Warning of high-flux hemodialysis

In order to estimate the influence of flux on plasma refilling during hemodialysis (HD), prospective crossover studies were performed in 10 HD patients with low-flux and high-flux dialyzers. Hematocrit was continuously monitored to assess changes in blood volume. In addition, plasma osmolarity and total protein concentration were measured. Intradialytic reductions in body weight (-5 +/-1 vs -5 +/-1%) and plasma osmolarity (-5 +/-1 vs -5 +/-1%) were similar in both conditions. Although mean blood pressure remained unchanged in either state, the decrease in blood volume was larger in high-flux HD (-13 +/-2 vs -10 +/-2%, p < 0.05). In spite of greater contraction in blood volume during high-flux HD, total proteins were increased equally between low-flux and high-flux HD (11 +/-4 vs 11 +/-4%). Our data that although high-flux HD failed to induce significant drops in blood pressure, it elicited greater magnitude of decreases in blood volume, implicate the judicious application of highflux HD.