A low-hemolysis blood aspirator conserves blood during surgery

Blood damage caused by traditional vacuum-operated suction tubes, particularly when air is aspirated along with the blood, usually exceeds damage from all other components. In addition to platelet injury, there is a high degree of hemolysis, which leads to high plasma hemoglobin levels and reduces the number of red blood cells available for reinfusion during cases of blood conservation, such as autologous transfusion and cardiac bypass. This work was undertaken to minimize hemolysis, and the accompanying platelet destruction, during aspiration, with the design of a jet-driven aspirator that separates and removes air from blood immediately within the suction tip. The jet-driven aspirator can suction blood at a range of rates from 100 to at least 700 ml/min, separates and removes 80-100% of aspirated air, operates at any orientation, and generates subatmospheric pressures on the order of only 1 inch H2O. In-vitro hemolysis testing showed a significant reduction in average plasma hemoglobin release, from 19.4 mg/dl to 1.8 mg/dl, when air was removed during blood aspiration. In comparative testing with a conventional vacuum suction tube, the jet-driven aspirator showed significantly less hemolysis than the conventional aspirator at comparable rates of air and blood aspiration.