JPH0628122Y2 - Baking soda dialysis machine - Google Patents

Description

[Detailed Description of the Invention] "Industrial field of application" This invention relates to a baking soda dialysis device that uses a hemodialysis technique such as a so-called artificial kidney and mixes an acetic acid dialysis stock solution and a baking soda dialysis stock solution into a dialysis solution. .

"Prior Art" A conventional baking soda dialysis device will be described with reference to FIG.

FIG. 5 shows an example of a personal dialysis machine. Water (treated water) is introduced from the water supply port 1, passes through the heating / deaeration tank 2, and is then introduced into the first mixing tank 3. On the other hand, B as the first stock solution
Liquid (Sodium bicarbonate: NaHCO ₃ liquid) is B liquid tank 4
Is introduced into the first mixing tank 3 by the liquid B pump 5 and mixed and diluted with the water at a constant ratio. This B liquid concentration is measured as an electric conductivity by the first densitometer 6 provided at the mixing tank outlet line. The diluted solution of the liquid B that has left the first densitometer 6 is subsequently introduced into the second mixing tank 7. A liquid A (a liquid containing components other than bicarbonate ions such as sodium acetate and sodium chloride) is introduced into the second mixing tank 7 from a liquid A tank 8 by a liquid A pump 9 as a second stock liquid to dilute the liquid B. The final dialysate is prepared by mixing with the liquid in a fixed ratio. The concentration of this final dialysate is measured by the second densitometer 10 as the electric conductivity, as in the case of the first densitometer 6. After this, the dialysate passes through the temperature measuring unit 11 and is then supplied to the dialyzer 13 via the first liquid stop valve 12.

The dialysate in contact with the extracorporeal circulation blood in the dialyzer 13 passes through the second liquid stop valve 14, and then is drained from the drain port 18 via the blood leak meter 16 and the dialysate pump 17. The inlet line of the first liquid stop valve 12 and the second liquid stop valve 14
A bypass valve 15 is provided between the outlet line and the outlet line. Although this bypass valve 15 is normally closed, it is released when the dialysate concentration is abnormal and the dialysate temperature is abnormal, and at the same time, the first and second liquid stop valves 12 and 14 are closed to bring the abnormal dialysate to the dialyzer 13. It is not supplied.

"Problems to be solved by the invention" Conventional dialysis has a uniform dialysate composition, and most of them are acetic acid dialysis. However, in addition to acetic acid dialysis, as the number of cases of dialysis patients increases and the dialysis performance of dialysis machines improves,
Baking soda dialysis and high sodium dialysis are performed. In particular, sodium bicarbonate dialysis has come to be widely used for patients with acetic acid intolerance as well as patients with asthma acetate and other accidents. Unlike conventional acetic acid dialysis, baking soda dialysis is used by diluting two types of stock solutions, solution A and solution B. Regarding the order of this dilution, in the conventional example, the solution B is diluted and then mixed with the solution A, but this order varies depending on the manufacturer of the dialysis machine. Therefore, it is not possible to deny the possibility that the operator mistakes the A liquid and the B liquid, but there are some cases where the operator actually made the mistake. If the dialysis facilities of the same manufacturing company use the same dialysis machine, this error is thought to be almost nonexistent. I have to say that the possibility is high.

When liquid A and liquid B are used interchangeably, the composition of ions other than sodium ions (calcium ion, potassium ion, bicarbonate ion, etc.) deviates greatly from the normal value, resulting in imbalance syndrome, hemolysis, disturbance of consciousness, etc. Occurs,
In severe cases, death may occur. Despite this situation, no measures were taken against this problem in the example of baking soda dialysis equipment.

In most of the conventional examples, the one detected as the conductivity is converted into the sodium ion concentration. For concentration control, the value of the sodium ion concentration calculated from the conductivity is fed back so that the first concentration meter 6 and the second concentration meter 10 have the B solution pump 5 and the solution concentration A, respectively, so that the concentration becomes a predetermined concentration. In many cases, the liquid pump 9 is controlled to set the respective mixing ratios in the first mixing tank 3 and the second mixing tank 7 to predetermined values. Since both liquid A and liquid B contain sodium ions, no warning will be given if liquid A and liquid B are mixed up, and only the sodium ions will be set to the specified value when they are mixed up. The device works to match.

As a means for preventing such a dangerous state, one-handed dropping is serious by simply calling the dialysis operator's attention and sticking a label on the device so as not to mix them up.
Moreover, medical litigation has become more commonplace in recent years, and the responsibility of manufacturing companies has become heavier. Therefore, even if a mistake is made, it is essential that the device quickly detect it, issue an alarm, and stop the supply of dialysate to the dialyzer.

[Means for Solving the Problem] According to the present invention, as means for detecting a misunderstanding between the liquid A and the liquid B, means for measuring the hydrogen ion concentration of the diluting liquid,
Means for measuring the carbon dioxide partial pressure of the diluent, means for calculating the bicarbonate ion concentration from these two measured values, means for storing the normal bicarbonate ion concentration of the diluent, and bicarbonate ion by the above calculation The sodium bicarbonate dialysis device is provided with a comparing means for comparing the concentration with the normal bicarbonate ion concentration.
Further, when the comparing means determines that the calculated bicarbonate ion concentration deviates from the normal bicarbonate ion concentration, means for issuing an alarm and stopping the supply of dialysate to the dialyzer are provided.

"Embodiment" First Embodiment An embodiment of the present invention is shown in FIG. The same parts as those in FIG. 5 are designated by the same reference numerals, and the duplicate description will be omitted.

In the present embodiment, the mixing order of the liquid B and the liquid A is the same as the conventional example. That is, the first stock solution is the solution B, and the second stock solution is
This is the case where the solution A is used as the stock solution. In FIG. 1, a measuring tank 19 for measuring the hydrogen ion concentration of the diluting liquid and the carbon dioxide gas partial pressure is provided in the flow path immediately after the first concentration meter 6, and the hydrogen ion concentration measuring electrode 20 and the carbon dioxide are measured in the measuring tank 19. The gas partial pressure measuring electrode 21 is incorporated. The hydrogen ion concentration measuring electrode 20 (details not shown) is a compound electrode composed of a reference electrode and a thermistor in addition to the measuring electrode composed of ISFET (ion sensitive FET), but its specific description is known. Therefore, it is omitted here. Further, the carbon dioxide partial pressure measuring electrode 21 (details not shown) surrounds the pH-ISFET and the silver / silver chloride reference electrode with a porous hollow fiber as an internal liquid (NaCl + NaHCO ₃ ) holding body, and the outside thereof is gas. The permeable membrane is covered with a silicon tube, but its detailed description is omitted here because it is known as is the case with the hydrogen ion electrode. Further, the data of each unit is input to the control unit 30 and each unit is controlled by the control unit 30.

FIG. 2 is a block system diagram showing the main part of this embodiment. A microcomputer is used for the control unit 30, and a CPU is used.
The (central processing unit) 31 decodes the system program stored in the ROM (read only memory) 32 and controls it. A control program for the whole dialysis machine is stored in the ROM 32, and the hydrogen ion concentration measuring electrode 20 (FIG. 1) of the diluting liquid and the carbon dioxide gas partial pressure measuring electrode 21 of the diluting liquid are measured.
When the signals from (Fig. 1) are taken in, the bicarbonate ion concentration of the diluting solution is calculated by these two signals, the calculation result is compared with the normal bicarbonate ion concentration, and the A solution and the B solution are confused. Of an alarm based on the comparison result in the first liquid stop valve 12, the second liquid stop valve 14, the bypass valve 1
A program for controlling 5 is also included therein. I
The / O 35 receives signals from the CPU 31 and exchanges inputs and outputs. In this embodiment, the first liquid stop valve 12, the second liquid stop valve 14, and the bypass valve 1 are connected via a drive circuit 36.
In case of mistakenly driving A liquid and B liquid, warning light 4
0 and the buzzer 41 are driven.

The original signals of the hydrogen ion concentration and the carbon dioxide gas partial pressure measured by the hydrogen ion concentration measuring electrode 20 and the carbon dioxide gas partial pressure measuring electrode 21 of the diluting liquid are the hydrogen ion concentration measuring circuit 38 in the control unit 30, the carbon dioxide gas, respectively. The partial pressure measuring circuit 39 adjusts the signal levels so that they can be post-processed.

These adjusted signals are converted into digital signals by the A / D converter 37 and stored in the RAM (random write / read memory) 33 via the CPU 31.

The control program stored in the ROM 32 is classified into a background routine and an interrupt routine generated every 0.1 seconds by the timer 34. Regarding the bicarbonate ion concentration of the diluting solution in the normal case, in the commercially available dialysate, it is 27.5 to 30.0 mEq / l, and in this example, it has a width of 20.0 to 37.5 mEq / l in the normal range. And is stored in the ROM 32.

FIG. 3 shows A / D conversion of the measurement signal of the diluent hydrogen ion concentration, the measurement signal of the diluent carbon dioxide gas, the calculation of the bicarbonate ion concentration of the diluent by the two converted signals, and the normal value of the calculation result. 7 is a flowchart showing an interrupt routine for comparing and determining with.

In the timer interrupt routine that is generated every 0.1 seconds by the timer 34, first, the registers of the CPU 31 used in the background routine are saved in the stack (S1).
After that, the A / D converter 37 performs A / D conversion on the signal indicating the hydrogen ion concentration pH of the diluting liquid and the signal indicating the carbon dioxide partial pressure PCO ₂ (S2 to S3), and these converted data are obtained. Is stored in the RAM 33 (S4).

After that, the CPU 31 calculates the bicarbonate ion concentration HCO ₃ ⁻ of the diluting liquid from the two converted data. Regarding this calculation, basically the Henderson-Hass in the acid-base equilibrium is calculated.
Formula conforming to formula elbach (1), pH = 6.1 + log [(HCO ₃ ^-)
/(0.03×PCO ₂ )] (1) is modified to obtain the equation (2), HCO ₃ ⁻ = 0.031 × PCO ₂ × 10 ^(pH-6.1) (2). A few other formulas have been proposed as the formula for obtaining the bicarbonate ion concentration, but the calculation results are similar, so the formula (2) was adopted in this example.

The CPU 31 calculates the bicarbonate ion concentration of the diluting liquid according to the above formula (2).
After determining (mEq / 1) (S5), the normal bicarbonate ion concentration range from the ROM 32 (20.0 to 37.5 mEq / in this embodiment).
1) is read (S6) and compared with the calculation result (S6)
7). As a result of comparison, the calculated value is within the normal range (20.0 ≤ (HCO
₃ ^-) when in ≦ 37.5) is bicarbonate ion concentration of the diluted solution was determined to be normal, and resets the A liquid · B liquid mix-up flag (S8). Conversely, the calculated value is outside the normal range ((HCO
₃ ^-) <20.0 or (HCO ₃ ^-)> If there 37.5) is, A
It is judged that the liquid and the liquid B are mixed up, and the liquid A / liquid B mixed up flag is set (S9). Then, the registers of the CPU 31 saved in the stack in step S1 are restored (S1
0), the interrupt routine of is ended.

Next, in the background routine shown in FIG. 4, the liquid A set / reset in the interrupt routine
The state of the B liquid mistaking flag is checked, and an alarm corresponding thereto is generated, the first liquid stop valve 12, the second liquid stop valve 14,
Also, the bypass valve 15 is controlled.

In the background routine, first, the state of the A / B liquid mix up flag is checked (S1).

If the flag is set, the CPU 31
The warning light 40 is turned on via the O35 and the drive circuit 36,
The buzzer 41 is sounded (S2), the first liquid stop valve 12 and the second liquid stop valve 14 are closed, and the bypass valve 15 is opened (S3).

If the flag is reset in step S1, the warning light 40 is not turned on and the buzzer 41 is not sounded (S4).
It is clear that the first liquid stop valve 12 and the second liquid stop valve 14 are opened and the bypass valve 15 is closed (S5).

Now, in FIG. 1 of the present embodiment, when the liquid A and the liquid B are mistaken, the liquid B tank 4 and the liquid A tank 8 are replaced with each other.

In this case, since water and liquid A are mixed in the first mixing tank 3, the liquid after passing through the first densitometer 6 does not contain bicarbonate ions at all. Therefore, the carbon dioxide gas partial pressure measuring electrode 21 only measures a very small amount of dissolved carbon dioxide gas in the diluent,
It is clear that it does not fall within the normal range (20.0-37.5 mEq / 1).

Second Embodiment A second embodiment of the present invention will be described below. As in the first embodiment, this embodiment is an example of a personal dialysis apparatus, but the mixing order of the liquid A and the liquid B is opposite to that in the first embodiment. In other words, this is the case where the A solution is used as the first stock solution and the B solution is used as the second stock solution. Therefore, the figure will be described by referring to FIG. 1 as it is.
The liquid tank is the liquid A tank, the liquid A tank 8 is the liquid B tank,
The description will be made by substituting the solution B pump 5 and the solution A pump 9 for the solution A and the solution B, respectively.

Now, in the second embodiment, when both liquids A and B are normally mixed,
In the first mixing tank 3, water and liquid A are added, and in the second mixing tank 7, water +
Solution A and solution B are mixed. Therefore, the solution in the hydrogen ion concentration / carbon dioxide partial pressure measuring tank 19 contains no bicarbonate ions. Therefore, the carbon dioxide partial pressure is only the dissolved amount and is close to zero.

Therefore, 0 to 2 mEq / 1 is stored in the ROM 32 in FIG. 2 as the normal range of bicarbonate ion in this example.

The case where the liquid A and the liquid B were mistaken in this example corresponds to the case of normal mixing in the above-mentioned first example, and the hydrogen ion concentration measuring electrode 20 and the carbon dioxide gas partial pressure measuring electrode 21 were measured. From the value adjusted by the hydrogen ion concentration measuring circuit 38 and the carbon dioxide partial pressure measuring circuit 39, the A / D converter 37
The value of the bicarbonate ion concentration calculated by the conversion formula (2) after A / D conversion is about 27.5 to 30.0 mEq / 1. Therefore, it is obvious that the detection can be surely performed when the liquid A and the liquid B are mistaken. The alarm process and the process of stopping the supply of the abnormal dialysate to the dialyzer 13 in this case are the same as those in the first embodiment, and will not be repeated.

Although both the first and second embodiments have described the case of the personal dialysis machine as an example, the mixing amount of water, solution A and solution B is expanded to the necessary number of people in the case of the dialysis solution supply apparatus for a large number of people. However, the mixing method is the same in principle.
Therefore, if the hydrogen ion concentration measuring electrode and the carbon dioxide gas partial pressure measuring electrode of the present embodiment are installed for the diluted liquid mixed in the first mixing tank, as in the present embodiment, liquid A and liquid B are surely obtained.
It is no wonder that it is possible to detect the mix-up of liquids.

"Effect of the Invention" According to the present invention, the mistake is surely detected regardless of the mixing order of the A solution and the B solution, and in this case, an alarm is immediately issued and at the same time, the dialysate is supplied to the dialyzer. Supply is stopped. For this reason, it becomes possible to detect the mistaken mixing of the solutions A and B on the dialysis machine side, and the psychological burden on the dialysis operator can be significantly reduced. And above all, the safety of the life of dialysis patients can be secured.

Thus, the present invention can significantly expand the range of applications of dialysis machines.

[Brief description of drawings]

FIG. 1 is a first embodiment and a second embodiment of the baking soda dialysis device of the present invention.
FIG. 2 is a block system diagram showing an embodiment, FIG. 2 is a block system diagram showing an essential part of the embodiment shown in FIG. 1, and FIG. 3 is a flow chart showing an interrupt routine of a control program of the embodiment shown in FIG. FIG. 5 is a flow chart showing the background routine of the embodiment of FIG. 1, and FIG. 5 is a block system diagram showing a conventional baking soda dialysis device.

Claims (1)

[Scope of utility model registration request] Claim: What is claimed is: 1. Water and first stock solution are mixed at a predetermined ratio in a first mixing tank, and the diluted solution and the second stock solution are mixed at a predetermined ratio in a second mixing tank, and the mixture is mixed. In a baking soda dialysis device that supplies the prepared solution as a dialysate to a dialyzer, means for measuring the hydrogen ion concentration (pH) of the diluent, and means for measuring the carbon dioxide partial pressure (PCO ₂ ) of the diluent, from two measurements of hydrogen ion concentration and carbon dioxide partial pressure, bicarbonate ion concentration of the measurement dilution solution (HCO ₃ ^-) means for calculating a means for storing a normal bicarbonate ion concentration of the diluted solution And a comparing means for comparing the calculated bicarbonate ion concentration with the stored bicarbonate ion concentration, and when the comparing means determines that the calculated bicarbonate ion concentration deviates from the stored bicarbonate ion concentration, an alarm is issued. And the supply of the above dialysate to the dialyzer. A baking soda dialysis device having means for stopping supply.