Anticoagulation options for pediatric hemodialysis.

Blood coagulation in the extracorporeal hemodialysis circuit is one of the manifestations of bio-incompatibility that is related to the activation of monocytes, platelets, and the coagulation cascades. Compared to adults, in pediatric patients, the surface area of the extracorporeal circuit is increased relative to blood volume. This is due to the patient's smaller blood volume and the combination of the higher relative surface area of the dialyzer, smaller lumen lines, and small-bore vascular catheters, potentially increasing contact activation of coagulation proteins, platelets, and inflammatory cells. Although unfractionated heparin remains the most commonly used anticoagulant, low molecular weight heparin offers the advantages of a single bolus, less fibrin and platelet deposition in the dialyzer, and perhaps more importantly, less osteoporosis, hyperkalemia, and abnormal lipoprotein profile. Although regional anticoagulants are available, these are often prohibitively expensive or require increased complexity of the dialysis procedure (e.g., citrate), but have the advantage of reducing the risk of bleeding when compared to heparin. Thrombin inhibitors are now available, and with the advent of argatroban, which is metabolized in the liver, have become the anticoagulants of choice for the few patients who develop heparin-induced thrombocytopenia type II.