Elevated removal of middle molecules without significant albumin loss with mixed-dilution hemodiafiltration for patients unable to provide sufficient blood flow rates.

BACKGROUND: We examined the hypothesis that mixed-dilution online hemodiafiltration (MIXED) rather than predilution online hemodiafiltration (PRE) could enable patients with low blood flow rate (Qb) to benefit from advantages of convective therapies. METHODS: Thirty-eight patients were included in a prospective, randomized, crossover and multicenter study conducted with a view to comparing the equilibrated Kt/V, reduction ratio (RR) of phosphates, ß2-microglobulin (ß2-M) and myoglobin (myo) between PRE and MIXED, each at two Qb values of 250 and 300 ml/min during 4 h sessions with a FX1000HDF dialyzer. Albumin losses (Alb) were also measured in 12 patients. RESULTS: MIXED was always found to be more efficient compared to PRE notably for middle molecules (MM). RRß2-M: MIX250: 81.3 ± 3.6 vs. PRE250: 75.2 ± 5.9; MIX300: 82.7 ± 3.6 vs. PRE300: 78.1 ± 5.4; RRmyo: MIX250: 70.2 ± 3.6 vs. PRE250: 42.6 ± 2.6; MIX300: 70.6 ± 3.6 vs. PRE300: 45.7 ± 3.6 and with Alb <3.0 g/session. CONCLUSION: MIXED allows patients unable to provide sufficiently high Qb to achieve high levels of MM removal.