Transmembrane pressure modulation in high-volume mixed hemodiafiltration to optimize efficiency and minimize protein loss

Abstract

The aim of the present study was transmembrane pressure (TMP) modulation in high-volume mixed hemodiafiltration (HDF) to optimize efficiency and minimize protein loss. The optimal flow/pressure conditions in on-line mixed HDF assisted with a feedback control of TMP were defined in this prospective randomized study in order to obtain maximal efficiency in solute removal while minimizing potential side effects. Two different TMP profiles in mixed HDF were compared in 12 unselected patients who underwent two study periods of 2 weeks each in cross-over randomized sequence: (A) constant TMP at around 300 mmHg and (B) profiled TMP, in which TMP was slowly increased from a low initial value to the maximal value. In both procedures, the mean volume exchange was 10.6+/-1.4 l/h. Mean filtration fraction was 53%. Instantaneous beta2-microglobulin (beta2-m) clearance was higher at the start of the session with profiled TMP (207+/-35 vs 194+/-28 ml/min, P<0.005), whereas no differences were found at the end (135+/-19 vs 132+/-19 ml/min). Profiled TMP resulted in a higher mean beta2-m clearance of the session (97.0+/-15.4 vs 87.8+/-18.3 ml/min, P<0.01), in lower albumin loss in the first 30 min (0.62+/-0.14 vs 0.98+/-0.18 g, P<0.0001), and, in the whole session (3.98+/-1.19 vs 5.24+/-0.77 g, P<0.001), in higher dialyzer ultrafiltration coefficients and lower resistance indexes. This study showed that the TMP feedback modulation in mixed HDF was highly effective in maintaining very high ultrafiltration rates and filtration fractions, and minimized potential side effects as a result of the improved preservation of membrane permeability and more favorable dialyzer pressure regimen.

Elevated Removal of Middle Molecules without Significant Albumin Loss with Mixed-Dilution Hemodiafiltration for Patients Unable to Provide Sufficient Blood Flow Rates

“…It is not dialyzer-dependent but depends on the 5008 dialysis machine. Its main principle [12,13,14] is to make Q s Pre and Q s Post strictly depend on a preselected TMP range between two limits not to be exceeded. Given the more positive TMP influence of PostD vs. PreD, one can predict a Q s Pre increase with a Q s Post decrease when TMP reaches its upper limit and inversely when it reaches its lower one.…”

Mid-Dilution Hemodiafiltration: A Comparison with Pre- and Postdilution Modes Using the Same Polyphenylene Membrane

“…The predilution mode, while partially preventing any technical problems, reduces cumulative solute transfer as a consequence of the diluted concentration [3,4] . Simultaneous pre-and postdilution (mixed HDF) could be a highly effective technique to re- move uremic toxins, while avoiding the disadvantages of traditional infusion modes [5,12,13] . Mid-dilution infusion is a recent alternative to mixed HDF, in which the fibers are divided into 2 bundles by a special annular ring that, in reverse configuration, allows blood passage through the central bundle (postdilution) to an infusion port where blood flow reverse direction and predilution is performed in the ascending way at the periphery.…”

Patterns of Proteins Removed with High-Flux Membranes on High-Volume Hemodiafiltration Detected with a MultiDimensional LC-MS/MS Strategy

“…All study sessions were performed with a Fresenius 5008 machine (FMC, Bad Homburg, Germany) under the same operating conditions of Q B eff , inlet dialysis fluid flow rate (Q Din ), duration, dialysate/infusate composition, and anticoagulation protocol. The highest ultrafiltration rate (Q UF ) was applied under the control of a feedback system ensuring the maximum filtration pressure under safe operating conditions [14]. …”