Evaluation of Microparticle Leakage during DALI LDL Adsorption in a Simulated Clinical Setting

Abstract

The aim of the present study was to investigate microparticle (Mp) leakage during simulated LDL-hemoperfusion using 12 DALI 750 adsorbers and the original DALI hardware under conditions strictly comparable to the clinical situation. Thus, the sessions were divided into 4 sections, i.e. priming and preparation of the adsorber followed by treatment (6–7 L at a flow rate of 60 ml/min) and reinfusion. As Mp counts can be performed only in clear, cell-free media, blood was replaced by normal saline in sections 2–4 of the simulated sessions.

Mp counts were analysed for ≥ 2, ≥ 5, ≥ 10 and ≥ 25 μm particle sizes in the efferent line post adsorber using a standard light blockage method. As there are no official thresholds for particle release in extracorporeal circuits, the limits for infusion of large fluid volumes of 500, 100 (80), 25 and 5 (3) Mp/ml according to the Europäische Arzneimittelbuch, the British and American Pharmacopoeias were used. Mean particle counts for the sections 3 and 4 in which the patient is connected to the efferent line were 19, 7, 2 and 0 Mp/ml and amounted to < 10% of the above mentioned limits. Modifications of the standard simulation procedure by inserting additional pump stops or using different flow rates during the treatment phase slightly increased Mp leakage, but never exceeded the prescribed limits. In summary, no undue particle release could be detected during simulations of the clinical DALI LDL-adsorption procedure.