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

Abstract

As a change from Diapes to polyphenylene membrane in the mid-dilution filter has recently been developed, the aim of this study was to compare mid-dilution using this new dialyzer versus pre- and postdilution. The prospective study included 20 patients who underwent 4 hemodiafiltration (HDF) sessions: 1.7 m² polyphenylene and predilution infusion flow (Qi) 200 ml/min, 1.7 m² and postdilution Qi 100 ml/min, 1.9 and 2.2 m² mid-dilution both with Qi 200 ml/ min. The urea and creatinine reduction ratios were slightly higher in postdilution. The β₂-microglobulin (85.8%), myoglobin (73.6%), prolactin (67.8%) and retinol-binding protein (29.2%) reduction ratios with 1.9 m² mid-dilution, which was similar to 2.2 m² mid-dilution, were significantly higher than with the post- and predilution modes. Mid-dilution appears to be a good HDF alternative that allows a better removal of larger molecules than postdilution and, mainly, predilution. Mid-dilution using 1.9 or 2.2 m² dialyzers, at the same convective volume, showed a similar removal.

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

“…The first on the market was mid-dilution ol-HDF (MID) [8,9,10]. It relies on a specific hollow-fiber dialyzer (Olpur MD; 1.9 or 2.1 m 2 ; Bellco, Mirandola, Italy) and a polyphenylene membrane succeeding an anterior polyethersulfone one.…”

“…Dialysate circulates then co-current with entering blood. LM and MM removals have been regularly confirmed very efficient [9,10], possibly because of an obligatory first-step PostD participation estimated 100 ml/min [11] minimum.…”

What Infusion Flow Should Be Used for Mid-Dilution Hemodiafiltration?

“…Potier [17] reported ␤ 2 -microglobulin reduction rates of 82.3% in mid-dilution (Qi 200 ml/min). In a previous study [18] , we reported ␤ 2 -microglobulin reduction rates of 85% in mid-dilution (Qi 200 ml/min). The present results provide similar data: 84.9, 84.0, 84.8 and 84.0% ␤ 2 -microglobulin reduction rates per session were obtained with Qi 150, 200, 250 and 300 ml/min, respectively.…”

“…Feliciani et al [22] compared middilution (standard infusion) with mixed HDF using Qi 166 8 17 ml/min. With reverse mid-dilution, Potier [17] and Maduell et al [18] used a constant Qi of 225 and 200 ml/min, respectively, with no technical problems. Pedrini et al [23] compared standard mid-dilution (1.9 m 2 ) with reverse mid-dilution (2.2 m 2 ) using a Qi of 166 8 14 and 169 8 2 ml/min, respectively.…”

“…This technique could be highly effective in removing uremic toxins, avoiding the disadvantages of pre-and post-dilutional infusion modes [15][16][17][18] . Although this HDF modality allows higher infusion volumes, there is still no consensus on the optimal infusion flow (Qi).…”