Hemolysis in a Laminar Flow-Through Couette Shearing Device: An Experimental Study

Abstract

Reducing hemolysis has been one of the major goals of rotary blood pump development and in the investigational phase, the capability of hemolysis estimation for areas of elevated shear stresses is valuable. The degree of hemolysis is determined by the amplitude of shear stress and the exposure time, but to date, the exact hemolytic behavior at elevated shear stresses and potential thresholds for subcritical shear exposure remain vague. This study provides experimental hemolysis data for a set of shear stresses and exposure times to allow better estimations of hemolysis for blood exposed to elevated shearing. Heparinized porcine blood with a hematocrit of 40% was mechanically damaged in a flow-through laminar Couette shear flow at a temperature of 23°C. Four levels of shear stress, 24, 592, 702, and 842 Pa, were replicated at two exposure times, 54 and 873 ms. For the calculation of the shear stresses, an apparent viscosity of 5 mPas was used, which was verified in an additional measurement of the blood viscosity. The hemolysis measurements were repeated four times, whereby all conditions were measured once within the same day and with blood from the same source. Samples were taken at the inlet and outlet of the shear region and an increase in plasma-free hemoglobin was measured. An index of hemolysis (IH) was thereby calculated giving the ratio of free to total hemoglobin. The results are compared with data from previously published studies using a similar shearing device. Hemolysis was found to increase exponentially with shear stress, but high standard deviations existed at measurements with elevated IH. At short exposure times, the IH remained low at under 0.5% for all shear stress levels. For high exposure times, the IH increased from 0.84% at 592 Pa up to 3.57% at the highest shear stress level. Hemolysis was significant for shear stresses above ∼600 Pa at the high exposure time of 873 ms.

Centrifugation-induced release of ATP from red blood cells

“…More recent work by Boehning et al [37] suggested that increased duration of shear increases the probability of hemolysis, even at lower shear stresses, consistent with earlier work by Offeman & Williams [38]. Thus, our hypothesis of increasing hemolysis with increasing centrifugation forces and times is consistent with earlier observations in different shear environments.…”

A near-superhydrophobic surface reduces hemolysis of blood flow in tubes

“…4b that the hemolysis rates generally rise from ow setting I to VI, which is associated with increased mean ow rates and higher wall shear stresses (Table 1 and Fig. 7,8,11 To further conrm this, the microscopy images of the red blood cells before and aer being subjected to extracorporeal pumping were examined. This is consistent with previous studies which showed that exposure to shear stresses can lead to red blood cell damage.…”

A linear shear model of cell viability loss during hepatocyte transplantation

“…The relationship between shear stress and red blood cell hemolysis (Paul et al,2003, Boehning et al, 2014 or viability loss in hepatocytes (Yasuda et al, 2015) has been noted, although the process of viability loss or cell lysis was not clearly identified. Also, the effects of cell sedimentation and fluid shear stress on cell viability loss were investigated using a microchannel model to imitate the narrow channel of a catheter (Sufiandi et al, 2015).…”