JPS636022B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ultrafiltration device using a molecular membrane. In the present invention, ultrafiltration refers to operations that involve separating all or most of cellular components such as red blood cells, white blood cells, and platelets from blood, as well as operations that include separating all or part of protein components such as globulin and albumin. say.

In recent years, various blood purification methods have been implemented to remove and treat toxic substances present in the blood of patients suffering from renal failure, liver failure, etc. Among these blood purification methods, there is a new type of treatment that uses a body fluid separation membrane with a pore size of 0.002 to 2μ to remove body fluids containing toxic substances, such as large amounts of water containing medium-molecular substances, or waste products from blood. By over-separating the blood plasma, etc., discarding the separated fluid, and remixing the blood with another body fluid that does not contain toxic substances or an artificial body fluid (hereinafter referred to as a replenishment fluid), A method of removing harmful substances from blood (post-dilution method), or a method of removing harmful substances by passing blood pre-diluted with replenisher (pre-dilution method)
is proposed. This method requires that the blood flow rate entering the diaphragm be substantially equal to the remixed blood flow rate, or to maintain a predetermined ratio for effective filtration. If it deviates or fluctuates significantly, the patient's circulating blood volume changes, which increases the burden on the patient's circulatory system, resulting in a very alarming situation.

Devices of this type have already been disclosed in Japanese Patent Application Laid-open Nos. 75093-1983 and 93899-1989. The former consists of a first weighing device that measures the weight of the liquid separated from blood and a second weighing device that measures the weight of the replenisher, and the quotient of the weights measured by the first and second weighing devices is always constant. It is configured to control the amount of liquid or replenisher so that the value of . The latter is configured to measure the total weight of the liquid and the replenisher using a weighing device, and to control the amount of liquid supplied so that the total weight always remains a preset constant weight.

The above-mentioned devices have high measurement accuracy and are suitable for this type of treatment because they use a balance, but all of them use a dummy method in which a weight is placed at one end of the balance and the weight of the weight is balanced against the weight of the liquid. Therefore, there is a possibility of measurement errors due to weights. Therefore, the measured liquid and the replenisher are not equivalent, resulting in cumulative errors and a disadvantage in that the amount of liquid and the amount of replenisher differ.

Furthermore, the former method has two weighing devices, while the latter method uses one weighing device to measure the added weight of the liquid and the replenisher, which has the disadvantage of increasing the size of the device. In particular, since the latter device uses an additive weight measurement method, the load applied to the fulcrum of the balance is large, so it is necessary to use a balance with high mechanical strength. On the other hand, in order to improve detection accuracy, it is also necessary to make this fulcrum sharp, and special consideration is required in setting to satisfy both requirements.

As a compact and easy-to-operate device that improves the drawbacks of the above-mentioned devices, a roller pump is used in each of the liquid circuit and the replenisher circuit, and the flow rate is controlled by the rotation speed of the pump, or a dual roller pump is used. A more compact device was published in Japanese Patent Application Publication No. 1986-
It is disclosed in No. 18199 and Japanese Unexamined Patent Publication No. 18475/1983.

However, it is known that, even if the rotational speed of the pump motor remains unchanged, the actual amount of liquid delivered during use of a roller pump decreases due to fatigue of the tube. Therefore, in an oversized artificial kidney device in which the ratio between the amount of fluid and the amount of replacement fluid must be maintained with high accuracy, it is dangerous to control the flow rate only by the rotation speed of the roller pump.

The present inventors have developed a device that eliminates the drawbacks of the above-mentioned devices using balances and devices using roller pumps. The present invention has been arrived at as a result of intensive study to provide an extrafiltration device. The present invention relates to an ultrafilter provided in an extracorporeal blood circulation circuit, a liquid outlet circuit connected to a liquid outlet of the ultrafilter to draw out a liquid, and a replenisher that draws out the replenisher from a replenisher storage means. A liquid drawn out from the liquid drawing circuit is collected in a liquid container attached to one end of the balance, and a liquid drawn out from the liquid drawing circuit is collected in a liquid container attached to the other end of the balance. a weighing device that collects and balances the replenisher from the replenisher; a fluid discharge circuit that discharges the fluid collected in the replenisher container; and a blood extracorporeal circulation circuit that discharges the replenisher collected in the replenisher container. a replenisher supply circuit that supplies the mixer and mixes with the ultrafiltered concentrated blood; a valve provided in each of the fluid derivation circuit, the replenisher derivation circuit, the fluid discharge circuit, and the replenisher supply circuit; A balance detector detects the balance of the balance, a liquid level detector detects the level of the liquid collected in the liquid container, and a valve installed in the liquid outlet circuit is opened in response to an external start command. and an ultrafiltration starting means for collecting the liquid passed through the ultrafilter into a liquid container, and a valve provided in the liquid derivation circuit in response to a detection signal from a liquid level detector provided in the liquid container. a replenisher collecting means which collects the replenisher into a replenisher container by closing the valve and opening a valve provided in the replenisher outlet circuit; In response to a detection signal from a balance detector that detects that the liquid has been removed, a valve installed in the liquid discharge circuit is opened to discharge the liquid collected in the liquid container.
a replenisher supply means for supplying replenisher to the mixer by closing a valve provided in the replenisher supply circuit and opening a valve provided in the replenisher supply circuit; A liquid that closes the valve installed in the liquid discharge circuit and opens the valve installed in the liquid lead-out circuit upon receiving a detection signal from the balance detector that detects when the liquid and replenisher are discharged and the balance is balanced. An ultraviolet device comprising collection means.

The novel idea of the present invention is to collect liquid and replenisher liquid in small quantities in containers provided at both ends of the balance and measure them while balancing them. With this idea, we were able to provide a device that does not have measurement errors caused by weights, which is a drawback of conventional weighing methods, that is, a device that keeps the replenisher volume and fluid volume equal, and a system that directly balances the replenisher and replenisher in small amounts. This made it possible to make weighing devices smaller and lighter.

Next, an embodiment of the ultraviolet device of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating the outline of the device of the present invention, which includes an ultrafilter 1 equipped with a body fluid separation membrane provided in an extracorporeal blood circulation circuit;
Weighing device 2 that weighs the amount of liquid and the amount of replenishment liquid little by little
The main part is a control device that automatically controls the supply or discharge of liquid to the device.

The ultrafilter 1 has a built-in body fluid separation membrane in the form of a hollow fiber, a flat membrane, or a tube. Such membranes are made of polysulfone, polyacrylonitrile,
polypropylene, polymethyl methacrylate,
There are membranes made of cellulose acetate, polycarbonate, polyvinyl alcohol, etc., and the pore size can be selected depending on the purpose of use. For example, as a membrane for an oversized artificial kidney that removes a large amount of water containing medium-molecular substances, a membrane that does not allow proteins with a molecular weight of 40,000 or more to permeate can be used. Further, as a blood separation membrane for separating plasma containing waste products, a membrane having a pore size of 0.05 μ to 1 μ can be used. The membranes are each housed between housings in a conventional manner.

The weighing device 2 is of a balance type, and can be used by modifying a commercially available experimental balance or the like. A container 5 for collecting liquid or replenisher and a replenisher container 6 are attached to both ends of the balance so as not to move. The liquid container 5 needs to have a shape that is easy to clean, and it is preferable to use a plastic container with an open top, for example. In addition, the replenisher container 6 needs to be disposable, inexpensive, and in a shape that does not allow dust to get in. For example, a sealed container is preferable, and polyethylene, polypropylene, polyvinyl chloride, polyvinyl alcohol, etc., which are harmless to living organisms, are used. Containers made of plastic or commercially available infusion packs made of polyvinyl can be used. It is preferable that the above-mentioned container be hung in order to make the point of action on the balance clear. In addition, in order to accurately control the ratio of liquid and replenisher, the smaller the volume of the container, the better, and usually 10c.c.
cc, preferably 20 c.c. to 30 c.c. containers. Although the volumes and weights of the liquid and replenisher containers may be different, it is preferable that each container has the same volume and weight to facilitate control of the ratio of each liquid.

Examples of the replenishing fluid include physiological saline, electrolyte solution, extracellular fluid replenishing fluid such as electrolyte-glucose solution, purified plasma, and the like.

A control device that detects the balance of the balance and controls the supply or discharge of the liquid or replenisher to each of the above containers based on the detection result to maintain a constant weight ratio between the amount of replenisher and the amount of liquid is outside the limit. A valve 7 provided in a liquid discharge circuit 50 that is connected to the liquid outlet of the filter 1 to draw out the liquid, a valve 8 provided in the liquid discharge circuit 23 that discharges the liquid collected in the liquid container, and a replenisher liquid storage. A valve 9 provided in a replenishment fluid deriving circuit 22 that draws out replenishment fluid from the means 51 and a replenishment fluid that is collected in a replenishment fluid container and supplied to a mixer 53 provided in an extra-blood circulation circuit 52 using a pump 4. A valve 10 provided in the liquid supply circuit 24 is opened and closed based on detection signals from a liquid level detector 11 that detects the level of the liquid collected in the liquid container 5 and a balance detector 12 that detects the balance of the balance. The amount of liquid and the amount of replenishment liquid are made equal.

The opening and closing of each of the above-mentioned valves is controlled by a control circuit 3 consisting of an ultraviolet starting means 55, a replenisher collecting means 56, a replenishing fluid supply means 57, and a liquid collecting means 58.
The valves 7 and 8 provided in the liquid derivation circuit 50 and the liquid discharge circuit 23 are preferably ON-OFF valves, and for example, direct-acting solenoid valves can be used. In addition, valves 9 provided in the replenisher supply circuit 22 and the replenisher supply circuit 24,
10 is a tube 22, 2 because the circuit is disposable.
A pinch-cock valve that closes the tube by compressing it from the outside of the tube is preferred because the tube can be easily replaced. Further, the circuits connected to the liquid and replenisher containers must be constructed so that the weight of the circuits is not added to the containers.
For example, as a countermeasure, a flexible tube or the like can be interposed in the circuit. The operation of the above-mentioned valve is controlled by a sequence control method consisting of a combination of a known relay circuit and a timer circuit, or a control method using a microcomputer, after detecting the liquid level of the liquid container and the balance of the balance.

The operation of the above control device will be explained with reference to FIG. The upper part of FIG. 2 shows changes in the weight of the liquid and replenisher containers, with the vertical axis representing weight and the horizontal axis representing time. Further, the solid line is the weight of the liquid container, and the chain line is the weight of the replenisher liquid container.
The lower part of FIG. 2 shows the operation of the control device corresponding to the liquid container.

When the main switch is turned on, all valves 7,
8, 9, and 10 are closed, and the pump 4 is driven.

(1) First, when the start button is pressed, an open signal is issued from the ultraviolet starting means 55 to the valve 7 provided in the liquid derivation circuit 50, and the valve opens and the liquid drawn out from the ultraviolet device 1 is released. , are collected in the liquid container 5.

(2) When a predetermined amount of liquid is collected in the container 5, the liquid level detector 11 provided in the container is activated. When the replenisher collecting means 56 operates in response to this signal, the valve 7 closes, and at the same time, the valve 9 provided in the replenisher deriving circuit 22 opens, and the replenisher is collected from the replenisher storage means 51 into the replenisher container 6. .

(3) When the balance detector 12 detects the balance between the weights of the replenisher containers attached to both ends of the balance and the replenisher containers in which the replenisher is collected, the replenisher supply means 57 is activated. Valve 9 closes, and at the same time valve 10 provided in replenisher supply circuit 24 closes.
is opened and the replenisher in the container is pumped into the mixer 5 by the pump 4.
Supply to 3. When the replenisher is discharged and the balance becomes unbalanced (the balance detector is released), the valve 8 provided in the liquid discharge circuit 23 opens and the liquid in the liquid container is discharged by a drop.

Further, in FIG. 2, the timer TM ₂ is operated simultaneously with the operation of the balance detector 12.
At the end of the timer operation, valve 10 closes. When the valve 10 is closed, a certain amount of replenisher remains in the container. (In this case, it is necessary to set the liquid discharge rate to be smaller than the replenishment liquid discharge rate.) (4) Balance is detected when the liquid is discharged until it balances with the amount of remaining replenishment liquid in the replenishment liquid container 6. vessel 12
detects the balance balance again, the liquid collecting means 58 is actuated to close the valve 8, and the timer TM ₁ is activated.
is activated to catch the end point. This timer can be omitted. At the same time as the timer ends, the valve 7 opens and the above-mentioned operations of liquid collection, replenishment liquid collection, liquid discharge, and replenishment liquid supply are repeated.

A specific example using the timer circuit and relay circuit of the above control device is shown in FIGS. 3 and 4. FIG. 3 is an explanatory diagram of the operation of the control device corresponding to FIG. 2,
FIG. 4 is a tangential expansion diagram of sequence control. In the figure, the valve 7 provided in the liquid introduction circuit 50 is
MV, valve 8 provided in the liquid discharge circuit 23 is MV', valve 9 provided in the replenisher introduction circuit 22 is PV, valve 10 provided in the replenisher supply circuit 24 is PV', liquid level detector
LA, balance detector PH, R ₀ , R ₁ , R ₂ ,
R ₃ and R ₄ are relays TM and timers. The operation of each valve based on a specific circuit can be further understood from these figures.

In order to operate as described above, the speed at which the liquid is introduced into the liquid container, the speed at which the liquid is discharged from the container,
It is necessary to change the rate of introduction of the replenisher into the replenisher container and the rate of supply of the replenisher from the container. That is, in the above description, the liquid introduction speed is set higher than the replenisher introduction speed, and the replenisher supply speed is set higher than the liquid discharge speed. The speed of such liquid or replenisher can be easily controlled by changing the flow path resistance, such as the opening of a valve or the inner diameter of the circuit.

The control device of the present invention is characterized in that the liquid and the replenisher are balanced twice and the replenisher remains in the container.
That is, in this method of collecting and balancing liquid in small quantities, a small error will occur in each measurement unless the liquid in the container is completely drained. Although such an error is small, if it is accumulated several dozen times, the cumulative error becomes large and poses a practical problem. Therefore, in the present invention, by leaving each liquid in the container during processing, it is possible to provide an apparatus with high accuracy in setting the ratio of liquid volume and replenishment liquid volume without cumulative errors.

In Fig. 1, there is only one weighing device, but since it takes time to process a large amount of blood, it is preferable to provide a plurality of weighing devices and to operate these devices every other two. .

FIG. 5 is a diagram showing a specific example of the device of the present invention,
In this figure, a dialysis device 30 with a built-in negative pressure pump used in hollow fiber type or keel type artificial kidneys is used as a liquid supply pump. Blood drawn from the patient's artery is passed through an ultrafilter 3. The liquid passed through the filter 3 is supplied to the weighing device 2 by a negative pressure pump of the dialysis device 30 through a flow meter 31 such as a rotameter. The flowmeter has upper, middle,
Liquid level detectors 32 such as phototubes are set at the bottom three locations, and the signals of the detectors are converted into voltages and a voltage comparator circuit 34 is used to link each liquid level detector with a valve 33 that adjusts the negative pressure. Change the supply amount. For example, when the flow rate increases and the rotameter's rotor rises and this rotor is detected by the upper detector, the negative pressure is lowered, and when the rotor falls and the lower detection part is activated, the negative pressure is increased to ensure that a predetermined amount of liquid is always maintained. can be supplied. The liquid supplied by the pump is collected in a liquid storage tank 35 and then supplied little by little to a liquid container 5 constituting a weighing device.
In the weighing device, the measured liquid is discharged into the container 36 as explained in FIG. On the other hand, bottle 3
The replenisher stored in the replenisher 7 and the like is supplied to the replenisher container 6 and measured, and then stored in the rectifier tank 38 and continuously sent to the mixer 39 by the metering pump 4. However, since the replenisher is measured in batches, if the same flow rate of replenisher is continuously pumped, the liquid level in the tank 38 will fluctuate. Therefore, unless the volume of the tank is increased, there is a risk that the tank will become empty or that the replenisher will overflow from the tank. However, increasing the size of the tank increases the size of the device, which is not preferable. Therefore, it is necessary to control the amount of liquid sent by the pump 4 so that the tank is small and a constant amount of replenisher is always stored in the tank. This control method can be controlled by a liquid level detector 40 that detects the liquid level in the tank at three locations (top, middle, and bottom) and a voltage comparison circuit 41 that interlocks the rotation speed of the pump 4, similar to the liquid supply method described above. . The replenishment fluid sent by the pump is mixed by the ultrafilter 3 with concentrated blood from which harmful substances have been removed in the mixer 39, and then returned to the patient's vein.

Further, when a required amount of water is removed from this system, a metering pump 43 is provided in the branch pipe 42 provided between the liquid discharge pump and the weighing device, and this can be done by driving the pump. When the water removal pump operates, the amount of the returned mixed liquid decreases by the amount of water removed from the amount of the liquid to be treated, and the blood concentration increases. Therefore, by operating the water removal circuit, it is possible to control the amount of the mixed liquid of blood and replenisher returned to the vein and the blood cell concentration thereof. Although the mixture of concentrated blood and replenisher may be reinjected intravenously as it is, it is preferable to warm it to near the patient's body temperature before intravenously injecting it. Such a warmer is, for example, one in which a tube is heated from the outside with a heater, or one in which a coiled flexible tube is housed between containers, and the liquid from the ultrafilter is guided into the container for heat exchange. Good too.

As described above, the device of the present invention collects and weighs the liquid and the replenisher in small amounts in containers provided at both ends of the balance, so it is a practically useful device with the following effects.

(1) Mutual equivalence is high because the replenisher is directly balanced with the liquid without using a dummy such as a weight.

(2) Since it uses a double balance method that detects the balance twice at the measurement start point and measurement end point, there is no measurement error caused by the liquid in the container.

(3) The device is small and lightweight because it collects and measures liquid in small quantities. Furthermore, since the mechanical load on the fulcrum of the balance is small, the balance is easy to manufacture and has high detection accuracy.

[Brief explanation of the drawing]

The drawings show one embodiment of the device of the present invention, and FIG. 1 is a diagram explaining the outline of the device of the present invention, FIG. 2 is a diagram explaining the operation of the control device that controls the weighing device, and FIG. 4 and 4 are diagrams illustrating a control device, and FIG. 5 is a diagram illustrating an embodiment of the apparatus of the present invention. 1... Ultrafilter, 2... Weighing device, 3... Control device, 4... Pump.

Claims (1)

[Claims] 1. An ultrafilter provided in the blood extracorporeal circulation circuit, a liquid outlet circuit connected to the liquid outlet of the ultrafilter to draw out the liquid, and a replenisher outlet circuit to draw out the replenisher from the replenisher storage means. Then, the liquid drawn out from the liquid lead-out circuit is collected in a liquid container attached to one end of the balance, and the liquid drawn out from the replenishment liquid lead-out circuit is collected in a replenishment liquid container attached to the other end of the balance. A weighing device that collects and balances the drawn out replenisher, a fluid discharge circuit that discharges the fluid collected in the replenisher container, and a blood extracorporeal circulation circuit that discharges the replenisher collected in the replenisher container. a replenisher supply circuit for supplying the replenisher to the ultrafiltered mixer and mixing it with the ultrafiltered concentrated blood, and valves provided respectively in the replenisher deriving circuit, the replenisher deriving circuit, the replenisher drain circuit and the replenisher supply circuit; , a balance detector that detects the balance of the balance, a liquid level detector that detects the level of the liquid collected in the liquid container, and a valve installed in the liquid outlet circuit in response to an external start command. An ultraviolet starting means that is opened and collects the liquid passed through the ultraviolet device into a liquid container, and a valve provided in the liquid derivation circuit in response to a detection signal from a liquid level detector provided in the liquid container. a replenisher collecting means that closes the replenisher and collects the replenisher into a replenisher container by opening a valve provided in the replenisher lead-out circuit; Upon receiving a detection signal from the balance detector that detects that the liquid has been removed, the valve installed in the liquid discharge circuit is opened to discharge the liquid collected in the liquid container, and the valve installed in the replenishment liquid output circuit is closed. Then, the valve provided in the replenisher supply circuit is opened, and the replenisher supply means supplies replenisher to the mixer, and the liquid container and the liquid in the replenisher container and the replenisher are discharged and the balance is balanced. An ultrafiltration device comprising a liquid collecting means that closes a valve provided in a liquid discharge circuit and opens a valve provided in a liquid derivation circuit in response to a detection signal from a balance detector that detects that the liquid has been discharged.