Patent Description:
In blood purification treatment called PA (Plasma Adsorption), DFPP (Double Filtration Plasmapheresis) or PE (Plasma Exchange), plasma is separated from blood of a patient, and then, purified plasma obtained by purifying the separated plasma or a replenishing liquid (a blood product such as fresh frozen plasma) is returned to the patient.

In blood purification devices for performing PA, DFPP or PE, plasma or a replenishing liquid remaining in a line through which plasma flows is generally recovered back to the patient while taking in air from a given position of the line after blood purification treatment (see, e.g., Patent Documents <NUM>-<NUM>). Further relevant prior art is for instance disclosed in Patent Documents <NUM>-<NUM>.

With the conventional blood purification devices, however, an alarm is generated in some cases because, e.g., excessive air is sent and air bubbles are detected by an air bubble detector located on a line for blood return to the patient. There are also cases where the plasma or replenishing liquid remains in the line due to insufficient air feed.

Therefore, it is an object of the invention to provide a blood purification device capable of recovering plasma or a replenishing liquid remaining in a line and also suppressing sending of air bubbles toward a patient after blood purification treatment.

A blood purification device according to the present invention comprises the technical features as defined in independent claim <NUM>. The blood purification device comprises: a chamber that is provided on a blood circuit for extracorporeally circulating patient's blood and configured to introduce purified plasma obtained by purifying plasma separated by a plasma separator provided on the blood circuit, or a replenishing liquid for replenishing the plasma separated by the plasma separator, into the blood circuit; a liquid feed line capable of sending the purified plasma or the replenishing liquid to the chamber; an air introduction unit capable of introducing air into the liquid feed line; a liquid level adjustment unit configured to be capable of adjusting a liquid level height in the chamber; and a control unit that is configured to, at an end of blood purification treatment, perform a liquid recovery process for sending the purified plasma or the replenishing liquid to the chamber via the liquid feed line while introducing air into the liquid feed line by the air introduction unit and maintaining the liquid level height in the chamber at a predetermined liquid level height by the liquid level adjustment unit.

The liquid level adjustment unit is configured to be capable of increasing the liquid level height in the chamber by discharging air from the inside of the chamber.

The blood purification device comprises a first liquid level detection sensor being provided at a first height position of the chamber and being capable of detecting whether or not a gas is present at the first height position in the chamber, wherein the control unit causes the liquid level adjustment unit to perform an operation of discharging air from the inside of the chamber when a gas is detected by the first liquid level detection sensor.

The blood purification device further comprises a second liquid level detection sensor being provided at a second height position of the chamber, which is higher than the first height position, and being capable of detecting whether or not a gas is present at the second height position in the chamber, wherein the control unit starts discharge of air from the inside of the chamber by the liquid level adjustment unit when a gas is detected by the first and second liquid level detection sensors, and stops the discharge of air by the liquid level adjustment unit when a gas is not detected by the first and second liquid level detection sensors.

The invention according to claim <NUM> is the blood purification device according to claim <NUM> comprising: a liquid feed pump capable of sending the purified plasma or the replenishing liquid to the chamber, wherein, during the liquid recovery process, the control unit is configured to drive the liquid feed pump while introducing air into the liquid feed line by the air introduction unit and is configured to maintain the liquid level height in the chamber at a predetermined liquid level height by the liquid level adjustment unit.

The invention according to claim <NUM> is the blood purification device according to claim <NUM>, wherein the liquid level adjustment unit comprises a level adjustment pump for discharging air from the inside of the chamber, and a discharge amount of the level adjustment pump is not less than a discharge amount of the liquid feed pump.

The invention according to claim <NUM> is the blood purification device according to claim <NUM> or <NUM>, wherein the liquid level adjustment unit comprises a level adjustment pump for discharging air from the inside of the chamber, and the control unit is configured to end the liquid recovery process by stopping the level adjustment pump and the liquid feed pump when an accumulated value of a rotation amount of the level adjustment pump becomes not less than a predetermined threshold.

The invention according to claim <NUM> is the blood purification device according to any one of claims <NUM> to <NUM>, wherein it is configured to discard the plasma separated by the plasma separator and introduce the replenishing liquid into the blood circuit, the liquid feed line comprises the replenishing liquid line for sending the replenishing liquid, and the liquid feed pump comprises a pump provided on the replenishing liquid line to send the replenishing liquid.

The invention according to claim <NUM> is the blood purification device according to any one of claims <NUM> to <NUM>, comprising: a plasma purifier for purifying plasma by adsorbing a specific component from the plasma separated by the plasma separator, wherein the liquid feed line comprises a purified plasma feed line for sending the purified plasma purified by the plasma purifier to the chamber, and the liquid feed pump comprises a waste liquid pump provided on a waste liquid line for sending the plasma separated by the plasma separator to the plasma purifier.

The invention according to claim <NUM> is the blood purification device according to any one of claims <NUM> to <NUM>, comprising: a plasma purifier for purifying plasma by separating a specific component from the plasma separated by the plasma separator, wherein the liquid feed line comprises a purified plasma feed line for sending a mixture of the purified plasma purified by the plasma purifier and the replenishing liquid to the chamber, and the liquid feed pump comprises a pump for sending the replenishing liquid to the plasma purifier.

The invention according to claim <NUM> is the blood purification device according to any one of claim <NUM> or <NUM>, wherein the liquid level adjustment unit comprises an atmosphere release valve allowing an interior of the chamber to be opened to atmosphere, and the control unit is configured to increase the liquid level height in the chamber by opening the atmosphere release valve and blocking the blood circuit on a downstream side of the chamber.

According to the invention of claim <NUM>, it is possible to provide a blood purification device capable of recovering plasma or a replenishing liquid remaining in a line and also suppressing sending of air bubbles toward a patient after blood purification treatment.

According to the invention of claim <NUM>, it is possible to maintain the liquid level height in the chamber even if air is sent into the chamber.

According to the invention of claim <NUM>, it is possible to maintain the liquid level height in the chamber in a given height range and to suppress frequent activation/stoppage of the liquid level adjustment unit.

According to the invention of claim <NUM>, it is possible to easily send the purified plasma or the replenishing liquid to the chamber and to easily introduce air into the liquid feed line.

According to the invention of claim <NUM>, it is possible to suppress sending of air bubbles toward the patient regardless of the delayed actuation of the level adjustment pump.

According to the invention of claim <NUM>, it is possible to appropriately determine end time of the liquid recovery process.

According to the invention of claims <NUM>, <NUM> and <NUM>, a pump used in another application can be used as the liquid feed pump in case of performing PE, PA or DFPP, and the device can be reduced in size as compared to when separately providing a liquid feed pump.

According to the invention of claim <NUM>, it is possible to omit the level adjustment pump and to reduce the size and cost of the device.

An embodiment of the invention will be described below in conjunction with the appended drawings.

<FIG> is a schematic configuration diagram illustrating a blood purification device in the present embodiment. A blood purification device <NUM> shown in <FIG> is a device for performing blood purification treatment called PE (Plasma Exchange) and is configured to discard plasma separated by a plasma separator <NUM> and introduce a replenishing liquid for replenishing the plasma separated by the plasma separator <NUM> (a blood product such as fresh frozen plasma or albumin preparation) into a blood circuit <NUM>.

The blood purification device <NUM> includes a chamber <NUM> that is provided on the blood circuit <NUM> for extracorporeally circulating patient's blood and supplies a replenishing liquid (fresh plasma) to the blood circuit <NUM>, a replenishing liquid line <NUM> as a liquid feed line <NUM> for sending the replenishing liquid, a total replacement pump <NUM> as a liquid feed pump <NUM> capable of sending the replenishing liquid, and a waste liquid line <NUM> for discharging the plasma separated by the plasma separator <NUM> provided on the blood circuit <NUM>.

The blood circuit <NUM> is composed of, e.g., a flexible tube, etc. An artery-side puncture needle <NUM> is provided at one end of the blood circuit <NUM>, and a vein-side puncture needle <NUM> is provided at the other end. In addition, a first pressure detector <NUM>, a blood pump <NUM>, a second pressure detector <NUM>, the plasma separator <NUM>, the chamber <NUM> and an air bubble detector <NUM> are sequentially provided on the blood circuit <NUM> from the artery-side puncture needle <NUM>-side toward the vein-side puncture needle <NUM>-side. The first pressure detector <NUM> is to detect pressure in the blood circuit <NUM> on the upstream side of the blood pump <NUM>, and the second pressure detector <NUM> is to detect pressure in the blood circuit <NUM> on the downstream side of the blood pump <NUM>. The air bubble detector <NUM> has an air bubble detection sensor for detecting air bubbles and a mechanism for clamping (gripping and blocking) the blood circuit <NUM> when air bubbles are detected.

The blood pump <NUM> is composed of a peristaltic pump that squeezes the tube to cause blood to flow toward the plasma separator <NUM>. The plasma separator <NUM> is a device also called a dialyzer and separates plasma from blood by a membrane (not shown). The blood (blood cells, etc.) after separation of plasma by the plasma separator <NUM> is sent to the chamber <NUM>. Meanwhile, the plasma separated by the plasma separator <NUM> is discharged into the waste liquid line <NUM>. The chamber <NUM> serves to remove air bubbles and also serves to introduce (join) the replenishing liquid into the blood circuit <NUM>. A pressure sensor <NUM>b is connected to an upper part of the chamber <NUM> via a hydrophobic filter <NUM>a.

An anticoagulant introduction line <NUM>a for introducing an anticoagulant from a syringe pump <NUM> is connected to the blood circuit <NUM> between the second pressure detector <NUM> and the plasma separator <NUM>. A check valve <NUM>b is provided on the anticoagulant introduction line <NUM>a so that blood flowing through the blood circuit <NUM> does not flow into the anticoagulant introduction line <NUM>a.

The replenishing liquid line <NUM> is composed of, e.g., a flexible tube, etc. One end of the replenishing liquid line <NUM> is connected to a replenishing liquid bag <NUM> storing the replenishing liquid. The other end of the replenishing liquid line <NUM> is connected to the chamber <NUM>. A replenishing liquid shortage detector <NUM>, a replenishing liquid transfer pump <NUM>, a replenishing liquid subdivision chamber <NUM>, the total replacement pump <NUM>, a warmer <NUM> and a check valve <NUM> are sequentially provided on the replenishing liquid circuit <NUM> from the replenishing liquid bag <NUM>-side toward the chamber <NUM>-side.

The replenishing liquid shortage detector <NUM> is to detect shortage of the replenishing liquid. The replenishing liquid transfer pump <NUM> is a pump for transferring the replenishing liquid stored in the replenishing liquid bag <NUM> to the replenishing liquid subdivision chamber <NUM>. The replenishing liquid subdivision chamber <NUM> is a chamber for temporarily storing the replenishing liquid. The total replacement pump <NUM> is a pump for sending the replenishing liquid stored in the replenishing liquid subdivision chamber <NUM> toward the chamber <NUM>. The warmer <NUM> warms the replenishing liquid. The check valve <NUM> is a valve for suppressing the backflow of the liquid from the blood circuit <NUM>-side toward the replenishing liquid line <NUM>. The replenishing liquid transfer pump <NUM> and the total replacement pump <NUM> are each composed of a peristaltic pump that squeezes the tube to cause the replenishing liquid to flow.

The waste liquid line <NUM> is composed of, e.g., a flexible tube, etc. One end of the waste liquid line <NUM> is connected to the plasma separator <NUM> and the other end serves as a discharge port <NUM> for discharging a waste liquid. A blood leakage detector <NUM>, a third pressure detector <NUM>, a waste liquid pump <NUM>, a waste liquid subdivision chamber <NUM> and a waste liquid transfer pump <NUM> are sequentially provided on the waste liquid line <NUM> from the plasma separator <NUM>-side toward the discharge port <NUM>.

The blood leakage detector <NUM> is a detector for detecting whether a component other than plasma, such as blood cells, is leaking toward the waste liquid line <NUM> due to damage, etc., on the plasma separator <NUM>. The third pressure detector <NUM> is a detector for detecting pressure in the waste liquid line <NUM> on an inlet side of the waste liquid pump <NUM>. The waste liquid pump <NUM> sends the plasma separated by the plasma separator <NUM> (the waste liquid) to the waste liquid subdivision chamber <NUM>. The waste liquid subdivision chamber <NUM> is to temporarily store the plasma (the waste liquid). The waste liquid transfer pump <NUM> is a pump for transferring the plasma (the waste liquid) stored in the waste liquid subdivision chamber <NUM> to the discharge port <NUM>. The waste liquid pump <NUM> and the waste liquid transfer pump <NUM> are each composed of a peristaltic pump that squeezes the tube to cause the plasma (the waste liquid) to flow.

The blood purification device <NUM> also includes a load meter <NUM> for detecting a total weight of the replenishing liquid subdivision chamber <NUM> and the waste liquid subdivision chamber <NUM>. The blood purification device <NUM> repeats a first step in which the replenishing liquid stored in the replenishing liquid bag <NUM> is transferred to the replenishing liquid subdivision chamber <NUM> by the replenishing liquid transfer pump <NUM> and the plasma (the waste liquid) stored in the waste liquid subdivision chamber <NUM> is discharged by the waste liquid transfer pump <NUM>, and a second step in which the replenishing liquid stored in the replenishing liquid subdivision chamber <NUM> is supplied toward the chamber <NUM> and the plasma (the waste liquid) from the plasma separator <NUM> is accumulated in the waste liquid subdivision chamber <NUM>. In the second step, the weight detected by the load meter <NUM> is constant when a supply amount of the replenishing liquid and a discharge amount of the plasma (the waste liquid) are equal. Therefore, in the blood purification device <NUM>, rotational speeds (discharge amounts) of the total replacement pump <NUM> and the waste liquid pump <NUM> are controlled so that the weight detected by the load meter <NUM> in the second step is constant.

Each of the pumps <NUM>, <NUM>, <NUM>, <NUM>, <NUM> is controlled by a control unit <NUM>. The control unit <NUM> is realized by appropriately combining an arithmetic element such as CPU, a memory, a storage device, a software, and an interface, etc..

The blood purification device <NUM> further includes an air introduction unit <NUM> that can introduce air into the replenishing liquid line <NUM> during the liquid recovery process. In the present embodiment, the air introduction unit <NUM> is configured to be able to introduce air into the replenishing liquid line <NUM> by pulling one end of the replenishing liquid line <NUM> out of the replenishing liquid bag <NUM> (see <FIG>). However, the specific configuration of the air introduction unit <NUM> is not limited thereto, and the configuration may be such that, e.g., air is introduced from the replenishing liquid subdivision chamber <NUM>. Alternatively, the air introduction unit <NUM> may be configured to push air into the replenishing liquid line <NUM> by, e.g., an air pump, etc..

The blood purification device <NUM> in the present embodiment includes a liquid level adjustment unit <NUM> capable of adjusting a liquid level height in the chamber <NUM>. At the end of the blood purification treatment, the control unit <NUM> performs a liquid recovery process for sending the replenishing liquid to the chamber <NUM> via the liquid feed line <NUM> by driving the liquid feed pump <NUM> (the total replacement pump <NUM> here) while supplying air into the replenishing liquid line <NUM> by the air introduction unit <NUM> and maintaining the liquid level height in the chamber <NUM> at a predetermined liquid level height by the liquid level adjustment unit <NUM>.

<FIG> is an explanatory diagram illustrating flows of air and the replenishing liquid in the blood purification device <NUM> during the liquid recovery process. As shown in <FIG>, in the present embodiment, the total replacement pump <NUM> as the liquid feed pump <NUM> is driven during the liquid recovery process while introducing air into the replenishing liquid line <NUM>. Thus, the replenishing liquid in the replenishing liquid line <NUM> is replaced with air, and the replenishing liquid remaining in the replenishing liquid line <NUM> is sent to the chamber <NUM>. In the present embodiment, both the total replacement pump <NUM> and the replenishing liquid transfer pump <NUM> are driven since the air is not sent toward the chamber <NUM> if the replenishing liquid transfer pump <NUM> remains stopped.

At this time, if excessive air is sent, the liquid level in the chamber <NUM> is lowered and air bubbles may flow toward the air bubble detector <NUM>. Therefore, in the present embodiment, the liquid level height in the chamber <NUM> is maintained at a predetermined liquid level height by the liquid level adjustment unit <NUM> during the liquid recovery process to suppress flow of air bubbles to the downstream side of the chamber <NUM> (the air bubble detector <NUM> side).

The liquid level adjustment unit <NUM> is configured to be capable of increasing the light level height in the chamber <NUM> by discharging air from the inside of the chamber <NUM>. In the present embodiment, the liquid level adjustment unit <NUM> has a level adjustment pump <NUM> for discharging air from the inside of the chamber <NUM>. The level adjustment pump <NUM> is connected to the chamber <NUM> via an air discharge line <NUM>. A clamp <NUM> capable of blocking the air discharge line <NUM> is provided on the air discharge line <NUM>.

The blood purification device <NUM> also includes a first liquid level detection sensor <NUM> that is provided at a first height position of the chamber <NUM> and is capable of detecting whether or not a gas is present at the first height position in the chamber <NUM>. The control unit <NUM> controls the liquid level adjustment unit <NUM> so that the liquid level height does not become lower than the first height. In particular, when a gas is detected by the first liquid level detection sensor <NUM>, the control unit <NUM> drives the level adjustment pump <NUM> to cause it to perform an operation of discharging air from the inside of the chamber <NUM>.

In the present embodiment, a second liquid level detection sensor <NUM> is further included, which is provided at a second height position of the chamber <NUM>, which is higher than the first height position, and is capable of detecting whether or not a gas is present at the second height position in the chamber <NUM>. The control unit <NUM> controls the liquid level adjustment unit <NUM> so that the liquid level height is between the first height and the second height. In particular, the control unit <NUM> starts discharge of air from the inside of the chamber <NUM> by driving the level adjustment pump <NUM> when a gas is detected by the first and second liquid level detection sensors <NUM>, <NUM>, and stops the discharge of air by stopping the level adjustment pump <NUM> when a gas is not detected by the first and second liquid level detection sensors <NUM>, <NUM>. Thus, it is possible to suppress frequent activation/stoppage of the level adjustment pump <NUM> and thereby suppress a load on the level adjustment pump <NUM>.

Optionally, a liquid level detection sensor for continuously measuring the liquid level height in the chamber <NUM> may be provided. In this case, based on the detection result from the liquid level detection sensor, the blood purification device <NUM> determines whether or not the liquid level height in the chamber <NUM> is higher than the first height position and whether or not the liquid level height in the chamber <NUM> is lower than the second height.

The level adjustment pump <NUM> is composed of a peristaltic pump that squeezes the tube to cause the air to flow. The replenishing liquid transfer pump <NUM> and the total replacement pump <NUM> continue to be driven during the liquid recovery process, but the level adjustment pump <NUM> is actuated at the middle of the process and thus cannot avoid a slight delay in air discharge. To cover this delay, the discharge amount (the pump speed) of the level adjustment pump <NUM> is desirably not less than the discharge amount (the pump speed) of the liquid feed pump <NUM> (the total replacement pump <NUM>), and further desirably, the discharge amount (the pump speed) of the level adjustment pump <NUM> is more than the discharge amount (the pump speed) of the liquid feed pump <NUM> (the total replacement pump <NUM>). In addition, the liquid level may be adjusted by driving the level adjustment pump <NUM> in a state in which the liquid feed pump <NUM> is stopped (the discharge amount (the pump speed) of zero). Furthermore, the liquid feed pump <NUM> may be repeatedly driven and stopped intermittently. In this case, the discharge amount (the pump speed) of the level adjustment pump <NUM> should be more than an average value of the discharge amount of the liquid feed pump <NUM>.

After a predetermined time by which the operation of the level adjustment pump <NUM> is considered to be stabilized has elapsed, the discharge amount (the pump speed) of the level adjustment pump <NUM> may be controlled to be equal to the discharge amount (the pump speed) of the liquid feed pump <NUM> (the total replacement pump <NUM>). In other words, the discharge amount (the pump speed) of the level adjustment pump <NUM> may be controlled to be greater than the discharge amount (the pump speed) of the liquid feed pump <NUM> (the total replacement pump <NUM>) for a predetermined time from the start of driving, and controlled to be equal to the discharge amount (the pump speed) of the liquid feed pump <NUM> (the total replacement pump <NUM>) after the predetermined time has elapsed. Although the example in which the discharge amount of the level adjustment pump <NUM> is changed has been described here, the discharge amount (the pump speed) of the level adjustment pump <NUM> may be controlled to be not less than the discharge amount (the pump speed) of the liquid feed pump <NUM> (the total replacement pump <NUM>) by changing (decreasing) the discharge amount of the liquid feed pump <NUM> (the total replacement pump <NUM>).

The level adjustment pump <NUM> is also provided with a rotation amount detection unit capable of detecting the rotation amount thereof. As the rotation amount detection unit, it is possible to use, e.g., an encoder, etc. When a stepping motor is used for driving the level adjustment pump <NUM>, it is possible to know the rotation amount also based on the number of pulses output to the stepping motor.

The control unit <NUM> calculates an accumulated value of the rotation amount of the level adjustment pump <NUM> based on the detection result from the rotation amount detection unit, and ends the liquid recovery process by stopping the level adjustment pump <NUM> and the liquid feed pump <NUM> when the accumulated value of the rotation amount becomes not less than a predetermined threshold. At this time, both the total replacement pump <NUM> and the replenishing liquid transfer pump <NUM> are stopped. Meanwhile, the blood pump <NUM> continues to be driven to suppress blood coagulation. When the number of revolutions of the level adjustment pump <NUM> can be regarded constant, the liquid recovery process may be ended by stopping the level adjustment pump <NUM> and the liquid feed pump <NUM> when operating time of the level adjustment pump <NUM> becomes not less than a predetermined threshold.

Now, a control flow of the liquid recovery process will be described. <FIG> is a flowchart showing the control flow of the liquid recovery process. The liquid recovery process is performed at the end of the blood purification treatment.

In the liquid recovery process, firstly, air is introduced into the liquid feed line <NUM> (the replenishing liquid line <NUM>) by the air introduction unit <NUM> in Step S<NUM>, as shown in <FIG>. In the present embodiment, air is introduced into the replenishing liquid line <NUM> by pulling one end of the replenishing liquid line <NUM> out of the replenishing liquid bag <NUM>. At this time, both the total replacement pump <NUM> and the replenishing liquid transfer pump <NUM> are in the operating state.

After that, in Step S<NUM>, the control unit <NUM> determines whether a gas is detected by the first liquid level detection sensor <NUM>. When the determination made in Step S<NUM> is NO, the process returns to Step S<NUM>. When the determination made in Step S<NUM> is YES, the level adjustment pump (LAP) <NUM> is driven in Step S<NUM> to start discharge of air from the inside of the chamber <NUM>.

After that, in Step S<NUM>, the control unit <NUM> determines whether a gas is detected by the second liquid level detection sensor <NUM>. When the determination made in Step S<NUM> is NO, the level adjustment pump <NUM> is stopped in Step S<NUM> and the process then returns to Step S<NUM>. When the determination made in Step S<NUM> is YES, the level adjustment pump <NUM> continues to be driven in Step S<NUM> and it is then determined in Step S<NUM> whether the accumulated value of the rotation amount of the level adjustment pump <NUM> has become not less than the predetermined threshold. When the determination made in Step S<NUM> is NO, the process returns to Step S<NUM>.

When the determination made in Step S<NUM> is YES, the level adjustment pump <NUM> and the liquid feed pump <NUM> are stopped in Step S<NUM>. In the present embodiment, both the total replacement pump <NUM> and the replenishing liquid transfer pump <NUM> are stopped. After that, the process ends.

Although the liquid level adjustment unit <NUM> is composed of the level adjustment pump <NUM> in the present embodiment, the specific configuration of the liquid level adjustment unit <NUM> is not limited thereto. The liquid level adjustment unit <NUM> may be, e.g., an atmosphere release valve allowing the interior of the chamber <NUM> to be opened to atmosphere. In this case, the control unit <NUM> increases the liquid level height in the chamber <NUM> by sending plasma using the liquid feed pump <NUM> while opening the atmosphere release valve and blocking the blood circuit <NUM> on the downstream side of the chamber <NUM>. Blocking of the blood circuit <NUM> on the downstream side of the chamber <NUM> may be achieved by, e.g., using a clamp of the air bubble detector <NUM> or providing a dedicated clamping device or an on/off valve, etc. Since such a configuration allows the level adjustment pump <NUM> to be omitted, it is possible to simplify the device and reduce the size and cost of the device.

When the atmosphere release valve is used as the liquid level adjustment unit <NUM> and the blood circuit <NUM> is blocked by using the clamp of the air bubble detector <NUM>, the atmosphere release valve is opened in response to detection by the first liquid level detection sensor <NUM> and, after the clamp of the air bubble detector <NUM> is operated (after the blood circuit <NUM> is blocked), the liquid feed pump <NUM> is stopped being driven on condition that the accumulated value of the rotation amount of the liquid feed pump <NUM> has reached a specified value.

As described above, the blood purification device <NUM> in the present embodiment is configured that, during the liquid recovery processing, the replenishing liquid is sent to the chamber <NUM> via the liquid feed line <NUM> while introducing air into the liquid feed line <NUM> by the air introduction unit <NUM> and the liquid level height in the chamber <NUM> is maintained at a predetermined liquid level height by the liquid level adjustment unit <NUM>.

With such a configuration, it is possible to recover the replenishing liquid remaining in the liquid feed line <NUM> and also to suppress sending of air bubbles toward the patient after blood purification treatment. As a result, generation of an alarm due to detection of air bubbles by the air bubble detector <NUM> is suppressed during the liquid recovery process and it is thus possible to reduce burden on workers.

A blood purification device <NUM>a shown in <FIG> is a device for performing blood purification treatment called PA (Plasma Adsorption). The same members as those of the blood purification device <NUM> shown in <FIG> are denoted by the same reference numerals in <FIG> and the description of these members will omitted.

In the blood purification device <NUM>a, a detachable connector <NUM> is provided at the most upstream of the waste liquid line <NUM> (in the vicinity of the plasma separator <NUM>) and the air introduction unit <NUM> is configured to be able to introduce air into the waste liquid line <NUM> by detaching the connector <NUM>. The air introduction unit <NUM>, however, is not limited thereto and may be configured to introduce air by, e.g., opening a port of the plasma separator <NUM> on the opposite side to a plasma output side or may be configured to introduce air into a chamber <NUM>a of a secondary membrane pressure port <NUM> (described later).

In addition, the waste liquid line <NUM> of the blood purification device <NUM>a is configured that the plasma separated by the plasma separator <NUM> is sent to a plasma purifier (a selective-type plasma component adsorber) <NUM>. An end of the waste liquid line <NUM> on the opposite side to the plasma separator <NUM> is connected to the plasma purifier <NUM>. The plasma purifier <NUM> is also called a selective-type plasma component adsorber which adsorbs a specific component from the plasma separated by the plasma separator <NUM> and thereby purifies the plasma.

The secondary membrane pressure port <NUM> is provided on the waste liquid line <NUM> between the plasma purifier <NUM> and the waste liquid pump <NUM>. The secondary membrane pressure port <NUM> has the chamber <NUM>a and a pressure sensor <NUM>c provided on the chamber <NUM>a via a hydrophobic filter <NUM>b. The secondary membrane pressure port <NUM> serves to separate air bubbles from plasma to be introduced into the plasma purifier <NUM> and also serves to measure pressure on an inlet side of the plasma purifier <NUM>.

The purified plasma purified by the plasma purifier <NUM> is sent to the chamber <NUM> through a purified plasma feed line <NUM>. The warmer <NUM> for warming the purified plasma and the check valve <NUM> are provided on the purified plasma feed line <NUM>.

In the blood purification device <NUM>a, the waste liquid pump <NUM> is used as the liquid feed pump <NUM> for sending the purified plasma and air during the liquid recovery process. In more particular, the blood purification device <NUM>a is configured that, during the liquid recovery process, the connector <NUM> is detached to allow air to be introduced and the waste liquid pump <NUM> is driven. Thus, the plasma in the waste liquid line <NUM>, the plasma purifier <NUM> and the purified plasma feed line <NUM> is replaced with air and the purified plasma is recovered back to the patient.

In addition, in the blood purification device <NUM>a, the liquid level height in the chamber is maintained at a predetermined liquid level height by the liquid level adjustment unit <NUM> during the liquid recovery process in the same manner as the blood purification device <NUM> described above. In particular, the control unit <NUM> starts discharge of air from the inside of the chamber <NUM> by driving the level adjustment pump <NUM> when a gas is detected by the first and second liquid level detection sensors <NUM>, <NUM>, and stops the discharge of air by stopping the level adjustment pump <NUM> when a gas is not detected by the first and second liquid level detection sensors <NUM>, <NUM>. The control unit <NUM> also calculates the accumulated value of the rotation amount of the level adjustment pump <NUM> and ends the liquid recovery process by stopping the level adjustment pump <NUM> and the liquid feed pump <NUM> (the waste liquid pump <NUM> here) when the accumulated value of the rotation amount becomes not less than the predetermined threshold.

A blood purification device <NUM>b shown in <FIG> is a device for performing blood purification treatment called. The blood purification device <NUM>b is a device for performing blood purification treatment called DFPP (Double Filtration Plasmapheresis).

The blood purification device <NUM>b includes a plasma purifier <NUM> for purifying plasma by further separating a specific component from the plasma separated by the plasma separator <NUM>. The plasma purifier <NUM> is also called a plasma component separator and is configured so that only a specific component (a normal component) of plasma is extracted and added to the replenishing liquid by bringing the replenishing liquid into contact with the plasma through a membrane.

The blood purification device <NUM>b is similar to the blood purification device <NUM>a of <FIG> but is configured that the plasma purifier <NUM> and a second waste liquid pump <NUM> are sequentially provided on the waste liquid line <NUM> on the downstream side of the secondary membrane pressure port <NUM> and the other end of the waste liquid line <NUM> serves as the discharge port <NUM> for discharging the waste liquid (the plasma). In addition, the purified plasma feed line <NUM> is provided so as to connect a replenishing liquid outlet of the plasma purifier <NUM> to the chamber <NUM>. Furthermore, the replenishing liquid line <NUM> extending from the replenishing liquid bag <NUM> is branched into two, one of branches is connected to a replenishing liquid inlet of the plasma purifier <NUM> via a pre-replacement pump <NUM> and the other branch is connected via the total replacement pump <NUM> to the purified plasma feed line <NUM> on the downstream side of the plasma purifier <NUM>. In the blood purification device <NUM>b, the purified plasma and the replenishing liquid are mixed and sent to the chamber <NUM> through the purified plasma feed line <NUM>.

The air introduction unit <NUM> of the blood purification device <NUM>b is also configured to be able to introduce air into the replenishing liquid line <NUM> by pulling one end of the replenishing liquid line <NUM> out of the replenishing liquid bag <NUM> in the same manner as the blood purification device <NUM> of <FIG>. In addition, in the blood purification device <NUM>b, the pre-replacement pump <NUM> is used as the liquid feed pump <NUM> for sending the purified plasma and air during the liquid recovery process. The air introduced by the air introduction unit <NUM> is sent to the chamber <NUM> through the replenishing liquid line <NUM>, the pre-replacement pump <NUM>, the plasma purifier <NUM> and the purified plasma feed line <NUM>, and the purified plasma and the replenishing liquid are recovered.

In addition, in the blood purification device <NUM>b, the liquid level height in the chamber is maintained at a predetermined liquid level height by the liquid level adjustment unit <NUM> during the liquid recovery process in the same manner as the blood purification device <NUM> described above. In particular, the control unit <NUM> starts discharge of air from the inside of the chamber <NUM> by driving the level adjustment pump <NUM> when a gas is detected by the first and second liquid level detection sensors <NUM>, <NUM>, and stops the discharge of air by stopping the level adjustment pump <NUM> when a gas is not detected by the first and second liquid level detection sensors <NUM>, <NUM>. The control unit <NUM> also calculates the accumulated value of the rotation amount of the level adjustment pump <NUM> and ends the liquid recovery process by stopping the level adjustment pump <NUM> and the liquid feed pump <NUM> (the pre-replacement pump <NUM> here) when the accumulated value of the rotation amount becomes not less than the predetermined threshold.

Although the embodiments of the invention have been described, the invention according to claims is not to be limited the embodiments described above. In addition, all combinations of the features described in the embodiments are not necessary to solve the problem of the invention as defined by the apended claims.

Claim 1:
A blood purification device (<NUM>; 1a; 1b) comprising:
a chamber (<NUM>) that is provided on a blood circuit (<NUM>) for extracorporeally circulating patient's blood and configured to introduce purified plasma obtained by purifying plasma separated by a plasma separator (<NUM>) provided on the blood circuit, or a replenishing liquid for replenishing the plasma separated by the plasma separator, into the blood circuit;
a liquid feed line (<NUM>) capable of sending the purified plasma or the replenishing liquid to the chamber;
an air introduction unit (<NUM>) capable of introducing air into the liquid feed line;
a liquid level adjustment unit (<NUM>) configured to be capable of adjusting a liquid level height in the chamber and configured to be capable of increasing the liquid level height in the chamber by discharging air from the inside of the chamber;
a control unit (<NUM>) that is configured to, at an end of blood purification treatment, perform a liquid recovery process for sending the purified plasma or the replenishing liquid to the chamber via the liquid feed line while introducing air into the liquid feed line by the air introduction unit and maintaining the liquid level height in the chamber at a predetermined liquid level height by the liquid level adjustment unit;
a first liquid level detection sensor (<NUM>) being provided at a first height position of the chamber and being capable of detecting whether or not a gas is present at the first height position in the chamber,
wherein the control unit causes the liquid level adjustment unit to perform an operation of discharging air from the inside of the chamber when a gas is detected by the first liquid level detection sensor; and
a second liquid level detection sensor (<NUM>) being provided at a second height position of the chamber, which is higher than the first height position, and being capable of detecting whether or not a gas is present at the second height position in the chamber,
wherein the control unit starts discharge of air from the inside of the chamber by the liquid level adjustment unit when a gas is detected by the first and second liquid level detection sensors, and stops the discharge of air by the liquid level adjustment unit when a gas is not detected by the first and second liquid level detection sensors.