Gambro Cobe Spectra Essentials Manual page 110

Fluid Volumes
Overview
To understand the Spectra system fluid volumes, you must understand the
difference between disposable tubing set volume, total equivalent whole
blood volume, total RBC volume, and residual RBC volume. The
definitions of the volumes are below. The volumes are different for each
apheresis procedure (see Table 9-1).
Disposable tubing set volume
The total volume within the disposable tubing set fluid path. It equals the
amount of saline required to completely fill the disposable tubing set.
Volume within the collection, saline, waste and/or replacement tubing is not
included.
Total equivalent whole blood volume
The calculated average whole blood volume in the disposable tubing set
during the Run. This volume is equal to the total RBC volume in the
disposable tubing set divided by the donor or patient Hct. (The volumes in
Table 9-1 are based on an Hct of 40%.) Different disposable tubing sets
have different equivalent whole blood volumes based on the volume of
RBCs needed to correctly position the interface.
For Single-Needle procedures, the volume also depends on the residual
volume in the Single-Needle bag.
In WBC disposable tubing sets, the total equivalent whole blood volume
and the disposable tubing set volume are approximately equal.
Total RBC volume
The average volume of packed RBCs in the disposable tubing set during the
Run mode (determined from clinical tests using packed RBCs with
hematocrits between 35% and 45%). This value is used to calculate the
equivalent whole blood volume.
9-2
Residual RBC volume
The average volume of packed RBCs in the disposable tubing set after
Rinseback mode. This value is used to calculate the equivalent whole blood
values for residual volume cited in Chapter 13, "Specifications."
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COBE Spectra™ Apheresis System • Essentials Guide