EFFECT OF HEMATOCRIT ON DIALYZER UREA AND CREATININE CLEARANCE INDEXES IN A HEMODIALYSIS PATIENT WITH ERYTHROCYTOSIS

The association between azotemic index dialyzer clearances and hematoc rit was investigated in a 63-year-old dialysis-dependent man with acqu ired renal cysts. During 43 months of hemodialysis, hematocrit rose fr om 27.3 to 65.0 vol%, as a consequence of high serum erythropoietin le vels. Concomitantly, dry weight also increased from 116.8 to 140.8 kg. Both hematocrit and dry weight correlated with: (a) urea reduction ra tio, (b) creatinine reduction ratio (CRR), and (c) KT/V urea. All corr elations were negative. Stepwise regression showed that only hematocri t was an independent correlate of the CRR (CRR = 0.662 - 007 Hct, R(2 ) = 0.770); whereas, both hematocrit (Hct) and weight (W) were indepen dent correlates of KT/V urea (KT/V = 2.070 - 0.005Hct - 0.009*W,R(2) = 0.721). In addition to creatinine clearance, urea clearance through the dialyzer is reduced by a rising hematocrit. The effect of hematocr it on urea clearance is relatively small. Therefore, it requires large changes in hematocrit in order to be detected (Int J Artif Organs 199 4; 17: 591-4)