dialyzer

Abstract

To provide a stable dialysis using a biological monitoring data and the like by appropriately suppressing a decrease in blood pressure during a dialysis treatment.SOLUTION: A dialyzer includes: an extracorporeal circulation blood passage; a dialysis liquid passage; a dialysis membrane provided to partition a part of the extracorporeal circulation blood passage and the dialysis liquid passage; circulation blood amount change rate measurement means for measuring the circulation blood amount change rate ΔBV of the patient; and water removal means for removing a part of the dialysis liquid flowing in the dialysis liquid passage to outside of the system to remove water in the blood from the extracorporeal circulation blood passage to the dialysis liquid passage. The water removal means is controlled such that the water removal speed at the end of the dialysis process is at a constant speed. The water removal means is controlled such that the water removal speed decreases when an inclination of a graph showing a change over time of the circulation blood amount time change rate ΔBV becomes a predefined first value or less in the period other than the end of the process.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a dialysis machine used in hemodialysis treatment. [Background technology]

[0002] Hemodialysis treatment involves taking the blood of a dialysis patient into an extracorporeal circuit, introducing it into a blood purifier, where it comes into contact with a dialysis solution through a semipermeable membrane, and using the principles of ultrafiltration and diffusion to remove waste products and excess water from the blood. Additionally, medicinal components contained in the dialysis solution are used to adjust the electrolytes in the blood, and the purified blood is then returned to the patient.

[0003] During dialysis treatment, there are cases where blood pressure drops suddenly, especially in the latter half of treatment. The main causes of this drop in blood pressure are thought to be a decrease in the rate of change of circulating blood volume (ΔBV) and vasodilation. In the former case, as intravascular fluid decreases due to fluid removal, plasma refilling (PR) moves fluid from within the cells to maintain blood pressure. However, if the rate of fluid removal is too fast, PR cannot keep up, resulting in a drop in blood pressure. In the latter case, as fluid removal progresses, vasoconstriction attempts to maintain blood pressure, but a decrease in external heat dissipation causes a rise in core body temperature, which dilates the blood vessels, resulting in a drop in blood pressure.

[0004] In order to reliably prevent hypotension caused by various factors, constant efforts are being made to review and improve existing dialysis technology from every aspect.

[0005] For example, Patent Document 1 discloses a hemodialysis device that performs a first treatment period in which water is removed at an arbitrary speed and a second treatment period in which water is removed so that the rate of change in circulating blood volume ΔBV becomes a predetermined value, and controls the device to transition from the treatment conditions of the first treatment period to the treatment conditions of the second treatment period when the measured pulse rate or blood pressure reaches a set value.

[0006] Patent Document 2 discloses a dialysis device that includes an extracorporeal blood circulation flow path, a dialysate flow path, a dialysis membrane that separates a portion of the extracorporeal blood circulation flow path from a portion of the dialysate flow path, a blood temperature measuring means that measures the temperature of blood flowing through the extracorporeal blood circulation flow path, and a dialysate temperature adjusting means that adjusts the temperature of the dialysate flowing through the dialysate flow path to a predetermined dialysate set temperature, and that changes the dialysate set temperature based on the blood temperature.

[0007] Hypovolemia during dialysis treatment is said to affect life prognosis and places a heavy burden on patients. Furthermore, when hypovolemia occurs, sudden intervention by medical staff is required, so it is important to appropriately suppress hypovolemia and provide stable dialysis treatment. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-143815 [Patent Document 2] Japanese Patent Application Publication No. 2023-173980 Summary of the Invention [Problem to be solved by the invention]

[0009] In view of the problems of the conventional technology as described above, an object of the present invention is to appropriately suppress a drop in blood pressure during dialysis treatment in order to achieve stable dialysis by utilizing biological monitoring data, etc. [Means for solving the problem]

[0010] In order to solve the above problems, the dialysis apparatus according to the present invention comprises an extracorporeal circulating blood flow path, a dialysate flow path, a dialysis membrane provided so as to separate a part of the extracorporeal circulating blood flow path from a part of the dialysate flow path, a circulating blood volume change rate measuring means for measuring a circulating blood volume change rate ΔBV of a patient, and a water removal means for extracting a part of the dialysate flowing through the dialysate flow path to the outside of the system in order to remove water in the blood from the extracorporeal circulating blood flow path to the dialysate flow path, The water removal means is controlled so that the water removal rate at the end of the dialysis process is constant, The method is characterized in that, other than at the end stage, the water removal means is controlled so that the water removal rate decreases when the slope of the graph showing the change over time in the circulating blood volume time rate of change ΔBV becomes equal to or less than a predetermined first value.

[0011] According to the dialysis device of the present invention, by monitoring ΔBV, which is biological data that can be monitored in real time, it is possible to effectively prevent a drop in the patient's blood pressure during dialysis treatment.

[0012] In the dialysis apparatus of the present invention, the water removal means is preferably controlled so that the water removal rate increases when the slope exceeds a predetermined second value, except at the end of the dialysis process. A sudden drop in ΔBV can cause a drop in blood pressure, so the water removal rate must be reduced to prevent a drop in blood pressure. However, as long as ΔBV is stable (i.e., the slope is equal to or greater than the second value), the water removal rate can be increased to allow dialysis treatment to proceed. Ensuring a sufficient amount of water removal at times other than the end of the dialysis process can keep the water removal rate low, effectively preventing a drop in blood pressure. It is preferable to predetermine an upper limit for the water removal rate to prevent the water removal rate from becoming excessively high, even in this case.

[0013] In the dialysis device of the present invention, it is preferable that the total amount of water removed during the dialysis process is predetermined. The total amount of water to be removed throughout the entire dialysis process, including the final stage, is determined, and the amount of water to be removed at the final stage of the dialysis process is calculated by subtracting the amount of water removed at stages other than the final stage to determine the water removal rate (= amount of water to be removed at the final stage / dialysis time at the final stage). This enables stable control of the water removal rate at a constant level during the final stage of the dialysis process, when blood pressure is likely to decrease. However, if the water removal rate at the final stage calculated in this manner is excessively high, stable control of the final stage of the dialysis process may become difficult. Therefore, it is preferable to set an upper limit for the water removal rate at the final stage and appropriately extend the dialysis time at the final stage so that water removal is completed at or below the upper limit of the water removal rate.

[0014] The dialysis device of the present invention further comprises a blood temperature measuring means for measuring the temperature of blood flowing through the extracorporeal blood circulation flow path, and a dialysate temperature adjusting means for adjusting the temperature of the dialysate flowing through the dialysate flow path to a predetermined dialysate set temperature, It is preferable that the dialysate set temperature be changed based on the blood temperature at least at the final stage of the dialysis process.

[0015] In the dialysis device of the present invention, by additionally combining temperature control at the end of the dialysis process, where the water removal rate is controlled to a constant, the dialysate temperature can be appropriately adjusted while appropriately changing the dialysate set temperature, thereby suppressing an increase in the patient's blood temperature during dialysis treatment. In particular, by performing temperature control only at the end of the dialysis process, it is possible to avoid interference between water removal rate control and temperature control at times other than the end of the dialysis process.

[0016] In the dialysis device of the present invention, it is preferable that the set dialysate temperature is maintained when the blood temperature is within a predetermined reference temperature range, the set dialysate temperature is decreased when the blood temperature exceeds the predetermined reference temperature range, and the set dialysate temperature is increased when the blood temperature is below the predetermined reference temperature range. In this way, by constantly monitoring whether the blood temperature is within the reference temperature range and appropriately changing the set dialysate temperature only when the blood temperature is outside the range, temperature control can be performed simply and stably.

[0017] In the dialysis device of the present invention, it is preferable to increase or decrease the dialysate set temperature in a stepwise manner by a predetermined amount. Continuously increasing or decreasing the dialysate set temperature can cause overshooting or hunting during hemodialysis treatment, where the blood temperature fluctuates depending on the number of patients in treatment and the constitution and physical condition of each patient. Therefore, by changing the dialysate set temperature in a stepwise manner, temperature control can be performed simply and stably.

[0018] In the dialysis device of the present invention, it is preferable that the set temperature of the dialysate be changed within a range of predetermined upper and lower limits. If a rise or fall in the blood temperature cannot be suppressed even when the set temperature of the dialysate is changed in stages, the set temperature of the dialysate will repeatedly rise and fall. However, there may be cases where the blood temperature does not easily fall within the reference temperature range due to malfunctions of the instruments or temperature control means, or problems such as water leakage. Therefore, it is preferable to set in advance that the set temperature of the dialysate be changed within a range of predetermined upper and lower limits.

[0019] In the dialysis device of the present invention, it is preferable that the change of the dialysate set temperature be carried out at predetermined time intervals. Since there is still no change in the measured values ​​of the dialysate temperature and blood temperature immediately after the change of the dialysate set temperature, the change of the dialysate set temperature can be forcibly suspended until the dialysate temperature and blood temperature stabilize, and the next change of the dialysate set temperature can be accepted at a predetermined time interval from the previous change of the setting. [Effects of the Invention]

[0020] According to the dialysis device of the present invention, stable dialysis treatment can be achieved by monitoring the rate of change in circulating blood volume ΔBV of the patient and appropriately suppressing a drop in blood pressure during dialysis treatment. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a schematic flow diagram illustrating the basic configuration of the dialysis device of the present invention. [Figure 2] 1 is a composite chart ([time-rate of change in circulating blood volume ΔBV] and [time-water removal rate]) showing an operating method of a dialysis apparatus according to one embodiment of the present invention. [Figure 3] Figure 3 shows a composite chart ([time-rate of change in circulating blood volume ΔBV] and [time-rate of water removal]) to explain the first half of the water removal process in Figure 2. (A) shows an example in which ΔBV is stable, and (B) shows an example in which ΔBV drops suddenly. [Figure 4] 1 is a time-temperature chart illustrating a method of operating a dialysis machine according to another embodiment of the present invention. [Figure 5] 5 is a time-temperature chart for explaining the latter half of water removal (final stage of the dialysis process) in FIG. 4. [Figure 6] 5 is a timing chart for explaining the latter half of water removal (final stage of the dialysis process) in FIG. 4. DETAILED DESCRIPTION OF THE INVENTION

[0022] Preferred embodiments of the present invention will be described below with reference to the drawings. Figure 1 is a schematic flow diagram illustrating the basic configuration of the dialysis machine of the present invention. The dialysis machine 1 is equipped with various monitoring devices, such as a blood monitor, and is capable of obtaining various biological information from a patient 2, including the rate of change in circulating blood volume ΔBV.

[0023] The patient 2 and the dialysis membrane module 3 are connected by an arterial blood circuit 4, which connects the patient's artery to the inlet of the dialysis membrane module 3, and a venous blood circuit 5, which connects the patient's vein to the outlet of the dialysis membrane module 3. The arterial blood circuit 4 is equipped with a blood pump 6 that sends blood drawn from the patient 2 to the dialysis membrane module 3, a clamp 7 that can close the upstream side of the blood pump 6, a syringe 8 that can inject a drug solution into the arterial blood circuit 4 downstream of the blood pump 6, and an air trap chamber 9. The venous blood circuit 5 is equipped with an air trap chamber 19 and a clamp 17 that can close the downstream side of the chamber 19. Dialysis fluid is supplied to the dialysis membrane module 3 from a dialysate supplying device 10, and hemodialysis is performed via the dialysis membrane. The used dialysate (discharged dialysate) is returned to the dialysate supplying device 10. Various monitoring devices, such as blood monitors, are installed at various locations on the patient 2 and the dialysis machine 1, allowing various biological information to be acquired from the patient 2 and the blood drawn from the patient 2.

[0024] The dialysate circulation path, which is connected to the dialysate supply device 10 and is a substantially closed circuit, receives pre-dialysis dialysate from the dialysate outflow path by a circulation pump, and performs hemodialysis, exchanging waste products, salts, minerals, water, and the like between the dialysate circulation path and the blood circuit via the dialysis membrane of the dialysis membrane module 3. The dialyzed dialysate is then returned to the dialysate return path. As described above, the dialysate circulation path is configured as a substantially closed circuit. However, when a fixed amount of dialysate is discharged from the closed circuit by a water removal pump (not shown), a corresponding small amount of water is extracted from the blood via the dialysis membrane into the dialysate circulation path. The operation of moving water from the blood into the dialysate flow path in this way is called water removal.

[0025] Figure 2 shows a composite chart ([time-rate of change in circulating blood volume ΔBV] and [time-rate of water removal rate]) illustrating the operation of a dialysis machine according to one embodiment of the present invention. The rate of change in circulating blood volume ΔBV can be calculated using the hematocrit value Ht [%] monitored by the blood monitor in Figure 1 using the following formula, and can therefore be monitored in real time. ΔBV [%] = (Ht initial value [%] / Ht current value [%] - 1) x 100

[0026] As shown in Figure 2, in this embodiment, the water removal rate is controlled by different methods in the first and second halves of the dialysis process. In the first half of the dialysis process, the water removal rate is gradually increased while monitoring the rate of change in circulating blood volume ΔBV. When a significant decrease in ΔBV is observed, the water removal rate is controlled to decrease, and when ΔBV increases and returns to a normal level, the stepwise increase in the water removal rate is resumed to suppress a drop in blood pressure. An upper limit may be set for the water removal rate to prevent it from increasing too much. In the second half of the dialysis process, which is the final stage of the dialysis process, the water removal rate is controlled to be kept constant regardless of whether ΔBV increases or decreases.

[0027] In the latter half of the dialysis process, the water removal rate is maintained below a predetermined standard rate to prevent a drop in blood pressure due to the water removal operation. The water removal rate in the latter half is calculated by subtracting the amount of water removed in the first half from the amount of water to be removed throughout the entire dialysis process, and dividing the remaining required amount by the dialysis time in the latter half. If the calculated water removal rate in the latter half exceeds the standard rate, the dialysis time in the latter half is extended, and the dialysis schedule is adjusted so that the water removal rate is below the standard rate. In this way, the dialysis process can be performed safely and stably in the latter half, where a drop in blood pressure is likely to occur.

[0028] Figure 3 is a composite chart ([time-rate of change in circulating blood volume ΔBV] and [time-rate of water removal]) to explain the first half of the water removal process in Figure 2. (A) shows an example in which ΔBV is stable, and (B) shows an example in which ΔBV drops suddenly.

[0029] Figure 3(A) shows an example in which the rate of change in circulating blood volume ΔBV remains stable even when the water removal rate is increased stepwise. After the water removal rate reaches its upper limit, it is maintained constant without any further increase. In contrast, Figure 3(B) shows an example in which the water removal rate is reduced when the slope of the graph showing the change in ΔBV over time falls below a predetermined first value, as described in the explanation of Figure 2. When the decrease in ΔBV stops and the slope of the graph returns to the normal range, the water removal means is controlled to resume the stepwise increase in the water removal rate.

[0030] FIG. 4 is a time-temperature chart showing an operating method of a dialysis apparatus according to another embodiment of the present invention, illustrating an example in which the set dialysate temperature is controlled while monitoring the blood temperature in the latter half of the dialysis process. In the first half of the dialysis process, the water removal rate is controlled as described in the description of FIG. 3, while the set dialysate temperature is not changed. In the latter half of the dialysis process, which is the final stage of the dialysis process, the dialysate temperature is gradually decreased to maintain the blood temperature within a predetermined range. In this way, by monitoring the temperature of the blood flowing through the extracorporeal blood flow path and increasing or decreasing the temperature of the dialysate flowing through the dialysate flow path in accordance with the blood temperature, it is possible to prevent a drop in blood pressure due to fluctuations in blood temperature.

[0031] As shown in Figure 4, the method for controlling the dialysate temperature is not limited, but for example, the method described in Patent Document 2 (Japanese Patent Laid-Open No. 2023-173980) can be applied. Figures 5 and 6 of the present application correspond to Figures 2 and 3 of Patent Document 2. By using the control method described in this publication in combination at the end of the dialysis process of the present invention, it is possible to suppress a drop in the patient's blood pressure during dialysis treatment and to suppress an increase in the patient's blood temperature.

[0032] Figure 5 is a time-temperature chart for explaining the second half of water removal (the final stage of the dialysis process) in Figure 4. After the preparation for operation is complete and a predetermined time (5 minutes) has elapsed since operation began, the blood temperature at the inlet of the dialysis machine is obtained and set as the reference temperature. The reference temperature can be obtained with high accuracy by calculating the moving average of the blood temperature measurement results within the predetermined time.

[0033] In Figure 5, even after the reference temperature is acquired, the blood temperature at the inlet of the dialysis machine continues to be sampled at a predetermined time interval (1 minute). If the sampled blood temperature falls outside the reference temperature range, which is defined by a predetermined upper and lower bound (0.5°C increments) around the reference temperature (35.0°C), the set value of the dialysate temperature is reset to adjust the blood temperature. In Figure 5, a blood temperature (35.6°C) outside the reference temperature range (34.5°C to 35.5°C) was sampled after 10 minutes had elapsed, so the set value of the dialysate temperature was reset to 35.2°C, lowered by a predetermined lower bound (0.8°C) from the initial value (36.0°C). Blood pressure can also be measured when the set value of the dialysate temperature is changed.

[0034] 5, even if the sampled blood temperature is outside the reference temperature range, no further resetting is performed until a predetermined time interval (8 minutes) has elapsed since the dialysate temperature was reset. This predetermined time interval is provided because the dialysate temperature and blood temperature do not change instantaneously even if the dialysate temperature is reset.

[0035] In Figure 5, after 18 minutes have passed, the dialysate temperature is reset a second time to 34.4°C. Even after 26 minutes have passed, the blood temperature is still outside the reference temperature range (34.5°C to 35.5°C), so a third reset of the dialysate temperature should result in 33.6°C. However, because this is below the separately set lower limit (34.0°C) for resetting the dialysate temperature, the dialysate temperature is not reset.

[0036] Figure 6 is a timing chart for explaining the latter half of the water removal process (the final stage of the dialysis process) in Figure 4. After the preparation for operation is complete and a predetermined time (5 minutes) has elapsed since the start of operation, the blood temperature at the inlet of the dialysis machine is obtained and set as the reference temperature. The reference temperature can be obtained with high accuracy by calculating the moving average of the blood temperature measurement results within the predetermined time.

[0037] In Figure 6, even after the reference temperature is acquired, the blood temperature at the inlet of the dialysis machine continues to be sampled at a predetermined time interval (1 minute). If the sampled blood temperature falls outside the reference temperature range defined by a predetermined upper and lower bound (0.5°C increments) around the reference temperature (35.0°C), the set value of the dialysate temperature is reset to adjust the blood temperature. In Figure 6, a blood temperature (35.6°C) outside the reference temperature range (34.5°C to 35.5°C) was sampled after 10 minutes had elapsed, so the set value of the dialysate temperature was reset to 35.9°C, lowered by the predetermined lower bound (0.1°C) from the initial value (36.0°C).

[0038] In Fig. 6, even if the sampled blood temperature is outside the reference temperature range, the dialysate temperature is not further reset until a predetermined time interval (8 minutes) has elapsed since the dialysate temperature was reset. This predetermined time interval is provided because the dialysate temperature and blood temperature do not change instantly even if the dialysate temperature is reset.

[0039] In the embodiments shown in Figures 5 and 6, in order to simply maintain a constant blood temperature, it is possible to control the blood temperature while changing the dialysate temperature by implementing well-known feedback control (e.g., PID control). However, in order to appropriately manage the blood temperature, which varies depending on the number of patients at the time of hemodialysis treatment and the constitution and physical condition of each patient, it is desirable to change the dialysate temperature in stages at predetermined time intervals. [Industrial Applicability]

[0040] The dialysis device according to the present invention can be widely used to suppress a drop in blood pressure during hemodialysis treatment. [Explanation of symbols]

[0041] 1 Dialysis machine 2 patients 3 Dialysis membrane module 4 Arterial blood circuit 5 Venous blood circuit 6. Blood Pump 7, 17 Clamp 8 syringes 9, 19 Chambers 10 Dialysate supply device

Claims

1. the system comprises an extracorporeal circulation blood flow path, a dialysate flow path, a dialysis membrane provided to separate a part of the extracorporeal circulation blood flow path from a part of the dialysate flow path, a circulating blood volume change rate measuring means for measuring a circulating blood volume change rate ΔBV of a patient, and a water removal means for extracting a part of the dialysate flowing through the dialysate flow path to the outside of the system in order to remove water in the blood from the extracorporeal circulation blood flow path to the dialysate flow path, The water removal means is controlled so that the water removal rate at the end of the dialysis process is constant, a control unit for controlling the water removal means so that the water removal rate is reduced when the slope of a graph showing the time change in the circulating blood volume time rate of change ΔBV becomes equal to or less than a predetermined first value, other than at the end of the period.

2. 2. The dialysis apparatus according to claim 1, wherein the water removal means is controlled so that the water removal rate increases when the slope becomes equal to or greater than a predetermined second value other than the final stage.

3. The dialysis apparatus according to claim 2 , wherein an upper limit of the water removal rate is predetermined except for the final stage.

4. The dialysis device according to claim 1 , wherein the total amount of water removed in the dialysis step is predetermined.

5. The dialysis apparatus according to claim 4, wherein an end time of the final stage is set so that the constant value of the water removal rate in the final stage is equal to or less than a predetermined reference value.

6. The device further comprises a blood temperature measuring means for measuring the temperature of blood flowing through the extracorporeal blood circulation flow path, and a dialysate temperature adjusting means for adjusting the temperature of the dialysate flowing through the dialysate flow path to a predetermined dialysate set temperature, The dialysis machine according to claim 1 , wherein the dialysate set temperature is changed based on the blood temperature at least at the final stage of the dialysis process.

7. 7. The dialysis machine according to claim 6, wherein the set dialysate temperature is maintained when the blood temperature is within a predetermined reference temperature range, the set dialysate temperature is decreased when the blood temperature is above the predetermined reference temperature range, and the set dialysate temperature is increased when the blood temperature is below the predetermined reference temperature range.

8. The dialysis machine according to claim 7, wherein the dialysate set temperature is increased or decreased in steps by a predetermined amount.

9. The dialysis machine according to claim 8, wherein the set temperature of the dialysate is changed within a range of predetermined upper and lower limits.

10. The dialysis machine according to claim 6, wherein the change in the dialysate set temperature is carried out at predetermined time intervals.

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