Towards bedside washing of stored red blood cells: a prototype of a simple apparatus based on microscale sedimentation in normal gravity

• Published in: Vox sanguinis Vol. 113; no. 1; pp. 31 - 39
• Main Authors: Khanal, G., Huynh, R. A., Torabian, K., Xia, H., Vörös, E., Shevkoplyas, S. S.
• Format: Journal Article
• Language: English
• Published: England S. Karger AG 01-01-2018
• Subjects: Bifurcations; Blood; blood component production; blood processing; Blood Proteins; Blood Safety - instrumentation; Blood Safety - methods; Blood Transfusion; Byproducts; Centrifugation; Coiling; Deformability; Deformation; Dilution; Efficiency; Erythrocyte Count; Erythrocyte sedimentation rate; Erythrocytes; Erythrocytes - cytology; Erythrocytes - physiology; Feasibility studies; Formability; Gravitation; Hematocrit; Hemoglobin; Humans; Microvasculature; Plasma proteins; Proteins; red cell components; Sedimentation; Sedimentation & deposition; transfusion ‐ pediatrics; Washing; Waste disposal; transfusion - pediatrics; blood component production; blood processing; red cell components
• ISSN: 0042-9007; 1423-0410
• DOI: 10.1111/vox.12605

Background and Objectives
Infusion of by‐products of red blood cell (RBC) storage‐induced degradation as well as of the residual plasma proteins and the anticoagulant‐preservative solution contained in units of stored blood serve no therapeutic purpose and may be harmful to some patients. Here, we describe a prototype of a gravity‐driven system for bedside washing of stored RBCs.
Materials and Methods
Stored RBCs were diluted to 10% haematocrit (Hct) with normal saline, matching the conventional washing procedure. The dilute RBC suspensions were passed through a column of coiled tubing to allow RBC sedimentation in normal gravity, thus separating them from the washing solution. Washed RBCs were collected using bifurcations located along the tubing. Washing efficiency was quantified by measuring Hct, morphology, deformability, free haemoglobin and total‐free protein.
Results
The gravity‐driven washing system operating at 0·5 ml/min produced washed RBCs with final Hct of 36·7 ± 3·4% (32·3–41·2%, n = 10) and waste Hct of 3·4 ± 0·7% (2·4–4·3%, n = 10), while removing 80% of free haemoglobin and 90% of total‐free protein. Washing improved the ability of stored RBCs to perfuse an artificial microvascular network by 20%. The efficiency of washing performed using the gravity‐driven system was not significantly different than that of conventional centrifugation.
Conclusions
This proof‐of‐concept study demonstrates the feasibility of washing stored RBCs using a simple, disposable system with efficiency comparable to that of conventional centrifugation, and thus represents a significant first step towards enabling low‐cost washing of stored blood at bedside.