Hemodialysis catheter locking solutions and the prevention of catheter dysfunction: a meta-analysis

Guidelines on vascular access for hemodialysis from the Brazilian Society of Angiology and Vascular Surgery

Chronic kidney disease is a worldwide public health problem, and end-stage renal disease requires dialysis. Most patients requiring renal replacement therapy have to undergo hemodialysis. Therefore, vascular access is extremely important for the dialysis population, directly affecting the quality of life and the morbidity and mortality of this patient population. Since making, managing and salvaging of vascular accesses falls within the purview of the vascular surgeon, developing guideline to help specialists better manage vascular accesses for hemodialysis if of great importance. Thus, the objective of this guideline is to present a set of recommendations to guide decisions involved in the referral, evaluation, choice, surveillance and management of complications of vascular accesses for hemodialysis.

Clinical application of 4% sodium citrate and heparin in the locking of central venous catheters (excluding dialysis catheters) in intensive care unit patients: A pragmatic randomized controlled trial

OBJECTIVES

The feasibility of utilizing 4% sodium citrate as an alternative locking solution for central venous catheters (CVCs) (excluding dialysis catheters) was assessed.

METHODS

Using heparin saline and 4% sodium citrate as locking solution, then 152 patients in ICU undergoing infusion with central venous catheters, were randomly assigned to receive either 10 U/mL heparin saline or 4% sodium citrate. The used outcome indicators include: four indexes of blood coagulation at 10 minutes after locking and 7 d after the first locking, bleeding around the puncture site and subcutaneous hematoma rate, gastrointestinal bleeding rate, catheter indwelling time, catheter occlusion rate, catheter-related bloodstream infection (CRBSI) rate, rate of ionized calcium < 1.0 mmol/L. The main outcome indicator was the activated partial thromboplastin time (APTT) at 10 min after tube locking. The trial was approved by relevant authorities (Chinese Clinical Trial Registry, no: ChiCTR2200056615, registered on February 9, 2022, http://www.chictr.org.cn; Ethics Committee of People's Hospital of Zhongjiang County, no: JLS-2021-034, approved at May 10, 2021, and no: JLS-2022-027, approved at May 30, 2022).

RESULTS

Among the main outcome measures, the heparin group showed a significant increase in APTT compared to the sodium citrate group at 10 min after locking (LSMD = 8.15, 95%Cl 7.1 to 9.2, P < 0.001). Among the secondary outcome measures, the heparin group demonstrated a significant increase in prothrombin time (PT) compared to the sodium citrate group at 10 minutes after locking (LSMD = 0.86, 95%CI 0.12 to 1.61, P = 0.024). It is found that APTT (LSMD = 8.05, 95%CI 6.71 to 9.4, P < 0.001), PT (LSMD = 0.78, 95%CI 0.14 to 1.42, P = 0.017) and fibrinogen (FB) (LSMD = 1.15, 95%CI 0.23 to 2.08, P = 0.014) at 7 d after locking are increased in the heparin group compared to sodium citrate group. There was no significant difference in catheter indwelling time between the two groups (P = 0.456). The incidence of catheter blockage was lower in sodium citrate group (RR = 0.36, 95%CI 0.15 to 0.87, P = 0.024). No CRBSI occurred in the two groups. Among the safety evaluation indexes, the incidence of bleeding around the puncture site and subcutaneous hematoma was lower in sodium citrate group (RR = 0.1, 95%CI 0.01 to 0.77, P = 0.027). There was no significant difference in the incidence of calcium ion < 1.0 mmol/L between the two groups (P = 0.333).

CONCLUSIONS

In ICU patients using CVCs (excluding dialysis catheters) infusion, employing 4% sodium citrate as a locking liquid can reduce the risk of bleeding and catheter occlusion without any hypocalcemia.

Vancomycin and daptomycin stability in heparin or sodium citrate lock solutions

BACKGROUND

We investigated physical and chemical stability of daptomycin and vancomycin in heparin or sodium citrate lock solutions. The aim of this study was to find the optimal combination of antimicrobials and additives for lock solutions, which maximized patient safety.

METHODS

Vancomycin and daptomycin were diluted with heparin or sodium citrate to achieve final concentrations of vancomycin-heparin 2.5 mg/mL-833.33 U/mL, vancomycin-citrate 2.5-33.3 mg/mL, daptomycin-heparin 5 mg/mL-800 U/mL, and daptomycin-citrate 5-32 mg/mL and they were stored at room temperature (+25°C), 4°C, -20°C, and 37°C. Physical and chemical stability were analyzed for each antibiotic-anticoagulant combination in all conditions immediately after preparation, at 24, 48, 72 h and at different time points until unstable concentrations were obtained. Daptomycin-sodium citrate microbiological activity was also studied by evaluating two Staphylococcus aureus cultures in a calcium enriched medium with a daptomycin E test, with and without sodium citrate.

RESULTS

After incubation at 37°C vancomycin and daptomycin combined with heparin retained at least 90% of the initial concentration over 48 h. Vancomycin-sodium citrate solution stored at 37°C reduced more than 10% of the initial concentration at 24 h. On the other hand, daptomycin-sodium citrate preparation was stable at 37°C for 72 h but the microbiological activity of daptomycin was lower in the presence of sodium citrate.

CONCLUSIONS

The purpose is to prepare vancomycin and daptomycin lock solutions combined with heparin. They should be changed at 48 h and its stability is over 3 days at 25°C and 7 days at 4°C, which allow Hospital Pharmacy Services to manage their stocks. Daptomycin-sodium citrate combination is more stable for extended periods but its bioactivity has not been demonstrated.

Effect of taurolidine citrate and unfractionated heparin on inflammatory state and dialysis adequacy in hemodialysis patients

BACKGROUND AND AIM

HD patients using dialysis catheters have been associated with chronic inflammatory state. In Egypt 6.6% of HD patients use catheters, of which short term catheters represent 59.6% and 40.4% with long-term catheters. In this study, we aimed to assess the effect of Taurolidine citrate and unfractionated heparin combination (Taurolock-hep500™) as a lock solution compared to unfractionated heparin alone on inflammatory markers, incidence of catheter related blood stream infections (CRBSI) and dialysis adequacy in HD patients with temporary HD catheters only, for 4 weeks duration.

METHODS

Sixty ESRD patients from hemodialysis units in Ain-Shams University hospitals (ASUH) at the time of catheter insertion we enrolled in our study. They were randomized into two groups: Group 1: Thirty patients received Taurolock-hep500™ as a catheter lock solution at the end of each hemodialysis session. Group 2: Thirty patients received unfractionated heparin as a catheter lock solution. hsCRP and IL-6 were measured at baseline and 1 month after using the lock solutions. Blood cultures were done in patients who developed symptoms of catheter related infections.

RESULTS

At the end of the study, Inflammatory markers were significantly higher in group 2 (p-value: 0.045, 0.001, and 0.018 for WBCs, hsCRP and IL-6, respectively). Group 1 had better dialysis adequacy assessed by URR (p-value: 0.007 and 0.001, respectively). CRBSI were demonstrated in nine patients in group 2 (30%) in contrast to one patient only in group 1(3.3%) (p-value: 0.006) with pseudomonas being the most common isolated organism (27.7%).

CONCLUSION

Use of (Taurolock-hep500™) for temporary hemodialysis catheters was associated with lower levels of inflammation markers and lower incidence of CRBSI and better catheter performance.

Locked Away-Prophylaxis and Management of Catheter Related Thrombosis in Hemodialysis

Reliable vascular access is necessary for effective hemodialysis. Guidelines recommend chronic hemodialysis via an arteriovenous fistula (AVF), however, in a significant number of patients, permanent central venous catheters (CVCs) are used. The use of a tunneled catheter is acceptable if the estimated dialysis time is less than a year or it is not possible to create an AVF. The main complications associated with CVC include thrombosis and catheter-related bloodstream infections (CRBSIs), which may result in loss of vascular access. The common practice is to use locking solutions to maintain catheter patency and minimize the risk of CRBSI. This paperwork summarizes information on currently available locking solutions for dialysis catheters along with their effectiveness in preventing thrombotic and infectious complications and describes methods of dealing with catheter dysfunction. The PubMed database was systematically searched for articles about locking solutions used in permanent CVCs in hemodialysis patients. Additional studies were identified by searching bibliographies and international guidelines. Articles on end-stage kidney disease patients dialyzed through a permanent CVC were included. Information from each primary study was extracted using pre-determined criteria including thrombotic and infectious complications of CVC use, focusing on permanent CVC if sufficient data were available. Of the currently available substances, it seems that citrate at a concentration of 4% has the best cost-effectiveness and safety profile, which is reflected in the international guidelines. Recent studies suggest the advantage of 2+1 protocols, i.e., taurolidine-based solutions with addition of urokinase once a week, although it needs to be confirmed by further research. Regardless of the type of locking solution, if prophylaxis with a thrombolytic agent is chosen, it should be started from the very beginning to reduce the risk of thrombotic complications. In case of CVC dysfunction, irrespective of the thrombolysis attempt, catheter replacement should be planned as soon as possible.

Hemodialysis catheter heparin lock related bleeding: Hemorrhagic shock every other day

Catheter dysfunction is an important cause of catheter loss. In order to prevent this, locking solutions with minimal risk of systemic anticoagulation are used to ensure catheter patency. At present the most commonly used solutions are either heparin or sodium citrate. According to the literature use of sodium citrate may be advantageous in reducing bleeding events. We report a case of hemorrhagic shock following hemodialysis catheter lock with heparin, reversed after switching solution to sodium citrate.

Heparin locks with low and high concentration in haemodialysis patients: A systematic review and meta-analysis

AIM

There is no evidence-based consensus on the optimal concentration for heparin locks; several randomized controlled trials (RCTs) have evaluated the concentration of heparin locks, yet the results remain inconsistent. We aimed to assess heparin locks with low and high concentration in haemodialysis patients.

METHODS

We performed a systematic review and meta-analysis of RCTs focusing on the concentration in heparin locks. Studies were identified by searching PUBMED, EMBASE, Science Direct, Cochrane Central Register of Controlled Trials, China National Knowledge Infrastructure (CNKI) and Wanfang databases (from inception to 15 March 2020). Summary risk ratios or mean differences with 95% confidence interval were calculated.

RESULTS

A total of 370 patients with four RCTs were included. Heparin locks with 1000 U/ml could significantly reduce the activated partial thromboplastin time (APTT) compared with 5000 U/ml. No significant differences were seen in the occurrence of catheter-related thrombosis, the length of catheter stay, the rates of bleeding and catheter occlusions between the two groups.

CONCLUSIONS

Lower concentrations in heparin lock are optimal for shortening APTT in haemodialysis patients; further studies are needed to elucidate the role of heparin concentration in the lock practice.

New Directions in Ensuring Catheter Safety

Tunneled dialysis catheters remain the most common vascular access used to initiate hemodialysis. Unfortunately, their use is associated with higher morbidity and mortality when compared with arteriovenous fistulae or grafts. Different types of catheters with different designs and material properties function differently. Additional devices and medications can be used to decrease the rates of infection and thrombosis. The current available tunneled dialysis catheters remain far from the desired goal and innovation in the field of dialysis vascular access remains in dire need.

Advances in the prevention and management of central-line-associated bloodstream infections: The role of chelator-based catheter locks

The proper functioning of central lines is imperative for the management of patients with cancer or on hemodialysis. However, these lifelines can become infected and can malfunction.Chelators such as citrate and EDTA have been widely studied alone or in combination with other antimicrobial agents in catheter lock solutions to prevent catheter-related bloodstream infections and to maintain catheter patency. Given their anticoagulation, antiplatelet aggregation, antibiofilm, antimicrobial activity, safety profile, as well as their low cost, chelators have long been considered alternatives to heparin and a vital component of catheter lock solutions. In this review, we present a detailed summary of the properties of chelators and in vitro and in vivo studies of chelator-containing lock solutions.

Infection of Small-Bore Tunneled Central Venous Catheters

OBJECTIVE. The purpose of this study is to evaluate the association of common clinical variables with small-bore tunneled central venous catheter (CVC) infection. MATERIALS AND METHODS. Retrospective data were collected from all small-bore (6-French) tunneled CVCs placed by the interventional radiology service between 2012 and 2015. Only patients who had a documented reason for tunneled CVC removal were included in the analysis to capture all events. Transfemoral, transhepatic, and translumbar placements were excluded to reduce cohort heterogeneity. Multiple clinical variables were collected from a review of the medical record. The t test and Fisher exact test were used for two-group comparisons for continuous variables and categoric variables, respectively. Logistic regression analyses were further used to identify variables that were associated with catheter infection. RESULTS. One hundred eighty-two patients (105 women [57.7%] and 77 men [42.3%]) with a mean (± SD) age of 49.7 ± 16 years were included. Thirty-two catheters (17.6%) were removed because of infection. Noninfected lines were removed at a mean of 39 (SD, 57.3) days, whereas infected lines were removed at a mean of 95.9 (SD, 113.4) days after placement (p < 0.001). There was a statistically significant difference in the number of tunneled CVCs removed for infection when the indication for tunneled CVC placement was the administration of IV antibiotics (p = 0.04). By multivariate analysis, only time to removal (p = 0.002; odds ratio, 0.992; 95% CI, 0.986-0.998) and a history of tunneled CVC (p = 0.01; odds ratio, 0.306; 95% CI, 0.121-0.772) were associated with catheter removal for infection. CONCLUSION. Time to catheter removal and history of tunneled CVC were associated with an increased risk of tunneled CVC removal because of infection.

Tissue plasminogen activator vs heparin for locking central venous catheters between apheresis procedures

BACKGROUND

Central venous catheters (CVCs) for apheresis procedures require regular locking/flushes to maintain adequate flow rates. Literature comparing locking solutions for apheresis, where the time interval between procedures can be longer than for hemodialysis (many days to weeks), is lacking. In this study, catheter malfunction rates using recombinant tissue plasminogen activator (rt-PA) vs heparin for locking CVC between apheresis procedures were compared.

STUDY DESIGN AND METHODS

A retrospective review of 93 extracorporeal photopheresis procedures in 10 patients was performed at our institution. About 1000 U/mL heparin or 2 mg rt-PA was used as the locking solution. Heparin locks were changed at least once per week and rt-PA locks could be left in place for up to 4 weeks. Following these locks, inadequate blood flow noted on accessing CVC and/or during the procedure was scored on as: no issues, some issues, or significant issues. Binary logistic regression was used to evaluate for potential statistical difference in outcomes. Cost analysis was also performed.

RESULTS

No statistically significant difference was noted in outcomes between heparin and rt-PA lock (P value = 0.15). Total cost of heparin lock administration ($91-$362.50) was found to be more than rt-PA lock ($76) when more than one flush was needed between procedures.

CONCLUSIONS

For apheresis use, rt-PA and heparin CVC locks seem to have similar outcomes in preventing CVC malfunction. The convenience of not needing any flushes between procedures and overall cost of administering fewer locks favors rt-PA use when the interval between procedures is >7 days.

Dialysis catheter management practices in Australia and New Zealand

AIM

Dialysis catheter-associated infections (CAI) are a serious and costly burden on patients and the health-care system. Many approaches to minimizing catheter use and infection prophylaxis are available and the practice patterns in Australia and New Zealand are not known. We aimed to describe dialysis catheter management practices in dialysis units in Australia and New Zealand.

METHODS

Online survey comprising 52 questions, completed by representatives from dialysis units from both countries.

RESULTS

Of 64 contacted units, 48 (75%) responded (Australia 43, New Zealand 5), representing 79% of the dialysis population in both countries. Nephrologists (including trainees) inserted non-tunnelled catheters at 60% and tunnelled catheters at 31% of units. Prophylactic antibiotics were given with catheter insertion at 21% of units. Heparin was the most common locking solution for both non-tunnelled (77%) and tunnelled catheters (69%), with antimicrobial locks being predominant only in New Zealand (80%). Eight different combinations of exit site dressing were in use, with an antibiotic patch being most common (35%). All units in New Zealand and 84% of those in Australia undertook CAI surveillance. However, only 51% of those units were able to provide a figure for their most recent rate of catheter-associated bacteraemia per 1000 catheter days.

CONCLUSION

There is wide variation in current dialysis catheter management practice and CAI surveillance is suboptimal. Increased attention to the scope and quality of CAI surveillance is warranted and further evidence to guide infection prevention is required.

Spanish Clinical Guidelines on Vascular Access for Haemodialysis

Vascular access for haemodialysis is key in renal patients both due to its associated morbidity and mortality and due to its impact on quality of life. The process, from the creation and maintenance of vascular access to the treatment of its complications, represents a challenge when it comes to decision-making, due to the complexity of the existing disease and the diversity of the specialities involved. With a view to finding a common approach, the Spanish Multidisciplinary Group on Vascular Access (GEMAV), which includes experts from the five scientific societies involved (nephrology [S.E.N.], vascular surgery [SEACV], vascular and interventional radiology [SERAM-SERVEI], infectious diseases [SEIMC] and nephrology nursing [SEDEN]), along with the methodological support of the Cochrane Center, has updated the Guidelines on Vascular Access for Haemodialysis, published in 2005. These guidelines maintain a similar structure, in that they review the evidence without compromising the educational aspects. However, on one hand, they provide an update to methodology development following the guidelines of the GRADE system in order to translate this systematic review of evidence into recommendations that facilitate decision-making in routine clinical practice, and, on the other hand, the guidelines establish quality indicators which make it possible to monitor the quality of healthcare.

In Vitro and In Vivo Activity of a Novel Catheter Lock Solution against Bacterial and Fungal Biofilms

Central-line-associated bloodstream infections are increasingly recognized to be associated with intraluminal microbial biofilms, and effective measures for the prevention and treatment of bloodstream infections remain lacking. This report evaluates a new commercially developed antimicrobial catheter lock solution (ACL), containing trimethoprim (5 mg/ml), ethanol (25%), and calcium EDTA (Ca-EDTA) (3%), for activity against bacterial and fungal biofilms, using in vitro and in vivo (rabbit) catheter biofilm models. Biofilms were formed by bacterial (seven different species, including vancomycin-resistant Enterococcus [VRE]) or fungal (Candida albicans) species on catheter materials. Biofilm formation was evaluated by quantitative culture (CFU) and scanning electron microscopy (SEM). Treatment with ACL inhibited the growth of adhesion-phase biofilms in vitro after 60 min (VRE) or 15 min (all others), while mature biofilms were completely inhibited after exposure for 2 or 4 h, compared to control. Similar results were observed for drug-resistant bacteria. Compared to the heparinized saline controls, ACL lock therapy significantly reduced the catheter bacterial (3.49 ± 0.75 versus 0.03 ± 0.06 log CFU/catheter; P = 0.016) and fungal (2.48 ± 1.60 versus 0.55 ± 1.19 log CFU/catheter segment; P = 0.013) burdens in the catheterized rabbit model. SEM also demonstrated eradication of bacterial and fungal biofilms in vivo on catheters exposed to ACL, while vigorous biofilms were observed on untreated control catheters. Our results demonstrated that ACL was efficacious against both adhesion-phase and mature biofilms formed by bacteria and fungi in vitro and in vivo.