Control device and method based on pulsatility and ventricular assist system

Abstract

The invention provides a pulsatility-based control device and method and a ventricular assist system, and relates to the field of medical instrument control. The device comprises a current pressure difference determining module, a target pressure difference determining module and a motor control module. The current pressure difference determination module is used for obtaining a current pressure difference according to a current current and a current rotating speed of a motor of the ventricular assist device; wherein the current pressure difference represents the pressure difference between the blood vessel and the ventricle; the target pressure difference determination module is used for constructing a target pressure difference curve based on the pulsatility of the blood vessel, and obtaining a target pressure difference according to the target pressure difference curve; and the motor control module is used for controlling the rotating speed of the motor based on the current pressure difference and the target pressure difference. By using the control device provided by the embodiment of the invention, the pulsatility of the blood vessel can be considered, and differential pressure control is carried out; the control requirement of the ventricular auxiliary device can be met, and the problem that the valve cannot be opened can be solved.

Description

Technical Field

[0001] The present application relates to the field of medical device control, and in particular, to a pulsatility-based control device, method and ventricular assist system. Background Art

[0002] A ventricular assist device (VAD) is a mechanical pump used to support cardiac function and blood flow in patients with heart failure. Common ventricular assist devices include left ventricular assist devices (LVAD) and right ventricular assist devices (RVAD), both of which can maintain continuous blood flow. There are different gears in ventricular assist devices, and different gears correspond to different speeds of the motor of the ventricular assist device, which will produce different pressure differences between the blood vessels and the ventricles, corresponding to different patient needs.

[0003] Currently, the control method for ventricular assist devices is to directly control the speed or current of the ventricular assist device; such a control method does not take the intracardiac environment into consideration, the resulting control quantity cannot match the physiological laws of the human body, and is prone to structural damage to the aorta and aortic valve. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a control device, method and ventricular assist system based on pulsation, wherein a current pressure difference determination module obtains a current pressure difference through a current rotation speed and a current current of a motor, and a target pressure difference determination module constructs a target pressure difference curve based on the pulsation of blood vessels, thereby obtaining a target pressure difference corresponding to the current pressure difference; then, a motor control module obtains a control amount for controlling the motor rotation speed based on the target pressure difference and the current pressure difference, thereby realizing pulsation-based control of a ventricular assist device; the pulsation of blood vessels can be taken into account to perform pressure difference control; the control requirements of the ventricular assist device can be met, and the problem of valve failure to open can be improved.

[0005] In a first aspect, an embodiment of the present application provides a control device based on pulsatility, the device comprising: a current pressure difference determination module, a target pressure difference determination module and a motor control module; the current pressure difference determination module is used to obtain a current pressure difference according to a current current and a current speed of a motor of a ventricular assist device; wherein the current pressure difference represents the pressure difference between a blood vessel and a ventricle; the target pressure difference determination module is used to construct a target pressure difference curve based on the pulsatility of the blood vessel, and obtain a target pressure difference according to the target pressure difference curve; the motor control module is used to control the speed of the motor based on the current pressure difference and the target pressure difference.

[0006] In the above-mentioned implementation process, the current pressure difference determination module of the pulsation-based control device provided in the embodiment of the present application obtains the current pressure difference according to the current speed and current current of the motor, and the target pressure difference determination module constructs a target pressure difference curve based on the pulsation of the blood vessels, thereby obtaining the target pressure difference corresponding to the current pressure difference, and then the motor control module obtains the control amount for controlling the motor speed based on the target pressure difference and the current pressure difference, thereby realizing the pulsation-based control of the ventricular assist device; since the pulsation control of the pressure difference is realized, the control device provided in the embodiment of the present application can meet the control requirements of the ventricular assist device while also improving the situation where the valve cannot open due to the aortic pressure being continuously higher than the left ventricular pressure.

[0007] Optionally, in an embodiment of the present application, the target pressure difference curve includes a curve of a target pressure difference function; the target pressure difference determination module includes a pressure difference curve construction unit; in the process of constructing the target pressure difference curve based on the pulsation of the blood vessels: the pressure difference curve construction unit is used to obtain a pulsating pressure difference function based on the pulsation of the blood vessels; wherein the pulsating pressure difference function includes a periodic nonlinear function; the pressure difference curve construction unit is also used to determine the parameter value of the pulsating pressure difference function to obtain the target pressure difference function.

[0008] In the above implementation process, the pulsation-based control device provided in the embodiment of the present application constructs a target pressure difference function through a pressure difference curve construction unit in order to obtain a target pressure difference based on pulsation; the target pressure difference function is a periodic nonlinear function constructed based on the pulsation of the blood vessel, and after the pressure difference curve construction unit adjusts the parameters of the pulsating pressure difference function, the final target pressure difference function can be obtained; it can be seen that the control device provided in the embodiment of the present application constructs a target pressure difference function based on the pulsation of the blood vessel, thereby ensuring the control requirements of the heart assist device while controlling the pressure difference between the aorta and the left ventricle within a reasonable range and improving the pulsation of the aorta.

[0009] Optionally, in an embodiment of the present application, the parameter value also includes a synchronization control period; in the process of determining the parameter value of the pulsating pressure difference function: the pressure difference curve construction unit is specifically used to determine the synchronization control period T according to a preset multiple of the cardiac cycle through the formula T = n (time / bt); wherein bt is the heart rate value, time / bt is the cardiac cycle, and n is a positive integer; the synchronization control period characterizes that the fluctuation of the pulsating pressure difference function is synchronized with the contraction and relaxation process of the heart.

[0010] In the above-mentioned implementation process, the pulsation-based control device provided in the embodiment of the present application, in order to make the synchronous control period of the target pressure difference function correspond to the human heartbeat cycle, that is, to the contraction and relaxation process of the heart, the pressure difference curve construction unit of the control device obtains the synchronous control period of the target pressure difference function according to the cardiac cycle. When the current pressure difference follows the target pressure difference obtained based on the target pressure difference function, the problem of low aortic pulsation can be solved.

[0011] Optionally, in an embodiment of the present application, the parameter value includes an amplitude; in the process of determining the parameter value of the pulsating pressure difference function: the pressure difference curve construction unit is specifically used to control the difference between the peak and valley values ​​of the pulsating pressure difference function to be greater than or equal to the pulsating pressure difference threshold value according to a preset pulsatility requirement; and determine the amplitude based on the difference between the peak and valley values.

[0012] In the above implementation process, in order to make the ventricular assist device meet the basic requirements that the aortic valve closes when the pressure difference is high pressure and opens when the pressure difference is low pressure, it is necessary to control the pressure difference between high pressure and low pressure within the pulsating pressure difference range. The pressure difference curve construction unit of the control device provided in the embodiment of the present application determines the amplitude of the pulsating pressure difference function according to the principle in the above implementation process, which can ensure the normal operation of the ventricular assist device.

[0013] Optionally, in an embodiment of the present application, the parameter value also includes a deviation adjustment value of the function; in the process of determining the parameter value of the pulsating pressure difference function: the pressure difference curve construction unit is specifically used to determine the deviation adjustment value of the function according to a preset mean range of the pressure difference; wherein the deviation adjustment value of the function is used to ensure that the lowest pressure of the blood vessel does not exceed the low pressure threshold based on the amplitude.

[0014] In the above-mentioned implementation process, in the process of constructing the target pressure difference function, the pressure difference curve construction unit of the control device provided in the embodiment of the present application sets the deviation adjustment value of the function so that the average value of the target pressure difference function is above 50 mmHg, thereby ensuring that the aortic pressure will not be too low and that the cardiac output can meet the control requirements; on the other hand, the deviation adjustment value can be used to adjust the average pressure difference to achieve regulation of the average cardiac output.

[0015] Optionally, in an embodiment of the present application, the control device also includes a reflux control module; after constructing a target pressure difference curve based on the pulsation of the blood vessel and obtaining a target pressure difference according to the target pressure difference curve, the reflux control module is used to connect a low-pressure control function in series after the target pressure difference curve to reduce the blood vessel pressure after the target pressure difference control.

[0016] In the above-mentioned implementation process, the pulsation-based control device provided in the embodiment of the present application realizes effective control of aortic valve regurgitation by setting up a regurgitation control module; the regurgitation control module controls the increase of aortic pressure caused by target pressure difference control through the low-pressure control function by connecting a low-pressure control function in series after the target pressure difference curve, thereby effectively reducing the aortic pressure and avoiding structural damage to the valve to a great extent.

[0017] Optionally, in an embodiment of the present application, the control device also includes a preprocessing module; before obtaining the current current and current speed of the motor of the ventricular assist device, the preprocessing module is used to obtain the current current and current original speed of the ventricular assist device; and filter the current original speed to obtain the current speed.

[0018] In the above implementation process, the pulsation-based control device provided in the embodiment of the present application also includes a preprocessing module; the preprocessing module is used to perform filtering operations on the collected speed signal; it can eliminate or weaken the influence of interference and noise, and improve the reliability and accuracy of the measurement.

[0019] In a second aspect, an embodiment of the present application provides a ventricular assist system based on pulsation, which comprises: a ventricular assist device, a detection module and the control device provided in the first aspect of the present application; the detection module is used to obtain the current speed of the motor and the current current of the motor; the control device is used to control the speed of the motor of the ventricular assist device according to the current speed of the motor and the current current of the motor.

[0020] In a third aspect, an embodiment of the present application provides a control method based on pulsatility, which is used to control the speed of a motor of a ventricular assist device; the method comprises: obtaining a current pressure difference based on a current current and a current speed of the motor; wherein the current pressure difference represents the pressure difference between a blood vessel and a ventricle; constructing a target pressure difference curve based on the pulsatility of the blood vessel, and obtaining a target pressure difference based on the target pressure difference curve; and controlling the speed of the motor based on the current pressure difference and the target pressure difference.

[0021] In a fourth aspect, an embodiment of the present application provides an electronic device, comprising a memory and a processor, wherein the memory stores program instructions, and when the processor reads and runs the program instructions, it executes the steps in the implementation method of the third aspect above.

[0022] In a fifth aspect, an embodiment of the present application further provides a computer-readable storage medium, wherein the computer program instructions are stored in the computer-readable storage medium. When the computer program instructions are read and executed by a processor, the steps in the implementation method of the third aspect are executed. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 A first schematic diagram of a module of a pulsation-based control device provided in an embodiment of the present application;

[0025] Figure 2 A second schematic diagram of a module of a pulsation-based control device provided in an embodiment of the present application;

[0026] Figure 3 A first example image of a target pressure difference curve provided in an embodiment of the present application;

[0027] Figure 4 A second example image of a target pressure difference curve provided in an embodiment of the present application;

[0028] Figure 5 A schematic diagram of the system architecture of a pulsation-based control device provided in an embodiment of the present application;

[0029] Figure 6 A control flow chart based on pulsation provided in an embodiment of the present application;

[0030] Figure 7 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be described below in conjunction with the accompanying drawings in the embodiments of the present application. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architectures, functions and operations of the systems, methods and computer program products according to multiple embodiments of the present invention. In this regard, each box in the flowchart or block diagram may represent a module, a program segment or a part of a code, and the module, a program segment or a part of a code contains one or more executable instructions for implementing the specified logical functions. It should also be noted that in some alternative implementations, the functions marked in the box may also occur in an order different from that marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they may sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or the flowchart, and the combination of boxes in the block diagram and / or the flowchart, can be implemented by a dedicated hardware-based system that performs a specified function or action, or can be implemented by a combination of dedicated hardware and computer instructions. In addition, the functional modules in the various embodiments of the present invention can be integrated together to form an independent part, or each module can exist separately, or two or more modules can be integrated to form an independent part.

[0032] Heart failure is the terminal stage of heart disease. It is manifested in the inability to fully discharge venous blood from the heart due to heart dysfunction, which leads to blood congestion in the venous system and insufficient blood perfusion in the arterial system, thus causing cardiac circulation disorders. Due to the shortage of heart donors, ventricular assist devices (VADs) have become one of the important treatments for patients with end-stage heart failure; therefore, the study of control strategies for left ventricular assist devices can improve the utilization of the device.

[0033] The applicant discovered during the research that, currently, the control of a ventricular assist device is often performed by directly controlling the current or speed of the motor of the ventricular assist device, and no control method based on a specific intracardiac environment is proposed.

[0034] Taking the left ventricular assist device as an example, during the contraction and relaxation period of the heart, the opening and closing of the valve directly affects the pressure difference between the aorta and the left ventricle. At the same time, the pressure difference also directly reflects the blood supply capacity of the catheter pump.

[0035] Therefore, the pressure difference can be regarded as a characteristic value of the heart beat, and a control method based on the pressure difference can be considered. When the patient's heart failure is more serious, the catheter pump is required to provide a higher auxiliary cardiac output to meet the body's blood supply needs, but a higher cardiac output means a high speed and a high pressure difference. When the pressure difference is high enough, the aortic pressure increases, which may cause the aortic pressure to be higher than the left ventricular pressure, resulting in the inability of the valve to open, causing a certain degree of structural damage to the patient's aortic valve in the long term; based on this, this scheme provides a control method based on pulsation, which improves the problem of the valve being unable to open while meeting the control requirements of the ventricular assist device through pulsation control of the pressure difference.

[0036] Before introducing the specific content of this application, a brief introduction to ventricular assist devices is first given. Ventricular assist devices include left ventricular assist devices (LVAD) and right ventricular assist devices (RVAD), which are also often referred to as artificial hearts; among them, the left ventricular assist device is a mechanical cardiac assist device that provides circulation support when the left ventricle cannot meet the system perfusion needs. The right ventricular assist device is usually only used for short-term support of the right ventricle after LVAD surgery or other heart surgery. The right ventricular assist device helps the right ventricle pump blood to the pulmonary artery (PULL-mun-ary), the artery that transports blood to the lungs to absorb oxygen.

[0037] Please see Figure 1 , Figure 1 This is a first schematic diagram of a module of a pulsation-based control device 100 provided in an embodiment of the present application; the control device provided in an embodiment of the present application includes a current pressure difference determination module 110, a target pressure difference determination module 120 and a motor control module 130.

[0038] The current pressure difference determination module 110 is used to obtain the current pressure difference according to the current current and current speed of the motor.

[0039] The current pressure difference determination module 110 obtains the current pressure difference between the ventricle and the blood vessel of the ventricular assist device according to the current speed and current current of the motor of the ventricular assist device; it should be understood that the current pressure difference represents the pressure difference between the blood vessel and the ventricle. For example, taking the left ventricular assist device as an example, the current pressure difference is the current pressure difference between the left ventricle and the aortic valve.

[0040] The target pressure difference determination module 120 is used to construct a target pressure difference curve based on the pulsation of the blood vessel, and obtain the target pressure difference according to the target pressure difference curve.

[0041] It should be noted that pulsation refers to the fluctuation of the arterial blood vessel wall caused by the contraction of the heart, and the pulsation formed by the periodic fluctuation of the heart. The pulsation of human blood circulation is the result of the continuous interaction between blood flow and elastic blood vessel walls. In other words, the pulsation of blood vessels is related to the contraction and relaxation of the heart. Taking the pulsation of blood vessels as one of the control factors can make the control of ventricular assist devices more in line with the laws of the human body.

[0042] The motor control module 130 is used to control the speed of the motor based on the current pressure difference and the target pressure difference.

[0043] After the target pressure difference determination module 120 completes the construction of the target pressure difference curve, the motor control module 130 can obtain the target pressure difference corresponding to the current pressure difference according to the target pressure difference curve; further, the speed of the motor can be controlled according to the current pressure difference and the target pressure difference.

[0044] pass Figure 1 It can be seen that the current pressure difference determination module 110 of the pulsation-based control device provided in the embodiment of the present application obtains the current pressure difference according to the current speed and current current of the motor, and the target pressure difference determination module 120 constructs a target pressure difference curve based on the pulsation of the blood vessels, and then the motor control module 130 obtains the target pressure difference corresponding to the current pressure difference, so as to obtain the control amount for controlling the motor speed based on the target pressure difference and the current pressure difference, thereby realizing the pulsation-based control of the ventricular assist device; since the pulsation control of the pressure difference is realized, the control device provided in the embodiment of the present application can meet the control requirements of the ventricular assist device while also improving the situation where the valve cannot open due to the aortic pressure being continuously higher than the left ventricular pressure.

[0045] Please see Figure 2 , Figure 2 A second schematic diagram of a module of a pulsation-based control device 100 provided in an embodiment of the present application; in an optional implementation of an embodiment of the present application, the target pressure difference curve corresponds to a curve graph of a target pressure difference function; the target pressure difference determination module 120 includes a pressure difference curve construction unit 121.

[0046] In the process of constructing a target pressure difference curve based on the pulsatility of the blood vessels:

[0047] The pressure difference curve construction unit 121 is used to obtain a pulsating pressure difference function based on the pulsation of the blood vessel.

[0048] In the above implementation process, the pressure difference curve construction unit 121 first constructs a basic function formula of a pulsating pressure difference function based on the pulsation principle of the blood vessels; it should be noted that, since the pulsation is periodic and nonlinear, the pulsating pressure difference function in the embodiment of the present application is a periodic nonlinear function, which can conform to the pulsation to the greatest extent.

[0049] Furthermore, the pressure difference curve construction unit 121 is used to determine parameter values ​​of the pulsating pressure difference function to obtain a target pressure difference function.

[0050] After determining a periodic, nonlinear basic function, the pressure difference curve construction unit 121 needs to adjust the parameters of the function based on physiological laws to obtain the required target pressure difference function. For example, the parameter values ​​in the above process can be parameters such as amplitude and period. In the process of constructing the target pressure difference curve, the pulsation-based control method provided in the embodiment of the present application adjusts the parameter values ​​of the pulsating pressure difference function to obtain the final target pressure difference function.

[0051] pass Figure 2 It can be seen that in order to obtain a target pressure difference based on pulsation, the pulsation-based control device 100 provided in the embodiment of the present application constructs a target pressure difference function through the pressure difference curve construction unit 121; the target pressure difference function is a periodic nonlinear function constructed based on the pulsation of the blood vessel, and after the pressure difference curve construction unit 121 adjusts the parameters of the pulsating pressure difference function, the final target pressure difference function can be obtained; it can be seen that the control device provided in the embodiment of the present application constructs a target pressure difference function based on the pulsation of the blood vessel, so as to control the pressure difference between the aorta and the left ventricle within a reasonable range while ensuring the control requirements of the heart assist device.

[0052] In an optional implementation, the parameter value also includes a synchronization control period.

[0053] In the process of determining the parameter value of the pulsating pressure difference function: the pressure difference curve construction unit 121 is specifically used to determine the synchronization control period T according to the preset multiple of the cardiac cycle through the formula T=n*(time / bt). Wherein, bt is the heart rate value, time / bt is the cardiac cycle, and n is a positive integer; illustratively, the cardiac cycle in seconds is generally 60 / bt. It should be noted that the synchronization control period characterizes that the fluctuation of the pulsating pressure difference function is synchronized with the contraction and relaxation process of the heart.

[0054] It should be understood that the cardiac cycle refers to the process that the cardiovascular system goes through from the start of one heartbeat to the start of the next heartbeat. For example, if the average heart rate (bt) of an adult is 75 beats per minute, each cardiac cycle is 0.8 seconds on average, that is, T = n (time / bt) = n*0.8. In the embodiment of the present application, the synchronous control period of the target pressure difference function is generally an integer multiple of the human heartbeat period; it has been verified that when n is 3, that is, when T = 3*0.8 = 2.4, the synchronous control effect is best.

[0055] It can be seen from this that the pulsation-based control device provided in the embodiment of the present application, in order to make the synchronous control period of the target pressure difference function correspond to the human heartbeat cycle, that is, to the contraction and relaxation process of the heart, the pressure difference curve construction unit 121 of the control device 100 obtains the synchronous control period of the target pressure difference function according to the cardiac cycle. When the current pressure difference follows the target pressure difference obtained based on the target pressure difference function, the problem of poor aortic pulsation can be solved.

[0056] In an optional embodiment, the parameter value includes an amplitude.

[0057] In the process of determining the parameter value of the pulsating pressure difference function: the pressure difference curve construction unit 121 is specifically used to control the difference between the peak and valley values ​​of the pulsating pressure difference function to be greater than or equal to the pulsating pressure difference threshold value according to the preset pulsatility requirement; and determine the amplitude according to the difference between the peak and valley values.

[0058] The nonlinear function has peaks and troughs, and the peak and trough values ​​correspond to the high and low pressures of the pressure difference respectively; the preset pulsatility requirement in the above process can be understood as the minimum difference to ensure the pulsatility of the blood vessel; for example, to ensure the pulsatility of the blood vessel, the pressure difference between the high pressure and the low pressure usually needs to be above 20 mmHg. Only when this requirement is met, when the pressure difference is high pressure, the aortic valve is closed, and when the pressure difference is low pressure, the aortic valve is opened, can the aortic valve performance be guaranteed.

[0059] It can be seen that in order for the ventricular assist device to meet the basic requirements that the aortic valve closes when the pressure difference is high pressure and opens when the pressure difference is low pressure, the pressure difference between the high pressure and the low pressure needs to be controlled within the pulsating pressure difference range. The pressure difference curve construction unit 121 of the control device 100 provided in the embodiment of the present application determines the amplitude of the pulsating pressure difference function according to the principle in the above implementation process, which can ensure the normal operation of the ventricular assist device.

[0060] In an optional embodiment, the parameter value also includes a deviation adjustment value of the function.

[0061] In the process of determining the parameter value of the pulsating pressure difference function: the pressure difference curve construction unit 121 is specifically used to determine the deviation adjustment value of the function according to the preset mean range of the pressure difference. It should be noted that the deviation adjustment value of the function is used to ensure that the lowest pressure of the blood vessel does not exceed the low pressure threshold on the basis of the amplitude. The low pressure threshold, that is, the low pressure of the artery, is generally between 60-80 mmHg.

[0062] When the aortic pressure is too low, the blood supply to all parts of the body will be reduced accordingly; it is understandable that the average value of the nonlinear function must be above 50 mmHg to ensure that the aortic pressure is not too low and that the cardiac output can meet the control requirements.

[0063] It can be seen that in the process of constructing the target pressure difference function of the control device 100 provided in the embodiment of the present application, the pressure difference curve construction unit 121 sets the deviation adjustment value of the function so that the average value of the target pressure difference function is above 50 mmHg, thereby ensuring that the aortic pressure will not be too low and that the cardiac output can meet the control requirements; on the other hand, the deviation adjustment value can be used to adjust the average pressure difference to achieve regulation of the average cardiac output.

[0064] Please see Figure 3 , Figure 3 A first example image of a target pressure difference curve provided in an embodiment of the present application; Figure 3 In the graph, the horizontal axis is time (in seconds) and the vertical axis is pressure difference (in millimeters of mercury); the curve reflects the change of pressure difference over time.

[0065] Figure 3 The function form of the target pressure difference curve in is ΔP set =A+Bsin(wt), since the peak value of the sin function is 1 and the valley value is -1; according to the function requirements provided in the embodiment of the present application, to satisfy the maximum minus minimum amplitude greater than 20, it is sufficient that B is greater than 10; Figure 3 As an example, B is set to 20. Wherein, A represents the average value of the nonlinear function, and according to the function requirements provided in the embodiment of the present application, it needs to be greater than 50; Figure 3 As an example, A is taken as 60.

[0066] Furthermore, if the heart rate bt = 75, then the cardiac cycle is 60 / bt = 0.8; the synchronous cycle of pulsation control = n*cardiac cycle, if n is 3, then the angular frequency That is, the final target pressure difference function is ΔP set =60+20sin(2.6t), different target pressure differences ΔP can be obtained according to this function set .

[0067] Please see Figure 4 , Figure 4 A second example image of a target pressure difference curve provided in an embodiment of the present application; Figure 4 In the graph, the horizontal axis is time (in seconds) and the vertical axis is pressure difference (in millimeters of mercury); the curve reflects the change of pressure difference over time.

[0068] Figure 4 The function form of the target pressure difference curve in is ΔP set =a+b*(t-kT), T is the control period, T=3*cardiac period, a is the intercept, which reflects the average value A, and a>A-0.5*b*T; b is the slope, which reflects the amplitude of change, and b>B / T. Figure 4As an example, T=2.4, a=40, b=10, the average value within the period is (64+40) / 2=52>50, which meets the requirement, and the amplitude is 64-40=24>20, which meets the requirement.

[0069] In an optional implementation of the embodiment of the present application, the motor control module 130 controls the speed of the motor based on the current pressure difference and the target pressure difference, which can be achieved by the following steps:

[0070] Step S100: Calculate the pressure difference value according to the current pressure difference and the target pressure difference.

[0071] In the above step S100, the pressure difference value is calculated according to the current pressure difference and the target pressure difference. For example, the current pressure difference is ΔP e , the target pressure difference is ΔP set ; then the pressure difference is ΔP set -ΔP e .

[0072] Step S101: Perform proportional-integral control on the pressure difference to obtain a target control amount.

[0073] In the above step S101, the pressure difference is subjected to proportional integral control to obtain the target control amount. It should be noted that proportional integral control, i.e. PI control, is a method of controlling a controlled object by linearly combining the proportion and integral of the deviation to form a control amount based on the control deviation between a given value and an actual output value.

[0074] Step S102: Control the speed of the motor according to the target control amount.

[0075] In the above step S102, after the target control amount is obtained, the target control amount is used to control the speed of the motor. For example, the controller sets different A and B value target pressure differences ΔP according to the gear position. set , perform PI control of the pressure difference, and perform proportional integral control on the above pressure difference as follows:

[0076]

[0077] Among them, K p and K i is a PI control parameter, which can be obtained through empirical debugging in practical applications. In the embodiment of the present application, the target control quantity obtained by PI control is the current, that is, after obtaining the control quantity I, the current I is used to control the speed of the motor, thereby realizing the control of the auxiliary device.

[0078] It should be noted that the function form corresponding to the target pressure difference curve is ΔP set=A+Bsin(wt) as an example, the higher the gear of the ventricular assist device, the faster the motor speed, the higher the average aortic pressure, so A needs to be continuously increased with the gear. Similarly, the higher the gear, the faster the motor speed, the pulsation of the aorta itself is significantly reduced, and the motor needs to generate a larger fluctuation to improve the pulsation of the aorta, so B also increases with the gear.

[0079] The gear of the ventricular assist device, for example, the preset flow value of P1 gear is 0.5L / min, the preset flow value of P2 gear is 1.5L / min, and the preset flow value of P3 gear is 2.5L / min. Different A and B values ​​need to be set according to different gears. For example, P1 gear: A=50, B=15; P2 gear: A=60, B=20; P3 gear: A=70, B=30.

[0080] On the other hand, the higher the heart rate, the higher the required cardiac output, and A needs to be increased to increase the motor speed and increase the blood supply capacity of the pump. After A increases, the aortic pulsatility decreases, so B needs to be increased to increase the pulsatility.

[0081] In the same gear, different heart rates correspond to different A and B values. For example, in P1 gear, if the heart rate is 70, A=50, B=15; if the heart rate is 80, A=60, B=30; if the heart rate is 90, A=70, B=50.

[0082] It should be noted that the above values ​​are only exemplary, and as long as the average pressure difference A is above 50 mmHg, the pressure difference between the high pressure and the low pressure needs to be above 20 mmHg.

[0083] It can be seen that after the pressure difference curve construction unit 121 obtains the target pressure difference corresponding to the current pressure difference according to the constructed target pressure difference function, the motor control module 130 calculates the pressure difference value according to the current pressure difference and the target pressure difference, and performs proportional integral control on the calculated pressure difference value to obtain the target control amount of the control motor. Realizing that the current pressure difference follows the target pressure difference can not only solve the problem of poor aortic pulsation, but also improve the structural damage of the aortic valve caused by excessively high pressure difference.

[0084] In an optional embodiment, the control device 100 provided in the present application also includes a reflux control module; after constructing a target pressure difference curve based on the pulsation of the blood vessel and obtaining a target pressure difference according to the target pressure difference curve, the reflux control module is used to connect a low-pressure control function in series after the target pressure difference curve to reduce the blood vessel pressure after the target pressure difference control.

[0085] If the control cycle composed of the target pressure difference function corresponding to the target pressure difference curve and the low pressure control function is regarded as a comprehensive control cycle for controlling the ventricular assist device; the low pressure difference control function can be understood as a function that can control the pressure difference or the mean pressure difference within a comprehensive control cycle within an appropriate range; wherein, the appropriate range can be understood as being able to ensure the control requirements of the ventricular assist device (each gear has a corresponding cardiac output, and the control requirements of the ventricular assist device can be understood as being able to achieve basic gear control of the ventricular assist device); at the same time, under the control of the low pressure difference control function, the mean pressure difference within the comprehensive control cycle can be controlled within a lower range to a certain extent to slow down the problem of blood regurgitation through the aortic valve.

[0086] The process of constructing the low voltage control function can be:

[0087] The minimum value of the target pressure difference function corresponding to the target pressure difference curve is obtained, and the target function whose function average value is less than the minimum value of the target pressure difference function is determined as the low pressure control function. For example, if the minimum value of the target pressure difference corresponding to the target pressure difference function is 30 mmHg, then the average value of the low pressure difference control function only needs to be less than 30 mmHg; that is, any function whose average value is less than 30 mmHg can be determined as the low pressure difference control function in the embodiment of the present application, which can play a role in reducing aortic pressure.

[0088] Furthermore, in order to achieve a better effect in controlling aortic valve regurgitation, it is necessary to determine the control proportion time of the target pressure difference function and the low-pressure control function in the entire comprehensive control cycle; among them, the low-pressure difference proportion time is positively correlated with the average value of the low-pressure difference control function; that is, the higher the average value of the low-pressure difference control function is set, the longer its control time should be appropriately extended.

[0089] For example, the function corresponding to the target pressure difference curve is ΔP set =A+Bsin(wt) as an example, the piecewise function expression composed of the target pressure difference function and the low pressure control function can be:

[0090]

[0091] Among them, k is a positive integer, T0 is the comprehensive control cycle, and μ is the proportion control parameter; it can also be seen from the piecewise function that μ can adjust the proportion of low pressure difference. C is any natural number less than AB, and the effect of reducing the average value of the final pressure difference within the comprehensive control cycle is to slow down the degree of blood regurgitation through the aortic valve.

[0092] For example, the function corresponding to the target pressure difference curve is ΔP set =A+Bsin(wt) as an example, the piecewise function expression composed of the target pressure difference function and the low pressure control function can also be:

[0093]

[0094] It can be understood that the average value of the low-pressure control function connected in series in the embodiment of the present application is lower than the minimum value of the target pressure difference function, and the comprehensive control function corresponding to the comprehensive control strategy after series connection is not unique or fixed, as long as it can reduce the low speed of the ventricular assist device.

[0095] Since connecting a comprehensive control function in series after the target pressure difference function may result in the cardiac output generated during the entire comprehensive control cycle being insufficient to meet the cardiac output requirement; in this case, the A value can be appropriately increased to compensate for the loss of cardiac output caused by the low pressure difference.

[0096] Additionally, the aortic regurgitation can be monitored by a regurgitation detection device or a regurgitation detection module. When the aortic regurgitation exceeds a threshold value, the regurgitation detection device or module can send a regurgitation signal. When the control device provided in the embodiment of the present application receives a regurgitation signal, the motor speed of the ventricular assist device can be controlled by a comprehensive control strategy, thereby timely reducing the aortic regurgitation. In the above process, the low-pressure control function can be a function whose average value is lower than the minimum value of the target pressure difference curve, thereby reducing the mean pressure difference within the comprehensive control cycle while meeting the control requirements of the ventricular assist device, effectively reducing the problem of blood regurgitation through the aortic valve.

[0097] It should be noted that when the heart is in diastole, the valve is closed, but due to the presence of the catheter pump, there is a gap between the valve and the heart; therefore, reflux will occur, which can easily lead to structural damage to the human valve.

[0098] It can be seen that the pulsation-based control device 100 provided in the embodiment of the present application realizes effective control of aortic valve regurgitation by setting up a regurgitation control module; the regurgitation control module controls the increase in aortic pressure caused by target pressure difference control through the low-pressure control function by connecting a low-pressure control function in series after the target pressure difference curve, thereby effectively reducing the aortic pressure and avoiding structural damage to the valve to a great extent.

[0099] In an optional embodiment, the control device 100 also includes a preprocessing module; before the current current and current speed of the motor of the ventricular assist device: the preprocessing module is used to obtain the current current and current original speed of the ventricular assist device; and filter the current original speed to obtain the current speed.

[0100] The current speed and current data of the pump are collected. In practical applications, the current and speed are inherent parameters of the blood pump and can be obtained in real time without additional sensors.

[0101] Due to the nonlinearity of the pump itself, the Extended Kalman Filter (EKF) algorithm can be used to estimate the pressure difference ΔP from the noisy speed signal. e .

[0102] It should be noted that it is an extended form of the standard Kalman filter in the nonlinear case. The EKF algorithm Taylor expands the nonlinear function, omits the high-order terms, and retains the first-order terms of the expanded terms to achieve the linearization of the nonlinear function. Finally, the Kalman filter algorithm is used to approximate the state estimate and variance estimate of the system to filter the signal. The extended Kalman filter is an improvement of the Kalman filter, and the model form is:

[0103] x k =f(x k-1 ,u k )+w k

[0104] z k =h(x k )+v k

[0105] Among them, x k is the state value at time k, x k-1 is the state value at time k-1, u k is the control input at time k, w k 、v k is the interference at time k, z k is the measured value at time k.

[0106] In the above process, the pressure difference calculated or estimated according to the current speed and the current current can be obtained through the HQ curve. It should be noted that the use of the extended Kalman filter to filter the speed signal in the above process is only exemplary, and other filters can be selected to achieve filtering, such as Wiener filters, adaptive filters, etc.; the selection of filters cannot be a limitation on the protection scope of the embodiments of this application.

[0107] It can be seen from this that the pulsation-based control device provided in the embodiment of the present application also includes a preprocessing module; the preprocessing module is used to perform filtering operations on the collected speed signal; it can eliminate or weaken the influence of interference and noise, and improve the reliability and accuracy of the measurement.

[0108] A second aspect of the present application provides a ventricular assist system, which includes: a ventricular assist device, a detection module, and the control device provided in the first aspect of the present application.

[0109] The detection module is used to obtain the current speed of the ventricular assist device motor and the current current of the ventricular assist device motor. Exemplarily, the detection module may include a detection device for detecting the current speed of the ventricular assist device motor and a detection device for detecting the current current of the ventricular assist device motor. It should be noted that the method for detecting the current speed of the ventricular assist device motor may use methods such as tachometer generator speed measurement, photoelectric digital speed measurement, magnetoelectric speed sensor speed measurement, leakage magnetic speed measurement method speed measurement and vibration speed measurement.

[0110] The control device is used to control the speed of the motor of the ventricular assist device according to the current speed of the motor of the ventricular assist device and the current current of the motor of the ventricular assist device, so as to achieve the purpose of controlling the flow of the ventricular assist device.

[0111] Please see Figure 5 , Figure 5 A schematic diagram of the system architecture of a pulsation-based control device provided in an embodiment of the present application; Figure 5 In the present invention, the target pressure difference determination module 120 constructs a target pressure difference curve based on the pulsation of the blood vessels, obtains the target pressure difference according to the target pressure difference curve, and finally outputs DPset; the current pressure difference determination module 110 obtains the current pressure difference according to the current current I and the current speed N of the motor, and finally outputs DPe; the motor control module 130 obtains the motor control quantity I based on the current pressure difference DPe and the target pressure difference DPset, and controls the speed of the motor of the ventricular assist device (VAD).

[0112] Please see Figure 6 , Figure 6 A control flow chart based on pulsation provided in an embodiment of the present application; a third aspect of an embodiment of the present application provides a control method based on pulsation, which may include the following steps:

[0113] Step S200: Obtain the current pressure difference according to the current current and current speed of the motor.

[0114] In the above step S200, the current pressure difference between the ventricle and the blood vessel of the ventricular assist device is obtained according to the current speed and current current of the motor of the ventricular assist device; it should be understood that the current pressure difference represents the pressure difference between the blood vessel and the ventricle. Exemplarily, taking the left ventricular assist device as an example, the current pressure difference is the current pressure difference between the left ventricle and the aortic valve.

[0115] Step S201: constructing a target pressure difference curve based on the pulsation of the blood vessel, and obtaining a target pressure difference according to the target pressure difference curve.

[0116] In the above step S201, a target pressure difference curve is constructed based on the pulsation of the blood vessel; and then the target pressure difference is obtained according to the constructed target pressure difference curve.

[0117] Step S202: Based on the current pressure difference and the target pressure difference, the speed of the motor is controlled.

[0118] In the above step S202, after the target pressure difference curve is constructed, the target pressure difference corresponding to the current pressure difference can be obtained according to the target pressure difference curve; further, the speed of the motor can be controlled according to the current pressure difference and the target pressure difference.

[0119] pass Figure 6 It can be seen that the control method based on pulsatility provided in the embodiment of the present application obtains the current pressure difference according to the current speed and current current of the motor, and constructs a target pressure difference curve based on the pulsatility of the blood vessels, thereby obtaining a target pressure difference corresponding to the current pressure difference, and then deriving a control amount for controlling the motor speed based on the target pressure difference and the current pressure difference, thereby realizing the control of the ventricular assist device based on pulsatility; because the pulsatility control of the pressure difference is realized, the control method provided in the embodiment of the present application can meet the control requirements of the ventricular assist device while also improving the situation where the valve cannot open due to the aortic pressure being continuously higher than the left ventricular pressure. Deviation adjustment value of function Deviation adjustment value of function Deviation adjustment value of function.

[0120] See also Figure 7 , Figure 7 The electronic device 300 provided in the embodiment of the present application includes: a processor 301 and a memory 302, wherein the memory 302 stores machine-readable instructions executable by the processor 301, and when the machine-readable instructions are executed by the processor 301, the control method provided in the third aspect of the embodiment of the present application is executed.

[0121] Based on the same inventive concept, an embodiment of the present application also provides a computer-readable storage medium, in which computer program instructions are stored. When the computer program instructions are read and run by a processor, the steps in the implementation method provided in the third aspect of the embodiment of the present application are executed.

[0122] The computer-readable storage medium may be a random access memory (RAM), a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or any other medium that can store program codes. The storage medium is used to store the program, and the processor executes the program after receiving the execution instruction. The method executed by the electronic terminal of the process definition disclosed in any embodiment of the present invention can be applied to the processor or implemented by the processor.

[0123] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, and the indirect coupling or communication connection of the devices or units can be electrical, mechanical or other forms.

[0124] In addition, the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0125] Furthermore, the functional modules in the various embodiments of the present application may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

[0126] Alternatively, the present invention may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented by software, the present invention may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present invention is generated in whole or in part.

[0127] The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means.

[0128] In this article, relational terms such as first and second, etc. are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "include..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0129] The above description is only an embodiment of the present application and is not intended to limit the protection scope of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A control device based on pulsation, characterized in that: The device comprises: a current pressure difference determination module, a target pressure difference determination module and a motor control module; The current pressure difference determination module is used to obtain the current pressure difference according to the current current and current speed of the motor of the ventricular assist device; wherein the current pressure difference represents the pressure difference between the blood vessel and the ventricle; The target pressure difference determination module is used to construct a target pressure difference curve based on the pulsation of the blood vessel, and obtain the target pressure difference according to the target pressure difference curve; The motor control module is used to control the rotation speed of the motor based on the current pressure difference and the target pressure difference.

2. The device according to claim 1, characterized in that in, The target pressure difference curve includes a curve of a target pressure difference function; the target pressure difference determination module includes a pressure difference curve construction unit; In the process of constructing a target pressure difference curve based on the pulsatility of the blood vessels: The pressure difference curve construction unit is used to obtain a pulsating pressure difference function based on the pulsation of the blood vessel; wherein the pulsating pressure difference function includes a periodic nonlinear function; The pressure difference curve construction unit is further used to determine parameter values ​​of the pulsating pressure difference function to obtain the target pressure difference function.

3. The device according to claim 2, characterized in that in, The parameter value also includes a synchronization control period; In the process of determining the parameter value of the pulsating pressure difference function: The pressure difference curve construction unit is specifically used to determine the synchronization control period T according to a preset multiple of the cardiac cycle through the formula T=n(time / bt); wherein bt is the heart rate value, time / bt is the cardiac cycle, and n is a positive integer; the synchronization control period characterizes that the fluctuation of the pulsating pressure difference function is synchronized with the contraction and relaxation process of the heart.

4. The device according to claim 2, characterized in that in, The parameter value includes an amplitude; In the process of determining the parameter value of the pulsating pressure difference function: The pressure difference curve construction unit is specifically used to control the difference between the peak value and the valley value of the pulsating pressure difference function to be greater than or equal to the pulsating pressure difference threshold value according to the preset pulsatility requirement; and The amplitude is determined according to the difference between the peak value and the valley value.

5. The device according to claim 4, characterized in that in, The parameter value also includes a deviation adjustment value of the function; In the process of determining the parameter value of the pulsating pressure difference function: The pressure difference curve construction unit is specifically used to determine the deviation adjustment value of the function according to a preset mean range of the pressure difference; wherein the deviation adjustment value of the function is used to ensure that the lowest pressure of the blood vessel does not exceed the low pressure threshold based on the amplitude.

6. The device according to claim 1, characterized in that The control device further comprises a reflux control module; after constructing a target pressure difference curve based on the pulsatility of the blood vessels and obtaining a target pressure difference according to the target pressure difference curve, The reflux control module is used to connect a low pressure control function in series after the target pressure difference curve to reduce the blood vessel pressure after the target pressure difference control.

7. The device according to claim 1, characterized in that The control device further comprises a preprocessing module; before the current current and current speed of the motor of the ventricular assist device are determined, The preprocessing module is used to obtain the current current and the current original rotation speed of the ventricular assist device; as well as The current raw rotation speed is filtered to obtain the current rotation speed.

8. A pulsatility-based ventricular assist system, characterized in that: The ventricular assist system comprises: a ventricular assist device, a detection module and a control device according to any one of claims 1 to 7; The detection module is used to obtain the current rotation speed of the motor and the current current of the motor; The control device is used to control the rotation speed of the motor of the ventricular assist device according to the current rotation speed of the motor and the current current of the motor.

9. A control method based on pulsation, characterized in that: The control method is used to control the speed of a motor of a ventricular assist device; the method comprises: Obtaining a current pressure difference according to a current current and a current rotation speed of the motor; wherein the current pressure difference represents a pressure difference between a blood vessel and a ventricle; Based on the pulsation of the blood vessel, a target pressure difference curve is constructed, and a target pressure difference is obtained according to the target pressure difference curve; Based on the current pressure difference and the target pressure difference, the rotation speed of the motor is controlled.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer program instructions, and when the computer program instructions are executed by a processor, the steps of the method according to claim 9 are executed.

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