Deformability of Red Blood Cells and Its Relation to Blood Trauma in Rotary Blood Pumps

Abstract

In this study, mechanical trauma to red blood cells was evaluated by conventional hemolysis test and a newly developed cyclically reversing shear flow generator. The fresh porcine blood obtained from a local slaughterhouse was subjected to the conventional hemolysis test using a commercial centrifugal blood pump for the duration of 8 h. The measurements consisted of (i) plasma-free hemoglobin based on the standard optical measurement and (ii) the deformability of red blood cells (RBCs) using a cyclically reversing shear flow generator and microscope image acquisition system. The deformability of RBCs was expressed by the L/W value where L and W were the longer and shorter axes of the elongated RBCs' images. Although the plasma-free hemoglobin level increased with the pumping duration, the L/W remained unchanged for the duration of 8 h of pumping to indicate no alteration in the deformability. It was speculated that (i) although RBCs might have been circulated for so many times through the test pump, after each exposure to mechanical stress, RBCs might have recovered, and net effect due to shear stress-exposure time might have been small; and (ii) RBCs' deformability might be maintained near normal until sudden burst or membrane rupture, or the hemoglobin might have continuously leaked through the pores of the thinned membrane created by the mechanical stress. The deformability testing under a fluctuating shear flow could be a new method to quantify subhemolytic mechanical damage that has been accumulated in the RBCs' membrane and that may not be assessed by the conventional hemolysis test.

Technique for Prolonged Normothermic Ex Vivo Lung Perfusion

“…18,19 The use of red blood cells can be problematic because of the mechanical damage inflicted on the circulating red cells over time. 20,21 However, further studies are required to compare acellular versus cellular perfusates, and post-transplant testing in large animals will shed further light on the pros and cons of having red blood cells in the perfusate in the context of the EVLP maintenance strategy.…”

Feasibility study of a sinusoidal shear flow generator for using counter-oscillating flow fields in monitoring of individual red blood cells under shear flow conditions

“…On the basis of a previously published design of a slidercrankshaft mechanism [28][29][30], we developed a counteroscillation mechanism composed of two plates. A schematic diagram of the mechanism is shown in Fig.…”

“…To realize such an improvement, we adopted previous observation techniques utilized for cyclically reversing shear flow [28][29][30]. However, those methods lack the ability to monitor the shape changes of individual cells over time and the shear flow was generated by one-sided oscillation only.…”

Extracorporeal perfusion of isolated organs of large animals – Bridging the gap between in vitro and in vivo studies

“…Isolated erythrocytes, as the body's natural oxygen carriers, are very well suited for this purpose although their use in closed systems entails the risk of mechanical cell damage over time (Watanabe et al, 2007;Lee et al, 2007). In early experiments them popular additives to perfusates (Tindal, 1957;Drapanas et al, 1966;Cameron et al, 1972;Rehfeld et al, 1982;Domingo-Pech et al, 1991;Kietzmann et al, 1993;Hansen et al, 2000).…”

“…The limited volume of available blood might require use of a recirculating system to ensure perfusion at adequate flow rates over the desired length of time. However, closed or recirculating systems are also associated with damage to blood cells (Watanabe et al, 2007;Lee et al, 2007) and metabolic waste products such as lactate will accumulate over time (Bristol et al, 1991). Furthermore, the use of blood collected from animals under anesthesia or following euthanasia contains drug residues that may affect blood physiology (Barlow and Knott, 1964;Gentry and Black, 1976;Honkanen et al, 1995).…”