Optimum Conditions for the Efficacy and Safety of Cryofiltration Apheresis: An Analysis of Circuit Temperatures Depending on Plasma Flow Rate and Cooling Coil Lengths/Turns.

A system providing both appropriate cooling and warming are needed for the efficacy and safety of cryofiltration (CF) plasmapheresis. We measured some points of CF circuit temperatures with varying plasma flow rates (QP = 10-40 mL/min) and the numbers of connecting cooling coils (one or two) under the conditions of blood flow rate (QB ) 100 mL/min with 7700-mm coil length, 19 turns, and 50-mL priming volume. We measured the respective temperatures of each point of starting/returning for an extracorporeal circuit (TA /TV ), intracooling coil (TC ), and post-plasma fractionator (PF) (TPF ). The subtraction of TV from TA (ΔT) was used as an indicator of safe return. There were no significant differences in TC , TPF , or ΔT in accordance with each QP between that of one and two coils. All of the Tc values under the condition QP ≤ 20 mL/min achieved <4°C. The TPF under the condition QP ≥ 20 mL/min was not significantly different compared to that of QP 30 mL/min (the lowest condition). Although the ΔT increased depending on the QP increase, the ΔT under the condition QP ≤ 15 mL/min was not significantly different from that of the control (one-way double-filtration plasmapheresis [DFPP]) group. We conclude that (i) one coil is enough for effective cooling in CF, and (ii) an ideal QP that fulfills the required conditions for both effective cooling and sufficient warming of returning fluid does not exist, but QP from 15 to 20 mL/min may be a relevant range.

Analysis of protein removal properties during cryofiltration apheresis using the Evaflux-5A plasma fractionator in a patient with hepatitis C virus-associated cryoglobulinemic glomerulonephritis.

Cryofiltration (CF) is a technique in which separated plasma is chilled before being subjected to a plasma fractionator (PF), leading to cryoglobulin precipitation or cryogel formation. In CF using the Evaflux-5A as the PF, there is no consensus on the necessity of albumin supplementation, and when or how often the PF column should be washed. We analyzed the sieving effects of various solutes (albumin, IgG, IgM, LDL, HCV-RNA, and cryoglobulin) depending on transmembrane pressure (TMPPF ) during CF using the Evaflux-5A in a patient with hepatitis C virus-associated cryoglobulinemic glomerulonephritis. Five CF treatments were initially performed and a sixth one later, at disease recurrence. Quantitative detection of cryoglobulin and a marked rise in TMPPF to 400 mm Hg were observed only at the first and sixth treatment, and albumin losses during these treatments were very high, at 16.8 g, and 14.6 g, respectively, while those of others (from the second to fifth) were 6.7 g, 6.4 g, 5.9 g, and 7.0 g, respectively. The sieving coefficients (SCs) of both albumin and IgG were stable (0.8-1.0) at TMPPF < 200 mm Hg, but significantly decreased at TMPPF ≥ 200 mm Hg (P < 0.01). The SC of IgM tended to decrease at TMPPF ≥ 200 mm Hg, but not significantly, while that of LDL was zero regardless of the TMPPF . Albumin loss per treatment likely depends on degree of TMPPF rise, which is mainly affected by the patient's cryoglobulinemic status. In CF using Evaflux-5A, washing the PF column to keep TMPPF < 200 mm Hg during treatment may be a recommended for selective removal and albumin salvage.