Haemonetics LN9000-110-EWC, Operation Manual

Page: 68 / 110

4-10 Describing the MCS+ Disposable Collection Material
P/N 85213-30, Manual revision: B
Understanding
bowl operation
Both types of centrifuge bowls will function during the first part of the DRAW
cycle in the following way:
! The head of the bowl remains stationary during operation. The body of the
bowl, held in the centrifuge chuck by the system-sealing mechanism will
be spun between 3000 and 7000 rpm, depending on the selected MCS+
protocol. The header shield covers the rotary seal between the head and
body of the bowl and slightly compresses the seal when the bowl is in-
stalled.
!
Anticoagulated whole blood arrives from the donor-line tubing, passes the
inlet port, moves through the feed tube and enters the processing chamber
at the base of the bowl.
!
As the bowl spins, the centrifugal force inside of the bowl separates the
products into the cellular components and plasma. The denser cellular
components move to the outside of the bowl, while the lighter compo-
nents move toward the center.
! When the bowl is full, plasma, the lightest of the separated blood compo-
nents, will exit the bowl first through the outlet port, pass through the ef-
fluent tubing and be collected. The red blood cells, being the densest of
the cellular components, will exit the bowl last.
Applications for the Latham bowl
During the DRAW cycle, the design of Latham bowl permits the MCS+ device to
conduct the “surge” process when the optical bowl sensor has detected the buffy
coat at the appropriate level.
Surge involves the elutriation (or extraction) of platelets from the buffy coat, by
re-circulating collected plasma through the bowl at a high speed. The “surging”
plasma passes through the cellular layers of the blood components and promotes
separation between the layers. This allows the platelets, being the lightest of the
cellular components, to exit the bowl with the plasma. The other heavier cellular
components remain in the bowl.
Once the desired components have been collected, the bowl will stop spinning.
The remaining components will settle to the base, re-mix and subsequently be
returned to the donor/patient.
Applications for a Blow Molded bowl
Once a DRAW cycle has been completed, the bowl will stop spinning and the
uncollected cellular components in the bowl will be pumped through the feed
tube and returned to the donor. The cycle will be repeated until the programmed
target volume of the selected blood component has been collected.