Impact of erythropoietin on the dialysis prescription.

Close on the heals of the first successful reports of recombinant human erythropoietin (rHuEPO) use in dialysis-associated anemia, concern surfaced that raising the hematocrit level could threaten both the safety and efficacy of hemodialysis. Theoretical considerations prompted the conclusion that by decreasing the plasma water space available for dialysis, removal of plasma solutes would decrease in direct proportion to the increase in hematocrit. Predictions of thrombotic disaster were also aired, citing the increase in blood viscosity expected after correction of anemia. After 18 months of widespread use of rHuEPO in the United States, clinical experience has shown that correction of anemia can be accomplished without serious impact on either safety or efficacy in both conventional and high efficiency/high dialysis. Although predialysis concentrations of creatinine, phosphate, and potassium may increase whenever the hematocrit increases substantially, the magnitude of the rise is limited. Increased predialysis solute concentrations, which may be caused by either decreased dialyzer efficiency or increased dietary intake due to improved appetite, are readily managed by increasing dialysis blood flow rate, dialyzer surface area, and dialysis time. Since these measures may have little effect on increased phosphate levels, increased administration of phosphate binders may be required. However, by way of caution, the ready dialyzability of urea renders the predialysis blood urea nitrogen (BUN), as well as urea kinetics, relatively unaffected by the change in hematocrit, thereby masking adverse effects on other solutes. Fortunately, serious thrombotic consequences have not been seen, probably because anticoagulation is adequately managed by routine increases in heparin utilization.