SE461192B - SETTING AND DEVICE COLLECTING THE BLOOD PLASMA WHEN PLUSING - Google Patents

Abstract

A centrifuge apparatus for batch centrifugal separation of a liquid, preferably blood and other biological liquid. The separation is carried out in a flexible collapsible annular container (20) connected to one or more component containers (21). An annular separation compartment (1) receiving the flexible annular container (20) is provided in the centrifuge apparatus. Moreover, the apparatus is provided with a pressure medium compartment (13) communicating with the separation compartment and holding an elastic body (14) adapted during the centrifugation to be pressed against the separation compartment by the action of the centrifugal field and to exert pressure on the annular container positioned in the separation compartment. A separated component is thereby expelled to a component container (21) during the centrifugation. The centrifuge apparatus is particularly suited for carrying out plasmapheresis.

Description

461 19ë 2 the same blood donor whereby the nen gets a so-called double plasmapheresis, which gives 500-600 ml of plasma including originally added anticoagulant.

The disadvantages of the system are many: - there are many work steps with disconnection and connection of hoses - separation of plasma from the centrifuged bag is done manually and while the fractions are kept separate only by the normal gravity with the result that the quality is not high, ie that there is cellular material remains in the plasma. In order to obtain high quality, double centrifugation and transfer of the plasma to an additional secondary bag is required, which entails an additional cost. - the method has the potential to lead to confusion because the bag is physically separated from the blood donor - the method is time consuming, ie takes about an hour. It is easy to get a blood donor to donate blood, which takes about 15 minutes, but harder to find people who can give up an hour. The object of the present invention is to provide a method and a device which allows a small-scale semi-automated extraction of blood plasma during blood donation, for example in mobile units such as blood buses and which in relation to manual plasmapheresis: is faster gives higher plasma quality (fewer cells in the plasma) simplifies the procedure and reduces the number of operations increases safety by reducing the risk of confusion necessitates a large stationary centrifuge.

This is achieved by a method and a device as defined by the claims.

In the method according to the invention, a centrifuge of the type described in Swedish patent application 8602242-3 can be used. The said patent application describes a centrifuge in which the treatment space of the rotor comprises an annular separation chamber and a center chamber. Furthermore, the volume of the separation chamber can be reduced during centrifugation in order to displace a component separated by the centrifugation into the center chamber. The rotor can be given a reciprocating motion and the treatment space can be pressurized or underpressure. In the method of the present invention, blood is drawn from the blood donor to a flexible treatment set arranged in the rotor of the centrifuge, which comprises a substantially circular disc-shaped unit which is divided by a joint into an annular primary container along the periphery of the unit, and in which primary container the blood is taken. the bottling, as well as a secondary container in the center of the unit. The centrifuge can be located in direct connection with the blood donor table. During bottling, the rotor is oscillated to mix the blood with anticoagulant with which the primary container has been prepared or which is added simultaneously with the blood. The next step consists of centrifuging the blood in the primary container, separating blood cells and plasma. After a certain time of centrifugation, the plasma is forced via a hose connection over to the secondary container during centrifugation. This transfer of the plasma can preferably take place by increasing the speed of the centrifuge so that a centrifugally actuated valve opens the connection between the primary and secondary containers at the same time as the primary container is subjected to a compressing pressure.

The hose connection is then caused to close and the plasma thus recovered to be enclosed in the secondary container. Thereafter, the centrifugation is stopped and diluent (physiological saline solution) is fed to the primary container during renewed agitation by oscillating the rotor. The blood cell fraction thus resuspended can then be returned to the blood donor.

The invention also relates to a closed, flexible treatment set for use in carrying out the method. The treatment set is intended to be placed in a suitable treatment space in the rotor of a centrifuge and receive the liquid to be centrifuged. The set comprises a substantially circular, disc-shaped unit, which is made up of two plastic foils joined to a first annular joint along the edges of the foils and a second annular joint arranged inside it, which divides the disc-shaped unit into an annular primary container and a substantially circular secondary container in the center of the unit. The part of the primary container facing the center of the unit communicates with the secondary container through a collapsible hose connection. An additional hose for supplying and draining liquid to and from the treatment set is connected to the primary container. 461 192 4 The invention will be described in more detail below in connection with the accompanying figures.

Figure 1 shows a side view of an embodiment of a treatment set according to the invention.

Figure 2 shows the same treatment set seen from above.

Figure 3 schematically shows a section through a centrifuge rotor, according to SE 862242-3.

Figures 4a-e show the various steps in a method according to the invention.

In Figures 1 and 2, 1 denotes a treatment set consisting of an annular primary container 2 and a secondary container 3 in the center of the ring. 4 denotes a hose which is connected to the primary container, passes through a sealing body 5 and terminates with a sterile coupling 6. 7 denotes a collapsible hose which connects the part of the primary container 2 facing the center of rotation 2 to the secondary container 3. The hose 7 is provided with a backflow valve 21 , which allows the flow of liquid from the primary container to the secondary container but closes the flow in the opposite direction. The hose 7 is also pulled through the sealing body 5 and describes a loop 8 on its outside before it goes back down through the sealing body. The sealing body 5, which may, for example, consist of a rubber stopper, has the task of sealing the separation space of the rotor towards the environment after the treatment set has been put in place in the separation space.

The treatment set 1 can be made of plastic foils which are joined together by an outer annular joint 9 and an inner annular joint 10. An annular primary container 2 and a plate-shaped secondary container 3 are formed in the middle part of the ring. The inner joint is suitably provided with a perforation 11 in the middle of the joint so that the containers can be detached from each other. The plastic foil is suitably made of PVC or polyethylene and the joining can be done by heat sealing in a known manner. The hoses 4 and 7 are welded in a corresponding manner to the plastic foil, possibly with a reinforcing bounce in the joint. 461 192 Figure 3 schematically shows a section through a rotor which is well suited for use in the practice of the present invention. A centrifuge rotor of the embodiment shown is described in more detail in Swedish patent application 862242-3. The treatment set 1 is placed in the treatment space 12,13 of the rotor. 12 denotes an annular separation chamber and 13 a center chamber communicating with the separation chamber. In the rotor cover 14 there is a hole 15 over the center chamber. When the treatment set is put in place in the rotor, this hole is sealed by pulling the sealing body 5 up into the hole 15. The treatment space of the rotor can then be increased under overpressure or under pressure via the connection 16. The valve 6 of the hose 4 and the hose loop 8, rifugal-actuated pinch valve 17, is then located outside the sealed separation space. 18 denotes a pressure medium, for example a rubber mass, which during the centrifugation is deformed and exerts a pressure on the primary container 2 present in the separation chamber 12. The rotor is driven by a program-controlled motor (not shown).

When using the device according to Figures 1 and 2, a treatment set is placed in the rotor and its treatment space is sealed with the sealing body 5. The hose loop 8 is placed in the clamping valve 17. Figures 4a-e illustrate the various steps in the procedure that follows.

Figure 4a shows blood draw during agitation. The coupling 6 is connected to a standard draining unit, which is also connected to a blood donor (BG). Blood is drawn from the blood donor during the concomitant addition of anticoagulant (CPD). Alternatively, the primary container may be pre-loaded with anticoagulant if only a single tapping is to be performed. In case of double tapping, anticoagulant is supplied continuously via the blood donor assembly as shown in Figure 4 or by priming the primary container with one unit of anticoagulant. If the hydrostatic negative pressure from the donor to the primary container is too small for normal blood donation, the centrifuge's treatment space can be pressurized. In the centrifuge according to SE 862242-3 there is a negative pressure pump which is connected to channel 16 (figure 3) and which provides the desired addition of negative pressure. The donor blood now flows into the primary container 2. To ensure good mixing of anticoagulants in the blood, the centrifuge is programmed to oscillate during this phase with predetermined amplitude and frequency. 461 19? The primary container is suitably designed to hold a blood donation (usually 500 ml) so that the blood donation automatically stops when this quantity is lost. The centrifuge can be equipped with an alarm that is activated when the primary container is filled. In this case, the staff are alerted and the blood donating unit is disconnected from the coupling 6 and the blood donor receives saline solution in the usual way as a replacement for a part of the donated blood and to keep the blood donating tubes clean. At the same time, centrifuge step I (Figure 4b) is initiated by switching the centrifuge from oscillation to rotation and accelerating the rotor to the selected separation speed. During centrifuge step I, the blood cells settle in the peripheral part of the primary container while the plasma collects in the center-facing part of the ring 2. The connecting hose 7 is kept closed during this step, for example by a centrifugal valve 17. After a calculated time, centrifuge step II (Figure 4c) begins. the plasma is caused to flow over to the secondary container 3 past the non-return valve 21. This is achieved by reducing the volume of the separation chamber during centrifugation, whereby the primary container 2 is compressed and the plasma fraction is displaced to the secondary container 3. According to an embodiment of the centrifuge described in SE 862242-3 by means of a rubber mass 18 inserted in the rotor (figure 3), which has a higher specific gravity than the blood and / or is affected by radially displaceable weight segments. During centrifugation, the rubber mass exerts a pressure on the primary container located in the separation chamber. However, the blood volume that is centrifuged cannot be moved when the valve 17 is closed. During centrifuge step II, the valve 17 is opened and the rubber mass 18 is deformed into the separation chamber and pressed over a corresponding volume of plasma to the secondary container. According to a preferred embodiment, centrifuge step II is performed at a higher centrifuge speed than centrifuge step I. The transfer of the plasma takes place while the separated phases are under the influence of a g-field which is even stronger than that prevailing during the sedimentation phase itself (centrifuge step I ).

The risk of blood cells being resuspended in the plasma fraction during the transfer process is thus very small. When two centrifugal speeds are used, the valve 17 may be a centrifugal valve which is adjusted to be closed at the lower speed and open at the higher speed. The rubber mass 18 and the weight segments, or the like, may also be adapted to provide the required transfer pressure only at the higher speed. The transmission can also be monitored by photocells at, for example, the hose loop 8, which must then be transparent. If cells reach the radius of the photocell, the overflow is interrupted, for example by reducing the centrifugal speed so that the centrifugal valve 17 closes and / or the pressure effect of the rubber mass ceases.

After a predetermined time, the centrifuge stops and the slurry phase begins (Figure 4d). Diluent (physiological saline) is now supplied to the primary tank via the coupling 6 during renewed oscillation of the rotor. The treatment space of the centrifuge can then be pressurized in the same way as in the case of blood drawing to facilitate the introduction of the saline solution into the primary container. The cell concentrate remaining in the primary container is diluted in this way to the desired concentration and can then be returned to the blood donor (Figure 4e).

Another hose is then connected to the coupling 6 and the treatment space of the rotor is put under predetermined overpressure, for example by pumping air through the channel 16. The contents of the primary container then flow through the now connected hose via a deaeration unit and connected transfusion unit with filter back to blood.

When the primary container 2 is empty, a simple plasmapheresis is completed. In the case of double plasmapheresis, the secondary container 3 is made so large that it holds two batches of plasma and the procedure is repeated in the same treatment set.

The cover 14 is then lifted off and the hose connection 7 is closed and cut, for example down a hose welding rod. The secondary container with recovered plasma is torn off from the primary container along the perforation 11 in the joint 10. The secondary container can then be immediately frozen, in order to preserve the plasma quality. I '

Claims (8)

Claims: A method of recovering blood plasma during blood donation, characterized in that a quantity of blood is drawn from a blood donor to a flexible treatment set (1) arranged in the rotor of a centrifuge, which comprises a substantially circular and disc-shaped unit which is divided by a joint (10) into a annular primary container (2) along the periphery of the unit, and in which primary container the blood is taken up during collection, and a secondary container (3) in the center of the unit; causing the rotor to perform an oscillating movement during agitation of the blood in the primary container; the blood being centrifuged in the primary container for division into blood cells and plasma; that the primary container is compressed during centrifugation and that the plasma fraction is pressed over to the secondary container (3) via a hose connection (7) and that the hose connection is subsequently caused to close and the plasma so recovered to be enclosed in the secondary container; that diluent is supplied to the primary container for resuspending the blood cell fraction during renewed agitation by oscillating the rotor so that the blood cell fraction can then be returned to the blood donor. Method according to claim 1, characterized in that the blood is centrifuged at a first speed at which the hose connection (7) between the primary and secondary container is closed and that the rotor speed is then increased to a second speed at which said connection is open. Method according to Claim 1, characterized in that the treatment space (12, 13) of the rotor is pressurized during the discharge of blood to the primary container. End flexible treatment set suitable for use in carrying out the method according to any one of claims 1-3, which treatment set is intended to be placed in a suitable treatment space in a centrifuge rotor and receive a liquid to be centrifuged, characterized by * M5 9 461 192 a) a substantially circular, disc-shaped unit, which is built up of two plastic foils joined to a first annular joint (9) along the edges of the foils and a second annular joint (10) arranged inside it, which divides the disc-shaped unit into a annular primary container (2) and a substantially circular secondary container (3) in the center of the unit and b) a collapsible hose connection (7) connecting the part of the primary container (2) facing the center of the unit to the secondary container (3) and c) a hose (4) connected to the primary container for supplying and draining liquid to and from the treatment set. Treatment set according to claim 4, characterized by a sealing body (5) with which the treatment space (12, 13) of the rotor is sealed to the environment after the treatment set has been placed in said space with the hose (4) accessible from the outside. Treatment set according to claim 5, characterized in that the collapsible hose connection (7) between the primary and secondary containers is pulled through the sealing body (5) so that it forms a loop (8) on the outside of the sealing body. Treatment set according to claim 4, characterized in that the hose connection (7) contains a non-return valve (21) which allows liquid flow from the primary to the secondary container. Treatment set according to Claim 4, characterized in that the second annular joint (10) is perforated so that the containers can be detached from one another.