Читать книгу Transfusion Medicine - Jeffrey McCullough - Страница 169

The Haemonetics system uses a disposable, transparent Lucite centrifuge bowl for blood separation [9]. After venipuncture is performed and the donor is connected to the instrument, the operator activates the instrument and blood is pumped from the donor into the centrifuge bowl (Figure 6.2). Anticoagulant–citrate–dextrose anticoagulant is added to the blood as it leaves the donor. The centrifuge bowl spins at approximately 4,800 rpm and continuously separates the blood as it enters the bowl. When the volume of blood removed from the donor exceeds the capacity of the bowl, plasma begins to exit the bowl and is collected in a bag. The platelet/buffy coat layer accumulates at the top of the red cells, and as the bowl continues to fill, this layer moves toward the exit port. When the platelets—visible as a white band between the red cells and plasma—reach the exit port, a valve is activated, diverting the flow pathway into a separate bag, where the platelets are collected. When the platelets have been collected, the blood flow is stopped, the pumps reversed, and the plasma and red cells recombined and returned to the donor. This cycle of filling the centrifuge bowl is repeated several times to obtain the desired platelet yield.

Figure 6.2 Flow pathway and blood separation in the Haemonetics Latham bowl system.

(Source:Courtesy of Haemonetics Corporation)

The Haemonetics Multiple Component Systems (MCS and MCS+) have the flexibility to collect various combinations of platelets, plasma, and red cells [41, 42] (Table 6.1). The MCS and MCS+ can collect approximately 4 × 10¹¹ platelets in 90 minutes [41, 42]. A combination of platelets and plasma can also be collected [43]. This exciting approach was finally the first step to provide flexibility to the donor center to determine on a daily basis or for individual donors the particular mix of components to collect.