Pressure cuff draw mode enhancement system and method for a single

Abstract

A pressure cuff draw mode enhancement system for a blood fractionation system having a single-lumen phlebotomy needle, a flow-through plasma separation filter, and an in-process fluid reservoir, includes a pressure cuff in operative association with the donor. During an initial draw cycle of the system whole blood is pumped by an inlet pump through the filter to the in-process reservoir. When a predetermined volume of filtered plasma-deficient blood has been collected in the reservoir, as sensed by the weight of the reservoir, the system reverts to a return cycle wherein a portion of the plasma-deficient blood in the reservoir is pumped back to the phlebotomy needle by a return pump. Depending on the relative operating rates of the inlet and return pumps, an operator-controllable portion of the plasma-deficient blood from the in-process reservoir is returned to the donor through the phlebotomy needle, and the remaining portion is recirculated through the filter. To facilitate higher whole blood draw rates, the pressure cuff draw mode enhancement system pressurizes the pressure cuff during each draw cycle. Upon completion of the draw cycle, the pressure cuff is depressurized to facilitate the return of blood to the donor during the succeeding return cycle. A safety circuit prevents operation of the return pump unitl the pressure cuff has adequately depressurized.