A Randomized Controlled Trial of Comparative Efficacy between Sodium Bicarbonate and Heparin as A Locking Solution for Tunneled Central Venous Catheters Among Patients Requiring Maintenance Hemodialysis

Background:

Sodium bicarbonate (NaHCO₃) is one of the promising solutions that has good safety profile and theoretical advantages regarding antimicrobial and antithrombotic properties but there are still limited reports.

Objective:

To compare the efficacy in lowering rate of catheter loss due to catheter-related thrombosis (CRT) or catheter-related blood stream infection (CRBSI) between sodium bicarbonate and heparin lock in prevalent chronic hemodialysis (HD) patients.

Design:

A multicenter, randomized, open-label study

Setting:

In a developing country, Thailand

Patients:

Chronic HD patients with tunneled central venous catheter

Measurements:

Catheter loss rate, rate of catheter-related blood stream infection, catheter-related thrombosis, and exit site or tunnel infection

Methods:

The prospective multicenter randomized controlled trial was conducted, we randomly assigned 118 patients undergoing HD with tunneled central venous catheter to receive a catheter locking solution of sodium bicarbonate or heparin. The primary outcome was a catheter loss rate due to CRT or CRBSI, while the secondary outcome was a composite outcome of CRT, CRBSI, or exit site/tunnel infection (ESI/TI).

Results:

The present study was stopped early due to an excess of catheter-related thrombosis in the sodium bicarbonate group. From the first 6 weeks of follow-up, there were no catheter losses due to CRT or CRBSI in both groups. The sodium bicarbonate group had a significantly higher rate of the secondary composite outcomes and this was entirely caused by CRT with the median time to thrombosis of 23.6 days. Every CRT event could be successfully rescued by using a single dose of recombinant tissue plasminogen activator (rt-PA).

Limitations:

Short follow-up period.

Conclusions:

In prevalent HD patients with tunneled CVCs, use of a sodium bicarbonate locking solution for prevention of CRT is inferior to heparin and is associated with a high rate of catheter-related thrombosis.

Trial registration:

The study was registered with the Thai Clinical Trials Registry TCTR 20200610003

A prospective observational study of the change in systemic ionised calcium following 4% citrate locking of venous haemodialysis catheters in intensive care patients

Traditionally heparin has been the anticoagulant of choice for venous dialysis catheter locking. There is systemic leakage of heparin catheter locking solutions at the time of injection. Alternative agents, such as citrate, are increasingly being used. We are not aware of any data in the critical care literature on the effect of citrate locking of venous dialysis catheters on systemic ionised calcium (iCa²⁺). To assess the effect of 4% citrate locking of venous dialysis catheters on systemic iCa²⁺ in intensive care patients we performed a prospective observational study of 50 paired samples in 26 intensive care patients receiving 4% citrate dialysis catheter locking in an adult tertiary intensive care unit between May 2016 and December 2016. Arterial blood gas (ABG) analysis was performed prior to venous dialysis catheter locking and a baseline iCa²⁺ result obtained. The catheter was locked with 4% citrate solution. A further ABG was sampled between 30 and 120 seconds later and the iCa²⁺ results were compared. Patients were observed for clinical signs of hypocalcaemia. On average, there was little difference between the pre- and post-catheter locking iCa²⁺ (median pre-locking iCa²⁺ 1.19 mmol/l, mean change of +0.004 mmol/l, 95% confidence interval [CI] -0.004 to 0.013, P=0.34). There was no evidence this difference differed by length of catheter P=0.26) or site of catheter P=0.85) insertion, but there was some evidence that this differed by receipt of citrate dialysis circuit anticoagulation P=0.013). Patients who received citrate dialysis circuit anticoagulation had an increase in catheter locking iCa²⁺ by 0.017 mmol/l (95% CI 0.00 to 0.028). Locking of venous dialysis catheters with 4% citrate solution has no clinically significant effect on systemic iCa²⁺ in intensive care patients with indwelling venous dialysis catheters.

Effectiveness and Cost of Weekly Recombinant Tissue Plasminogen Activator Hemodialysis Catheter Locking Solution

BACKGROUND AND OBJECTIVES

Evidence to guide hemodialysis catheter locking solutions is limited. We aimed to assess effectiveness and cost of recombinant tissue plasminogen activator (rt-PA) once per week as a locking solution, compared with thrice weekly citrate or heparin, in patients at high risk of complications.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We used a prospective design and pre-post comparison in three sites across Canada. Pre-post comparisons were conducted using multilevel mixed effects regression models accounting for cluster with site and potential enrollment of patients more than once. In the pre period, catheter malfunction was managed as per site-specific standard of care. The intervention in the post period was once weekly rt-PA as a locking solution (with citrate or heparin used for other sessions). The primary outcome was rate of rt-PA use for treatment of catheter malfunction. Secondary outcomes included rates of bacteremia, management of catheter malfunction, and cost.

RESULTS

There were 374 patients (mean age 68 years; 52% men) corresponding to 506 enrollments. Mean length of enrollment was 200 days (SD 119) in the pre period and 187 days (SD 101) in the post period. There was a significant decline in rate of rt-PA use for treatment of catheter malfunction in the post compared with pre period (adjusted incidence rate ratio, 0.39; 95% confidence interval, 0.30 to 0.52); however, there was no difference in the rate of bacteremia, or catheter stripping or removal/replacement. The increase in mean total health care cost in the post period was CAD$962 per enrollment, largely related to costs of rt-PA as a locking solution.

CONCLUSIONS

Once weekly rt-PA as a catheter locking solution was associated with a reduction in rt-PA use for treatment of catheter malfunction. Our results showing a reduction in rescue rt-PA use are consistent with a prior randomized trial, although we did not observe a reduction in bacteremia or catheter stripping/removal and did observe an increased incremental cost of this strategy primarily accounted for by the cost of the rt-PA.