Effect of perfluorochemical emulsion on blood trauma and hemorheology

One of the major problems of development and improvement of heart assist devices is the reduction of blood cell damage. The extremely high levels of shear stress, turbulence, prolonged contact between blood and foreign surfaces, and other abnormal hydrodynamic circumstances have been shown to cause hemolysis, activation of platelets, and changes in mechanical properties of red blood cells. Hemolysis, in turn, can drastically increase red blood cell aggregation at low shear conditions. A new pharmacologic approach to reduce blood trauma and improve rheologic properties of blood subjected to mechanical stress was investigated. These experiments showed that the replacement of 20% of the plasma volume with Fluosol (Alpha Therapeutic Corp., Los Angeles, CA), a perfluorochemical that transports oxygen, reduced mechanical fragility of human (P < 0.01) and ovine (P = 0.054) red blood cells by approximately 30%. The same replacement of plasma with Fluosol reduced hemolysis (plasma free Hb) by approximately 40% compared to control (P < 0.05) during in vitro pumping of blood with a centrifugal pump. A 20% replacement of plasma volume with Fluosol remarkably reduced low shear blood viscosity (from 31.9 +/- 6.1 to 18.2 +/- 4.8 cP, for shear rate gamma = 0.277 sec-1) and erythrocyte sedimentation rate (from 16.7 +/- 9.2 to 3.1 +/- 3.1) mm/hr) in human blood. Decrease of these parameters indicates the reduction of red blood cell aggregation. Results of this study demonstrate the potential feasibility of Fluosol to improve mechanical properties of blood in patients with heart assist devices.