Temporary vascular access for extracorporeal therapies

Complications of therapeutic plasma exchange: A retrospective, single-center study of 2505 procedures performed in 338 patients over 15 years

INTRODUCTION

Therapeutic plasma exchange (TPE) may involve complications. We aimed to review the demographic data, indications, technical information, and complications.

METHODS

Data for TPE procedures (TPEPs) performed between 2004 and 2018 were retrospectively.

RESULTS

This study covered 2505 TPEPs performed on 338 patients; 55% of them were female (n = 186), and the median age was 36 years (range, 11-93 years). Most TPEPs were administered for hematological (40.6%) indications. The incidence of complications on the first procedure was 3.2% (n = 80); only 16 procedures (0.6%) were failed. The complication incidence was 19.8% (n = 497), with 789 total complications. Most of the complications were patient-related (90.4%), and the most of them were urticaria (29.1%), occlusion (3.2%), and faulty systems (1.01%), respectively. The use of only fresh frozen plasma as replacement fluid caused a higher complication rate (22.1%, p < 0.01).

CONCLUSION

The number of TPEPs is increasing every day. Hematologic indications for TPE and the use of fresh frozen plasma may increase the risk of complications.

Catheter-related bloodstream infections in a nephrology unit: Analysis of patient- and catheter-associated risk factors

BACKGROUND

Central venous catheter use is rising in chronic and acute hemodialysis. Catheter-related bloodstream infections are a major complication of central venous catheter use. This article examines clinical factors associated with catheter-related bloodstream infections incidence.

METHODS

In this retrospective, single-center study, 413 patients undergoing extracorporeal treatments between 1 February 2014 and 31 January 2017 with 560 central venous catheters were recruited. Clinical parameters, such as gender, age, kidney disease status, diabetes, immunosuppression, and vintage dialysis, were collected at study entry. An incidence rate ratio (95% confidence interval) was calculated to assess the association between catheter-related bloodstream infections incidence rate and each clinical variable/central venous catheter type. Significant associations at the univariate analyses were investigated with multivariate Cox models.

RESULTS

During a cumulative time of 66,686 catheter-days, 54 catheter-related bloodstream infections (incidence rate: 0.81) events occurred. Gram negative bacteria were more frequent in patients with age < 80 years (16 (36%) vs. 0, p = 0.02). At the univariate analyses, male sex (incidence rate ratio: 1.9 (1.1-3.5), p = 0.03), age < 80 years (incidence rate ratio: 2.4 (1.1-5.5), p = 0.016) and acute kidney injury (incidence rate ratio: 5.6 (3.1-10), p < 0.0001) were associated with higher catheter-related bloodstream infections incidence rate. Compared with tunneled jugular central venous catheter, higher catheter-related bloodstream infections incidence rate was associated with non-tunneled jugular (incidence rate ratio: 6.45 (2.99-13.56), p < 0.0001) and non-tunneled femoral (incidence rate ratio: 12.90 (5.87-27.61), p < 0.0001) central venous catheter use; tunneled femoral central venous catheter was associated with higher non-significant incidence rate (incidence rate ratio: 2.45 (0.93-5.85), p = 0.07). The multivariate analyses showed that acute kidney injury (hazard ratio: 3.03 (1.38-6.67), p = 0.006), non-tunneled (hazard ratio: 3.11 (1.30-7.41), p = 0.01) and femoral (hazard ratio: 2.63 (1.36-5.07), p = 0.004) central venous catheter were associated with higher catheter-related bloodstream infections incidence rate.

CONCLUSION

Central venous catheter characteristics and acute kidney injury are independently associated with higher catheter-related bloodstream infections rate.

The choice of vascular access for therapeutic apheresis

Therapeutic apheresis (TA) is performed using either centrifugation-based or filter-based systems. The blood flow rate (BFR) used for TA using centrifugation-based systems is less than 100 mL/min. Because of this low BFR requirement, even peripheral veins can be considered as an option for TA, especially for less-frequent treatments and those performed for short periods. Other options for vascular access (VA) include central venous catheters (temporary or tunneled), totally implantable ports, and arteriovenous fistulae (AVF) or grafts (AVG). Nontunneled catheters should be considered as the choice of VA for relatively short-term treatments mainly in the inpatient settings. For long-term treatments, ports and tunneled catheters should be considered because of lower rates of infections compared to nontunneled catheters. However, studies in hemodialysis (HD) patients have demonstrated significantly higher morbidity and mortality rates associated with the use of tunneled catheters as compared to AVF. Therefore, if TA is being considered for several years, AVG and AVF would be the preferred options of VA. Studies in HD population indicate far better outcomes with the use of AVF as compared to AVG. This article, as presented at the Therapeutic Apheresis Academy in September 2011, is an overview of the available VA options for TA based on indication and duration of treatment. Pros and cons of each option are mentioned briefly. Finally, for those considered for AVF placement for chronic TA, specific recommendations are made for the care of AVF based on our own experience at University of Virginia.

Fluid Mechanics and Clinical Success of Central Venous Catheters for Dialysis-Answers to Simple but Persisting Problems

Over 60% of patients initiating chronic hemodialysis in the United States have a chronic central venous catheter (CVC) as their first blood access device. Although it would be better if these patients started dialysis with fistulas, the CVC is used because it is a reliable and relatively safe method for obtaining blood access over a period of months. Drawing blood from a vein at 300-400 ml/minute is a relatively delicate and somewhat unpredictable process, and there is always a tendency for the vein wall to draw over the arterial tip and obstruct flow. Several methods have been employed to minimize this problem and maximize blood flow, and differing catheter designs have resulted. With all of the different catheter designs now on the market, it is natural to ask what is the logic of different designs. Moreover, in the absence of many direct comparative studies it is natural to ask whether one design is really better than another. There is some misinformation regarding catheter design and function. The following is a list of 10 frequently asked questions In this review, the hydraulic features of CVC are discussed and explained, and logical answers are provided for the following questions: 1. Why do ''D'' catheters flow better than concentric or side by side catheters? 2. Why are all catheters about the same diameter? Does making them bigger really decrease the resistance to flow? 3. Why might a split tip catheter flow better than a solid body catheter? 4. What happens to injections of lock solution at catheter volume? 5. What's better-numerous side holes or none? 6. Why does blood rise into some internal jugular catheters over time, displacing the lock solution? 7. How can a little kink (or stenosis) decrease flow so much? 8. Where should the tips be placed-superior vena cava or right atrium? 9. Which is really better, splitsheath or over-the-wire placement? 10. Which dialysis access has a lower complication rate--CVC or arteriovenous (AV) graft? There remain important problems with CVC for dialysis. With a few more improvements, chronic CVC for dialysis could become a painless, effective and safe long-term access for the majority of dialysis patients and acceptable as an alternative to AV grafts.

Long-term therapeutic plasma exchange in the outpatient setting using an implantable central venous access device

We presented the results of our prospective trial of the Bard CathLink 20 in outpatient therapeutic plasma exchange in May 2000. Since the close of that study, three of the original subjects and one additional subject have received continuous outpatient treatment using the device. We report herein on its long-term use. Four patients with demyelinating polyneuropathy underwent outpatient plasma exchange of 1-1 1/4 plasma volumes using Bard CathLink 20 venous access devices for up to 2 1/2 years. Treatment schedules varied according to the status of the patient's neuropathy. Four men (age 59, 60, 76, 79) underwent 55, 56, 38, and 41 plasma exchanges over 18.5, 18, 20, and 38.5 months, respectively, all in the outpatient setting. Ninety-one percent were completed in <150 min (mean 120 +/- 28 min) with 3,783 +/- 314 ml of plasma removed. Mean access flow rates were approximately 70 +/- 11 ml/min. Plasma flow rates were approximately 38 +/- 6 ml/min. (During our original 6-month prospective trial, access and plasma flow rates were approximately 54 and 32 ml/min, respectively). There were no adverse effects resulting from use of the CathLink and no hospitalizations were needed for plasma exchange. Pressure alarms were infrequent. Access and plasma flow rates achieved with the CathLink 20 have increased by about 30 and 16%, respectively, with long-term use. The conclusion from our prospective trial of this device, that it could conveniently be used for long-term outpatient plasma exchange, is supported by our follow-up experience.

Peripherally inserted veno-venous ultrafiltration for rapid treatment of volume overloaded patients

BACKGROUND

Veno-venous ultrafiltration may benefit patients with acute or chronic circulatory volume overload. Use of conventional systems, however, may be cumbersome, requiring physician placement of a double-lumen central venous catheter and use of a dedicated dialysis technician and apparatus.

METHODS

A simplified peripheral ultrafiltration system including a miniaturized disposable circuit was evaluated in patients with volume-overload states. Separate intravenous catheters (16-18 G) for withdrawal and return of blood (blood flow <or= 40 mL/min, ultrafiltrate <or= 500 mL/h) were placed by nonphysician personnel in upper extremity veins. Twenty-five treatments of up to 8 hours were performed in 21 patients.

RESULTS

The primary endpoint of greater than 1 L fluid removal in less than 8 hours was achieved in 23 of 25 treatments. On average, 2611 +/- 1002 mL (maximum 3,725 mL) of ultrafiltrate was removed per treatment (treatment period 6:43 +/- 1:47 hours:minutes). Patient weight decreased from 91.9 +/- 17.5 to 89.3 +/- 17.3 kg (P <.0001) after ultrafiltration. No major adverse events occurred.

CONCLUSIONS

Rapid removal of extracellular and intravascular fluid volume excess can be safely achieved via peripherally inserted ultrafiltration without the need for central venous catheter placement.

Vascular access for apheresis in intensive care patients

In the intensive care unit, apheresis therapy (including plasma exchange, selective immunoadsorption and -affinity and detoxification by hemoperfusion) is limited to certain disease entities. Temporary insertion of large-bore central venous catheters is necessary for efficient performance of apheresis therapy. The choice of the optimal catheter insertion site (femoral, subclavian or internal jugular vein route) depends on the individual situation, the experience of the operator and the anticipated treatment period. Morbidity and mortality of the patients concerned can be substantially increased by insertion and use of central venous catheters. Early and delayed complications are briefly discussed. Appropriate selection of the catheter insertion site, the catheter type, strictly aseptic insertion procedures and optimal care of catheter and insertion site are essential to avoid complications.

The Acute Dialysis Quality Initiative--part VI: access and anticoagulation in CRRT

Both the choice of vascular access and anticoagulant regimen for continuous renal replacement therapy (CRRT) are a major determinant of not only circuit life span but also affect solute clearance. This evidence-based review critically examines the published rature on different vascular access sites, access types, and anticoagulation regimens, to provide clinical guidelines for good working practices and to direct future studies.

Prospective investigation of a subcutaneous, implantable central venous access device for therapeutic plasma exchange in adults with neurological disorders

Standard alternatives to antecubital access for long-term therapeutic plasma exchange, including percutaneous polyurethane or tunneled silicone catheters, are associated with complications and inconvenience for the patient. We have investigated the Bard CathLink 20, a subcutaneously implantable central venous access device, as an alternative for outpatient plasma exchange. The CathLink 20 consists of a funnel-shaped titanium port connected to a soft polyurethane-derived catheter and is accessed percutaneously using an 18-gauge catheter-over-needle Angiocath. Six patients with paraproteinemic polyneuropathies underwent 64 outpatient plasma exchanges using the CathLink 20 for access, 31 using 2 CathLink 20's (draw and return), 20 using a single CathLink 20 as the draw site and 13 using a single CathLink 20 as the return site. Mean (+/- SD) plasma removed was 3,680 +/- 551 ml in 115.2 +/- 25.3 min. Apheresis personnel were able to access the ports in 1.23 +/- 0.6 attempts per port per procedure. Six of 70 planned procedures were aborted: 3 because of failure of an antecubital access site and 3 because of catheter occlusion resolved using a thrombolytic agent. Whole blood flow rate was approximately 54 ml/min, and plasma flow rate was about 32 ml/min for 135 min. Access pressures were stable at -150 to -200 torr (P = 0.1395). Return line pressures varied between 90 and 130 torr (P = 0.0147). No patient required hospitalization during the study. Though not optimized for apheresis, the CathLink 20 provides a reasonable option for chronic apheresis patients who lack adequate peripheral venous access.

The evolution and function of central venous catheters for dialysis

The use of central venous catheters (CVC) for acute or chronic dialysis has been a relatively recent innovation in Nephrology. The first problem addressed has been how to allow removal and return of blood at high flow rates throughout a dialysis treatment. Four solutions have emerged: place the lumens within the right atrium; place the removal lumen on the inside of the catheter; use a large catheter size; or provide independent limbs with multiple blood-entry ports to draw and return blood in all directions. Many other requirements include resistance to infection, especially the passage of organisms around the catheter. A subcutaneous Dacron cuff within a tunnel has successfully accomplished this goal for most chronic CVC dialysis catheters, but other immobilizing devices such as plugs have also been successful. Materials for CVC dialysis catheters have improved, providing strength to allow the catheters to last for several years, with flexibility to avoid vein damage (in general). However, component and material failures still occur, and some materials are incompatible with medications placed at the exit site. CVC for dialysis will remain a necessary choice for many patients beginning and continuing dialysis therapy.