Central venous catheter stiffness and its relation to vascular perforation

Stability of navigation in catheter-based endovascular procedures

Endovascular procedures provide surgeons and other interventionalists with minimally invasive methods to treat vascular diseases by passing guidewires, catheters, sheaths and treatment devices into the vasculature to and navigate toward a treatment site. The efficiency of this navigation affects patient outcomes, but is frequently compromised by catheter "herniation", in which the catheter-guidewire system bulges out from the intended endovascular pathway so that the interventionalist can no longer advance it. Here, we showed herniation to be a bifurcation phenomenon that can be predicted and controlled using mechanical characterizations of catheter-guidewire systems and patientspecific clinical imaging. We demonstrated our approach in laboratory models and, retrospectively, in patients who underwent procedures involving transradial neurovascular procedures with an endovascular pathway from the wrist, up in the arm, around the aortic arch, and into the neurovasculature. Our analyses identified a mathematical navigation stability criterion that predicted herniation in all of these settings. Results show that herniation can be predicted through bifurcation analysis, and provide a framework for selecting catheter-guidewire systems to avoid herniation in specific patient anatomy.

Hemodynamic performance evaluation of neonatal ECMO double lumen cannula using fluid-structure interaction

Extra corporeal membrane oxygenation (ECMO) is an artificial oxygenation facility, employed in situations of cardio-pulmonary failure. Some diseases i.e., acute respiratory distress syndrome, pulmonary hypertension, corona virus disease (COVID-19) etc. affect oxygenation performance of the lungs thus requiring the need of artificial oxygenation. Critical care teams used ECMO technique during the COVID-19 pandemic to support the heart and lungs of COVID-19 patients who had an acute respiratory or cardiac failure. Double Lumen Cannula (DLC) is one of the most critical components of ECMO as it resides inside the patient and, connects patient with external oxygenation circuit. DLC facilitates delivery and drainage of blood from the patient's body. DLC is characterized by delicate balance of internal and external flows inside a limited space of the right atrium (RA). An optimal performance of the DLC necessitates structural stability under biological and hemodynamic loads, a fact that has been overlooked by previously published studies. In the past, many researchers experimentally and computationally investigated the hemodynamic performance of DLC by employing Eulerian approach, which evaluate instantaneous blood damage without considering blood shear exposure history (qualitative assessment only). The present study is an attempt to address the aforementioned limitations of the previous studies by employing Lagrangian (quantitative assessment) and incorporating the effect of fluid-structure interaction (FSI) to study the hemodynamic performance of neonatal DLC. The study was performed by solving three-dimensional continuity, momentum, and structural mechanics equation(s) by numerical methods for the blood flow through neonatal DLC. A two-way coupled FSI analysis was performed to analyze the effect of DLC structural deformation on its hemodynamic performance. Results show that the return lumen was the most critical section with maximum pressure drop, velocity, shear stresses, and blood damage. Recirculation and residence time of blood in the right atrium (RA) increases with increasing blood flow rates. Considering the structural deformation has led to higher blood damage inside the DLC-atrium system. Maximum Von-Mises stress was present on the side edges of the return lumen that showed direct proportionality with the blood flow rate.

Quantification of the flexural rigidity of peripheral arterial endovascular catheters and sheaths

Endovascular catheter-based technologies have revolutionized the treatment of complex vascular pathology. Catheters and endovascular devices that can be maneuvered through tortuous arterial anatomy have enabled minimally invasive treatment in the peripheral arterial system. Although mechanical factors drive an interventionalist's choice of catheters and sheaths, these decisions are mostly made qualitative and based on personal experience and procedural pattern recognition. However, a definitive quantitative characterization of endovascular tools that are best suited for specific peripheral arterial beds is currently lacking. To establish a foundation for quantitative tool selection in the neurovascular and lower extremity peripheral arterial beds, we developed a nonlinear beam theory method to quantify catheter and sheath flexural rigidity. We applied this assessment to a sampling of commonly utilized commercially available peripheral arterial catheters and sheaths. Our results demonstrated that catheters and sheaths adopted for existing practice patterns to treat peripheral arterial disease in the lower extremities and neurovascular system have different but overlapping ranges of flexural rigidities that were not sensitive to luminal diameters within each procedure type. Our approach provides an accurate and effective method for characterization of flexural rigidity properties of catheters and sheaths, and a foundation for developing future technologies tailored for specific peripheral arterial systems.

Acute mediastinitis secondary to delayed vascular injury by a central venous catheter and total parenteral nutrition

Vascular injury caused by a central venous catheter (CVC) has been reported to be a rare complication, especially delayed vascular injury due to CVC has a few cases and it can be fatal because of delayed recognition and more serious complications. A 59-year-old woman with no available medical history was admitted for treatment of ovarian cancer. For the surgery, a triple-lumen CVC was placed through the left subclavian vein. Parenteral nutrition through the CVC was used for postoperative nutritional management in the first postoperative day. On the sixth postoperative day (POD), the patient suddenly complained of dyspnea. The CT revealed bilateral pleural effusion and irregular soft tissue density and air bubble in anterior mediastinum suggesting migration of the distal portion of the CVC into the anterior mediastium. In the intensive care unit (ICU) bilateral thoracentesis and percutaneous drainage were performed. She was discharged from the ICU in 3 days later and transferred to the general ward. This case emphasizes the possibility of the delayed vascular injury related to CVC and some strategies for prevention of vascular injury.

Pericardial effusion and cardiac tamponade associated with central venous catheters in children: an uncommon but serious and treatable condition

PURPOSE

Pericardial effusion (PCE) resulting in cardiac tamponade (CT) is a rare complication associated with central venous catheters (CVCs) in children. The goal of this study was to determine the demographics, presenting clinical picture and CVC characteristics in children developing CT as a result of a CVC.

METHODS

An institutional review board-approved retrospective review of children treated at a tertiary-care pediatric hospital from 1998 to 2007 was conducted. Patients were identified through institutional database search for diagnostic codes of PCE and simultaneously assigned patient codes for the presence of CVC. Patients with incidentally discovered effusions, those with recent cardiac surgery, or those with causative factors other than a CVC were excluded.

RESULTS

Over the 10-year study period, 463 patients were identified using the search criteria. Six cases of CVC-associated PCE causing CT were identified (1.3%). Corrected postgestational age at diagnosis ranged from 34 to 41 weeks with a median corrected postgestational age of 38.5 weeks (median, 38.5 weeks). The median time from CVC placement to diagnosis was 2.5 days (range, 0-6 days). Radiographs obtained before diagnosis demonstrated CVC tip to be overlying the cardiac silhouette in 5 patients (83%). Five (83%) of the 6 patients were receiving hyperalimentation via the CVC at the time of PCE. All patients presented with clinical signs of cardiorespiratory distress and/or cardiac arrest. Pericardiocentesis was performed in 5 patients (83%) and resulted in rapid stabilization. All CVCs were removed at diagnosis. There was 1 mortality (17%).

CONCLUSIONS

Pericardial effusion and CT associated with CVC is rare and is chiefly a concern among infants. Characteristics of CVCs including infusate and tip position may be associated with increased risk of PCE. This diagnosis should be considered in any infant with a CVC who experiences acute respiratory distress or cardiovascular collapse.

Vascular erosion by central venous catheters used for total parenteral nutrition

OBJECTIVE

To establish the incidence of central venous catheter erosion in a patient cohort receiving total parenteral nutrition and to examine risk factors and complications of vascular erosion.

DESIGN AND SETTING

Review of prospectively collected intravenous nutrition service audit records in a tertiary university hospital.

RESULTS

Records of 1,499 patients (2,992 catheters) were studied over the 14 year period 1991-2005. Fisher's exact test was used to determine statistical significance. Five erosions occurred, representing an incidence of 0.17% per catheter or 0.28 per 1,000 catheter days. One of the five patients died from ensuing complications. Mean time to onset of symptoms was 3.6 days following catheter insertion. Symptoms/signs included dyspnoea (n=5), chest pain (n=2) and pleural effusion (n=5). Diagnosis was delayed by a mean of 1.6 days. Three erosions occurred in left subclavian catheters (n=583); two in left internal jugular catheters (n=453). None occurred in right-sided catheters (n=1956). The relative risk of erosion occurring in left-sided catheters compared to right was 2.9 (95% CI 2.76-3.00; p=0.009). There was no statistically significantly greater risk of vascular erosion in subclavian than internal jugular catheters (relative risk 0.9; p=1.0). Older age was a statistically significant risk factor (p=0.009); female sex was not (p=0.18).

CONCLUSION

In patients receiving total parenteral nutrition via central venous catheters, erosion has an incidence per catheter of 0.17% and is more likely to occur in left-sided catheters and elderly patients.

Buckling test as a new approach to testing flexural rigidities of angiographic catheters

The general design of catheters is bound by many needs. Angiographic catheters must be rigid enough to be torquable and to maintain lumen structural integrity, but also flexible enough to bend with the curves of a blood vessel. They should cause minimal tissue damage; avoid biocompatibility-related complications, and be reliable over time. This study proposes a new testing approach to clearly identify the flexural rigidity of catheters by using a buckling test to evaluate the peak compressive load. This study also tests several angiographic catheters for axial and torsional rigidity. Seven different catheters used for short-term procedures, with and without reinforcement and of various sizes, were evaluated as a preliminary evaluation of test methods for future in vitro testing of catheters; it was found that the buckling test works very well and provides repeatable results.

Design of braided composite cardiovascular catheters based on required axial, flexural, and torsional rigidities

Cardiovascular catheterization is a common medical procedure. A single braided catheter with different rigidities at the proximal and distal ends can, if properly designed, provide the necessary control and flexibility and thus replace the current two-piece (external catheter/internal guidewire) system. An analytical model based on classical laminate plate theory was developed in order to predict the elastic properties of angle-plied, single-overlap two-dimensional fiber composite tubular braids, which are required for the determination of the axial, flexural, and torsional rigidities. In this work the analytical model has been used to design one-piece cardiovascular catheters with axial, flexural, and torsional rigidities similar to those values for existing two-piece catheters, thus validating the model as a tool for designing braided cardiovascular catheters.

Pericardial effusion and tamponade in infants with central catheters

OBJECTIVE

To describe the clinical presentation, cause, and outcome of central venous catheter (CVC)-related pericardial effusions (PCE) in infants.

METHODS

A retrospective case review was conducted of CVC-related PCE at university and private neonatal intensive care units. Data from our cases were combined with published case reports and included clinical presentation and outcome; biochemical evaluation of pericardial fluid; days until diagnosis; cardiothoracic ratios; and CVC characteristics, insertion site, and tip placement site.

RESULTS

In our cases, 6 different neonatology groups cared for 14 patients at 6 different hospitals in 2 cities. These data were combined with 47 cases reviewed from the literature. Pericardial fluid was obtained in 54 cases from the combined group and was described qualitatively as consistent with the infusate in 53 of 54 cases (98%). Biochemical analysis was performed in 37 cases, and in 36 of 37 cases (97%), the pericardial fluid was consistent with the infusate. The median gestational age at birth was 30.0 weeks (range: 23.5-42). The median time from CVC insertion to diagnosis was 3.0 days (range: 0.2-37; n = 59). Sudden cardiac collapse was reported in 37 cases (61%), and unexplained cardiorespiratory instability was reported in 22 cases (36%). The CVC tip was last reported within the pericardial reflections on chest radiograph in 56 cases (92%) at the time of PCE diagnosis. The mean cardiothoracic ratio increased 17% (n = 14). No patients died among our cases. Among the reviewed cases, 45% mortality was reported. For the combined group, mortality was 34%. For the combined group, mortality was 8% (3 of 37) in the patients who underwent pericardiocentesis versus 75% (18 of 24) for the patients who did not. In 21 patients, the catheter was withdrawn and remained in use. Survivors and nonsurvivors had comparable gestational age at birth, birth weight, days to PCE diagnosis, and day of life of PCE symptoms/diagnosis. Access site, catheter type, and catheter size were not associated with mortality. An association between larger catheters and shorter time to PCE may be present. Access site and catheter type were not associated with time to PCE. Autopsy specimens reported 6 cases of myocardial necrosis/thrombus formation, 9 cases of perforation without myocardial necrosis/thrombus formation, and 2 cases in which both were reported.

CONCLUSIONS

The pericardial fluid found in CVC-associated PCE is consistent with the infusate. We speculate that there are several mechanisms, ranging from frank perforation that seals spontaneously to CVC tip adhesion to the myocardium with diffusion into the pericardial space. Routine radiography should be performed, and the CVC tip should be readily identifiable. The CVC tip should remain outside the cardiac silhouette but still within the vena cavae (approximately 1 cm outside the cardiac silhouette in premature infants and 2 cm in term infants). A change in cardiothoracic ratio may be diagnostic of a PCE, and pericardiocentesis is associated with significantly reduced mortality. Increased awareness of this complication may decrease the mortality associated with CVC-related PCE.

Depth of central venous catheter insertion in adults: an audit and assessment of a technique to improve tip position

A technique of subclavian vein catheterization is described, tailored to the individual patient, to reduce the risk of right atrial placement with central venous catheter (CVC) insertion. Using data gathered retrospectively for Quality Improvement purposes, CVC tip location was assessed. The standard technique used in our cardiac anaesthesia unit at that time was to insert all CVCs to a depth of 15 cm from the skin. We then compared CVC tip location using a new "tailored" technique. The tailored method involved measuring the distance from the skin at which venepuncture occurred and using this distance to determine depth of CVC insertion. Using the tailored technique significantly decreases the frequency with which CVC tips enter the right atrium (P < 0.001). An advantage of the tailored technique is that the distance between the most proximal and the distal ports of multi-lumen CVCs is taken into consideration, reducing the risk of extravasation via the proximal port.

Seldinger technique as an alternative approach for percutaneous insertion of hydrophilic polyurethane central venous catheters in newborns

The use of hydrophilic central venous catheters, percutaneously inserted by means of the Seldinger technique, was evaluated in this prospective study. Between 1988 and 1991, 138 catheters were inserted in newborns who were admitted to our neonatal intensive care unit. An adequate position of the tip, evaluated radiographically, was achieved in 130 (94.2%) of these insertions. The side effects associated with these 130 catheters and the duration of their use were recorded. Results were compared with those of percutaneously inserted Silastic catheters described in the literature. The rate of adequate catheter placement seems comparable. Because of a high rate of minor mechanical complications, the mean catheter duration was rather short (8.3 days). However, the incidence of serious complications, especially infectious complications, was low.

A new method of veno-venous bypass during human orthotopic liver transplantation

Veno-venous bypass is commonly used during orthotopic liver transplantation, but there is some controversy as to whether it contributes to a better outcome. Low shunt flows frequently reduce the efficacy of portofemoro-axillary systems and so a percutaneous cannulation technique for the subclavian and femoral vein with large bore catheters was developed in order to facilitate bypass management. This study reports the performance and complications of a portofemoro-subclavian bypass system during the anhepatic phase of human orthotopic liver transplantation in 85 patients. A percutaneous cannulation technique and two 7 mm (subclavian and femoral) catheters, inserted pre-operatively, were used in a pump driven portofemoro-subclavian bypass system. Coagulation profiles, shunt flows, haemodynamic parameters, and peri-operative complications associated with bypass were recorded for each patient. Percutaneous cannulation of the left femoral and subclavian vein was successful in 78 patients (91.8%). Mean femoro-subclavian shunt flow was 1.45 l.min-1 (SD 0.37), and mean portofemoro-subclavian flow was 4.28 l.min-1 (SD 1.03). Although oxygen delivery was not maintained at pre-shunt levels (559.7 (SD 147) vs 506 (SD 107) ml.min-1.m-2, p < 0.05) renal perfusion pressure stayed above 50 mmHg (during shunt it was 56 (SD 9) mmHg). One intra-operative air embolism was observed (1.2%), and in one patient a myocardial infarction occurred during the anhepatic phase; neither complication was considered to be related to the percutaneous cannulation technique. There were no bleeding complications. After operation, all chest X rays were normal and clinical examination revealed no adverse effects of portofemoro-subclavian bypass.(ABSTRACT TRUNCATED AT 250 WORDS)