Patent Application
20150367063
The present invention relates to a blood component separation device for collecting a predetermined blood component from blood.
Conventionally, in the field of blood sampling, a blood component, such as platelet liquid, is collected by collecting only the component from sampled blood and returning the remaining blood components to the blood donor. In such an operation, a blood component separation device including a centrifugal separator is used.
In recent years, in the field of radiation therapy for cancer or the like, transfusion of platelet liquid has been widely performed, and high-concentration platelet liquid has become necessary for the therapy. To obtain high-concentration platelet liquid, Patent Literature 1 discloses an art using a blood component separation device to temporarily store low-concentration platelet liquid in a buffy coat bag and store only high-concentration platelet liquid in a platelet intermediate bag.
To surely collect platelet liquid satisfying a target concentration, an extracorporeally circulating volume of platelet liquid (sampled blood volume) during collecting operation should properly be adjusted. A technique of adjusting the extracorporeally circulating volume taking the hematocrit value of blood in account is not disclosed in Patent Literature 1.
To adjust the extracorporeally circulating volume taking the hematocrit value of blood in account, the hematocrit value of blood may be measured with a blood cell counter (blood cell counting device).
However, if there is a large difference between the hematocrit value measured with a blood cell counter and the actual hematocrit value, in other words, if the measuring accuracy of the blood cell counter is low, the collected platelet liquid may not satisfy the target concentration.
An example case will be explained where a hematocrit value measured with a blood cell counter is 40% while the actual hematocrit value is 45%. The hematocrit value measured with the blood cell counter is smaller than the actual hematocrit value. The target extracorporeally circulating volume of platelet liquid per one cycle during the collecting operation required of the blood component separation device is, for example, 450 ml according to calculation from the hematocrit value (40%) measured with the blood cell counter. Since the actual hematocrit value is 45%, which is different from the hematocrit value measured with the blood cell counter, the actual extracorporeally circulating volume per one cycle may be adjusted to 400 ml. When the actual extracorporeally circulating volume is significantly smaller than the target extracorporeally circulating volume, the concentration of the collected platelet liquid may be lower than the target concentration (unit shortage of platelets).
In another case, where the hematocrit value measured with a blood cell counter is larger than the actual hematocrit value, the concentration of collected platelet liquid may be higher than the target concentration (unit excess of platelets).
As described in these examples, the collected platelet liquid may not satisfy the target concentration due to the low measuring accuracy of the blood cell counter.
The present invention is made to solve the aforementioned problem. The object of the present invention is to provide a blood component separation device capable of collecting a predetermined blood component to satisfy a target concentration regardless of the measuring accuracy of the blood cell counter.
To solve the problem, one aspect of the present invention is a blood component separation device which includes a centrifugal separator configured to separate a plurality of blood components from blood and a container for containing a predetermined blood component centrifugally separated, and which is configured to perform a plurality of steps of collecting the predetermined blood component which is separated, and the blood component separation device includes a calculation unit configured to calculate an estimated extracorporeal circulation volume as a target sampled blood volume per one cycle of an operation of collecting the predetermined blood component from a hematocrit value obtained by correcting a hematocrit value measured with a blood cell counter. The calculation unit is configured to calculate a correction value used for the correction from a data value of the estimated extracorporeal circulation volume of a plurality of finished and immediately preceding collecting operations and a data value of sampled blood volume measured in a first cycle of each of a plurality of immediately preceding collecting operations.
According to the aspect, a correction value for correcting a measured hematocrit value is calculated from a data value of a plurality of finished and immediately preceding operations of collecting a predetermined blood component. The correction value is used for correcting the measured hematocrit value to calculate an estimated extracorporeal circulation volume of the present collecting operation. By correcting the hematocrit value measured with the blood cell counter, the blood component satisfying the target concentration can be collected even if the measuring accuracy of the blood cell counter is low. The correction value for correcting the measured hematocrit value is updated upon finishing each collecting operation, so that the measured hematocrit value is suitably corrected along with the change in the measuring accuracy of the blood cell counter. Therefore the blood component satisfying the target concentration can be collected regardless of the accuracy of measuring the hematocrit value of the blood cell counter.
According to the aspect, a data value of the estimated extracorporeal circulation volume and a data value of sampled blood volume measured in the first cycle are preferably calculated without using the data value of a collecting operation in which blood sampling is stopped before finishing the collecting operation.
According to the aspect, the correction value for correcting measured hematocrit value is calculated using only the data value of a collecting operation which succeeded in collecting the predetermined blood component. Thus the accuracy of correcting the measured hematocrit value improves and the estimated extracorporeal circulation volume can further accurately be calculated. Therefore the platelet liquid satisfying the target concentration can surely be collected regardless of the accuracy of measuring the hematocrit value of the blood cell counter.
Furthermore, according to the aspect, the blood component separation device preferably performs a) a centrifugal separation step of introducing whole blood drawn from a blood donor into the centrifugal separator to separate whole blood into a plurality of blood components, b) a circulation flow step of introducing a first blood component, among predetermined blood components separated in the centrifugal separation, into the centrifugal separator together with whole blood, c) a circulation/acceleration step, performed after a predetermined volume of the first blood component is separated in the circulation flow step, of stopping the supply of whole blood to the centrifugal separator to introduce only the first blood component into the centrifugal separator, further performing circulation for a predetermined period of time, and then increasing the circulation speed so that a second blood component is separated in the centrifugal separator and collected, and d) a blood returning step, performed after collecting a predetermined volume of the second blood component in the circulation/acceleration step, of returning blood components, which are not collected, to the blood donor. A cycle from the steps a) to d) is preferably performed a plurality of times.
According to the aspect, the predetermined blood component can accurately be separated from other blood components.
Furthermore, in the aspect, the circulation/acceleration step includes a first collecting step of transferring a portion of the second blood component with low-concentration among the second blood components to a temporary storage container and a second collecting step of collecting a portion of the second blood component with high-concentration among the second blood components. The second blood component with low-concentration transferred to the temporary storage container may preferably be introduced into the centrifugal separator together with the whole blood sampled in the following cycle.
According to the aspect, such a process can be used for BC recycling to obtain the second blood component with high-concentration, and thereby further larger volume of predetermined blood component can be collected.
In the aspect, it is preferable that the predetermined blood component is platelet liquid.
According to the aspect, the platelet liquid satisfying the target concentration can be collected regardless of the accuracy of measuring the hematocrit value of the blood cell counter.
According to the blood component separation device configured as described above, the predetermined blood component satisfying the target concentration can be collected regardless of the measuring accuracy of the blood cell counter.
Now, an embodiment of the blood component separation device according to the present invention will be described in detail referring to the drawings.
The blood component separation device according to the embodiment includes a blood component separation circuit 1. The blood component separation circuit 1 includes an initial flow blood collecting circuit 5 composed of a blood sampling needle 2, an initial flow blood collecting bag Y7 for collecting initial flow blood, a sampling port 3, and an initial flow blood collecting line 4.
The blood component separation circuit 1 includes a centrifuge bowl E1. The centrifuge bowl E1 includes a rotor (not shown) having therein a space for storing drawn blood, a rotor drive unit 14 for rotating the rotor, an inflow port (first port E1a), and an outflow port (second port E1b), and is configured to separate blood into a plurality of blood components by rotating the rotor. The blood component separation circuit 1 includes three containers for storing blood components separated in the centrifuge bowl E1, that is, a first container (plasma bag) Y1, a second container (temporary storage bag) Y2, and a third container (platelet intermediate bag) Y3.
The blood component separation circuit 1 includes a first line, a second line, a third line, a fourth line, a fifth line, a sixth line, and a seventh line.
The first line couples the blood sampling needle 2 and the centrifuge bowl E1 and includes a donor tube T1, a first blood pump P1, a tube T2, a tube T3a, a first open/close valve V1, a tube T3b, and a tube T4. The second line couples the centrifuge bowl E1 and the first container Y1 and includes a tube T5, a tube T6a, a second open/close valve V2, and a tube T6b. The third line couples the first container Y1 and the first line and includes a tube T8a, a third open/close valve V3, a tube T8b, a tube T9, a second blood pump P2, a tube T10b, a fourth open/close valve V4, and a tube T10a.
The fourth line couples the centrifuge bowl E1 and the second container Y2 and includes a tube T5, a tube T15, a tube T11a, a fifth open/close valve V5, and a tube T11b. The fifth line couples the second container Y2 and the first line and includes a tube T12, a tube T13b, a sixth open/close valve V6, and a tube T13a. The sixth line couples the second container Y2 and the first line, similarly to the fifth line, and includes a tube T12, a tube T14a, a seventh open/close valve V7, a tube T14b, a tube T9, the second blood pump P2, the tube T10b, the fourth open/close valve V4, and the tube T10a. The seventh line couples the centrifuge bowl E1 and the third container Y3 and includes the tube T5, the tube T15, a tube T16, a tube T17a, an eighth open/close valve V8, and a tube T17b.
The blood sampling needle 2 for sampling whole blood (blood) from a blood donor is coupled to the first port of the first blood pump P1 via the donor tube T1. The initial flow blood collecting bag Y7 is coupled to the blood sampling needle via a branch provided on the donor tube T1 and via the initial flow blood collecting line 4. The initial flow blood collecting bag Y7 includes a sampling port 3 for transferring collected initial flow blood to a test container (not shown). The sampling port 3 is constituted with a main body, a needle 6, and a cover 7 for covering the needle 6. Further, a clamp 8 is provided on the initial flow blood collecting line 4 to open/close the line.
The tube T2 coupled to the second port of the first blood pump P1 is branched into the tube T3a and the tube T13a. The tube T3a is coupled to the first port of the first open/close valve V1, and the second port of the first open/close valve V1 is coupled to the tube T3b. The tube T3b is branched into the tube T4 and the tube T10a. The tube T4 is coupled to the first port E1a of the centrifuge bowl E1, which is a centrifugal separator for separating collected blood into a plurality of blood components. The centrifuge bowl E1 is disposed on the rotor drive unit 14 to be rotated.
The blood sampling needle 2 and the first port E1a, which is an inlet port of the centrifuge bowl E1, are coupled via the first line (the donor tube T1, the first blood pump P1, the tube T2, the tube T3a, the first open/close valve V1, the tube T3b, and the tube T4).
A pressure sensor C1 is coupled to the donor tube T1.
The tube T5 coupled to the second port E1b of the centrifuge bowl E1 is branched into the tube T15 and the tube T6a. The tube T6a is coupled to the first port of the second open/close valve V2, and the second port of the second open/close valve V2 is coupled to the tube T6b. The tube T6b is coupled to the second port Y1b of the plasma bag (the first container) Y1.
The second port E1b of the centrifuge bowl E1 and the plasma bag Y1 are coupled via the second line (the tube T5, the tube T6a, the second open/close valve V2, and the tube T6b). Two plasma bags Y1 are provided, though only one plasma bag is illustrated in
The first port Y1a, or the outlet port, of the plasma bag Y1 is coupled to the tube T8a. The tube T8a is coupled to the first port of the third open/close valve V3. The second port of the third open/close valve V3 is coupled to the tube T8b, and the tube T8b is coupled to the tube T9. The tube T9 is coupled to the second port of the second blood pump P2. The first port of the second blood pump P2 is coupled to the tube T10b, and the tube T10b is coupled to the second port of the fourth open/close valve V4. The first port of the fourth open/close valve V4 is coupled to the tube T10a.
The tube T10a is coupled to the connection between the tube T3b and the tube T4 constituting the first line. The plasma bag Y1 and the first line are coupled via the third line (the tube T8a, the third open/close valve V3, the tube T8b, the tube T9, the second blood pump P2, the tube T10b, the fourth open/close valve V4, and the tube T10a). The plasma bag Y1 is thus configured to selectively communicate with the inlet port or the outlet port of the centrifuge bowl E1.
The tube T15 branched from the tube T5 branches into the tube T11a and the tube T16. The tube T11a is coupled to the first port of the fifth open/close valve V5, and the second port of the fifth open/close valve V5 is coupled to the tube T11b. The second port of the fifth open/close valve V5 is coupled to the second port Y2b of the temporary storage bag Y2 via the tube T11b. That is, the second port E1b of the centrifuge bowl E1 and the temporary storage bag Y2 are coupled via the fourth line (the tube T5, the tube T15, the tube T11a, the fifth open/close valve V5, and the tube T11b).
The first port Y2a of the temporary storage bag Y2 is coupled to the tube T12, and the tube T12 is branched into the tube T13b and the tube T14a. The tube T13b is coupled to the first port of the sixth open/close valve V6, and the second port of the sixth open/close valve V6 is coupled to the tube T13a. The tube T13a is coupled to the connection between the tube T2 and the tube T3a constituting the first line.
The tube T14a branched from the tube T12 is coupled to the first port of the seventh open/close valve V7, and the second port of the seventh open/close valve V7 is coupled to the tube T14b. The tube T14b is coupled to the connection between the tube T9 and the tube T8b, and the tube T9 is coupled to the second port of the second blood pump P2.
The first port of the second blood pump P2 is coupled to the tube T10b, and the tube T10b is coupled to the first port of the fourth open/close valve V4. The second port of the fourth open/close valve V4 is coupled to the tube T10a. The tube T10a is coupled to the connection between the tube T3b and the tube T4 constituting the first line. The temporary storage bag Y2 and the first line are coupled via the fifth line (the tube T12, the tube T13b, the sixth open/close valve V6, and the tube T13a) and the sixth line (the tube T12, the tube T14a, the seventh open/close valve V7, the tube T14b, the tube T9, the second blood pump P2, the tube T10b, the fourth open/close valve V4, and the tube T10a). The temporary storage bag Y2 is coupled so as to selectively communicate with the inlet port or the outlet port of the centrifuge bowl E1.
The tube T16 branched from the tube T15 branches into the tube T17a and the tube T18a. The tube T17a is coupled to the first port of the eighth open/close valve V8, and the second port of the eighth open/close valve V8 is coupled to the tube T17b. The tube T17b is coupled to the first port Y3a, or the inlet port, of the platelet intermediate bag (the third container) Y3. The tube T18a branched from the tube T16 is coupled to the first port of the ninth open/close valve V9, and the second port of the ninth open/close valve V9 is coupled to the tube T18b. The tube T18b is coupled to the air bag Y4. That is, the second port E1b of the centrifuge bowl E1 and the platelet intermediate bag Y3 are coupled via the seventh line (the tube T5, the tube T15, the tube T16, the tube T17a, the eighth open/close valve V8, and the tube T17b). The platelet intermediate bag Y3 is thus configured to communicate with the outlet port of the centrifuge bowl E1.
A turbidity sensor C2 for detecting the concentration of platelets and the pressure sensor C3 are attached to the tube T5 coupled to the second port E1b of the centrifuge bowl E1. The turbidity sensor C2 detects the turbidity, caused by platelets, of plasma flowing in the tube T5.
In the peripheral region of where the centrifuge bowl E1 is disposed, an interface sensor C4 for detecting the location of the interface of a buffy coat layer BC (see
The tube T19 coupled to the second port Y3b, or the outlet port, of the platelet intermediate bag Y3, is branched into the tube T20a and the tube T21. The tube T20a is coupled to the first port of the tenth open/close valve V10, and the second port of the tenth open/close valve V10 is coupled to the tube T20b. The tube T21 is coupled to the first port, or the output port, of the third blood pump P3. The second port, or the input port, of the third blood pump P3 is coupled to a platelet reserve liquid bottle through a sterilizing filter 9 and a bottle needle 10. The tube T20b is coupled to the platelet bag Y5 via a white blood cell removal filter 11. The air bag Y6 is coupled to the platelet bag Y5.
An output port of the ACD pump P4 is coupled to the donor tube T1. The input port of the ACD pump P4 is coupled to the output port of the sterilizing filter 12. The input port of the sterilizing filter 12 is coupled to the ACD storing bottle via a bottle needle 13.
As illustrated in
The detection signals from the sensors C1, C2, C3, and C4 are input to the controller 15 as needed. Instructed by these detection signals, the controller 15 controls the pumps P1, P2, P3, and P4 to operate or stop, and controls the rotational direction (normal or reverse) and the rotational speed of the pumps. The controller 15 also controls the open/close valves V1, V2, V3, V4, V5, V6, V7, V8, V9, and V10 to open or close, and controls the centrifuge bowl drive device 14 to operate as required. The data of hematocrit value (HCT value) measured with the blood cell counter 32 and the data of drawn volume of blood measured with the processed blood volume measuring unit 34 are input to the controller 15 as needed. The controller 15 also functions as the “calculation unit” of the present invention.
As a material of the tubes, for example, thermoplastic elastomers such as polyvinyl chloride, polyethylene, polypropylene, polyester such as PET and PBT, ethylene-vinyl acetate copolymer (EVA), polyurethane, and polyester elastomer may be used. Among these materials, in particular, polyvinyl chloride is preferably used. Polyvinyl chloride not only has sufficient ductility and flexibility but also is easy to handle and suitable to be choked by a clamp or the like.
As a material of the bags, soft polyvinyl chloride including DEHP as a plasticizer or products of polymerization or copolymerization of such olefins or diolefins as polyolefin, ethylene, propylene, butadiene, and isoprene can be used. Typical examples include ethylene-vinyl acetate copolymer (EVA), polymer blends formed between EVA and various thermoplastic elastomers, and arbitrary combinations thereof. Alternatively, PET, PBT, PCGT, or the like can be used. Among these materials, particularly, polyvinyl chloride is preferably used. Such material having high gas permeability is preferable for a container for storing platelet liquid to improve shelf life of platelet liquid. Therefore, polyolefin or DnDp-plasticized polyvinyl chloride may preferably be used for such material or a material formed in a thin sheet may preferably be used.
The inflow port E1a and the outflow port E1b are formed on the non-rotating fixed portion 20 in the blood component separation device. The fixed portion 20 includes a cover 17 and an inflow tube 18 extending downward. These fixed portions rotatably and integrally support a side wall 21, an outer shell 22, an inner shell 23, and a bottom plate 16. The bottom plate 16 is coupled to the centrifuge bowl drive device 14 by suctioning so that the rotational force can be transferred from the centrifuge bowl drive device 14 to the bottom plate 16.
That is, in the space between the outer shell 22 and the side wall 21 from the outer side to the inner side, in the descending order of specific gravity, a red blood cell layer RBC, a white blood cell layer WBC, a buffy coat layer BC, a platelet layer PLT, and a plasma layer PPP are formed by a centrifugal force. It is difficult to separate the white blood cell layer WBC and the platelet layer PLT, because the values of their specific gravities are close. Thus, the buffy coat layer BC including the white blood cell layer WBC and the platelet layer PLT is formed. Typically, the whole blood includes about 55% of plasma PPP, about 43.2% of red blood cells RBC, about 1.35% of white blood cells WBC, and 0.45% of platelets PLT.
The centrifuge bowl E1 has an outflow passage 19 in the inner periphery formed somewhat above the middle point of the inflow tube 18. So that the plasma layer PPP formed in the inner side of the space formed by the outer shell 22 and the side wall 21 flows out of the centrifuge bowl E1 through the outflow port E1b.
The operation of the blood component separation device configured as described above is illustrated in flow charts in
First, a priming step (S1) illustrated in
When the priming step (S1) is finished, the blood sampling needle 2 pierces the blood donor to start drawing of whole blood (S2). After the blood sampling needle 2 piercing the blood donor, the initial flow blood is collected in the initial flow blood collecting bag Y7 of the initial flow blood collecting circuit (see
The ACD pump P4 is operated again to supply the ACD liquid to the donor tube T1 so that the ACD liquid is mixed with the whole blood, which is then supplied to the centrifuge bowl E1. When whole blood is supplied to the rotating centrifuge bowl E1, the air inside the centrifuge bowl E1 (shown in dashed lines) is pushed by the plasma to flow out through the outflow passage 19 (see
In the centrifuge bowl E1, as illustrated in
Then when the turbidity sensor C2 detects that the fluid flowing in the tube has changed from air to plasma, the ninth open/close valve V9 is closed and the second open/close valve V2 is opened to store the plasma spilled out of the centrifuge bowl E1 in the plasma bag Y1, as illustrated in
Then when a certain volume of plasma (30 ml for the example) is stored in the plasma bag Y1 (S4: YES), the third open/close valve V3 is opened, the second blood pump P2 is operated, and the fourth open/close valve V4 is opened to draw whole blood from the blood donor, mix the whole blood with the plasma stored in the plasma bag Y1, and supply the mixture of the whole blood and the plasma to the centrifuge bowl E1, as illustrated in
When the interface sensor C4 detects that the interface between the buffy coat layer BC and the red blood cell layer RBC in
At the same time, whether the present cycle is the last cycle is determined. When the present cycle is not the last cycle (S7: NO), the sixth open/close valve V6 is opened, with the first blood pump P1 kept operating, to store the drawn whole blood in the temporary storage bag Y2 (S11). In other words, the drawing of whole blood can be continued by storing the drawn whole blood in the temporary storage bag Y2. Drawing of whole blood is continued until the circulation/acceleration step is finished, a predetermined time has elapsed, or a predetermined volume has been drawn. In the last cycle (S7: YES), the first blood pump P1 stops operating to stop blood drawing (S8).
In the circulation step in the circulation/acceleration step of the present example, the circulation speed is set higher than that of the critical flow step so that the plasma circulates at a speed of about 100 ml/min, thereby flowing through the centrifuge bowl E1 within 30 to 40 seconds. In this manner, the concentration of particulates in the buffy coat layer BC in
Then after the circulation step performed for a certain period of time, an acceleration step (the fifth step) in the circulation/acceleration step illustrated in
In the acceleration step, the platelets PLT receive ascending force and thereby flow out of the centrifuge bowl E1 through the outflow passage 19, as illustrated in
The outflow period TA of platelets can be divided into three periods, that is, a low-concentration period TB, which comes first, where low-concentration platelet liquid flows out, a high-concentration period TC, following the TB period, where high-concentration platelet liquid flows out, and a low-concentration period TD, following the TC period, where low-concentration platelet liquid flows out again. Low-concentration platelet liquid is not necessary for obtaining high-concentration platelet liquid.
In the present example, in the acceleration step as illustrated in
Note that, the temporary storage bag Y2 serves as a buffy coat bag as well as a whole blood bag.
When the turbidity sensor C2 detects that the concentration of platelet liquid is high, it is determined that the present period is the TC period (S23: YES), and the fifth open/close valve V5 is closed and the eighth open/close valve V8 is opened as illustrated in
If the present cycle is not the last cycle (S7: NO), the first blood pump P1 is kept operating so that the whole blood drawn from the blood donor continuously flows through the sixth open/close valve V6 and is stored in the temporary storage bag Y2.
When a predetermined volume of high-concentration platelet liquid is stored in the platelet intermediate bag Y3, it is determined that the present period is the TD period (S25: YES), and the eighth open/close valve V8 is closed to block the low-concentration platelet liquid from flowing into the platelet intermediate bag Y3 and the fifth open/close valve V5 is opened, as illustrated in
If the present cycle is not the last cycle (S7: NO), the first blood pump P1 is kept operating so that the whole blood drawn from the blood donor continuously flows through the sixth open/close valve V6 and is stored in the temporary storage bag Y2.
The volume of high-concentration platelet liquid stored in the platelet intermediate bag Y3 can easily be adjusted by controlling the time period of opening the eighth open/close valve V8 based on the rate of platelet liquid flowing out of the centrifuge bowl E1.
Then upon finishing the collection of a predetermined volume of platelet liquid, in other words, when a predetermined time period has elapsed after opening the eighth open/close valve V8, it is determined that the TD period has past (S27: YES), or the outflow of platelets is stopped, and the step proceeds to the blood returning step illustrated in
In the blood returning step, the centrifuge bowl E1 stops rotation, the sixth open/close valve V6 and the fifth open/close valve V5 are closed, the first open/close valve V1 and the ninth open/close valve V9 are opened, and the first blood pump P1 is reversely rotated, whereby the returning of the blood remaining in the centrifuge bowl E1 to the blood donor starts. The first blood pump P1 is reversely operated at double the rotational speed of the normal rotation to shorten the time of blood returning. Further, as required, the second blood pump P2 is operated to return the excessive plasma stored in the plasma bag Y1.
When the blood returning finishes, and if the present cycle is the last cycle (S7: YES), the entire process is finished. When the finished cycle is not the last cycle (S7: NO), the centrifuge bowl E1 starts rotating as illustrated in
Then when the turbidity sensor C2 detects that the fluid flowing in the tube has changed from air to plasma, the ninth open/close valve V9 is closed and the second open/close valve V2 is opened to store the plasma spilled out of the centrifuge bowl E1 in the plasma bag Y1, as illustrated in
Then when it is confirmed that all the blood in the temporary storage bag Y2 has returned to the centrifuge bowl E1 and that a predetermined volume of plasma is stored in the plasma bag Y1 (S4: YES), the seventh open/close valve V7 is closed with the second blood pump P2 kept operating, and the third open/close valve V3 is opened to mix the plasma stored in the plasma bag Y1 with whole blood and to supply the mixture of the plasma and the whole blood to the centrifuge bowl E1, whereby the critical flow step of plasma is started, as illustrated in
This cycle is repeated, typically three or four times, until a predetermined volume of platelets PLT is obtained. When the operation finishes with three cycles, for example, blood drawing is performed in parallel in a circulation period TF2 and an acceleration period TG2 in the second cycle to store whole blood in the temporary storage bag Y2. Then during blood drawing in the third cycle, the blood in the temporary storage bag Y2 is mixed with whole blood and supplied to the centrifuge bowl E1. Further, in a circulation period TF3 and an acceleration period TG3 in the third cycle, blood drawing is not performed. This is because there is no fourth cycle.
When the operation is to finish with three cycles, blood sampling finishes when the blood sampling needle 2 is removed from the blood donor after finishing the blood returning in the third cycle. As illustrated in
A method of correcting the HCT value (hematocrit value) measured with the blood cell counter 32 will now be described. In the present example, the correction of the HCT value measured with the blood cell counter 32 is performed automatically, and from the corrected HCT value, the estimated extracorporeal circulation volume, which is an estimated sampled blood volume (drawn volume of blood) per one cycle of the operation of collecting platelet liquid is calculated by a predetermined equation.
The HCT value measured with the blood cell counter 32 may have an error to deviate from the actual HCT value. This causes an error between the estimated extracorporeal circulation volume, which is the target sampled blood volume per one cycle, calculated in the controller 15 from the measured HCT value and the actual drawn volume of blood per one cycle measured with the processed blood volume measuring unit 34. This error may cause failure of the blood component separation circuit 1 to collect platelet liquid satisfying the target concentration (target number of platelets).
The present example is configured that the controller 15 calculates the true HCT correction value α from a data value A of the estimated extracorporeal circulation volume of a plurality of finished and immediately preceding operations of collecting platelet liquid and a data value B of the drawn volume of blood (sampled blood volume) measured with the processed blood volume measuring unit 34 in the first cycle of each of a plurality of finished and immediately preceding operations of collecting platelet liquid. The controller 15 corrects the HCT value measured with the blood cell counter 32 using the true HCT correction value α and then calculates the estimated extracorporeal circulation volume of the present collecting operation from the corrected HCT value. The controller 15 calculates the estimated extracorporeal circulation volume in each operation of collecting platelet liquid.
The true HCT correction value α is specifically calculated by the following equation. In the equation, α0 is the present HCT correction value, A is the data value of the estimated extracorporeal circulation volume, and B is the data value of drawn volume of blood measured in the first cycle.
α=α0×(A/B) [Equation 1]
The present HCT correction value (the correction value for the HCT value measured with the blood cell counter 32) is α0.
The data value A of the estimated extracorporeal circulation volume is the average of data value of estimated extracorporeal circulation volumes in a plurality of finished and immediately preceding operations of collecting platelet liquid. The data value B of the drawn volume of blood measured in the first cycle is an average of data value of drawn volume of blood measured in the first cycle of each of a plurality of finished and immediately preceding operation of collecting platelet liquid. In this manner the data value A of the estimated extracorporeal circulation volume and the data value B of the drawn volume of blood measured in the first cycle are updated after finishing each operation of collecting platelet liquid as needed. Thus a true HCT correction value α is updated at every operation of collecting platelet liquid as needed. The estimated extracorporeal circulation volume is accurately calculated in accordance with the accuracy of measuring the HCT value of the blood cell counter 32.
The data value of each of a plurality of immediately preceding operations of collecting platelet liquid is preferably calculated without using the data value of the operation in which blood sampling is stopped before finishing the collection of platelet liquid (data value of an incomplete collecting operation).
Data values of a plurality of immediately preceding operations of collecting platelet liquid may be, for example, but not limited to, the data values of immediately preceding 50 times of operations of collecting platelet liquid. Alternatively, the data values may be those of immediately preceding operations of collecting platelet liquid less than 50 times (for example, data values of immediately preceding 10 to 20 times of operations of collecting platelet liquid).
For example, when the present HCT correction value α0 is 1.00, the data value A of the estimated extracorporeal circulation volume is 404 ml (see
The controller 15 corrects the HCT value measured with the blood cell counter 32 using the true HCT correction value a to calculate the corrected HCT value. The estimated extracorporeal circulation volume of the present collecting operation is calculated from the corrected HCT value by using a predetermined equation.
In the present example, the controller 15 automatically corrects the HCT value measured with the blood cell counter 32 and calculates the estimated extracorporeal circulation volume by substituting the corrected HCT value in the predetermined equation.
The HCT correction value may be calculated for each centrifugal condition including the centrifugal speed, because the drawn volume of blood changes as the centrifugal speed (rotational speed of the centrifuge bowl E1) changes. The blood component separation device may be configured to turn on and off the function of correcting the HCT value.
As described above, the blood component separation device according to the first example includes the controller 15 which calculates the estimated extracorporeal circulation volume, or the target sampled blood volume per one cycle of the operation of collecting platelet liquid, from the HCT value calculated by correcting the HCT value measured with the blood cell counter 32. The controller 15 calculates the true HCT correction value a, which is used for correcting the measured HCT value, from the data value A of the estimated extracorporeal circulation volume of a plurality of finished and immediately preceding operations of collecting platelet liquid and the data value B of the sampled blood volume measured in the first cycle of each of a plurality of finished and immediately preceding operations of collecting platelet liquid.
The true HCT correction value a is calculated from the data value of a plurality of immediately preceding operations of collecting platelet liquid. The measured HCT value is corrected using the calculated true HCT correction value a to calculate the estimated extracorporeal circulation volume of the present collecting operation. Since the measured HCT value is corrected in such a manner, the platelet liquid satisfying the target concentration can be collected even if the measuring accuracy of the blood cell counter 32 is low. The correction value for correcting the measured HCT value is updated upon finishing each collecting operation, so that the measured HCT value is suitably corrected along with the change in the measuring accuracy of the blood cell counter 32. For example, when the measuring accuracy of the blood cell counter 32 is calibrated, the measured HCT value is automatically corrected with the calibrated measuring accuracy of the blood cell counter 32 in the blood component separation device. This improves the accuracy of calculation of the estimated extracorporeal circulation volume. Thus the platelet liquid satisfying the target concentration can be collected regardless of the accuracy of measuring the HCT value of the blood cell counter 32.
The data value A of the estimated extracorporeal circulation volume of a plurality of immediately preceding operations of collecting platelet liquid and the data value B of the sampled blood volume measured in the first cycle of each of a plurality of immediately preceding operations of collecting platelet liquid are calculated without using the data value of the collecting operation in which blood sampling is stopped before finishing the operation of collecting platelet liquid. The true HCT correction value a is calculated using only the data value of the collecting operation succeeded in collecting platelet liquid. The platelet liquid satisfying the target concentration can thus surely be collected regardless of the accuracy of measuring the HCT value of the blood cell counter 32.
Furthermore, the blood component separation device according to the first example performs a) a centrifugal separation step of introducing whole blood drawn from a blood donor into the centrifuge bowl E1 to separate whole blood into a plurality of blood components, b) a circulation flow step of introducing plasma, among predetermined blood components separated in the centrifugal separation, into the centrifuge bowl E1 together with whole blood, c) a circulation/acceleration step, performed after a predetermined volume of plasma is separated in the circulation flow step, of stopping the supply of whole blood to the centrifugal separator to introduce only plasma into the centrifugal separator, further performing circulation for a predetermined period of time, and then increasing the circulation speed so that platelet liquid is separated in the centrifugal separator and collected, and d) a blood returning step, performed after collecting a predetermined volume of platelet liquid in the circulation/acceleration step, of returning blood components, which are not collected, to the blood donor. A cycle from the steps a) to d) is performed a plurality of times. In this manner, the platelet liquid can accurately be separated from other blood components.
Furthermore, the circulation/acceleration step performed in the blood component separation device according to the first example includes a first collecting step of transferring a portion of platelet liquid with low-concentration to a temporary storage container and a second collecting step of collecting a portion of platelet liquid with high-concentration. The platelet liquid with low-concentration transferred to the temporary storage container is introduced into the centrifuge bowl E1 together with the whole blood drawn in the following cycle. This process can be used for BC recycling (buffy coat recycling) to obtain platelet liquid with high-concentration, and thereby further larger volume of platelet liquid can be collected.
Now, a second example will be described. The component similar to that of the first example is appended with the same reference sign and the description thereof will be omitted. Description will mainly be made for the difference between the second example and the first example. The major difference between the blood component separation device according to the second example and the blood component separation device of the first example is that the second example does not employ BC recycling.
The operation of the blood component separation device according to the second example will be described.
Similarly to the first example, the blood component separation device according to the second example first performs a priming step (S101). At the same time, as illustrated in
When a certain volume of plasma is stored in the plasma bag Y1 (S103: YES), as illustrated in
Then the first open/close valve V1 is opened to restart drawing of whole blood to introduce the blood into the centrifuge bowl E1 (S105: second blood sampling step).
When the interface sensor C4 detects that the interface between the buffy coat layer BC and the red blood cell layer RBC in
The first open/close valve V1 is opened to restart drawing of whole blood. The sampled blood volume of whole blood is automatically calculated according to the HCT value so that the collection of platelet liquid can surely be performed (S108: third blood sampling step).
The first open/close valve V1 is then closed to temporarily stop the drawing of whole blood and to circulate the plasma to return to the centrifuge bowl E1, by gradually increasing the circulation speed (S109: acceleration step). The circulation speed is first increased from 60 ml/min to 150 ml/min, and eventually to 200 ml/min.
When the circulation speed exceeds 150 ml/min in the acceleration step, platelets starts to flow out. When the turbidity sensor C2 detects the outflow of platelets, as illustrated in
When the outflow of platelets has stopped, the step proceeds to the blood returning step (S111), similarly to the first example.
When the blood returning is finished, and when the finished cycle is the last cycle (S112: YES), the platelet liquid stored in the platelet intermediate bag Y3 is injected into the platelet bag Y5 through the white blood cell removal filter 11. Then the two tubes of the platelet bag are sealed. The platelet bag Y5 storing high-concentration platelet liquid is thus prepared. Now the entire step is finished. If the finished cycle is not the last cycle (S112: NO), the step proceeds to the first blood sampling step (S102).
Similarly to the example 1, the blood component separation device according to the second example described above is also configured that the controller 15 calculates the true HCT correction value from the data value of a plurality of finished and immediately preceding operations of collecting platelet liquid so that the platelet liquid satisfying the target concentration can be collected regardless of the accuracy of measuring the HCT value of the blood cell counter 32.
The embodiments described above are merely exemplary representations and should not be construed to set any limit on the present invention. It goes without saying that various modifications and alterations can be made without departing from the spirit and scope of the present invention. In the embodiment described above, the temporary storage bag Y2 serves as a buffy coat bag as well as a whole blood bag, although the buffy coat bag may individually be provided in parallel with the whole blood bag.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2013/054881 | 2/26/2013 | WO | 00 |
