Optimization of heparin anticoagulation for hemodialysis

Abstract

Unfractionated heparin remains the most commonly used anticoagulant for extracorporeal therapies worldwide due to cost, years of clinical experience showing effectiveness and safety for outpatient hemodialysis. Most centers administer unfractionated heparin as an initial bolus followed by a constant infusion, which is then stopped prior to the end of the dialysis session. Although the anticoagulant effect of heparin can be monitored at the bedside, most centers take a pragmatic stance for routine outpatient hemodialysis, and adjust bolus doses and infusion rates based on visual inspection of the dialyzer header and venous air detector chamber for clots, and stop the heparin infusion based on the time taken for needle puncture sites to stop bleeding at the end of the hemodialysis session. Heparin is negatively charged and can bind to plasma proteins, leukocytes, and plastic. As such, it is important to achieve adequate mixing of heparin with blood to optimize anticoagulation within the extracorporeal circuit, by administering an intravenous bolus a few minutes prior to connecting the patient to the circuit and ensuring thorough mixing of the heparin infusion.

Use and Safety of Unfractionated Heparin for Anticoagulation During Maintenance Hemodialysis

“…In general, patients receive a bolus of 2,000-4,000 IU at the start of the dialysis treatment. 28 A continuous or hourly intermittent infusion often follows, which provides more consistent levels of anticoagulation (and presumably less risk of bleeding) than a single second bolus. 4,30 The hourly rate can range from 500-2,000 IU/h or more, depending on the dose of the initial bolus, and some centers avoid all heparin in the final hour of dialysis to decrease the likelihood of bleeding at the needle sites.…”

“…16,46 Generally, patients receive about half the full dose of heparin as a bolus of 10-25 IU/kg, followed by a maintenance infusion of 10 IU/kg/h (Table 1). 16,28,29 Our recommendation is to use the same protocol we suggested previously for all patients (a loading dose of 25 IU/kg, followed by a maintenance infusion of 1,000 IU/h to be stopped 30-60 minutes before the end of the session) because it already delivers a low dose of heparin when appropriately titrated, obviating the need for an explicit low-dose regimen.…”

“…Low-dose protocols have been suggested for patients with an increased risk of bleeding. 16,28,29 Abbreviation: UFH, unfractionated heparin. …”

Pharmacologic Treatment in Dialysis Patients Hospitalized for Cardiovascular Reasons: Do We Follow the Guidelines?

“…27 LMWH have become very popular in Western Europe for routine outpatient hemodialysis sessions due to the reliability of their clinical effect, ease of administration, and low cost. 28 Enoxaparin in our population was given for 5% of the patients with CAD, 12.5% of the patients with CHF, and 16.67% of the patients with DM between dialysis sessions for cardiovascular reasons.…”

Alternatives to standard unfractionated heparin for pediatric hemodialysis treatments

“…The disparity in half-life is greatest at the extremes of weight, particularly in pediatric practice in infants < 10 kg. In addition, as UFH is a series of large charged molecules, metabolism is also affected by nonspecific electrostatic binding to the endothelium, leukocytes and plasma proteins, and also binding to plastic tubing and dialyzer capillary membrane surfaces in the extracorporeal circuit [9]. Because of the variability of biological activity and nonspecific binding, studies using pharmacokinetic algorithms to predict UFH dosages failed to significantly improve anticoagulation regimes, due to UFH batch, and inter- and intra-patient variability [10, 11].…”