Sodium Citrate Better than Heparin for Dialysis Catheter Locks
Sodium citrate works as well as heparin as a catheter lock solution in hemodialysis patients with central venous catheters, but it is associated with significantly fewer catheter-related infections (CRIs), a new study found.
Calantha K. Yon, PharmD, and Chai L. Low, PharmD, both clinical nephrology pharmacists in the Veterans Affairs San Diego Healthcare System, compared lock solutions of sodium citrate 4% and heparin 5000 units/mL. They collected data from 360 patient-months among 60 HD patients who used the heparin lock and 451 patient-months among 58 HD patients who used the sodium citrate lock. Thirty-three patients were common to both study groups.
The researchers identified 20 CRIs that occurred during heparin solution use and 11 during sodium citrate solution use, a significant difference in infection rates, Drs. Yon and Low reported in the American Journal of Health-System Pharmacy (2013;70:131-136). The number of CRIs per 1,000 catheter-days was 1.9 with the heparin solution compared with 0.81, a significant difference between the treatments.
In addition, significantly more catheters were exchanged or removed when the heparin solution rather than the sodium citrate solution was used (34 vs. 18).
Although more CRI-related hospitalizations occurred during heparin use than sodium citrate use, the difference was not significant.
The investigators noted that heparin is the standard lock solution in catheters, but no standard optimal dosage of heparin exists. Consequently, systemic anticoagulant effects may result from the use of heparin locks, they observed. “Studies have found an increase in activated partial thromboplastin time and bleeding risk with inadvertent systemic exposure to heparin from heparin lock solutions,” they wrote. “This is particularly concerning, since patients with renal insufficiency have an increased risk of bleeding due to platelet dysfunction secondary to uremia.” Sodium citrate 4% has been proposed as an alternative to heparin. It acts as a local anticoagulant, but it also has antimicrobial properties. For example, a previous study demonstrated that, in vitro, sodium citrate concentrations above 0.5% inhibit biofilm formation and growth of Staphylococcus aureus and Staphylococcus epidermidis.
Drs. Yon and Low noted that the cost associated with one CRI episode, which includes catheter exchange or removal, hospitalization, and antibiotic treatment, “would most certainly offset the auxiliary costs associated with using sodium citrate 4% for a year. “A reduction in the incidence fo CRI is a significant clinical and economical outcome,” they concluded.