs and decrease the arrhythmia burden to normal or near normal range. Although procedural approach for parahisian PVCs requires a close look to avoid injury to native conduction system, TA PVCs are a real challenge due to inherent catheter instability and contact issue in sub tricuspid retrograde approach.     

Implantable device for intravenous drug delivery in the rat.

The experimental design of studies using small laboratory animals may require repeated venous access for the application of drugs or diagnostics. An appropriate device should provide quick intravenous access without causing severe handling stress to the animals or the necessity of anaesthesia. In addition, the system should be suitable for repeated injections over several weeks. A silicone catheter is connected to an intravenous indwelling cannula with fixation wings. A closure stopper with injection port completes this system. The device is fixed subcutaneously on the back of the animal and the catheter is inserted into the jugular vein. The device is easily and quickly assembled and is more economic than commercial systems. It is easily implanted and allows repeated intravenous injections for several weeks without anaesthesia or restraint of the animals. The method allows repeated intravenous drug delivery over a couple of weeks in small animals.     

Femoral Arterial and Venous Catheterization for Blood Sampling,Drug Administration and Conscious Blood Pressure and Heart Rate Measurements

In multiple fields of study, access to the circulatory system in laboratory studies is necessary. Pharmacological studies in rats using chronically implanted catheters permit a researcher to effectively and humanely administer substances, perform repeated blood sampling and assists in conscious direct measurements of blood pressure and heart rate. Once the catheter is implanted long-term sampling is possible. Patency and catheter life depends on multiple factors including the lock solution used, flushing regimen and catheter material. This video will demonstrate the methodology of femoral artery and venous catheterization of the rat. In addition the video will demonstrate the use of the femoral venous and arterial catheters for blood sampling, drug administration and use of the arterial catheter in taking measurements of blood pressure and heart rate in a conscious freely-moving rat. A tether and harness attached to a swivel system will allow the animal to be housed and have samples taken by the researcher with minimal disruption to the animal. To maintain patency of the catheter, careful daily maintenance of the catheter is required using lock solution (100 U/ml heparinized saline), machine-ground blunt tip syringe needles and the use of syringe filters to minimize potential contamination. With careful aseptic surgical techniques, proper catheter materials and careful catheter maintenance techniques, it is possible to sustain patent catheters and healthy animals for long periods of time (several weeks).     

90% of general hospital care now accredited

Embolization of catheter fragments or fractured spring guidewires used during cardiac catheterization or fractured central venous pressure (CVP) lines is not uncommon. Although CVP lines are usually used in seriously ill patients, often with complications secondary to prior surgical intervention, if the catheter fragments are not removed they can give rise to serious illness or death in about 50% of patients. Experience with the removal of nine such catheter fragments is reported. In eight patients a helical basket was available for removal through a Dotter retrieval catheter. With prolonged hyperalimentation therapy polyethylene catherters become very brittle. They are relatively easy to grip with the wire basket. Silicone elastomer catheters remain pliable but are so bouncy that they are difficult to grip. For removal of catheter fragments from vessels of small diameter, such as the subclavian vein, or vessels in which the catheter has to take an acute bend to enter, such as the right or left pulmonary artery, a smaller, more pliable Bean-Smith-Mahorner biliary stone helical basket was adapted by extending the length of wire to 100 cm. For removal of catheter fragments from the right pulmonary artery it is probably better to use a softer, 100-cm-long no. 8 French right heart catheter. A Dotter retriever catheter set with both large and small helical wire baskets should be available in any cardiac catheterization laboratory.     

Carotid Artery Infusions for Pharmacokinetic and Pharmacodynamic Analysis of Taxanes in Mice

When proposing the use of a drug, drug combination, or drug delivery into a novel system, one must assess the pharmacokinetics of the drug in the study model. As the use of mouse models are often a vital step in preclinical drug discovery and drug development^1-8, it is necessary to design a system to introduce drugs into mice in a uniform, reproducible manner. Ideally, the system should permit the collection of blood samples at regular intervals over a set time course. The ability to measure drug concentrations by mass-spectrometry, has allowed investigators to follow the changes in plasma drug levels over time in individual mice^{1, 9, 10}. In this study, paclitaxel was introduced into transgenic mice as a continuous arterial infusion over three hours, while blood samples were simultaneously taken by retro-orbital bleeds at set time points. Carotid artery infusions are a potential alternative to jugular vein infusions, when factors such as mammary tumors or other obstructions make jugular infusions impractical. Using this technique, paclitaxel concentrations in plasma and tissue achieved similar levels as compared to jugular infusion. In this tutorial, we will demonstrate how to successfully catheterize the carotid artery by preparing an optimized catheter for the individual mouse model, then show how to insert and secure the catheter into the mouse carotid artery, thread the end of the catheter out through the back of the mouse’s neck, and hook the mouse to a pump to deliver a controlled rate of drug influx. Multiple low volume retro-orbital bleeds allow for analysis of plasma drug concentrations over time.     

An ultrafiltration catheter for monitoring of venous lactate and glucose around myocardial ischemia

Early detection of myocardial ischemia is of major importance in critical-care medicine. Changes of lactate or glucose levels in the cardial venous efflux may be useful parameters. We succeeded in integrating an ultrafiltration membrane in a cardiac catheter for continuous sampling. The ultrafiltrate was analyzed outside the body, resulting in a lag-time of about 24 min. Biosensors in a flow-injection analysis system were used for minute by minute sample analyses. The coronary sinus of pigs was catheterized to monitor the effects of 5, 15 or 45 min ischemia by coronary artery obstruction or myocardial stress by dobutamine infusion. A total of 27 h was monitored. The intravascular response time was 1.33+/-0.61 min (10-90%). Linear regression in vivo of blood and ultrafiltrate samples was 0.977 for lactate and 0.994 for glucose. Lactate levels rose 0.38+/-0.10 mM above baseline within 5 min after ischemia. Reperfusion was clearly marked by a promptly peaking lactate release (maximum 9.27 mM). Myocardial stress by dobutamine increased glucose but not lactate levels. Once, a wall effect was noted at the catheter tip. In vivo semi-continuous myocardial monitoring of absolute lactate and glucose concentrations was thus achieved by an ultrafiltration catheter. Ischemia and reperfusion can be detected very early by a lactate level rise. Further, development of the ultrafiltration catheter will be focused on the diagnostic potential of lactate monitoring for patients.     

High speed solution of 2nd order curves with special application to planar sections of blood vessels

Rapid determination of the areas of planar sections through a blood vessel are required in an on-line blood flow measurement system which utilizes an intravascular ultrasonic catheter. Vessel areas are determined by: (1) using a fast algorithm to fit an ellipse to 6 data points of the vessel wall's location measured with the ultrasonic catheter; (2) computing the area of the determined ellipse. The program is implemented in a general purpose computer with a hardware floating point processor, using 3320 of 16 bit words of memory for storing variables, data, look-up tables, and computation instructions. The program executes in 3 ms, which, when combined with the other computations and timing requirements of the system, allows instantaneous flow computation every 7.3 ms. The system is fast enough to follow pulsitile blood flow. The algorithm applies in other areas which also require fast quantitative measurement, for example, in determining organ or tissue structural contours describable with a 2nd order equation.     

A Transtracheal Catheter for Recording the Static Tracheal Pressure in the Exercising Horse

After giving an account of the principles of pressure measurement in flowing air and a review of the literature on tracheal catheters, the authors describe the construction, the introduction and the function of their own transtracheal catheter. This is a teflon catheter with several side–ports which is introduced into the cervical trachea by a guide technique. After introduction, the catheter is stiffened by the insertion of 2 steel wires. The catheter was studied in model experiments concerning: a) the ability to measure the static pressure in flowing air, and b) the dynamic accuracy of a recording system built up around the catheter. The results indicated that the intratracheal pressure sensed in exercising horses well reflected the static pressure, and that the dynamic accuracy of the recording system was good to about 60 Hz. The present technique of recording the intratracheal pressure was used on 122 occasions in 69 exercising horses with only one complication referable to the catheter occurring. The transtracheal route of catheterisation may be superior, as catheters introduced by this route do not appear to influence the function of the pharynx and larynx. In contrast, nasotracheal catheters that traverse the larynx, might interfere with the respiratory function. kw|Keywords|k]upper airway obstruction k]frequency response     

A procedure to secure a jugular vein catheter system onto the neck of the hamster

We describe a procedure to secure a jugular vein catheter system at the dorsal nape of the neck in the hamster. An 8-cm piece of silicone tubing is connected with a 2.6 cm L-shaped metal tubing which is embedded in prosthetic material. The prosthetic material is placed underneath the neck skin of the hamster and keeps the metal end of the catheter system in a sturdy, upright position.     

麦默通微创手术结合导管冲洗负压引流治疗乳房脓肿的临床效果观察

目的：探讨麦默通微创手术结合导管冲洗负压引流治疗乳房脓肿的临床效果。方法：选择2007年10月~2012年9月在我院治疗的180例乳房脓肿患者,全部在超声定位引导下行麦默通微创手术结合导管冲洗负压引流治疗,并观察其临床效果。结果：180例乳房脓肿患者完全恢复,住院天数6~10天,无1例并发乳瘘。常规病理结果均符合临床诊断。1~2年随访中,临床检查及乳腺B超检查均未发现复发迹象。结论：麦默通微创手术结合导管冲洗负压引流技术治疗乳房脓肿,切口隐蔽,操作简便,治疗彻底,可减少由于反复穿刺引起的感染,尤其适用于脓腔直径较大、位置较深、细针反复穿刺无效或复发者;术后换药冲洗简单易行,换药次数降低,明显减轻了患者痛苦;拔管后切口无需缝合,瘢痕小,并能维持乳房良好形态,提高了病人术后的生活质量,符合当今女性的审美要求。     

Technical delivery of myogenic cells through an endocardial injection catheter for myocardial cell implantation

BACKGROUND: The next clinical frontier in the therapeutics of ischemic heart disease may involve the development and delivery of specific molecules and cells into the myocardium. The aim of the present study was to evaluate the efficiency and safety of the MyoStar injection catheter (Biosense-Webster Inc.) that has recently been developed to deliver molecules and cells to the myocardium. The 8 Fr (110 cm length) catheter comprises a navigation sensor with a 27 gauge needle at the distal tip. METHODS: Mouse myogenic cells (C2) were delivered to a tissue culture dish through different modalities: a standard laboratory pipette, a syringe needle (27 gauge) and the injection catheter. The cells were counted and monitored for growth and differentiation in the tissue culture immediately after delivery and two, three and six days later. Cells that were injected through a regular syringe needle or through the injection catheter demonstrated the same capacity to proliferate in tissue culture up to six days. RESULTS: The behavior of the cells in culture (fusion) was identical for the cells delivered to the tissue culture by a pipette or by the injection catheter. CONCLUSION: The results of the present study indicate that delivery of cells through the MyoStar injection catheter is a method with no significant loss or adverse effects to the cells along the path of the catheter. The catheter, which possesses both injection and navigation capabilities, can be used to deliver cell therapy to patients with ischemic heart disease.     

External irrigation of a non-irrigated ablation catheter for effective AV node ablation during conduction system pacing

Ablation using non-irrigated catheter can lead to rapid rise in temperature of electrode tissue interface from tissue desiccation, steam and coagulum formation and this may limit power delivery and lesion size. We present a novel technique of external irrigation through the long sheath while using a non-irrigated ablation catheter during AV Node ablation and conduction system pacing. By bringing the long sheath closer to the tip of non-irrigated catheter and injecting cold normal saline allows cooling of electrode tissue interface leading to increase in power delivery resulting in a deeper lesion.     

An absorbable catheter system for use in microvascular and peripheral vascular surgery: an experimental study in the canine.

An absorbable catheter for use in regional anticoagulation in microvascular and peripheral vascular surgery was studied in 20 sites in 10 adult beagle dogs to answer three questions: (1) Could the polyglycolic acid and trimethylene carbonate catheter withstand intraarterial pressures of infusion and completely absorb over a predictable time interval? (2) Could the catheter be filled with heparin and maintain patency for reuse after a 24-hour interval? (3) Could the catheter be placed in a side branch of a major artery and, after catheter dissolution, maintain long-term patency of the primary feeding artery? The catheters were completely absorbed from 24 to 34 weeks following implantation. The catheters were able to withstand intraarterial pressures, and no evidence of significant thrombosis of the primary feeding artery was seen in any animal studied. No complications of catheter leak, hematoma formation within the catheter placement sites, or sepsis were noted in any of the 20 catheter sites studied.