Abstract
Reynolds shear stress (RSS) has served as a metric for the effect of turbulence on hemolysis. Forstrom (1969) and Sallam and Hwang (1984) determined the RSS threshold for hemolysis to be 50,000 and 4,000 dyne/cm2, respectively, using a turbulent jet. Despite the order of magnitude discrepancy, the threshold by Sallam and Hwang has been frequently cited for hemolytic potential in blood pumps. We recreated a Sallam apparatus (SA) to resolve this discrepancy and provide additional data to be used in developing a more accurate hemolysis model. Hemolysis was measured over a large range of Reynolds numbers (Re) (Re = 1,000–80,000). Washed bovine red blood cells (RBCs) were injected into the free jet of phosphate buffered saline, and hemolysis was quantified using a percent hemolysis, Hp = h (100 − hematocrit [HCT])/ Hb, where h (mg/dl) is free hemoglobin and Hb (mg/dl) is total hemoglobin. Reynolds shear stress was calculated using two-dimensional laser Doppler velocimetry. Reynolds shear stress of ≥30,000 dyne/cm2 corresponding to Re of ≥60,000 appeared to cause hemolysis (p < 0.05). This RSS is an order of magnitude greater than the RSS threshold that Sallam and Hwang suggested, and it is similar to Forstrom’s RSS threshold. This study resolved a long-standing uncertainty regarding the critical values of RSS for hemolysis and may provide a foundation for a more accurate hemolysis model.
Original language | English (US) |
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Pages (from-to) | 63-69 |
Number of pages | 7 |
Journal | ASAIO Journal |
Volume | 64 |
Issue number | 1 |
DOIs | |
State | Published - Jun 15 2017 |
All Science Journal Classification (ASJC) codes
- Biophysics
- Bioengineering
- Biomaterials
- Biomedical Engineering