Abstrict A support for the ports of a blood bag for use in a centrifuge
in order to keep the ports upright during centrifugation so that
the ports will not trap blood cells which would later contaminate
the blood plasma. The support includes a base positionable adjacent
to the bottom of a centrifuge cup, an upstanding plate attached
to the periphery of the base and extending up adjacent to the side
of the cup, and hook means mounted on the top of the plate and extending
over the cup for engagement by the port area of the blood bag.
Claims Having described my invention in its preferred embodiment, I claim:
1. A blood centrifugation apparatus comprising in combination:
(a) a centrifuge having at least one substantially cylindrical
cup, being pivoted to pivot outwardly as the centrifuge spins;
(b) a blood bag for containing blood to be centrifuged, the blood
bag having a port area at the top thereof, and having engagable
means in the port area for holding it upright; and
(c) a blood bag port support including a substantially cylindrical
base positionable adjacent the bottom of the cup, an upstanding
plate attached substantially perpendicularly to the periphery of
the base and extending up adjacent to and substantially conforming
to the side of the cup, and hook means mounted on the top of the
plate and extending over the top of the cup and being configured
to engage the port area of the blood bag to hold the ports upright
during centrifugation.
2. The apparatus of claim 1 wherein the plate has a vertical bend
which forms the plate to approximate the curvature of the wall of
the centrifuge cup.
3. The apparatus of claim 1 wherein the base is substantially circular
in configuration and wherein the plate subtends an arc of between
20 degrees and 90 degrees.
4. A blood bag port support for use in a centrifuge having a substantially
cylindrical cup in which the blood bag is placed for centrifugation,
the support comprising:
(a) a substantially circularly configured base positionable adjacent
the bottom of the cup;
(b) a load bearing, upstanding plate attached substantially perpendicularly
to the periphery of the base, the plate being bent to conform approximately
to the periphery of the base and the curvature of the wall of the
centrifuge cup, and extending up adjacent the side of the cup; and
(c) hook means mounted on the top of the plate and extending over
the top of the cup and being configured to engage the port area
of the blood bag to hold the ports upright during centrifugation.
5. The support of claim 4 wherein the base comprises a wire having
an arcuate contour and being dimensioned to fit around the interior
bottom of the centrifuge cup, and wherein the base wire is bent
substantially vertically and extends adjacent the edges of the plate,
and wherein the edges of the plate are folded around the vertical
wires, and wherein the wires are bent at the top of the plate to
extend over the top of the cup and form the hook means.
6. The support of claim 5 further comprising a fillet at the lower
edge of the plate at its engagement with the base wire to form a
smooth surface.
7. The support of claim 5 wherein the plate has a rounded fold
at its bottom to smooth its lower edge.
8. The support of claim 4 wherein the plate subtends an arc of
between 20 degrees and 90 degrees.
9. The support of claim 4 wherein the hook means comprises two
similar wires, each extending from the top of the plate substantially
horizontally over the top of the cup and terminating in an upwardly
opening U-shaped curve forming a hook, the hooks being spaced apart
a distance substantially equal to the distance between the ports
on the blood bag.
10. A method of centrifuging blood in a blood bag, comprising:
(a) placing a port support apparatus in a centrifuge cup, the port
support apparatus including a base positioned adjacent the bottom
of the cup, a plate attached to the base and extending up adjacent
the side of the cup, and hook means mounted on the top of the plate
and extending over the top of the cup;
(b) placing a blood bag in the centrifuge cup;
(c) supporting the ports substantially upright by the hook means,
while allowing the majority of the weight of the blood to rest on
the bottom of the centrifuge cup;
(d) operating the centrifuge; and
(e) removing the blood bag from the centrifuge cup.
11. The method of claim 10 further comprising placing the blood
bag and the port support apparatus in the centrifuge cup together.
12. The method of claim 10 further comprising removing the blood
bag and the port support apparatus from the centrifuge cup together.
Description BACKGROUND OF THE INVENTION
This invention relates to human blood processing equipment, and
in particular to a device for supporting a blood bag during the
process of centrifugation.
It is the usual procedure to collect human blood by drawing it
into a plastic blood bag. The blood bag is simply a container formed
by sealing two sheets of plastic together. Of course, the sheets
of plastic bulge as the bag is filled with blood. Tubes are attached
to the bag through openings called ports. Often several ports are
provided as needed for the later handling or processing of the blood.
One of the principal techniques used in the processing of blood
is to centrifuge it to separate out various density fractions. For
this, the blood bag is placed in a a centrifuge and spun at an r.p.m.
and for a time necessary to cause the separation of the blood cells
and plasma.
It is not uncommon in this centrifugation process for the ports
on the blood bag to become inverted and retain a portion of the
blood so that it does not mix with the remainder of the blood. Consequently,
the blood trapped in the ports contains red blood cells which are
dumped into the plasma as the blood bag is removed from the centrifuge.
This is undesirable since the plasma is then contaminated by small
quantities of red blood cells.
Accordingly, it is the general object of the present invention
to provide a device which holds the ports of the blood bag upright
so that they do not trap a portion of the blood.
Another object is to provide a frame on which the blood bag may
be supported as it is placed into and removed from the centrifuge
cup.
Still another object is to provide a strong assembly capable of
withstanding the high pressures of centrifugation.
A further object is to provide a support which has no sharp edges
to damage the blood bag.
Still another object is to provide a simple device which is readily
incorporated into currently accepted blood processing procedures.
These and other objects and advantages of the present invention
and the manner in which they are achieved will be made apparent
as the following specification and claims progress, taken in conjunction
with the drawings which illustrate the preferred embodiment.
SUMMARY OF THE INVENTION
In its basic concept, the present invention is a support frame
for the ports of a blood bag for use in a centrifuge in order to
keep the ports upright during centrifugation. The support includes
a base positionable adjacent to the bottom of a centrifuge cup,
an upstanding plate attached to the periphery of the base and extending
up adjacent to the side of the cup, and hook means mounted on the
top of the plate and extending over the cup for engagement by the
port area of the blood bag.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top perspective view of the blood bag support of the
present invention, shown mounting a blood bag which is illustrated
in phantom line.
FIG. 2 is a bottom perspective view of the blood bag support of
FIG. 1.
FIG. 3 is a fragmentary section of the blood bag support, taken
along the line 3--3 of FIG. 1 illustrating the centrifuge cup in
phantom line.
FIG. 4 is a top view of a centrifuge apparatus incorporating four
of the blood bag supports of the present invention.
FIG. 5 is an enlarged top view of one of the centrifuge cups of
FIG. 4 showing the arrangement of the blood bag support and the
blood bag therein prior to centrifugation.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The purpose of centrifugation in processing human blood is to separate
the blood cells from the plasma. The blood cells are more dense
than the plasma and settle at the bottom of the blood bag, while
the plasma forms a layer at the top of the blood bag. The plasma
can then be decanted to separate the fractions.
FIG. 4 illustrates a centrifuge, generally at 10. Four centrifuge
cups 12 (FIGS. 3-5) are mounted in the centrifuge. Each cup has
a rounded bottom 14. An opening 16 in the centrifuge allows the
cups to pivot outwardly on pivot points 18 as the centrifuge spins.
It can be appreciated that significant G-forces are generated as
the centrifuges of this type are often operated at up to five thousand
r.p.m..
FIG. 1 illustrates a blood bag 20 which is simply two sheets of
plastic bonded together. As the blood bag is filled, the plastic
sheets bulge outwardly to accomodate a volume of blood.
Several ports 22 are located at the top (referring to the direction
the blood bag is placed in the centrifuge) of the blood bag. A port
is an entrance for a tube, or a place where the blood bag may be
spiked in order to draw off a portion of the blood or a blood fraction.
At the time of centrifuging, all of the ports are closed. Some of
the ports are sterily shielded by port covers 24. These are tabs
which cover the port but which may be pulled apart to expose the
ports. The port covers are provided with holes 26.
FIGS. 1 and 2 illustrate the blood bag support of the present invention.
A base is positionable adjacent the bottom of the cup. Preferably,
this base is a wire having an arcuate contour and being dimensioned
to fit around the interior bottom of the centrifuge cup as shown
in FIG. 3. Because the centrifuge cup is circular, this is also
preferably the configuration of the base wire.
Preferably, base wire 28 is bent perpendicularly to the base at
30 and extends vertically the height of centrifuge cup 12. Vertical
wires 32 (FIG. 3) are parallel and lie adjacent the wall of the
centrifuge cup.
An upstanding plate, denoted generally at 34 is attached substantially
perpendicularly to the periphery of the base and extends up adjacent
the side of the cup. Preferably, the edges of the plate are folded
around vertical wires 32 at folds 36. This mounts the plate on the
base.
Plate 34 also includes a rounded fold 38 at its bottom. A welded
fillet 40 smooths the attachment of the wires to the plate. It can
be appreciated that a substantial pressure is placed on the bottom
of the bag during centrifuging. The rounded edges of the plate prevent
the bag from breaking as it presses against the plate's edges. A
similar consideration is also applicable to the round base wire
28.
Plate 34 further has a center crease or bend 42 which extends vertically
and which forms the plate to approximate the curvature of the wall
of the centrifuge cup. In addition, this strengthens the plate considerably.
The plate has a significant width, and this may be described in
the terms that it subtends an arc of between 20.degree. and 90.degree.,
preferably about 60.degree. of the circumference of the centrifuge
cup. The width of the plate adds strength, but in addition, it is
also held upright by a considerable force placed radially on it
during the centrifugation.
Hook means are mounted on the top of the plate and extend over
the open top of the cup and are configured to engage the ports or
port area of the blood bag to hold the ports upright during centrifugation.
Preferably, wires 32 are bent at 44 to extend from the top of the
plate substantially horizontally over the top of the cup and terminate
in upwardly opening U-shaped curves. These form hooks 46 for engaging
holes 26 in port covers 24. The hooks are spaced apart a distance
substantially equal to the distance between the ports on the blood
bag. This holds the port area upright and prevents the ports from
folding over and trapping blood during the centrifugation process.
It must be realized that the hooks do not support the entire weight
of the blood bag, but only hold the port area upright while the
majority of the weight of the blood rests on the bottom of the centrifuge
cup.
OPERATION
The full blood bag is attached by its port cover holes 26 to the
hooks 46 on the blood bag support. The bottom of the blood bag rests
on the base wire 28. This assembly is then placed into the centrifuge
cup 12 and the majority of the weight is placed on the bottom 14
of the centrifuge cup.
The centrifuge is then operated at a speed and for a period of
time necessary to cause the blood to separate into layers. Centrifuge
cups 12 pivot at 18 and are spun to nearly a horizontal angle in
the centrifugation process. For purposes of the present discussion,
it is understood that the upright or vertical direction, as it has
reference to the blood bag or the blood bag support, is in the direction
of the top of the centrifuge cup, or opposite the direction of the
G-force created by the centrifuge.
The port area is held upright by the hooks and some weight is supported
by the hooks, but the majority of the weight is on the bottom of
the centrifuge cup. Considerable force is placed against the plate
34 which holds it vertical and does not allow its joint with the
base wire 28 to bend.
Upon completion of the centrifugation, the blood bag support and
the blood bag are withdrawn from the centrifuge cup. The port covers
are gently removed from the hooks. The plasma is in the top layer
of the bag, while the blood cells are in the bottom layer. The plasma
is then drawn off for further processing, and the same is true of
the remaining red blood cells. |