JPS58343B2 - Blood “filtration” type artificial kidney device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hemofiltration type artificial kidney device that processes and regenerates blood filtrate by removing urea and other toxic substances from the blood filtrate by adsorption.

The purpose of the present invention is to (1) greatly reduce the amount of so-called replacement fluid required and (2) make operation management extremely simple compared to the method of processing blood filtrate in conventional hemofiltration artificial kidney devices. Finally, the present invention provides a hemofiltration type artificial kidney device that is highly safe.

The hemofiltration type artificial kidney device is superior to the dialysis type artificial kidney device in terms of its ability to remove medium-molecular weight toxic substances from the patient's body fluids, and is therefore expected to be developed in the future.

However, in the hemofiltration method, a dialysate is not used, but a so-called replacement fluid (also called a dilution fluid) having a volume approximately equal to the volume of the hemofiltrate is used.

) must be added to the patient's blood.

Replacement fluid is an aqueous solution similar to a physiological saline solution that has approximately the same osmotic pressure as blood and contains various ions in concentrations approximately equal to those in blood.

The required amount of replacement fluid is 40 to 6 when added to blood before filtration.
When added to blood after filtration, it is about 20 degrees.

Unlike dialysate, replacement fluid is added directly to the patient's blood, so it must be free of toxic impurities and must be completely sterilized.

Therefore, it is more expensive than a dialysate solution in which chemicals are dissolved in tap water, and it is desirable that the amount required be as small as possible.

If the blood filtrate were processed to remove toxic substances and then returned to the patient's blood vessels, there would theoretically be no need for fluid replacement, and various ideas have been made regarding this.
Nothing has been put into practical use yet.

If an adsorbent such as activated carbon is used, it is relatively easy to remove creatinine, uric acid, middle-molecular toxic substances, etc. from blood filtrate, but it is difficult to remove urea using conventional simple adsorption methods.

In addition, various ions in the blood filtrate are also adsorbed and their concentration becomes lower than the concentration in the captured water, so there is a problem that the concentration must be corrected by adding them to the blood filtrate.

The present inventor has completed the present invention as a result of various studies in view of these circumstances, and the above-mentioned problems can be solved by applying the present invention.

That is, the hemofiltration type artificial kidney device according to the present invention uses one or more adsorption tanks filled with a replacement fluid and an adsorbent that has reached an adsorption equilibrium with the composition of the replacement fluid in advance to collect the blood filtrate from the filter. The blood filtrate is regenerated and treated by passing it through the adsorption tank to reduce the concentration of toxic substances such as urea contained in the blood filtration, and to prevent useful components of the blood filtrate other than toxic substances from being adsorbed by the adsorbent. It will happen as you do it.

However, it has been found that although the above-mentioned objectives (1) and (2) can be achieved with only such a configuration, it is difficult to achieve the objective (2).

Therefore, in the blood filtration artificial kidney device having the above-mentioned configuration, the present inventor made all the components that come into contact with blood, the filter, and the blood filtrate, including the adsorption tank, the filter, etc., disposable.

This technical idea uses a plurality of adsorption tanks filled with a replacement fluid and an adsorbent that has reached an adsorption equilibrium with the composition of the replacement fluid, and one of the adsorption tanks is sequentially selected by switching a valve.
The blood filtrate discharged from the filter is passed through the blood filtrate, and the amount of toxic substances adsorbed by a unit amount of adsorbent changes over time depending on the concentration of toxic substances such as urea in the blood filtrate. In order to process and regenerate the blood filtrate, the amount is increased in the adsorption tank used, and gradually decreased in the adsorption tanks used thereafter, and the active components of the blood filtrate other than toxic substances are not adsorbed by the adsorbent. The present invention can also be applied directly to a blood filtration type artificial kidney device.

In a hemofiltration artificial kidney device, in general, the filter and the replacement fluid, and in the case of the device of the present invention, the filter, the blood filtrate, and the replacement fluid are injected into the patient's blood vessels.
The inside of the device must be kept sterile at all times.

Therefore, the components that come into contact with the blood, the filter, and the blood filtrate must be thoroughly cleaned and sterilized before use, which is a time-consuming and tedious process.

Furthermore, even if cleaning and sterilization are carried out while ignoring these drawbacks, if adsorption tanks or valves with complex internal structures are used, it will not be possible to completely clean and sterilize them. difficult.

Of course, in the case of the former, it is possible to make the pipe connecting the adsorption tank and other parts removable with a joint, thereby making the adsorption tank disposable.

However, since valves are expensive, it is economically difficult to make them disposable.

Therefore, as a result of further research, the present inventor found that one of the plurality of adsorption tanks in the hemofiltration type artificial kidney device
When the blood filtrate is sequentially switched and used, an elastic soft tube is used as a blood filtrate conduit at the inlet and outlet of the adsorption tank, and the soft tube is closed and removed by compressing it mechanically using pure mechanical or electromagnetic force. It was made to open by pressing.

Next, the configuration of the present invention will be explained in detail based on the drawings.

FIG. 1 is a system explanatory diagram of an example of a hemofiltration type artificial kidney device to which the present invention is applied.

Blood continuously drawn from the patient's artery through conduit 1 is pressurized by blood pump 2, enters filter 4, and is filtered.

The filter containing blood cells and molecules with a molecular weight higher than protein exits the filter 4 and is passed through a conduit 18, a pressure regulating valve 19, and a mixer 20.
The mixture is mixed with the adsorption-treated blood filtrate described below.

3 is a pressure gauge. On the other hand, the blood filtrate exiting the filter 4 passes through a conduit 5, a filtrate part 6 equipped with a sterilization filter and communicating with the atmosphere, and a conduit 7, and is pressurized by a filtrate pump 8, and then a phosphorus compound removal tank 10 filled with alumina etc. The phosphorus compound is removed.

Next, toxic substances such as urea, uric acid, and creatinine are adsorbed in one or more adsorption tanks 11 via a conduit 12 and a switching valve 13, and then passed through a switching valve 13 and a conduit 14 into a dust removal filter/deaeration tank 15. Adsorbent debris and air bubbles are removed and mixed with the filter exiting the filter 4 in a mixer 20 via conduit 16.

The filter mixed with the blood filtrate passes through the conduit 21, is pressurized by the blood pump 2, and is delivered through the conduit 21 into the patient's vein.

If the blood pump 2 is a roller type, the two tubes on the blood extraction side and the blood inlet side are squeezed at the same rotation speed, so the flow rate of the blood on the extraction side and the donor blood is kept almost equal. However, two pumps may be used separately for the extraction surface and the donor blood, or other types such as a diaphragm type may also be used.

The adsorption tank 11 is filled with a replacement fluid and an adsorbent whose adsorption equilibrium has been reached in advance with the composition of the replacement fluid.

Moreover, by making the concentration of useful components such as various ions in the replacement fluid approximately equal to those in the blood filtrate after equilibrium is achieved, the useful components in the blood filtrate are not adsorbed by the adsorbent, and are absorbed by urea and uric acid. Only toxic components such as , creatinine, and medium molecular weight substances are adsorbed.

Activated carbon is the most economical adsorbent, and among these, synthetic resin-based adsorbents are the best in terms of not producing coal dust, followed by coconut shell-based adsorbents.

Although one adsorption tank 11 may be used, it is better to use a plurality of adsorption tanks and sequentially switch one of them to pass the blood filtrate for adsorption, compared to simply using one adsorption tank. This reduces the amount of adsorbent and replacement fluid required.

The reason for this is that the concentration of toxic substances such as urea in blood filtrate is highest at the beginning of filtration and then gradually decreases. Due to the adsorption equilibrium relationship, the amount of urea, etc. in the blood filtrate increases as the concentration thereof in the blood filtrate increases, so it is greatest in the adsorption tank used initially, and less in the adsorption tank used later.

On the other hand, if only one adsorption tank is used, the amount of urea etc. adsorbed by a unit amount of adsorbent will not exceed the equilibrium concentration with the final concentration of urea etc. in the blood filtrate. This is because a larger amount of adsorbent is required than switching and using one adsorbent one after another, and the amount of replacement fluid filled into the adsorption tank increases accordingly.

The switching valve used when multiple adsorption tanks are used may be manually operated at appropriate intervals, but the timer 17
It is convenient to use a solenoid valve 13 operated by a solenoid valve 13.

In this case, an ordinary solenoid valve may be used, but in order to save the trouble of cleaning and sterilizing after each use, a soft elastic conduit is closed by mechanical compression and opened by removal. It is even more convenient to use a solenoid valve.

An example of the structure of such a solenoid valve will be explained with reference to FIG.

An elastic soft conduit 23 is passed between a valve seat 24 fixed to a mounting washer 30 and a movable piece 25 attached to a movable rod 26.

Normally, the movable rod 26 is attached to a spring 29 fixed to a mounting washer 30.
Since the movable piece 25 is in a position where it does not press the conduit 23, the conduit 23 is open.

When an electric current is passed through the electromagnet 27, the iron piece 28 attached to the movable rod 26 is attracted to the electromagnet 27, so that the movable piece 25 compresses the conduit 23, and the conduit 23 is closed.

Note that if such a solenoid valve is used, it is also possible to open and close the inlet and outlet of one adsorption tank at the same time.

Furthermore, automatic valves that open and close such conduits by removing pressure and compression can also be operated purely mechanically without using electromagnetic force.

Reference numeral 9 in FIG. 1 is a detachable joint, and by separating the phosphorus compound removal tank and the adsorption tank 11 from other parts, the adjustment operation of the contents of the phosphorus compound removal tank 10 and the adsorption tank 11 can be performed in blood filtration operation. In addition, the phosphorus compound removal tank 10 and the adsorption tank 11
make it possible to make it disposable.

Although it is possible to use an ordinary valve or a pressure reducing valve as the pressure regulating valve 19, in order to save the trouble of cleaning and sterilizing the valve, it is preferable to use a manual valve that compresses an elastic soft conduit, such as a so-called screw cock. It is better to use a valve.

Note that by adjusting the opening degree of such a valve, it is also possible to automatically adjust the pressure of the blood filtrate at the outlet of the filter 4.

The blood filtration type artificial kidney device according to the present invention as shown in FIG. If it is disposable, it will be extremely convenient as it will save you the trouble of cleaning and sterilizing it during use.

For example, in FIG. 1, a filter 4, a filtrate section 6, a phosphorus compound removal tank 10, an adsorption tank 11, a dust removal filter and deaeration tank 15, a mixer 20, various conduits 1, 5, 7, 12, 14, 1
6, 21, etc. can be disposed of all at once while being connected to each other.

In this case, before use, the blood pump 2, filtrate pump 8, pressure regulating valve (in this case, screw cock)
19. Preparation for use is completed by simply fitting the elastic soft conduits into mechanical parts such as the automatic switching valve 13.

The data of experiments conducted using the blood filtration type artificial kidney device according to the present invention are as follows.

Simulated body fluid (hereinafter referred to as body fluid).

), using a replacement fluid with the composition shown in Table 1, containing 2.279 g/L of urea and 0.2 g/L of creatinine as toxic substances.
L, uric acid 0.192g/L, phosphoric acid (as phosphorus) 0
．． 30 L of the solution dissolved at a concentration of 0.094 g/L was placed in a storage tank, which was connected to the apparatus shown in FIG. 1 through conduits 1 and 21, body fluid was filtered instead of blood, and the filtrate was treated by adsorption.

The filter used was a hollow type with a membrane area of 3.5 m, through which body fluid was poured at a rate of 300 ml/mm, and the filtrate volume was 100 ml/mm.
mm.

Six adsorption tanks with an internal volume of 1 L were used, and each adsorption tank contained 500 g of activated carbon (coconut shell, bulk density 0.50 g/cm2, true density 2 g/cm2) and the composition after reaching adsorption equilibrium with the activated carbon in advance. was filled with 750 ml of replacement fluid as shown in Table 1, and the filtrate was passed through one of the six adsorption tanks, which was switched every hour, to adsorb toxic substances in the filtrate at a temperature of 30°C.

Table 2 shows the concentrations of urea, creatinine, and uric acid in the mud at the inlet of each adsorption tank, measured hourly (just before switching).
g/L) and the urea adsorption amount (g) of each adsorption tank.

The amount of each toxic substance adsorbed is the largest in the No. 1 adsorption tank, gradually decreases, and is the smallest in the No. 6 adsorption tank.

If we use one adsorption tank instead of six adsorption tanks to reduce the final concentration of toxic substances in the filtrate after 6 hours to the same level as in this experimental example, the amount of toxic substances adsorbed on 1 kg of activated carbon Since the amount of toxic substances is about the same as in the No. 6 adsorption tank in this experimental example, the total amount of activated carbon required is 4.2 kg, which is about 40% more than in the case of this experiment. As in the case of this experiment, one of the multiple adsorption tanks
It turns out that it is more advantageous to sequentially switch and use them.

Phosphoric acid is hardly adsorbed by activated carbon, so in this experiment the slurry was passed through a phosphorus compound removal tank filled with 300g of alumina to remove it, but about 90% of the phosphoric acid in the filtrate was removed. did it.

Na+, Ni+, Ca++ in body fluids (in mud).

No changes were observed in the concentrations of ions such as Mg++ and C1- within the experimental error range.

This is considered to be natural because the composition of the activated carbon and the replacement fluid were brought into adsorption equilibrium in advance.

Since the present invention has the configuration as described above, the above-mentioned various points
can be achieved, and has high practical value.

[Brief explanation of the drawing]

Fig. 1 is a system explanatory diagram of an example of a blood p-filtration type artificial kidney device that processes blood slurry by adsorption to which the present invention is applied;
The figure shows a cross-sectional explanatory view of an example of a solenoid valve used in the present invention. In the figure, 4...filter, 11...adsorption tank, 13...switching valve. (5)

Claims (1)

[Scope of Claims] 1. Using one or more adsorption tanks filled with a replacement fluid and an adsorbent whose adsorption equilibrium has been reached in advance with the composition of the replacement fluid, blood p fluid discharged from a filter is passed through the adsorption tank. In this way, the concentration of toxic substances such as urea contained in the blood filtrate is reduced, and the blood filtrate is treated and regenerated by preventing active components of the blood filtrate other than toxic substances from being adsorbed by the adsorbent. A hemofiltration artificial kidney device, characterized in that all components that come into contact with blood, the filter, and blood filtrate, including the adsorption tank, filter, etc., are disposable. 2 Using a plurality of adsorption tanks filled with a replacement fluid and an adsorbent whose adsorption equilibrium has been reached in advance with the composition of the replacement fluid, the blood discharged from the filter is sequentially transferred to one of the plurality of adsorption tanks by switching a valve. The amount of toxic substances adsorbed to a unit amount of adsorbent is large in the adsorption tank used initially, and then In a hemofiltration type artificial kidney device that processes and regenerates blood filtrate by gradually decreasing the amount in the adsorption tank used and preventing active components of the blood filtrate other than toxic substances from being adsorbed by the adsorbent. A hemofiltration type artificial kidney device, characterized in that all components that come into contact with blood, the filter, and blood filtrate, including the adsorption tank, filter, etc., are disposable. 3. When one of a plurality of adsorption tanks is sequentially switched and used, an elastic soft tube is used as a conduit for the blood filtrate at the inlet and outlet of the adsorption tank, and the soft tube is connected using pure mechanical or electromagnetic force. The hemofiltration type artificial kidney device according to claim 2, wherein the device is closed by mechanical compression and opened by removing pressure.