JP2932101B2 - Plasma filtration method and apparatus therefor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a plasma filtration method and an apparatus therefor, and more particularly, to a method for washing and regenerating a secondary filter portion in a plasma filtration method and an improvement of the apparatus.

BACKGROUND ART Various studies have revealed that high-molecular-weight substances causing the pathology of certain diseases such as rheumatoid arthritis and systemic lupus erythematosus are present in the blood of patients. Therefore, it has been attempted to treat the disease and reduce the symptoms by removing the high molecular weight substance from the blood of the patient, and a plasma filtration method has been adopted as one of the means.

The plasma filtration method includes a primary filter treatment for separating blood collected from a patient into blood cells and plasma first, and a secondary filter treatment for removing and purifying harmful high molecular weight substances from plasma.
This is a system in which purified plasma from the secondary filter is remixed with blood cells from the primary filter and returned to the blood supply source (patient).

The plasma filtration method is roughly classified into two types according to a mechanism of filtering a high molecular weight substance by a secondary filter. That is, a method of selecting a substance to be removed according to the pore size of a secondary filter (double filtration plasma separation / exchange method), and a method of cooling plasma once to about 4 ° C. and gel containing a high molecular weight substance which is a harmful component in plasma ( There is a method in which a so-called cryogel is produced and sieved with a relatively coarse secondary filter (plasma cooling filtration method). The latter is advantageous in that harmful high molecular weight substances can be reliably removed. It is receiving attention (for example, see Japanese Patent Publication No. 1-334626).

The plasma cooling filtration method is almost the same as the double filtration plasma separation / exchange method except that the plasma cooling means is provided and the pore size of the secondary filter is different. The method will be described with reference to FIG. The blood is sent from its source to the primary filter 3 through the blood supply line 2 by operating the blood pump 1, where it is separated into blood cells and plasma, and the separated blood cells are remixed with the purified plasma described below. Is sent to the blood cell return line 4 side.

On the other hand, the plasma is sent from the plasma supply line 6 to the secondary filter 8 through the cooling coil unit 7 on the line 6 by operating the plasma pump 5, where the plasma is filtered. The plasma is usually cooled to 4 ° C. to 25 ° C., preferably around 4 ° C. in the coil section 7, and the cryogel of a high molecular weight substance generated by this cooling is removed from the plasma by a filtration treatment with a secondary filter. The filtrate from the secondary filter, ie, the purified plasma, is returned to the purified plasma return line 9 while being remixed with the returned blood cells from the primary filter 3 and then heated to the original liquid temperature in the heating bag 10. While returning to the source again. In the figures, 11 is a drip chamber, 12 is a pressure detector, and A is a cooling zone.

However, while the plasma filtration is continued, the secondary filter 8 gradually becomes clogged, so it is necessary to eliminate the clogging and recover the function.

Conventionally, as such a clogging elimination method, a double filtration plasma exchange method such as (a) replacing a secondary filter, (b) washing the inside of the secondary filter with a physiological saline, and the like has been adopted. The method has been applied. For example, Japanese Patent Publication No. Sho 63-28626 discloses a method in which a plurality of secondary filters are connected in parallel, and when one is clogged, it is switched to the other. Japanese Patent Application Laid-Open No. Sho 59-129067 discloses that when clogging occurs,
A method is shown in which the inner chamber of the next filter is lowered to the atmospheric pressure, and a cleaning liquid is supplied from the outer chamber side of the secondary filter to perform reverse cleaning.

However, these methods (a) and (b) require the total amount of plasma remaining in the secondary filter in one washing operation,
For example, about 200 to 300 ml are discarded. Washing or replacement of the secondary filter is required at least twice in one plasma filtration operation, and a large amount of at least 400 to 600 ml of plasma is discarded out of the system. As a result, it is necessary to replenish expensive drug solutions such as albumin preparations, which increases the economic burden and, at the same time, some substances cannot be replenished. . Moreover, in the method using a plurality of secondary filters, the cost of the treatment increases because the filter is expensive.

In particular, in the plasma cooling filtration method, since a filter having a relatively large pore diameter is used as the secondary filter, the filtration efficiency is the lowest at the start of filtration, and the efficiency gradually increases due to accumulation of cryogel. Therefore, in the above method, there is also a problem that the filtering efficiency of the secondary filter is reduced at every switching or cleaning operation.

DISCLOSURE OF THE INVENTION One object of the present invention is to provide a plasma filtration method and apparatus capable of minimizing the amount of plasma discarded outside the system when washing and regenerating a secondary filter for performing plasma filtration.

Another object of the present invention is to provide a plasma filtration method and an apparatus thereof that can reduce the time required for washing and regeneration of the secondary filter and the amount of washing solution used.

Still another object of the present invention is to provide a plasma filtration method and a plasma filtration method capable of restarting plasma filtration after washing and regeneration of the secondary filter with substantially the same filtration efficiency as before cleaning and regeneration. It is in.

Other features of the present invention will become apparent from the following description.

The present invention separates blood into blood cells and plasma by a primary filter, and the separated plasma is led to a secondary filter via a supply line,
By passing the inside of the filter from the inner chamber to the outer chamber, a high molecular weight substance as a harmful component is filtered and purified from the plasma, and the purified plasma is returned from the secondary filter via a return line to the primary filter. In the plasma filtration method in which the blood is returned as blood while being mixed with the separated blood cells, every time a pressure increase limit value at the filter inlet side is detected based on an increase in the tendency of the secondary filter to be clogged, the inner space of the secondary filter is exposed to the atmosphere. After releasing the pressure and dropping the pressure inside the chamber,
The inside of the secondary filter is washed from both the inner and outer chambers with the washing liquid while the washing waste liquid is discharged from the inner chamber to the outside of the system, and the cleaning and regeneration of the secondary filter are measured by these operations. The present invention provides a plasma filtration method characterized by returning to the above.

According to the plasma filtration method of the present invention, when the pressure on the inlet side of the secondary filter reaches the rising limit value, the inner chamber of the filter is opened to the atmosphere, and the inner chamber pressure drops to the atmospheric pressure by this opening. .

Due to the pressure drop in the internal pressure of the secondary filter, a pressure difference is generated between the inner and outer chambers of the filter, and the purified plasma in the outer chamber with high pressure tends to flow back toward the inner chamber with low pressure. . In this case, if the return line for purified plasma is open,
The backflow tendency also occurs in the purified blood return section at the end side of the line, and the backflow in the blood return section is not preferable. In order to prevent backflow in the blood return section, the purified plasma return line may be temporarily closed, preferably at the portion from the secondary filter side, before opening the inner chamber to the atmosphere. .

Due to the backflow tendency between the secondary chamber and the outer chamber,
The filter part that separates the inner and outer chambers is preliminarily backwashed by the purified plasma flowing backward from the outer chamber side to the inner chamber side.

Following such a pressure drop operation in the inner chamber, the cleaning liquid is supplied to the outer chamber side, the reverse cleaning of the filter portion is started, and the cleaning liquid is also supplied from the inner chamber, and the cleaning from the filter inner chamber side is started. Is done.

According to the present invention, the preliminary backwashing with the purified plasma based on the pressure difference between the inner and outer chambers and the washing with the washing solution from both the inner and outer chambers can be performed in a short time, for example, about 10 seconds. In addition, the amount of cleaning liquid used is small, for example, a cooling zone.
When the cooling temperature of the filter is about 11-18 ° C, the washing and regeneration of the secondary filter can be performed with the used amount of about 20-30ml in the outside chamber.

During the operation of washing the secondary filter, plasma equivalent to the used amount of the washing solution, for example, about 20 to 30 ml, is discarded from the inside of the filter to the outside of the system.

The inside of the secondary filter is usually 200 to 300
It contains about ml of plasma. In the present invention, the amount of plasma discarded out of the system, e.g.
It is only a very small part of 0 to 300 ml, and the amount of plasma discarded can be reduced as compared with the conventional method in which the entire amount is discarded outside the system.

Since the washing and regeneration of the secondary filter is performed in a short time with a small amount of the washing solution, the clogging component (cryogel) is not completely removed from the filter, and a part thereof remains as it is. Therefore, the filtration efficiency does not drastically decrease as seen when the secondary filter is replaced with a new one, and plasma filtration can be resumed while maintaining the filtration performance.

In the present invention, the plasma supply from the primary filter to the secondary filter may be continued or interrupted during the operation of washing the secondary filter. If you want to continue the plasma supply,
Since the driving of the blood pump and the plasma pump can be continued even in the case of the washing operation, the trouble of stopping the driving of the pump for each washing operation is eliminated. Further, if continued, the entire amount of plasma supplied into the secondary filter during the washing operation is discarded outside the system, and thus the amount of plasma discarded outside the system increases. The amount of increase depends on the time required for the cleaning operation, for example,
If the washing time is about 10 seconds, 4 to
It is about 6 ml, and if there is such an increase, there is no particular problem. Of course, such an increase in plasma waste may be eliminated by interrupting the plasma supply to the secondary filter during the washing operation.

In the present invention, in order to further reduce the waste loss of plasma generated during the washing operation of the secondary filter to the outside of the system,
After the pressure drop in the inner chamber of the secondary filter, a plasma collection operation can be performed before starting the washing operation.

In the plasma collection operation, the plasma supply to the secondary filter is interrupted, and the cleaning liquid is supplied into the filter while the inner chamber is closed from the atmosphere, and the plasma in the secondary filter is removed from the inner chamber as the cleaning liquid is supplied. It is carried out by extruding and collecting into the purified plasma return line connected to the outer chamber via the outer chamber. This plasma collection operation is completed when the entire amount of plasma in the outer chamber of the secondary filter has been replaced with the cleaning liquid, that is, when the cleaning liquid corresponding to the inner volume of the secondary filter has been supplied. The washing operation of the secondary filter described in (1) is started.

In this case, the amount of the washing liquid of the secondary filter may be increased to such an extent that the filtration efficiency of the secondary filter is not extremely reduced, for example, to about the internal capacity of the secondary filter.

The plasma collection operation is performed in a state where the secondary filter is clogged. However, since the washing liquid, for example, physiological saline has a lower viscosity than the plasma, it can easily pass through the filter.

During the plasma collection operation, the plasma may be circulated from the supply line to the return line via a bypass line parallel to the secondary filter without stopping the operation of the blood pump and the plasma pump.

When performing the plasma collection operation, the inner and outer chambers of the secondary filter are filled with the washing liquid that has been replaced with plasma. Therefore, if the operation is immediately returned to the normal operation after the washing operation, the entire amount of the washing liquid in the inner and outer chambers remains unchanged. Enter the return line side.

In the present invention, in order to reduce the amount of the washing liquid entering the return line, after the washing operation of the secondary filter, the washing liquid can be discharged out of the system before returning to the normal operation.

In the operation of discharging the cleaning liquid, plasma is supplied to the inner chamber of the secondary filter with the inner chamber of the secondary filter opened to the atmosphere and the return line closed, and the cleaning liquid in the inner chamber is discharged out of the system as the plasma is supplied. By doing it. This ejection operation
The operation ends when the entire amount of the washing liquid in the inner chamber is replaced with plasma, and after this operation, the operation is returned to the normal operation. By performing such a cleaning liquid discharging operation, the amount of the cleaning liquid entering the return line side during the normal operation is equivalent to the volume of the outer chamber of the filter, and is reduced by the volume of the inner chamber.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows one of the devices used to carry out the plasma filtration method of the present invention.
It is a flowchart showing an example.

FIG. 2 is a schematic diagram for explaining the structure of the secondary filter in FIG.

FIG. 3 is a flowchart showing another example of the apparatus used for carrying out the plasma filtration method of the present invention.

 FIG. 4 is a flowchart for explaining the conventional method.

BEST MODE FOR CARRYING OUT THE INVENTION The plasma filtration method of the present invention is described below with reference to the accompanying drawings.

FIG. 1 shows one of the devices applied to carry out the plasma filtration method of the present invention.
4 is a flowchart showing an example, and portions common to the conventional device of FIG. 4 are indicated by common reference numerals.

The apparatus for implementing the present invention shown in FIG. 1 has a pressure detector 13 installed from the side of the secondary filter 8 on the plasma supply line 6 in addition to the configuration of the conventional apparatus shown in FIG. A waste liquid line 14 with a valve 14a connected to the inner chamber at the lower end of the filter 8 and open at the other end to the atmosphere, and one end connected to the plasma supply line 6 before the secondary filter 8 and the other end connected to the collecting line 17 A cleaning liquid supply line 15 with a valve 15a connected to the cleaning liquid supply source 18 via a valve, and a valve 16a having one end connected to the outer chamber at the upper part of the side wall of the secondary filter 8 and the other end connected to the cleaning liquid supply source 18 via the collecting line 17 A washing liquid supply line 16 is provided, and a valve 23 installed on the purified plasma return line 9 from the secondary filter 8 side.

The pressure detector 13 functions as a means for detecting a pressure rise limit value at the inlet of the secondary filter 8 based on an increase in the tendency of clogging, and as a means for detecting a pressure drop limit value in the inner chamber of the secondary filter 8. Works. Such pressure detection may be performed by the pressure detector 12 provided in the drip chamber 11 on the supply line 6 instead of the detector 13.

The waste liquid line 14 with the valve 14a functions as a means for opening the inner chamber to the atmosphere to lower the pressure, and as a means for discharging the cleaning waste liquid from the inner chamber to the outside of the system.

The cleaning liquid supply lines 15 and 16 with the valves 15a and 16a function as means for simultaneously cleaning the inside of the secondary filter 8 from both the inner and outer chambers after the pressure in the inner chamber drops.

The valve 23 on the return line 9 for the purified plasma is
In order to perform the pressure drop operation inside the line 9 while the line 9 is closed, the line 9 is kept open during normal operation.

FIG. 2 is a schematic diagram for explaining the structure of the secondary filter 8. The secondary filter 8 is usually a cellulose diacetate.
Thousands of hollow fibers (hollow fibers) made of fiber, polyvinyl alcohol, polyethylene, polypropylene, polysulfone, EVAL, PMMA (polymethyl methacrylate), PAN (polyacrylonitrile), etc.
In the figure, one of the hollow fibers 19 is enlarged and schematically shown for convenience. The hole diameter of the hollow fiber 19 is not particularly limited, and is usually selected from the range of 0.01 to 0.5 µ in consideration of the degree of plasma cooling. A hollow fiber is applied to the primary filter 3 as well as the secondary filter, and the hole diameter of the fiber is only required to be able to filter blood cells, and is suitably about 0.2 to 0.6 μm.

As shown by the thin arrow 20 in FIG. 2, during a normal plasma filtration operation, plasma is passed from the primary filter (see FIG. 1) through the plasma supply line 6 and the cooling coil section 7 on the line 6 to the plasma.
In the inner chamber portion 19a of the hollow fiber 19 with the built-in next filter 8,
That is, the filter 8 generally flows into the inner chamber 8a of the filter 8 at a flow rate of about 0.4 to 0.6 ml per second by a total.

In the plasma flowing into the lumen 19a, a gelled substance of a high molecular weight substance, a so-called cryogel is generated by cooling in the cooling coil section 7 and the secondary filter 8, and this cryogel is a thick section 19b of the fiber 19. Thick portion 19b when passing
And only the plasma component passes through the thick portion 19b. The plasma purified by passing through the thick portion 19b is separated from the thick portion 1b as usual.
It flows out of the outside 9b, that is, from the outer chamber 8b of the secondary filter 8 to the return line 9 connected thereto.

The cryogel captured by the thick portion 19b of the fiber 19 accumulates over time on the inside thereof and on the surface on the side of the cavity portion 19a, and the accumulation causes the inside of the cavity portion 19a of the fiber 19 and eventually the inside of the filter inner chamber 8a. The pressure gradually increases from 0 to 20 mmHg during normal operation, and this pressure increase is detected by the detector 13.

The pressure detected by the detector 13 is a limit value, for example, about 300 mmH
g, the valve 14a on the waste liquid line 14 changes from closed to open,
Therefore, the inner cavity portion 19a of the fiber 19, and thus the filter inner chamber 8a
The pressure inside drops to atmospheric pressure. Due to this pressure drop, the lumen 19a inside the thick portion 19b clogging is sandwiched.
Eventually, the filter inner chamber 8a and the filter outer chamber 8b outside thereof
And the purified plasma of the processing agent filled in the outer chamber 8b tends to flow back toward the inner chamber 8a due to the pressure difference. Is backwashed.

If the tendency of the backflow of the purified plasma spreads to the terminal side of the return line 9, the backflow of blood occurs at the purified blood return portion at the terminal side of the return line 9, which is not preferable. Such a tendency of the backflow of blood can be prevented by opening and closing the valve 23 on the return line 9 before the valve 14a on the line 14 is closed and opened.

The pressure drop in the inner cavity portion 19a and thus in the filter inner chamber 8a is detected by the detector 13, and at the same time as the pressure drop or with a slight time lag, the cleaning liquid supply line 16 connected to the filter outer chamber 8b side The valve 16a changes from closed to open. Therefore, the cleaning liquid is supplied from the supply source 18 to the collecting line 17 and the supply line.
For example, a pump is driven (not shown) into the outer chamber 8b through the sequence 16
Or it is supplied using a head. The supply of the cleaning liquid into the filter outer chamber 8b causes the thick portion 19b to be
Is backwashed. The back washing of the filter with the washing liquid is usually performed while the supply of the separated plasma to the secondary filter 8 is continued. During this back washing, the plasma sent from the line 6 into the secondary filter 8 is a waste liquid. Since the water is discharged out of the system through the line 14, the backwashing needs to be performed as quickly as possible in a short time. In addition, during the backwashing, the amount of plasma substantially corresponding to the amount of the washing solution is used in the lumen 9a (or the inner chamber).
Since it is discharged out of the system through the waste liquid line 14 from 8a), it is necessary to reduce the usage amount of the cleaning liquid as much as possible.

Furthermore, especially in the plasma cooling filtration method, the thick portion 19b
Since the filtration efficiency of the filter is better in the state where some amount of gliogel is present, the cryogel in the thick portion 19b will be lost if the amount of the cleaning liquid used is too large, and the filtration efficiency of the filter will be reduced at once. Would. However, when the amount of the cleaning solution used for back washing is reduced, the cryogel released from the thick portion 19b due to the back washing cannot be sufficiently and completely washed away. Incidentally, the plasma before treatment always flows in the lumen portion 19a by a total of 0.4 to 0.6 ml per second in total, but it is too small to wash out the cryogel.

Therefore, in the present invention, the cleaning liquid supply line 15 connected to the filter inner chamber 8a side at the same time as the valve 16a on the cleaning liquid supply line 16 for back cleaning is closed → open or with a time difference of about 2 to 3 seconds. Valve 15a is closed → open, and during backwashing,
Approximately the same amount of washing liquid as that for back washing is supplied from the line 15 through the plasma supply line 6 into the inner chamber 8a, that is, into the inner cavity 19a.

As shown by the bold arrow 22 in FIG. 2, the washing liquid flowing into the inner cavity 19a cooperates with the unprocessed plasma constantly flowing through the inner cavity 19a to remove the cryogel from the inner wall portion of the inner cavity 19a. It is discharged from the waste liquid line 14 outside the system while being washed away.

According to the present invention, the preliminary back washing of the treated plasma based on the pressure difference between the inner and outer chambers 8a and 8b and the simultaneous washing with the washing liquid from both the inner and outer chambers can be performed in a short time, for example, about 10 seconds. In addition, the amount of the cleaning liquid used is extremely small, and for example, clogging of the filter can be eliminated with a total usage of about 20 ml.

After the completion of the washing operation for a predetermined time, the on-off valves 14a, 15a, 16a on the lines 14, 15, 16 are changed from open to closed, while the valve 23 on the line 9 is changed from open to closed. Return.

The operation to clear the clogged filter is performed by the pressure detector 13.
Is repeated as a main index, and one plasma filtration operation is empirically performed about four times to eliminate clogging.

In the present invention, the amount of plasma discarded outside the system in one clogging operation is about 20 ml corresponding to the total amount of the washing solution.
And 4 to 6 ml of pre-processed plasma continuously sent (0.4 to
0.6 ml x 10 seconds), and the total amount is 24-26 ml.
The number of repetitions is 96 to 104 ml. This is 400-
Compared to 600 ml, it is much less, and the amount of plasma discarded outside the system can be reduced to about 1/5.

Even when the amount of the cleaning liquid used for one cleaning and the time for one cleaning are shorter than those described above, the same effect can be obtained by increasing the number of cleanings, and the amount of the cleaning liquid per one time can be slightly reduced. When the number of washings is increased, it can be dealt with by reducing the number of washings.

During the washing and regeneration of the secondary filter 8, the supply of plasma to the secondary filter may be continued or interrupted. As described above, when the supply of plasma to the secondary filter is continued, the driving of the pumps 1 and 5 can be continued even during the washing and regeneration operation.
Therefore, the trouble of stopping the driving of the pumps 1 and 5 for each cleaning and regenerating operation is eliminated. On the other hand, when the supply of the plasma is interrupted, the plasma is not supplied to the secondary filter 8 during the washing operation, so that the amount of loss of the plasma outside the system can be reduced.

In the present invention, an electromagnetic valve can be used as the valves 14a, 15a, 16a, and 23 in order to perform the cleaning and regeneration operation of the secondary filter 8 under automatic control. To briefly describe an example of automatic control, normal operation, that is, valves 14a, 15a, and 16a are closed and valve 2 is closed
3, when the pressure detector 13 detects the pressure rise limit value in the open state, receiving this detection signal, the valve 23 is opened → closed, the valve 14a is closed → open, and the pressure is released. When the detector 13 detects the pressure drop limit value by this pressure release, receiving this detection signal, the valves 15a and 16a are changed from the closed state to the open state, and the washing is started.
After a predetermined time elapses after the start of washing, the valves 14a, 15a, 16a are opened → closed by the action of a timer or the like, while the valve 23 is closed →
It opens and returns to normal operation.

FIG. 3 shows another example of an apparatus suitable for performing the plasma filtration method of the present invention.

The apparatus of the present invention shown in FIG. 3 includes, in addition to the depressurizing means and the washing means shown in FIG. 1, a plasma collecting means, a washing liquid discharging means, and a pre-treatment plasma circulating means.

The plasma collection means, after depressurizing the inner chamber of the secondary filter 8,
Before the washing operation, the plasma in the outer chamber of the secondary filter is collected on the return line 9 side.

After the secondary filter 8 has been washed and before returning to the normal operation, the washing liquid discharging means is provided for cleaning the remaining washing liquid in the inner and outer chambers.
This is for discharging the cleaning liquid in the inner chamber to the outside of the system.

The pre-treatment plasma circulating means is for circulating the plasma from the supply line to the return line 9 while the supply of the plasma to the secondary filter 8 is interrupted in the above various operations.

In order to configure the various means described above, in the apparatus shown in FIG. 3, in addition to the configuration of the apparatus shown in FIG. 1, a valve 24 installed on the plasma supply line 6 and a washing liquid pump 26 installed on the collecting line 17 are used. A bypass line 25 with a valve 25a connecting the supply line 6 to the return line 9 on the primary filter 3 side from the valve 24.
It has. Some components of the various means are shared.

One cycle of the washing and regenerating operation of the secondary filter 8 when performing the plasma filtration method of the present invention by applying the apparatus shown in FIG. 3 is as follows.

The open / close position of the valve during each operation in one cycle is as follows.

(During normal operation)

Open position: Valves 24, 23 Closed position: Valves 14a, 25a, 15a, 16a [During pressure release operation] Open position: Valves 24, 14 Closed position: Valves 23, 25a, 15a, 16a [During plasma collection operation] Open position … Valves 23, 25a, 15a Closed position… Valves 24, 14a, 16a [For cleaning operation] Open position… Valves 25a, 15a, 16a, 14a Closed position… Valves 24, 23 [For cleaning liquid discharge operation] Open position… Valve 24 , 14a closed position ... valves 25a, 15a, 16a, 23 Of the above operations, the depressurizing operation and the washing operation are substantially the same as those in FIG.

Hereinafter, the plasma collecting operation and the washing liquid discharging operation will be described with reference to FIG.

The plasma collection operation is performed with the valve 24 closed and the supply of the pre-processed plasma to the secondary filter 8 interrupted. In order to continue driving the pumps 1 and 5 during this interruption, the bypass line 25 is opened, and the plasma is circulated from the supply line 6 → the bypass line 25 → the return line 9.

On the other hand, the cleaning liquid is supplied from the line 15 into the inner chamber of the secondary filter 8 by the drive of the pump 26, and as the cleaning liquid is supplied,
The plasma in the inner and outer chambers is pushed out of the outer chamber into a return line 9 connected thereto and collected.

The supply of the washing liquid into the inner chamber is performed while the secondary filter 8 is clogged. However, since the washing liquid is usually physiological saline and has a lower viscosity than plasma, the inside of the clogged filter is removed from the inner chamber. Can pass to the room.

During the supply of the cleaning liquid to the inner chamber, when the pressure detector 13 detects the pressure rise limit value, the valve 14a is closed → opened without temporarily or without interrupting the supply of the cleaning liquid, What is necessary is just to perform a pressure relief operation.

The supply of the washing liquid into the inner chamber is continued until all the plasma into the inner and outer chambers is replaced with the washing liquid. Since the internal volume of the secondary filter 8 is known in advance, the end point of the replacement can be determined by measuring the flow rate with a flow meter (not shown) provided on the line 15, for example. When the replacement is completed, the washing operation is started as described above.

By replacing all the plasma in the inner and outer chambers with the washing solution and collecting it on the return line 9 side before starting the washing operation, the plasma disposal loss outside the system during the washing operation can be substantially eliminated.

Substantially all of the liquid remaining in the inner and outer chambers of the secondary filter 8 after the cleaning operation is the cleaning liquid. This is because the whole plasma was recovered from the inside and outside chambers by the replacement with the washing solution before the washing operation. Therefore, when the operation returns to the normal operation immediately after the cleaning operation, all the cleaning liquid in the inner and outer chambers enters the return line 9.

It is preferable that the amount of the cleaning liquid entering the return line 9 is as small as possible. For this purpose, the cleaning liquid is discharged following the cleaning operation.

During the cleaning liquid discharging operation, the valves 24 and 14a are open, and all other valves are closed. Therefore, during the plasma collection operation and the washing operation,
The plasma flowing to the bypass line 25 side enters the inner chamber of the secondary filter 8 by opening the valve 24, and the washing liquid is discharged from the waste liquid line 14 instead. Since the supply amount of plasma per second to the secondary filter 8 is known, after a predetermined time has elapsed and all the washing liquid in the inner chamber has been replaced with plasma, the valve 14a is opened by, for example, a timer or the like. Return to normal operation by closing → closing valve 23 → opening.

In the apparatus shown in FIG. 3, as in the case of FIG. 1, in order to automatically control the opening and closing of the valve at each operation,
A solenoid valve can be used as the valve.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hiroshi Kamogawa 96-1, Mitsuho, Matsumo-cho, Itano-gun, Tokushima Prefecture (56) References JP-A-59-11865 (JP, A) JP-A-63-127765 ( JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) A61M 1/02 540 A61M 1/34 500 A61M 1/36 540

Claims (6)

(57) [Claims] 1. A method according to claim 1, wherein the blood is separated into blood cells and plasma by a primary filter, and the separated plasma is led to a secondary filter via a supply line, and passes through the filter from an inner chamber to an outer chamber. In a plasma filtration device that filters and purifies high molecular weight substances as harmful components from plasma and purifies the purified plasma through a return line from a secondary filter and returns as blood while mixing with separated blood cells from the primary filter. Means for detecting the pressure rise limit value in the inlet of the secondary filter, means for detecting the pressure drop limit value in the inner chamber, and opening of the inner chamber to the atmosphere each time the means detects the pressure rise limit value. Means for lowering the pressure in the inner chamber, and means for supplying a cleaning liquid from the inner and outer chambers in the secondary filter each time the means detects a pressure drop limit value in the inner chamber. Plasma filtration characterized by Location. 2. A plasma filtering apparatus according to claim 1, further comprising a cooling zone for performing filtration of the plasma by a secondary filter in a cold state. 3. A return line for the purified plasma, which is closed when the pressure in the inner chamber of the secondary filter drops, and opened when the operation returns to normal operation.
3. The filtering device according to claim 1, further comprising a valve. 4. After the pressure drop in the inner chamber of the secondary filter, before the filter is washed, the plasma remaining in the outer and inner chambers of the filter is replaced with the washing liquid and collected on the return line side. Claim 1 characterized by comprising means
Item 4. The plasma filtration device according to any one of Items 3 to 3. 5. After the secondary filter has been washed, before returning to normal operation, a means for replacing the washing liquid in the inner chamber of the secondary filter with plasma sent from the supply line side and discharging it to the outside of the system is provided. The plasma filtration device according to claim 4, further comprising: 6. The apparatus according to claim 1, further comprising a bypass line for directly returning the plasma from the supply line to the return line while the supply of the pre-treatment plasma to the secondary filter is interrupted. 5. The plasma filtration device according to claim 4.