Blood Preservation and Storage - PowerPoint Presentation

Slide1

Blood Preservation and Storage

blood is collected as whole blood, as shown below:

Blood can be stored as whole blood (with all of the plasma present) or, much more commonly, as packed red blood cells (PRBC's) in which about 70% of the plasma has been removed.

 This is done by light centrifugation, as shown below:

The plasma with platelets can then be expressed off, leaving packed red blood cells (PRBC's) as shown here:

Both whole blood and PRBC's can be stored for up to 42 days at 1 - 6 degrees C.

The plasma can be centrifuged heavily a second time to separate the platelet rich plasma, as shown below:

The supernatant plasma can be expressed into a third bag and stored as fresh frozen plasma (FFP). The remaining platelet rich plasma is utilized as a platelet pack, as shown below:

As can be seen in the above diagram, a single donation of whole blood has supplied three separate components (packed red blood cells, platelets, fresh frozen plasma) that can potentially benefit three different patients.

FFP

PRBC

Platelets

After the expiration date, rare or valuable blood units can be "rejuvenated" with a biochemical solution that restores much of the original biochemical environment of the RBC's. The "rejuvenated" units are "washed" with saline in an automated device and then can be transfused as a saline-red blood cell suspension within 2 to 4 hours, or these units can be stored glycerolized and frozen for up to 10 years.

Cryopreservation of RBC's is done to store special, rare RBC's for up to 10 years. The RBC's are first incubated in a 40% glycerol solution which acts as an "antifreeze" within the cells. The units are then placed in special sterile containers in a deep freezer at less than -60 degrees C.

When test results are received, units suitable for transfusion are labeled and stored.

Red Cells are stored in refrigerators

at 1-6˚C for up to 42 daysPlatelets are stored at room temperature in agitators for up to five days

Plasma are frozen and stored in freezers for up to one year

Apheresis

APHERESIS

, FROM THE

Greek pheresis meaning “to take away,” involves the selective removal

of blood

constituents

and

returning the unused portion back to the donor

Separation

Techniques

Separation by Centrifugation

In most apheresis instruments,

centrifugal force

separates blood into

components on

the basis of differences in density.

The blood is

pumped into a rotating

bowl, in

which layering of

components

occurs on the basis of their densities

.

The desired fraction is diverted and the remaining elements are returned to the donor (or patient).

In the diagram below, the process is illustrated. Whole blood is introduced into a chamber that is spinning, and the blood separates into components (P = plasma; PRP = platelet rich plasma; WBC = leukocytes; RBC = red blood cells) by gravity along the wall of the chamber. The component to be removed can be selected by moving the level of the aspiration device at the right. In this example, plasma is being removed.

Separation by

Adsorption

Selective removal of a pathologic

material has

theoretical advantages over the

removal of

all plasma constituents.

Centrifugal devices

can be adapted to

protocols that

selectively remove specific

soluble plasma

constituents by exploiting

the principles

of affinity

chromatography.

Selective removal

of low-density

lipoproteins (LDLs

) in patients with familial

hypercholesterolemia has

been accomplished

using

immunoaffinity

(anti-LDL

) column.

Returning

the

depleted plasma along with the

cellular components

reduces or eliminates

the need

for replacement fluids.

By Mohammed Abu-basha

17

A

ffinity column

Anti-LDL

Plasma Contains LDL

Plasma without LDL