Functional Description - Gambro Cobe Spectra Essentials Manual

Introduction

Functional Description

Separation
The Spectra system uses a centrifuge to separate whole blood into its
major components: Erythrocytes (red blood cells), leukocytes (white
blood cells, including peripheral blood stem cells), thrombocytes
(platelets), and plasma. The system draws whole blood from a donor or
patient, adds anticoagulant, pumps it through the tubing set and into
the centrifuge, and separates it into components. The system collects
specific components and returns remaining components to the
donor/patient. In TPE and RBCX procedures, patients receive
appropriate replacement fluid with the returned components.
During single-stage separation (TPE, RBCX, and WBC procedures), the
system pumps anticoagulated whole blood through an inlet tube into the
tubing set channel, while the channel rotates clockwise in the centrifuge.
The highest density component (RBCs) flows to the outer wall of the
channel. The buffy coat, which contains WBCs, and the plasma form
layers on top of the RBCs. Platelet collection and AutoPBSC procedures
use dual-stage separation, which is described in detail in the Platelet
Collection Guide and the Cell Therapy Guide.
The channel contains several outlet tubes. The tubes route components
for collection or return to the donor/patient, depending on the apheresis
procedure.
In the TPE and RBCX channels, two tubes route components out of the
channel. The tube that routes cellular components extends from inside
the channel to the outer channel wall, and the tube that routes plasma
extends to the inner wall. In the WBC channel, three tubes route
components out of the channel.
A control tube helps to establish and maintain the RBC/plasma
interface, so platelets or WBCs collect at the interface. The relationship
between the centrifuge speed and specific gravity of platelets and WBCs
determines which cells collect at the interface.
2-22
Saturated Fluidized Particle Bed Separation in LRS/LRS Turbo
Platelet Procedures
The collect pump directs platelet-rich plasma and the few remaining
WBCs from the second stage of the channel into the LRS chamber. The
fluid dynamics of the conical separation chamber, the sedimentation
velocity of the platelets and WBCs, and the flow rate through the
separation chamber result in an advancing platelet bed, which upon
saturation, traps WBCs in the lower levels of the LRS chamber. Platelets
exit to the storage bags.
Fluid Flows
Four variable-speed peristaltic pumps on the front panel (Figure 2-2)
control fluid flows. See page 2-5 for a description of the pumps.
When using the Spectra keypad to change a pump flow rate during a
Dual-Needle procedure, enter the actual pump flow rate for the current
procedure. An exception occurs during platelet collection procedures
when the High Flow configuration is set to "On." When the system
establishes the RBC/plasma interface, it limits the inlet pump flow rate
to 45 mL/min. For more information on High Flow configuration, see
"Enabling the High Flow Protocol (ELP Procedures)" on page 5-6.
The system limits the inlet flow to 45 and then 65 mL/min while it
establishes a stable interface during the first part of all AutoPBSC
procedures.
Note: During ELP, LRS, LRST, TPE, and AutoPBSC procedures,
you can change only the inlet pump flow rate.
When changing a pump flow rate during a Single-Needle procedure, you
actually change the average rate for that pump. At any time during a
procedure, the instantaneous pump flow rate for a specific pump can be
faster or slower than the average pump flow rate. The average pump flow
rate is the average of the pump flow rates during the Draw and Return
phases.
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COBE Spectra™ Apheresis System • Essentials Guide