Note: Descriptions are shown in the official language in which they were submitted.
CA 02307517 2000-04-28
AN ARRANC~VT FOR THE TRANSFER OF BLOOD
The invention concerns an arrangement for the transfer of donor blood present
in
an acceptance bag or a similar fluid in a collection bag, having a carrying
means for
the acceptance bag that is arranged elevated relative to the collection bag,
having a
connection line between the acceptance bag and the collection bag, said line
exhibiting at least one filter element together with a bypass that can only be
traversed in the direction from the collection to the acceptance bag by means
of a
check element, and having an expression station for the collection bag by
means of
which the contents of the collection bag can be partially pressed back into
the
connection line to the acceptance bag via the check element.
The donor blood present in the acceptance bag (which is usually composed of
transparent plastic) after the blood donation must be transferred as gently as
possible from the acceptance bag according to current health standards prior
to
further processing and thereby passed through a filter element, usually
referred to
as leucocyte filters or such. Since one must pay particular attention thereby
that no
air or air bubbles are, in turn, in the blood being temporarily stored in the
collection bag, there are most often specific procedures prescribed for this
transfer
as can be implemented in a standardized manner using an arrangement of the
species described in the beginning. The acceptance bag is suspended at the
carrying
means elevated higher than the collection bag opposite it, such that the
connection
line (embodied in turn as a transparent plastic hose) to the collection bag
emerges at
its underside so that the transfer can principally ensue solely under the
influence of
gravity after opening potential shut-off elements on the bags or,
respectively, in the
connection line. After the blood has transferred completely from the
acceptance
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bag to the collection bag via the connection line and the filter element, the
collection bag is manually compressed on a suitable support base to remove
potential air or air bubbles that collect directly below the connection line
leading
into the collection bag at the top, whereby, first, air and air bubbles and
then air-
free blood are pressed out of the collection bag back into the connection line
to the
acceptance bag. To preclude a back washing of said filter elements, either
these can
only traversed in the original transfer direction (i.e. from donor bag to the
collection bag) or a shut-off element is provided on the dis;.h.arge side
which is to be
closed prior to the described press-back. In addition, a bypass is provided
for the
filter element in the connection line that enables this reverse flow of the
blood
toward the acceptance bag. The rising blood column is pressed back in the
direction of the acceptance bag as long as it takes until pure blood or,
respectively,
blood no longer exhibiting enclosed air bubbles re-enters the acceptance bag.
Depending on the requirements, the air-free collection bag can then be closed
and
withdrawn or other additional operations may be carried out - it is also
possible,
however, to allow the blood currently located in the connection line (provided
that
it is air-free) to flow at least partly into the collection bag again in order
to attain an
optimally high blood reclamation. The empty donor bag together with the
connection line and filter element with bypass are subsequently disposed of.
Disadvantageous in such known arrangements is particularly that the manual
manipulation and especially the described manual air removal is relatively
arduous,
on the one hand, given greater numbers of acceptance bags to be processed and,
on
the other hand, there are always certain sources of error with such a manual
handling process that, for example, lead to a qualitative loss given air
remaining in
the collection bag or, respectively, to storage damage of the blood stored
therein.
The object of the present invention is to avoid the described disadvantages of
the
known arrangements of the species mentioned in the beginning and particularly
to
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improve such an arrangement such that the described handling can be further
standardized and potential sources of errors can be further precluded.
In an arrangement of the species mentioned in the beginning, this object is
achieved
in accordance with the present invention as result thereof that the expression
station comprises a mechanical expression unit, in which the collection bag
can be
compressed between pressing elements moveable relative to each other by means
of
a compression drive. Apart from the manipulations - which are relatively non-
critical with respect to potential air inclusions - of the suspending of the
acceptance
bag or, respectively, of the corresponding arranging of the requisite
collection bag
together with the connection lines and elements described, a far-reaching
automation of, in particular, the described measures for expelling air from
the
collection bag becomes possible. The compressing of the collection bag can
ensue
to largely automatically via the expression unit, whereby the persons involved
with
the transfer also have far less arduous handling operations to perform.
In the preferred embodiment of the invention, two essentially planarly-
fashioned
compression plates are provided as compression elements preferentially adapted
to
the shape of the collection bag, one of said plates being stationary in the
expression
unit and the other being moveable by means of the compression drive
preferentially capable of swiveling on a lateral axis. This results in a very
simple
device that can be loaded with the collection bags in an uncomplicated way,
whereby a visual check of the ongoing procedures is also easily possible as
needed.
According to another preferred embodiment of the invention, the compression
drive comprises a ram cylinder actuatable with hydraulic fluid, preferentially
a
pneumatic cylinder, that engages at the swivel axis of the compression plate
via a
laterally arranged swivelling lever. Such mechanisms are small, powerful,
quiet and
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reliable, which enables a simple use of the inventive arrangement even, e.g.
in
hospital environs or in tight space conditions.
In another advantageous development of the invention, a spring-loaded element
is
inserted in the power path from the ram cylinder to the compression plate ,
which
simply and dependably prevents the compressed compression elements from
injuring the operating personnel in so far as these spring-loaded elements are
appropriately laid out.
In another advantageous development of the invention, the carrying means and
expression station are respectively constructed for the simultaneous
accommodation of several acceptance and collection bags, whereby the
compression
elements and preferentially also the compression drive are respectively
designed for
several collection bags together. Particularly the transfer of large
quantities of
donor blood can thereby be quickly implemented, whereby the control or,
respectively, supervision of the function can still be monitored by one
operating
person.
In a further embodiment of the invention, the compression plates are
respectively
arranged in pairs behind one another on a base plate of the expression station
with
a corresponding distance to the next plate pair, whereby the swivel axes - of
the
moveable compression plates - seated on the base plate are guided in a housing
on
the side of the base plate for the combined compression drive. Thus, a
relatively
small-sized arrangement is possible that is also very simply constructed as a
result of
the combined operation of the moveable compression plates.
In another development of the invention, the carrying means for the acceptance
bag
(bags) can comprise a lifting part that can be adjusted in height relative to
the
expression station, which enables, on the one hand, the provision of different
drop
CA 02307517 2000-04-28
heights for the transfer or filtering of blood and, on the other hand, it
naturally
allows the operating person to carry out the manual operations of suspending
the
acceptance bag at a comfortable height and thereby simplifying this task. In
this
latter context, a further embodiment of the invention is particularly
advantageous,
according to which the drives of the carrying means and the expression station
can
be operated via a common control unit, preferentially integrated at least in
part in
the housing for the compression drive. With this control, the required
function
sequences can be at least partially prescribed so that the operation becomes
simpler
and safer. Apart from the integration into the housing for the compression
drive
which is advantageous with respect to operation and accommodation, a control
could, of course, also be provided via external units,(e.g. SPS or such)
In a further embodiment of the invention, provision is made that the
acceptance
bags are arranged on the carrying means or, respectively, the lift part with
the
opening at their lowest point and the collection bags are arranged in the
expression
station or, respectively, the compression elements with the opening at their
highest
point, which very simply enables the transfer or filtration described already
at the
beginning solely under the influence of gravity so that no further measures
need to
be taken in this regard.
In further embodiments of the invention, flow- or, respectively, fill-level
sensors for
the fluid or, respectively, blood can be arranged within the area of the
carrying
means and/or the expression station and connected with the control unit or an
display and/or evaluation means, which enables a further automation of the
transfer or, respectively, filtration process as a result thereof that the
next steps
respectively described can always be made automatically dependent on the
response
of these sensors.
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The invention is also explained in the following on the basis of the exemplary
embodiments shown partly schematically in the drawing. Fig. 1 thereby shows a
basic arrangement of the type described at the beginning as the Prior Art;
Fig. 2
shows an arrangement according to the present invention in a perspective view;
and
Fig. 3 shows a partially opened, laterally diagonal view of the expression
station
according to Fig.2.
The arrangement according to Fig. 1 serves for the transfer of donor blood
present
in an acceptance bag 1 into a collection bag 2, whereby these two bags 1, 2
are
identically constructed - apart therefrom, however, a differing embodiment or
differing size would naturally be possible, whereby then e.g. also a larger
donor bag
could be connected with two correspondingly smaller collection bags via
connection branches.
These bags l, 2 are customarily made of transparent plastic and have diverse
connection openings for a variety of purposes not of interest here for the
further
processing of said bag contents. The arrangement that is of interest and
described
here can operate with a variety of embodiments and sizes of such bags 1, 2,
whereby only the collection bags 2 must be - for reasons still to be described
in the
following - capable of being compressed at least partially while their inner
volume
is diminishing.
The acceptance bag 1 is elevated relative to the collection bag 2 and
connected to
the collection bag 2 via a connection line 5 comprising a filter 3, e.g. a
leucocyte
filter that is traversed only in the direction of the depicted arrow 4. Here
it does
not matter if this connection in the sense of a bag system is ready-made and
only
destructively separable or, on the contrary, is pluggable or such. A check
element 7
that can only be traversed in the direction from the collection bag 2 to the
acceptance bag 1 (i.e. opposing arrow 4) is arranged in a bypass 6. Not shown
are
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any shut-off means (hose clamps and such) in the connection line 5 that may be
necessary or advantageous for the manipulation, yet, have nothing to do with
the
crux of the present invention.
The acceptance bag 1 is placed into the elevated position shown for the
transfer of
the donor blood present in the acceptance bag 1 into the collection bag 2,
e.g.
suspended from a carrying device not shown here, after which the blood flows
via
gravitational effect from the acceptance bag 1 into the collection bag 2 via
the
connection line 5 and the filter element 3 - possibly after opening the shut-
off
elements not shown here as mentioned. It is thereby not entirely possible to
avoid
that air or air bubbles collect under the mouth of the connection line 5 in
the
collection bag after it fills up, which makes the blood in collection bag 2
unusable
after an extended storage or, respectively, would make further processing of
said
blood more difficult or impossible. Consequently, after the collection bag 2
fills
up, it is compressed, whereby first air and then blood mixed with air bubbles
is
pressed back into the connection line 5, namely until is ascends in the
connection
line 5 via the bypass 6 and the check element 7 back into the acceptance bag 1
and
until air free blood emerges again in the acceptance bag 1. Then the
collection bag
2 connected to the connection line 5 can be closed and withdrawn after
disconnecting the connection line 5 or, however, the blood that is in the
connection line 5 and free of air can be allowed to at least partially flow
back and
only then is the collection bag 2 closed and withdrawn or, respectively, its
contents
are further processed.
The acceptance bag 1 together with the connection line 5 (with filter element
3 and
bypass 6) is subsequently disposed of.
According to Fig. 2, a carrying means 8 is provided only on the one side with
a
height-adjustable lifting part 9 for respectively six acceptance bags 1 and on
the
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other side a expression station 10 is provided with a mechanical expression
unit 11,
in which the six collection bags 2 arranged here can be compressed between
compression elements 13 that are moveable relative to one another by means of
a
compression drive. Provided as compression elements here are respectively two
planarly-fashioned compression plates 14 accommodating two collection bags 2,
of
which the one plate - the back one in the illustration - is stable in the
expression
unit 11 and the other, the front one in the illustration can swivel on an axis
15 on
the basis of the compression drive 12. Apart therefrom, other suitable
elements
could also be provided as compression elements 13, like parallel plates,
rollers or
such moveable relative to one another that, provided with a corresponding
drive,
permit a compression of the collection bags 2.
As is particularly clear in the detail illustration according to Fig. 3, the
compression
drive 12 comprises a hydraulically actuated ram cylinder 16, e.g. a pneumatic
cylinder, the piston rod 17 of which acts on an adjustable adjustment carriage
18,
which in turn activates the laterally arranged swivel lever 20 via spring-
loaded
elements 19, that engage for their part at the swivel axes 15 of the moveable
compression plates 14.
The compression plates 14 are arranged one behind the other in respective
pairs
with an appropriate distance from the next plate pair 14 on a base plate 21 of
the
expression station 10, whereby the swivel axes 15 of the moveable compression
plates 14 seated on the base plate 21 are guided in the housing 22 - provided
on the
side of the base plate 21 - for the combined compression drive 12. Thus a very
simple, mechanical pressing of the collection bags 2 is possible, whereby it
can
easily be assured on the basis of the described spring-loaded elements 19 in
the
power path from the ram cylinder 16 to the compression plate 14 that, on the
one
hand, foreign particles coming inadvertently between the compression plates 14
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cause no damage to the mechanism, and on the other hand, e.g. the fingers of
operating persons cannot also be injured by contusions.
As already mentioned, the carrying means 8 for the acceptance bag 1 comprises
a
lifting part 9 that is height-adjustable relative to the expression station
10, said
lifting part being located on e.g. a wall-mounted track 23 and being
vertically
moveable via drive elements not shown here (e.g. an electrical or pneumatic
linear
motor, manually supported cable-pull means or such). The drives of the
carrying
means 8 and the expression station 10 can be operated via a common control
unit
which is integrated here at least partially in the housing 22 for the
compression
drive 12 and symbolized by the operating knobs 24. In the scope of the
invention,
this control could, however, also naturally ensue separately or via external
units
such as series-parallel-series memory controls (SPS) or such. In place of the
pneumatic ram cylinder 16, one could naturally provide any other suitable
embodiment of the compression drive as well, e.g. hydraulic cylinder,
electrical
geared-motor, manually supported lever mechanisms or such.
Furthermore, flow- or, respectively, fill-level sensors which are not yet
shown here
could be provided in the area of the carrying means 8 and/or the expression
station
and connected with a control unit or, respectively, an display and/or
evaluation
means or such, which makes a largely automated transfer or filtration
possible.
The operating manner of the arrangement shown in Fig. 2 and 3 essentially
corresponds to that which is described above in connection with Fig. 1.
According
to Fig. 2, the lifting part 9 for suspending the acceptance bag 1 can be moved
downward in the drawing so that the operating person can accomplish this task
comfortably. Subsequently, the lifting part 9 is raised with the acceptance
bag
together with the attached connection lines ~ and r'.ie collection bags 2 are
laid
between the compression plates. After letting the contents of acceptance bag 1
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transfer, the described compression of the collection bag 2 ensues to expel
the air,
after which the transfer is concluded as described.
It is also clear from Fig. 2 that the expression station 10 as well as the
carrying
means 8 can be constructed for the simultaneous accommodation of a largely
arbitrary number of bags 1, 2, whereby the transfer and filtration of large
quantities
of blood can be accomplished and monitored quickly and easily by even one
operating person.
