A hemodialysis machine dialysate potassium ion real-time automatic regulation system

Abstract

The application discloses a hemodialysis machine dialysate potassium ion real-time automatic regulation system and belongs to the technical field of medical equipment, which solves the problem of how to accurately regulate the potassium ion concentration in the dialysate of a hemodialysis machine. The man-machine interface of the host computer mainly comprises blood potassium concentration display, regulation system function selection and lower computer function setting functions. The lower computer controller mainly completes the cooperative control of the clamping valve and the peristaltic pump, realizes the function control of the electrode, and, combined with the real-time optimal regulation strategy solved by the nonlinear MPC control algorithm, realizes the switching selection of dialysate with different potassium ion concentrations by electromagnetic valve driving control. The ion selective electrode is adopted to realize the real-time sampling detection of the potassium ion concentration in blood, and the control of the peristaltic pump and the rotary clamping valve is combined to realize the calibration, cleaning and activation of the electrode. The application realizes the real-time switching of dialysate with different potassium ion concentrations and completes the accurate regulation of dialysate with different potassium ion concentrations in the dialysis process.

Description

Technical Field

[0001] This invention belongs to the field of medical equipment technology and relates to a real-time automatic regulation system for potassium ions in dialysate of a hemodialysis machine. Background Technology

[0002] In current medical practice, hemodialysis is one of the main methods for treating patients with end-stage renal disease (ESRD). During hemodialysis, metabolic waste and excess water are removed from the blood through an artificial kidney membrane. However, it inevitably removes some essential electrolytes, such as potassium ions. Potassium ions are crucial for maintaining nerve and muscle function. Improper potassium concentration settings or insufficient monitoring in the dialysate can easily lead to dialysis-related hypokalemia or hyperkalemia, which may then cause serious heart problems.

[0003] Traditional hemodialysis machines typically use a pre-set dialysate with a fixed potassium concentration. This method cannot automatically adjust the concentration based on the patient's actual pre-dialysis serum potassium level. Furthermore, the lack of real-time potassium monitoring and regulation mechanisms during dialysis makes it difficult for healthcare professionals to respond promptly to sudden changes in the patient's potassium levels. Therefore, there is an urgent need for a technology that can dynamically adjust the potassium concentration in the dialysate based on the patient's real-time serum potassium level to improve the safety and effectiveness of dialysis treatment. Summary of the Invention

[0004] The technical solution of this invention is used to solve the problem of how to accurately control the potassium ion concentration in the dialysate of a hemodialysis machine.

[0005] The present invention solves the above-mentioned technical problems through the following technical solutions:

[0006] This invention provides a real-time automatic potassium ion control system for dialysate in a hemodialysis machine, comprising: a host computer human-machine interface, a lower-level dialysate potassium ion concentration controller module, and a potassium ion concentration detection module; the potassium ion concentration detection module detects the potassium ion concentration in the blood and sends the detection results to the lower-level potassium ion concentration controller module; the lower-level potassium ion concentration controller module designs an optimal potassium ion concentration strategy for the dialysate based on a nonlinear MPC controller, regulates the potassium ion concentration data, communicates with the host computer, sends the ion concentration data to the host computer's human-machine interface in real time, and simultaneously receives commands from the host computer to regulate the potassium ion concentration; the method for designing the optimal potassium ion concentration strategy for the dialysate based on a nonlinear MPC controller is as follows: 1) establishing a dynamic model of potassium ion concentration in simulated human blood; 2) establishing a prediction model of potassium ion concentration in blood based on the dynamic model of potassium ion concentration in simulated human blood; 3) constructing an optimization objective function and variable constraint function, and using a rolling optimization method to solve for the optimal strategy.

[0007] Furthermore, the dynamic model of potassium ion concentration in simulated human blood is expressed as follows:

[0008] (1)

[0009] (2)

[0010] Among them, China This refers to the concentration of potassium ions in the blood. This refers to the potassium ion concentration in the cell. Potassium ion concentration in dialysate It is the dialysis rate constant. , The rate of potassium ion exchange between blood and blood cells. This represents the lag time for changes in potassium ion concentration. It is a random process noise term, representing physiological processes or measurement errors that were not captured in the model.

[0011] Furthermore, the blood potassium ion concentration prediction model is expressed as follows:

[0012] (3)

[0013] (4)

[0014] Among them, China This refers to the concentration of potassium ions in the blood. This refers to the potassium ion concentration in the cell. Potassium ion concentration in dialysate It is the dialysis rate constant. , The rate of potassium ion exchange between blood and blood cells. This represents the lag time for changes in potassium ion concentration. It is a random process noise term, representing physiological processes or measurement errors that were not captured in the model.

[0015] Furthermore, the optimization objective function and variable constraint functions are as follows:

[0016] (5)

[0017] (6)

[0018] in, For the predicted blood potassium ion concentration, To achieve the desired potassium ion concentration, These are the weight parameter values.

[0019] Furthermore, the potassium ion concentration detection module performs the following process for detecting potassium ion concentration:

[0020] First, clean the A standard solution tubing, read the concentration data of A standard solution, and drain the A standard solution; sample aspiration is performed in two stages, the first stage being the collection of... Volume sample, immediately afterwards Volume of air, then absorb the second segment. Volume sample;

[0021] Then, the method for detecting sample concentration is as follows:

[0022] 1) Select an ISE of a specific ion-selective membrane and place it in a solution containing the ion to be measured;

[0023] 2) The ions to be tested pass through the semi-permeable membrane into the electrode body and react with the internal reference electrode, generating a small but stable potential difference;

[0024] 3) The concentration of potassium ions in the solution can be calculated based on a small potential difference. The formula is as follows:

[0025] (7)

[0026] in, For potential difference, This is the standard potential. Let be the ideal gas constant. Absolute temperature The charge number of the ion. It is Faraday's constant. The concentration of the ion to be measured. This represents the concentration of the reference ion.

[0027] Then, clean the tubing after testing the sample concentration;

[0028] Finally, re-absorb standard solution A and read its concentration to determine if it is correct, thereby determining if the sample testing process is correct. If not, repeat the test.

[0029] Furthermore, the cleaning process of the pipeline is as follows: First, flush the pipeline and electrode with standard solution A; then draw the cleaning solution to the ion electrode, wait for a period of time, and then drain it; finally, flush away the cleaning solution with standard solution A.

[0030] The advantages of this invention are:

[0031] The system of this invention includes a host computer human-machine interface, a slave controller, and a real-time potassium ion concentration detection system. The host computer human-machine interface mainly includes blood potassium concentration display, control system function selection, and slave function setting functions. The slave controller mainly handles the switching of dialysate with different potassium ion concentrations and the control of the clamping valve and peristaltic pump, achieving coordinated control of the potassium ion concentration selection and detection components. Simultaneously, it combines a real-time optimal adjustment strategy obtained through a nonlinear MPC control algorithm with electromagnetic valve drive control to achieve the switching selection of dialysate with different potassium ion concentrations. An ion-selective electrode is used to achieve real-time sampling and detection of potassium ion concentration in the blood, and the control of the peristaltic pump and rotary clamping valve enables the calibration, cleaning, and activation of the electrode. This invention effectively solves the problems of excessively rapid potassium ion removal during dialysis and post-dialysis hypokalemia in existing dialysis machines. It enables real-time monitoring of the patient's blood potassium concentration during dialysis, and simultaneously facilitates human-machine interaction through a host computer interface. Based on an improved nonlinear MPC control algorithm, it achieves real-time switching of dialysate with different potassium ion concentrations, thus completing real-time regulation of dialysate with varying potassium ion concentrations during dialysis. The system of this invention integrates real-time monitoring of the patient's blood potassium concentration during dialysis, prediction of the patient's blood potassium concentration, and automatic regulation of dialysate potassium ion concentration. This is of great significance for improving patient safety and comfort during dialysis and reducing the cost of medical dialysis. Attached Figure Description

[0032] Figure 1 This is an architecture diagram of the real-time automatic potassium ion regulation system for hemodialysis machine dialysate of the present invention;

[0033] Figure 2 This is the control logic diagram of the lower-level potassium ion concentration controller module of the real-time automatic potassium ion regulation system for hemodialysis machine dialysate of the present invention;

[0034] Figure 3(a) is a curve showing the change in serum potassium levels during routine dialysis when the initial serum potassium concentration is 4.5 mmol.

[0035] Figure 3(b) is a graph showing the change in dialysate potassium concentration under the optimal dialysate potassium concentration design strategy based on the nonlinear MPC controller of the present invention when the initial serum potassium concentration is 4.5 mmol.

[0036] Figure 3(c) shows the changes in serum potassium levels during routine dialysis at an initial serum potassium concentration of 5.5 mmol.

[0037] Figure 3(d) shows the autonomous adjustment curve of dialysate potassium change based on the optimal strategy for dialysate potassium concentration designed by the present invention with a nonlinear MPC controller when the initial serum potassium concentration is 5.5 mmol.

[0038] Figure 4This is a piping diagram of the potassium ion detection module of the real-time automatic potassium ion control system for hemodialysis machine dialysate of the present invention;

[0039] Figure 5 This is a flowchart of the potassium ion concentration detection process of the real-time automatic potassium ion control system for hemodialysis machine dialysate of the present invention;

[0040] Figure 6 This is a flowchart of the cleaning pipeline of the real-time automatic potassium ion regulation system for hemodialysis machine dialysate of the present invention;

[0041] Figure 7 This is a diagram of the interface of the host computer software for the real-time automatic control system of potassium ions in the dialysate of the hemodialysis machine of the present invention. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0044] Example 1

[0045] like Figure 1 As shown in the figure, a real-time automatic potassium ion control system for a hemodialysis machine according to an embodiment of the present invention includes: a host computer human-machine interface, a slave potassium ion concentration controller module, and a potassium ion concentration detection module; the potassium ion concentration detection module detects the potassium ion concentration in the blood and sends the detection result to the slave potassium ion concentration controller module; the slave potassium ion concentration controller module automatically adjusts the system according to the potassium ion concentration data from the detection module, communicates with the host computer, sends the ion concentration to the host computer's human-machine interface in real time, and simultaneously receives commands from the host computer to adjust the potassium ion concentration.

[0046] 1. Lower-level potassium ion concentration controller module

[0047] The lower-level potassium ion concentration controller module is used to receive data commands from the upper-level computer, coordinate the control of the clamping valve and peristaltic pump to achieve potassium ion concentration sampling and detection, and achieve switching control of dialysate with different potassium ion concentrations; according to the command mode set by the upper-level computer, the valve performs clamping selection control, while cooperating with the peristaltic pump to extract liquid; based on the target concentration given by the upper-level computer and the measurement data feedback from the blood potassium concentration detection module, the optimal strategy for dialysate potassium ion concentration is designed based on the nonlinear MPC controller.

[0048] The method for designing the optimal potassium ion concentration strategy for dialysate based on a nonlinear MPC controller is as follows:

[0049] First, a dynamic model of potassium ion concentration in simulated human blood is established, which is expressed as follows:

[0050] (1)

[0051] (2)

[0052] Among them, China This refers to the concentration of potassium ions in the blood. This refers to the potassium ion concentration in the cell. Potassium ion concentration in dialysate It is the dialysis rate constant. , The rate of potassium ion exchange between blood and blood cells. This represents the lag time for changes in potassium ion concentration. It is a random process noise term, representing physiological processes or measurement errors that were not captured in the model.

[0053] Secondly, based on the dynamic model of potassium ion concentration in human simulated blood, a prediction model for potassium ion concentration in blood is established. This prediction model is expressed as follows:

[0054] (3)

[0055] (4)

[0056] Finally, an optimization objective function and variable constraint functions are constructed, and the optimal strategy is solved using a rolling optimization approach. The optimization objective function and variable constraint functions are as follows:

[0057] (5)

[0058] (6)

[0059] in, For the predicted blood potassium ion concentration, To achieve the desired potassium ion concentration, These are the weight parameter values.

[0060] The lower-level potassium ion concentration controller module reads and judges the potassium ion concentration in the potassium ion concentration detection module to automatically control the relevant clamping valves, solenoid valves and peristaltic pumps. It also communicates with the upper-level computer to send the detected potassium ion concentration data to the upper-level computer's human-machine interface for real-time display. At the same time, it receives commands from the upper-level computer to perform manual sampling detection and manual control of potassium ion concentration.

[0061] The specific control logic of the lower-level potassium ion concentration controller module is as follows: Figure 2 As shown in the diagram. After system initialization, when ion concentration detection is required, the potassium ion concentration detection module is used to perform the detection, and then the corresponding potassium ion concentration data is read; otherwise, the potassium ion concentration data is read directly.

[0062] After reading the ion concentration data, the optimal strategy for potassium ion concentration in the dialysate is executed through a nonlinear MPC controller, which opens the corresponding solenoid valve of the dialysate and, in conjunction with a peristaltic pump, extracts the dialysate.

[0063] While the dialysate is being drawn, the lower-level potassium ion concentration controller module transmits the potassium ion concentration data to the upper-level human-machine interface for display in real time.

[0064] After receiving the command, the host computer determines whether the ion detection needs to be recalibrated. If recalibration is required, the potassium ion detection module is used again for ion detection calibration, and the control logic of the lower-level computer is re-completed to ensure the accuracy of the detected potassium ion concentration data. If recalibration is not required, the control of the lower-level computer is terminated directly.

[0065] Figures 3(a) to 3(d) illustrate the nonlinear MPC control with different dialysate concentrations. The figures compare conventional dialysis and dialysis using the nonlinear MPC control algorithm, testing serum potassium concentrations with initial values ​​of 4.5 mmol / L and 5.5 mmol / L, respectively. The horizontal axis represents time in hours; the vertical axis represents potassium ion concentration data in mmol / L. The blue curve represents the potassium ion concentration change curve; the red dashed line represents the dialysate selection with different potassium ion concentrations, with three different dialysate concentrations available for selection: 2 mmol / L, 2.5 mmol / L, and 3 mmol / L.

[0066] As can be seen from Figures 3(a) to 3(d), during routine dialysis, the blood potassium concentration gradually decreases as the dialysis process progresses, and dialysis patients may develop hypokalemia symptoms over time.

[0067] In the nonlinear MPC control algorithm, when the initial serum potassium concentration is 4.5 mmol / L, the algorithm automatically switches the dialysate from 2 mmol / L to 3 mmol / L within 2.5 hours. When the initial serum potassium concentration is 5.5 mmol / L, the algorithm switches the dialysate from 2 mmol / L to 2.5 mmol / L between 7 and 8 hours, and then switches it back to 3 mmol / L.

[0068] By using a nonlinear MPC control algorithm, the rate of decrease in blood potassium concentration is effectively slowed down as the concentration gradually decreases, ensuring the stability of blood potassium concentration during dialysis and avoiding hypokalemia during dialysis. This achieves the selection of the optimal concentration of dialysate and effectively completes the automated control of dialysate concentration selection.

[0069] 2. Potassium ion concentration detection module

[0070] Figure 4 The design of the potassium ion detection module piping is demonstrated. The detection piping mainly includes a sampling needle, a level sensor, an ion-selective electrode, various valves, and a peristaltic pump. In the piping, the sampling needle collects samples and introduces them into the system. The inlet, like the sampling needle, serves as the entry point for blood, standard solutions (including standard solution A and standard solution B), and air. Blood in the blood tubing reaches the inlet through a sampling valve, a sample cleaning solution three-way valve, a sampling switching valve, and a sample standard solution three-way valve. The cleaning solution reaches the inlet through a cleaning valve, a sample cleaning solution three-way valve, a sampling switching valve, and a sample standard solution three-way valve. Standard solutions A and B reach the inlet through their respective clamping valves, an AB standard solution three-way valve, a liquid valve, a liquid-air three-way valve, a sampling switching valve, and a sample standard solution three-way valve. Air reaches the inlet through an air valve, a liquid-air three-way valve, a sampling switching valve, and a sample specimen three-way valve. Whether it's various samples or blood, they are all drawn by a peristaltic pump to the liquid inlet, then enter the ion-selective electrode for potassium ion concentration detection, and are monitored in conjunction with a liquid level sensor, before finally reaching the waste liquid tank.

[0071] The procedure for potassium ion concentration detection is as follows: Figure 5 As shown. First, clean the A standard solution tubing, read the concentration data of A standard solution, and drain the A standard solution; sample aspiration is performed in two stages, the first stage collecting... Volume sample, immediately afterwards Volume of air, then absorb the second segment. The purpose of using volumetric samples is to flush out any residual cleaning solution in the tubing with the first sample, making the second sample even cleaner and resulting in higher detection accuracy.

[0072] The method for sample concentration detection is as follows:

[0073] (1) Select an ISE of a specific ion-selective membrane and place it in a solution containing the ion to be measured;

[0074] (2) The ions to be tested will pass through the semipermeable membrane into the electrode body and react with the internal reference electrode to generate a small but stable potential difference;

[0075] (3) The concentration of potassium ions in the solution can be calculated based on a small potential difference. The formula is as follows:

[0076] (7)

[0077] in, For potential difference, This is the standard potential. Let be the ideal gas constant. Absolute temperature The charge number of the ion. It is Faraday's constant. The concentration of the ion to be measured. This represents the concentration of the reference ion.

[0078] After testing the sample concentration, clean the tubing; finally, re-pipette standard solution A and read its concentration to determine if it is correct, thus verifying the accuracy of the sample testing process. If incorrect, repeat the test. The tubing cleaning procedure is as follows: Figure 6 As shown, firstly, the tubing and electrode are flushed with standard solution A; then, the cleaning solution is drawn into the ion electrode and waited for 5 minutes. After venting, rinse away the cleaning solution using standard solution A.

[0079] 3. Host computer human-computer interaction interface

[0080] The interface diagram of the host computer software is as follows: Figure 7As shown, the interface displays the current dialysate concentration and potassium ion concentration, a real-time potassium ion concentration change curve, sampling cycle, and logs of each operation step. The interface allows users to observe the automatic potassium ion concentration control through the potassium ion concentration change curve and operation logs. Manual sampling and selection of dialysate concentration are also possible, increasing system flexibility. The interface allows configuration of relevant parameters and retrieval of historical dialysis data. Operators can easily monitor potassium ion concentration changes during dialysis and take timely actions. The specific operation steps of the host computer's human-machine interface are as follows: Input patient information to test the patient's blood potassium level. Select "Automatic Blood Potassium Control Enabled" and set the automatic sampling cycle. The system will test blood potassium levels at fixed time intervals and display the data as a blood potassium curve. During automatic testing, the system dynamically switches the dialysate concentration based on the blood potassium level. The host computer's human-machine interface also allows for manual sampling and testing. Clicking the "Manual Sampling and Testing" button will detect the current blood potassium concentration level. At this point, you will need to manually switch between the three concentrations of the dialysate based on the current blood potassium level. The host computer's human-machine interface has an information display window where you can view the current task progress or analyze the reasons for task failure. It also supports querying historical data.

[0081] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A real-time automatic control system for potassium ions in dialysate of a hemodialysis machine, characterized in that, include: The system comprises a host computer human-machine interface, a slave potassium ion concentration controller module, and a potassium ion concentration detection module. The potassium ion concentration detection module detects the potassium ion concentration in the blood and sends the results to the slave potassium ion concentration controller module. The slave potassium ion concentration controller module designs an optimal strategy for dialysate potassium ion concentration based on a nonlinear MPC controller, regulates the potassium ion concentration data, and communicates with the host computer. It sends the ion concentration data to the host computer's human-machine interface in real time and receives commands from the host computer to regulate the potassium ion concentration. The method for designing the optimal potassium ion concentration strategy for dialysate based on a nonlinear MPC controller is as follows: 1) Establish a dynamic model of potassium ion concentration in simulated human blood; The dynamic model of potassium ion concentration in simulated human blood is expressed as follows: （1） （2） Among them, China This refers to the concentration of potassium ions in the blood. This refers to the potassium ion concentration in the cell. Potassium ion concentration in dialysate It is the dialysis rate constant. , The rate of potassium ion exchange between blood and blood cells. This represents the lag time for changes in potassium ion concentration. It is a random process noise term, representing physiological processes or measurement errors that were not captured in the model; 2) Based on the dynamic model of potassium ion concentration in human simulated blood, establish a predictive model for potassium ion concentration in blood; 3) Construct the objective function and variable constraint function, and use rolling optimization to solve for the optimal strategy; The optimization objective function and variable constraint functions are as follows: （5） （6） in, For the predicted blood potassium ion concentration, To achieve the desired potassium ion concentration, These are the weight parameter values.

2. The real-time automatic potassium ion control system for hemodialysis machine dialysate according to claim 1, characterized in that, The blood potassium ion concentration prediction model is expressed as follows: （3） （4） Among them, China This refers to the concentration of potassium ions in the blood. This refers to the potassium ion concentration in the cell. Potassium ion concentration in dialysate It is the dialysis rate constant. , The rate of potassium ion exchange between blood and blood cells. This represents the lag time for changes in potassium ion concentration. It is a random process noise term, representing physiological processes or measurement errors that were not captured in the model.

3. The real-time automatic potassium ion control system for hemodialysis machine dialysate according to claim 2, characterized in that, The potassium ion concentration detection module's potassium ion concentration detection process is as follows: First, clean the A standard solution tubing, read the concentration data of A standard solution, and drain the A standard solution; sample aspiration is performed in two stages, the first stage being the collection of... Volume sample, immediately afterwards Volume of air, then absorb the second segment. Volume sample; Then, the method for detecting sample concentration is as follows: 1) Select an ISE of a specific ion-selective membrane and place it in a solution containing the ion to be measured; 2) The ions to be tested pass through the semi-permeable membrane into the electrode body and react with the internal reference electrode, generating a small but stable potential difference; 3) The concentration of potassium ions in the solution can be calculated based on a small potential difference. The formula is as follows: （7） in, For potential difference, This is the standard potential. Let be the ideal gas constant. Absolute temperature The charge number of the ion. It is Faraday's constant. The concentration of the ion to be measured. The concentration of the reference ion; Then, clean the tubing after testing the sample concentration; Finally, re-absorb standard solution A and read its concentration to determine if it is correct, thereby determining if the sample testing process is correct. If not, repeat the test.

4. The real-time automatic potassium ion control system for hemodialysis machine dialysate according to claim 3, characterized in that, The cleaning process for the pipeline is as follows: First, flush the pipeline and electrode with standard solution A; then draw the cleaning solution to the ion electrode, wait for a period of time, and then drain it; finally, flush away the cleaning solution with standard solution A again.

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