Erythrocyte destruction under periodically fluctuating shear rate: comparative study with constant shear rate

Area of Science:

• Biophysics
• Hematology
• Fluid Mechanics

Background:

• Erythrocyte destruction is influenced by hydrodynamic forces.
• Understanding shear stress effects on red blood cells is crucial for transfusion medicine and artificial organs.

Purpose of the Study:

• To quantitatively investigate the impact of fluctuating shear rates on erythrocyte destruction in vitro.
• To compare red blood cell damage under constant versus periodically varying shear conditions.

Main Methods:

• Heparinized canine blood was subjected to controlled shear rates (<1,000 s-1) using a Couette flow machine.
• Shear rates were either constant or sinusoidally fluctuating over time (1.8-9.0 x 10^3 s) at 24°C.
• Erythrocyte destruction was assessed via the hemolysis ratio (plasma hemoglobin/whole blood hemoglobin).

Main Results:

• Erythrocyte destruction was significantly reduced when high shear rates (>500 s-1) were interspersed with lower shear rates (<300 s-1).
• Constant high shear rates led to greater hemolysis compared to fluctuating shear profiles.
• The pattern of shear rate application influences the extent of red blood cell damage.

Conclusions:

• Periodically fluctuating shear rates offer a protective effect against erythrocyte destruction compared to constant shear.
• Optimizing shear rate profiles may mitigate red blood cell damage in medical devices and procedures.
• This finding has implications for blood handling and the design of blood-contacting technologies.