RESUMO
Anemia correction by erythropoietin favorably affects dialysis outcome but may also reduce dialysis efficiency increasing morbidity and mortality. Single needle dialysis (SN) and high dialysate flow (DF) are dialysis variations. We studied the effect of hemoglobin (Hb) normalization on dialysis adequacy under high DF. We also compared double needle (DN) and SN dialysis efficiency. Seventeen stable anuric patients (13 M, 4 F), aged 62 (40-90), on hemodialysis for 48 months (8-204), were studied in two, 6 months apart, periods of low (A) and high Hb (B), during a midweek 4 h dialysis with DN and SN. DF was 500 in A and 800 ml/min in B. Rebound urea samples, 20 min post dialysis, were used for computer calculated double pool urea kinetics. Hb levels were 128 +/- 8 g/L (B) vs. 119 +/- 14 g/L (A), P < 0.03. Despite the use of higher DF less dialysis was delivered in B vs. A, under DN or SN (DN: URR 64.8 +/- 5.8 vs. 69.7 +/- 5.2%, Kt/Vequil. 1.09 +/- 0.19 vs. 1.26 +/- 0.21, nPCR 1.37 +/- 0.29 vs. 1.60 +/- 0.36g/kg/day, changes <0.001, SN: URR 49.7 +/- 7.5% vs. 52.6 +/- 8.8%, Kt/Vequil. 0.74 +/- 0.16 vs. 0.82 +/- 0.23, nPCR 1.05 +/- 0.33 vs. 1.20 +/- 0.31, changes NS). SN was found significantly (P < 0.001) less efficient than DN in A and B. Serum creatinine drop was significantly (P < 0.001) less in both periods with SN vs. DN. Hb (SN in B) correlated inversely to Kt/V (r = -0.5705, P < 0.02) and URR (r = -0.6432, P = 0.005). Hb correction to normality is associated with a decrease in dialysis efficiency. The use of high dialysate flow does not compensate for this loss. SN delivers inadequate dialysis independently of dialysate flow or hemoglobin concentration.
