Liquid purification or separation – Processes – Including controlling process in response to a sensed condition
Reexamination Certificate
1998-02-23
2001-01-16
Kim, John (Department: 1723)
Liquid purification or separation
Processes
Including controlling process in response to a sensed condition
C210S085000, C210S086000, C210S097000, C210S109000, C210S143000, C210S739000, C356S039000, C356S410000
Reexamination Certificate
active
06174447
ABSTRACT:
TECHNICAL AREA
The invention relates to a method for fluid separation of whole blood as a mixture of liquids into individual, differently-colored blood constituents, which blood is packed in flexible containers, in particular bags, wherein the bags are connected to one another with an at least partially light-transparent connection, in particular a flexible tube, and wherein the blood constituents are forced to flow from one container through the light-transparent connection into another container, in particular for the separation of concentrated thrombocytes from buffy coat, as well as to a device for performing the method.
STATE OF THE ART
There are various techniques for the separation of whole blood into its distinct constituents, in particular for the recovery of concentrated thrombocytes. At least one centrifugation for the recovery of the concentrated thrombocytes and an at least in part manual manipulation is common to all techniques. The starting product is whole blood, which is disposed in a flexible bag, wherein the flexible bag is connected air-tight and liquid-impermeable with transparent flexible tubes to further additional satellite bags, wherein the further additional satellite bags serve for receiving the separated concentrates.
After the main part of plasma and erythrocytes has been removed with a press from the bag filled with whole blood, the remaining mixture of erythrocyte cells and leucocyte cells, thrombocyte platelets as well a residue of plasma is centrifuged once again for the recovery of concentrated thrombocytes, and this so-called buffy coat is once again placed in a press in order to perform a separation of the erythrocytes and leucocytes from the now thrombocyte-rich plasma. During the pressing procedure, the operating person controls the flow of the pressed thrombocyte-rich plasma by means of a clamp at a transparent connection tube and observes as well during this procedure when the first erythrocytes and leucocytes appear in the connection tube after the transparent-yellowish plasma. If this occurs, the operating person clamps the tube, deventilates subsequently the thrombocyte bag, and welds the end of the tube.
Care is to be taken in this case that no erythrocyte cells and leucocyte cells pass into the thrombocyte bag, however also that all of the thrombocytes-platelets-plasma mixture is recovered from the original bag.
The operating person can manually control the flow rate within the tube with the clamp which surrounds the connection tube. If the flow rate is too high, there occurs a so-called siphon effect, i.e. the substantially larger erythrocyte cells and leucocyte cells are torn from the buffy-coat layer and contaminate the concentrated thrombocytes. It is difficult for the operating person to achieve a uniform flow-through rate. Based on a uniform flow and the normal bag size, this would take about 140 seconds, i.e. the operating person would have to hold the clamp for about 140 seconds at a uniform clamping pressure, which requires a high concentration of the operating person. In order to shorten this time, the operating person frequently lets the plasma-thrombocyte concentrate flow faster at the beginning and slower at the end, which indeed means a larger contamination with leucocyte cells and erythrocyte cells based on the siphon effect and leads to a non-optimum yield of the thrombocyte plasma because the buffy-coat layer was stirred up and whirled up. The operating person has to observe visually at the end of the pressing procedure when the first erythrocytes arrive in the tube. However, the operating person cannot see the first erythrocyte cells, since they are present in too small a concentration and, it is even harder that the operating person can optically perceive the practically colorless leucocyte cells. This means that the tube is clamped too early or too late depending on the disposition and attentiveness of the operating person. In case the clamping is performed too early, this means a too small thrombocyte yield up to the sorting out since the concentration of thrombocytes has to amount to >0.5×10
11
. Or the weight of 56 grams net of the plasma-thrombocyte yield falls short. If the tube is clamped too late, too many leucocytes and erythrocytes are present in the preparation (limit <1.0×10
8
WBC<2.0×10
9
RBC).
The manual recovery of thrombocyte platelets is therefore associated with a more or less large contamination of erythrocytes and leucocytes, which is the reason that the uniformity of the quality of the concentrated thrombocytes is subject to certain fluctuations. The operating person decides up to which point of discoloration, i.e. contamination, of the serum he or she allows the concentrated thrombocytes to pass. Lipaemic and strongly discolored, in particular red plasmas cannot be used in this case, since “ery” fragments and haemoglobin can for example be present in the red plasmas which cannot be centrifuged off. This means that it cannot be completely excluded that the operating person allows inadmissible concentrates of thrombocytes.
An apparatus for the separation of whole blood in a flexible, transparent bag with at least one outlet line and shut-off device is known from the German printed patent document DE 38 15 643 C1, wherein said apparatus comprises a casing with a front plate and a pressure plate, pivotable relative to the front plate, with a drive device for the pressure plate as well as a scanning device. The scanning device includes an optical detector, which can be a tube detector in the tube region and which actuates a shut-off device for one of the outlet devices when a specific component layer reaches a predetermined level in the bag. Furthermore, tube detectors as scanning devices are known from the British printed patent document GB-PS 15 37 096.
TECHNICAL TASK
It is the purpose of the invention to provide for a method and a device for the fluid separation of whole blood as a mixture of liquids into individual, differently-colored blood constituents, in particular for the separation of concentrated thrombocytes from buffy coat, wherein the separation procedure takes place automatically controlled, and wherein there occurs in particular a separation of high purity of the individual, differently-colored constituents of the whole blood.
DISCLOSURE OF THE INVENTION AND ITS ADVANTAGES
The solution of the task is characterized by a process wherein a light source, such as a transmitter diode or light-emitting diode (LED), with a more or less monochromatic radiation of the wave length in the range of either about 535 nm to 575 nm (green to red), preferably 565 nm, or from about 400 nm to 453 nm (blue), is employed as a transmitter of the photometer unit. The receiver, which is a photo resistor or photo diode or photo transistor, tuned to the wave length of the light source, detects changes in the color of the liquid and derives therefrom a signal which is transferred to a breaker unit. The connection between the containers is led through the breaker unit. The breaker unit controls the flow rate as a function of the output signal of the receiver of the photometer unit and, in particular, interrupts the flow when a predetermined limit value is reached.
The method is associated with the advantage that a fully automatically controlled separation of the whole blood or of the buffy coat into the individual, differently-colored blood constituents occurs with the method by means of a photometric differentiation and separation of the differently-colored constituents and that the individual constituents can be separated from each other and can be recovered in a high purity phase. Independent of the subjective impression of the operating person observing, a predetermined value of the color recognition of a blood constituent is again and again reproduced by the photometer unit. The preceding adjustment occurs automatically by means of the inherent coloration of the plasma. A maximum lower limit value can be determined, whereby lipaemic and haemolytic preparations are automatical
Deutsches Rotes Kreuz Blutspendendienst Baden-Wurttemberg Gemein
Kasper Horst M.
Kim John
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