Apheresis apparatus and method
First Claim
1. A method of increasing intermediate density blood component yield from donated whole blood in a centrifugation fractionation volume, the intermediate density component consisting primarily of at least one of a platelet constituent and a white blood cell constituent, the method comprising the steps of:
- (i) diluting whole blood, by mixing fluid with the whole blood at a first flow rate as the blood is introduced into the volume;
(ii) separating lower density component in the volume from higher density components in the volume including said intermediate density component, and displacing said lower density component to a first container;
(iii) recirculating the lower density component to the volume at a second, substantially constant flow rate to further dilute the components remaining in the volume and widen the region occupied by said intermediate density component without causing said intermediate density component to exit the fractionation volume;
(iv) recirculating the lower density component through the volume at a third, accelerating flow rate; and
(v) displacing said intermediate density component from the volume while the lower density component is recirculating through the volume at the third flow rate.
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Abstract
An apheresis apparatus and method is disclosed for increasing the purity and yield of platelets separated from donated whole blood in a centrifuge. The whole blood in the centrifuge is diluted by recirculating fluid, such as plasma or saline, at a first flow rate, to mix with further withdrawn whole blood prior to entering the centrifuge. As plasma is collected, it is recirculated through the centrifuge at a second flow rate to further improve the separation between the intermediate density components, i.e., platelets and white blood cells in the "buffy coat." The plasma is then recirculated through the centrifuge at a third flow rate and platelets are displaced out of the centrifuge while the plasma is recirculating through the centrifuge at the third flow rate.
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Citations
30 Claims
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1. A method of increasing intermediate density blood component yield from donated whole blood in a centrifugation fractionation volume, the intermediate density component consisting primarily of at least one of a platelet constituent and a white blood cell constituent, the method comprising the steps of:
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(i) diluting whole blood, by mixing fluid with the whole blood at a first flow rate as the blood is introduced into the volume; (ii) separating lower density component in the volume from higher density components in the volume including said intermediate density component, and displacing said lower density component to a first container; (iii) recirculating the lower density component to the volume at a second, substantially constant flow rate to further dilute the components remaining in the volume and widen the region occupied by said intermediate density component without causing said intermediate density component to exit the fractionation volume; (iv) recirculating the lower density component through the volume at a third, accelerating flow rate; and (v) displacing said intermediate density component from the volume while the lower density component is recirculating through the volume at the third flow rate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of increasing intermediate density component yield from donated whole blood in a centrifuge having an enclosed fractionation volume, the intermediate density component consisting primarily of at least one of a platelet constituent and a white blood cell constituent, the method comprising:
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(i) pumping whole blood into the volume along a first flow route; (ii) separating lower density component in the volume from higher density components in the volume including said intermediate density component, and displacing the lower density component to a first container; (iii) closing the first flow route and opening a second flow route, and returning the lower density component to the volume at a first, substantially constant flow rate to widen the region occupied by said intermediate density component without causing said intermediate density component to exit the fractionation volume; (iv) recirculating the lower density component through the volume at a second, accelerating flow rate; and (v) displacing said intermediate density component from the volume while the lower density component is recirculating though the volume at the second flow rate. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A method of increasing component yield from donated whole blood in a centrifuge having an enclosed fractionation volume, the method comprising:
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(i) pumping into the volume anticoagulated whole blood having components of varying density including an intermediate density component which consists primarily of at least one of a platelet constituent and a white blood cell constituent; (ii) separating lower density component in the volume from higher density components including said intermediate density component in the volume and displacing the lower density component to a first container; (iii) returning the lower density component to the volume at a first, substantially constant flow rate to dilute components remaining in the volume and widen the region occupied by said intermediate density component without causing said intermediate density component to exit the fractionation volume; (iv) recirculating the lower density component through the volume at a second, accelerating flow rate; and (v) displacing said intermediate density component from the volume while the lower density component is recirculating through the volume at the second flow rate. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30)
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Specification