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.

An atraumatic aspirator for use in autologous transfusion and cardiac bypass.

Surgical aspiration has long been seen as the weak link in surgical blood recovery. Aspiration causes a high degree of hemolysis that leads to high plasma hemoglobin levels and reduces the number of erythrocytes available for reinfusion. Aspiration also damages platelets, generates emboli, and increases bleeding time. The major source of the high hemolysis and the other blood damage that occurs during suction is the aspiration of air with the blood. To address this problem, a jet driven aspirator that immediately separates and removes air during suction was designed and tested. The aspirator suctions blood at a range of rates from 100 to at least 700 ml/min, separates and removes 80-100% of the aspirated air, operates at any orientation, and generates subatmospheric pressures on the order of only an inch of water. During in vitro hemolysis testing, the removal of air by the jet driven aspirator showed a significant reduction in hemolysis: plasma hemoglobin levels increased 19.4 mg/dl without air removal and only 1.8 mg/dl with air removal (p < 0.001). In comparative testing with a conventional vacuum operated suction tube, the jet driven aspirator showed significantly less hemolysis (p < 0.001) than did the conventional aspirator at comparable blood and air aspiration rates.