Citrate for regional anticoagulation. Effects on blood Po₂, ammonia, and aluminum

Infusion of citrate into the arterial line, followed by infusion of calcium into the venous line, has been used for regional anticoagulation during hemodialysis of patients with bleeding diatheses or heparin-induced antiplatelet antibodies. These patients are often hospitalized in intensive care units, where the use of a sorbent regeneration dialysis system is convenient. In this study, the use of regional citrate anticoagulation during dialysis with a cuprophan dialyzer on a REDY dialysis machine was investigated in eight patients. The white blood cell count, arterial Po₂, arterial and venous ammonia, and arterial, venous and dialysate aluminum were measured. Similar studies were carried out on four other patients undergoing dialysis with standard systemic heparin anticoagulation and cellulose acetate dialyzers. The white blood cell count was observed to decline moderately, reaching a nadir of 83.2% of control at 15 minutes. The Po₂ was unchanged or increased. However, blood ammonia rose in four of five patients, with the venous value always exceeding the arterial value. In two patients, aluminum levels in blood increased as well, and in one patient, a marked increase was observed in dialysate, and venous and arterial blood, with the concentrations being highest in the dialysate. No such changes were observed in the patients anticoagulated with heparin. It was concluded that although citrate is a useful agent for regional anticoagulation, it should not be used in sorbent regeneration systems.