Speed control method and device

Abstract

The invention provides a speed control method and device.The method comprises the steps that a target flow pulsation index is obtained, and the target flow pulsation index is the pulsation index of the pumping flow when a ventricular assist device operates in a first period; if the target flow pulsation index is smaller than or equal to the first threshold value, using a first speed mode to control the ventricular assist device to operate; if the target flow pulsation index is larger than the first threshold value and smaller than the second threshold value, the ventricular assist device is controlled to operate in a second speed mode. The target flow pulsation index is compared with the preset threshold value to judge the flow demand of the current ventricular assist device, and then the speed mode of the ventricular assist device is adjusted according to the flow demand, so that the cardiac output of the ventricular assist device better conforms to the physiological law of the heart; the probability of complications such as bleeding, thrombus and right heart failure possibly caused by low blood pulsation is reduced.

Description

Technical Field

[0001] This application relates to the technical field of medical devices, and particularly to a speed control method and device. Background Art

[0002] Pumps used as mechanical circulatory support devices include a pumping mechanism for pumping fluid from one location to another, such as a centrifugal pump, an axial flow pump, or a magnetic levitation pump for pumping blood from the heart to other parts of the body. The pump includes an impeller disposed within the pump housing to push the fluid through the pump housing from the inlet end of the pump to the outlet end, thereby realizing the fluid pumping function. The ventricular assist device is implanted in the patient's body for a long time, and the motor is an important component, and its lifespan directly determines the service life of the ventricular assist device.

[0003] Currently, the control of the ventricular assist device generally controls the operation of the motor at a constant speed, so that the ventricular assist device can operate at a constant speed. However, the constant speed may have problems in not being able to adapt to the actual needs of the patient's body. Summary of the Invention

[0004] Embodiments of this application provide a speed control method and device, which can make the cardiac output of the ventricular assist device more in line with the cardiac physiological law and achieve stable control of the cardiac output.

[0005] In a first aspect, embodiments of this application provide a speed control method applied to a ventricular assist device. The method includes:

[0006] Obtain a target flow pulsation index, where the target flow pulsation index is the pulsation index of the pumping flow when the ventricular assist device operates in a first period;

[0007] If the target flow pulsation index is less than or equal to a first threshold, control the operation of the ventricular assist device using a first speed mode;

[0008] If the target flow pulsation index is greater than the first threshold and less than a second threshold, control the operation of the ventricular assist device using a second speed mode.

[0009] In a second aspect, a control unit of a ventricular assist device provided by embodiments of this application includes one or more processors, and the one or more processors are used for:

[0010] Obtain a target flow pulsation index, where the target flow pulsation index is the pulsation index of the pumping flow when the ventricular assist device operates in a first period;

[0011] If the target flow pulsation index is less than or equal to a first threshold, control the operation of the ventricular assist device using a first speed mode;

[0012] If the target flow pulsation index is greater than the first threshold and less than the second threshold, control the operation of the ventricular assist device using the second speed mode.

[0013] In a third aspect, an embodiment of the present application provides a ventricular assist device, which includes:

[0014] A housing;

[0015] An impeller disposed within the housing;

[0016] A motor that drives the impeller to rotate in suspension;

[0017] The control unit connected to the motor, and the control unit is configured to execute some or all of the steps described in the method of the first aspect above.

[0018] In a fourth aspect, an embodiment of the present application provides a medical device, which includes a processor, a memory, a communication interface, and one or more programs. The one or more programs are stored in the memory and are configured to be executed by the processor. The programs include instructions for executing some or all of the steps described in the method of the first aspect above.

[0019] In a fifth aspect, an embodiment of the present application provides a computer-readable storage medium that stores a computer program for electronic data exchange, where the computer program causes a computer to execute some or all of the steps described in the method of the first aspect above.

[0020] In a sixth aspect, an embodiment of the present application provides a computer program product, where the computer program product includes a non-transitory computer-readable storage medium storing a computer program, and the computer program is operable to cause a computer to execute some or all of the steps described in the method of the first aspect of the embodiments of the present application. The computer program product can be a software installation package.

[0021] The technical solution provided by the present application obtains a target flow pulsation index, which is the pulsation index of the pumping flow when the ventricular assist device operates in the first cycle; if the target flow pulsation index is less than or equal to the first threshold, control the operation of the ventricular assist device using the first speed mode; if the target flow pulsation index is greater than the first threshold and less than the second threshold, control the operation of the ventricular assist device using the second speed mode. By comparing the target flow pulsation index with a preset threshold, the present application determines the current flow requirement of the ventricular assist device, and then adjusts the speed mode of the ventricular assist device according to the flow requirement, so that the cardiac output of the ventricular assist device is more in line with the physiological law of the heart, and reduces the probability of complications such as bleeding, thrombosis, and right heart failure that may be caused by low blood flow pulsation. Brief Description of the Drawings

[0022] To more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0023] Figure 1 is a schematic diagram of a ventricular assist system provided by an embodiment of the present application;

[0024] Figure 2 is a schematic structural diagram of a ventricular assist device provided by an embodiment of the present application;

[0025] Figure 3 is a schematic flowchart of a speed control method provided by an embodiment of the present application;

[0026] Figure 4 is a schematic waveform diagram of a square wave pulsation mode provided by an embodiment of the present application;

[0027] Figure 5 is a schematic waveform diagram of a sine wave pulsation mode provided by an embodiment of the present application;

[0028] Figure 6 is a schematic structural diagram of a medical device provided by an embodiment of the present application. Detailed Description of the Embodiments

[0029] To enable those skilled in the art to better understand the technical solutions of the present application, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, rather than all embodiments. Based on the description of the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative efforts fall within the scope protected by the present application.

[0030] The terms "first", "second", etc. in the specification, claims and above-mentioned drawings of the present application are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, software, product or device that includes a series of steps or units is not limited to the listed steps or units, but also includes unlisted steps or units, or other steps or units inherent to these processes, methods, products or devices.

[0031] References to "embodiments" in this specification mean that particular features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the present application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0032] The pump related to the present application can be a ventricular assist device in a medical assistance device. The pump can be an implantable or interventional ventricular assist device (Ventricular Assist Devices, VAD), and the VAD can be attached to the left ventricle, or the right ventricle, or both ventricles of the heart. The ventricular assist device can further include a centrifugal pump, an axial flow pump, etc. that can deliver the entire output of the pulmonary circulation or blood circulation to the left ventricle.

[0033] In the embodiments of the present application, a centrifugal magnetic levitation pump is taken as an example for description.

[0034] For example, please refer to Figure 1 , the ventricular assist system includes a ventricular assist device 100, an external controller 200, and a transmission component 300 that connects the ventricular assist device 100 to the external controller 200. One end of the transmission component 300 is connected to the motor inside the ventricular assist device 100, and the other end passes through the patient's skin and is connected to the external controller 200 provided outside the body. The external controller 200 is used to monitor the ventricular assist device 100, and it can implement functions such as control and data display of the ventricular assist device 100, fault detection and alarm, and data recording. The transmission component 300 can be a percutaneous cable, and the cable can include one or more power supply cables and one or more communication cables.

[0035] Among them, the ventricular assist device 100 includes an impeller, a motor that drives the impeller to rotate, and a built-in controller 110 that controls the operation of the motor. The built-in controller 110 is electrically connected to the external controller 200. The external controller 200 supplies power to the built-in controller 110 and sends operation control commands (such as motor start commands, speed setting commands, etc.) to the built-in controller 110 according to user operations. The built-in controller 110 controls the operation of the motor using the stored application software program, thereby realizing the pumping function of the ventricular assist device 100.

[0036] Please refer to Figure 2 , Figure 2 is a schematic structural diagram of a ventricular assist device 100 provided by an embodiment of the present application. The ventricular assist device 100 includes a housing assembly, an impeller 20 disposed inside the housing assembly, and a motor 10 that drives the impeller 20 to rotate in a suspended manner.

[0037] The housing assembly has a liquid inlet 14, a liquid outlet 15, and a first chamber 30 and a second chamber 40 that are spaced apart. Both the liquid inlet 14 and the liquid outlet 15 communicate with the first chamber 30. In the illustrated embodiment, the central axis of the liquid inlet 14 and the central axis of the liquid outlet 15 are perpendicular; the first chamber 30 and the second chamber 40 are arranged along the central axis of the liquid inlet 14. Among them, the first chamber 30 has a first chamber wall 31 and a second chamber wall 32 that are spaced apart and opposite along the central axis of the liquid inlet 14. The second chamber 40 is disposed close to the second chamber wall 32.

[0038] The impeller 20 is rotatably disposed in the first chamber 30. Among them, the impeller 20 is located between the first chamber wall 31 and the second chamber wall 32. Specifically, when the impeller 20 operates smoothly, the rotation axis 21 of the impeller 20 coincides with the central axis of the liquid inlet 14. By the rotation of the impeller 20, external liquid (such as blood) enters the first chamber 30 from the liquid inlet 14 and flows out from the liquid outlet 15.

[0039] The motor 10 includes a stator 11 and a rotor 13. The stator 11 is disposed in the second chamber 40, the rotor 13 is disposed in the first chamber 30, and the rotor 13 is fixedly connected to the impeller 20. Among them, the stator 11 can drive the rotor 13 to rotate in suspension, and the impeller 20 can rotate in suspension with the rotor 13. Specifically, the rotor 13 is disposed inside the impeller 20. The suspended rotation of the impeller 20 means that the impeller 20 does not contact the chamber wall of the first chamber 30 during rotation.

[0040] Exemplarily, the motor 10 can be a three-phase brushless direct current (BLDC) motor. The stator 11 has three windings controlled by different corresponding phases U, V, W of the power input controlled by a three-phase motor. The motor 10 may further include an inverter circuit, and the inverter circuit can be used to convert the DC input into a three-phase output. Exemplarily, the ventricular assist device 100 can receive a three-phase AC input.

[0041] The impeller 20 moves axially relative to the housing assembly along the rotation axis 21. During rotation, the impeller 20 is suspended within the housing assembly by a contactless bearing, such as a magnetic bearing, which can generate a magnetic levitation system. For example, in some embodiments, magnets (not shown in the figures) are also provided in the housing assembly and the impeller 20 respectively. The magnets in the housing assembly and the impeller 20 together form a magnetic bearing. The force generated by the magnetic bearing on the impeller 20 and the magnetic force generated between the stator 11 and the rotor 13 act on the impeller 20 together, enabling the impeller 20 to be suspended in the first chamber 30 in a state of magnetic balance, thereby realizing the floating and rotating motion state of the impeller 20. The control unit 33 can control the suspension attitude and position of the impeller 20 by controlling the magnetic force between the stator 11 and the rotor 13. At the same time, in the direction perpendicular to the rotation axis 21, a torsional force is generated by the attraction and repulsion between the stator 11 and the rotor 13, and this torsional force causes the impeller 20 to rotate in this direction. When the impeller 20 rotates at a preset speed, the attraction or thrust between the stator 11 and the rotor 13 causes the impeller 20 in the first chamber 30 to float and rotate in the first chamber 30.

[0042] The ventricular assist device 100 further includes a control unit 33 and a sensor 50. The control unit 33 is electrically connected to the stator 11, and the sensor 50 is electrically connected to the control unit 33. The sensor 50 is used to detect the magnetic pole angle and suspension height of the impeller 20, and the control unit 33 is used to receive the detection results of the sensor 50 and can control the speed and suspension height of the impeller 20 through the motor 10 according to the detection results. Specifically, the suspension height of the impeller 20 is the distance of the impeller 20 relative to the second chamber wall 32.

[0043] Further, the control unit 33 is used to monitor and control the start and subsequent operation of the motor 10, including implementing the Field-Oriented Control (FOC) method. The control unit 33 can be a module independent of the stator 11 or can be built into the stator 11. The control unit 33 includes hardware and software for controlling various aspects of the operation of the motor 10. The control unit 33 can be coupled to the motor 10 through an interface to collect at least one data of the motor 10. The at least one data can include the measured current flowing through the stator 11, the data measured by the sensor 50, the motor speed, the pressure difference across the pump, the flow pulsatility, the fluid flow rate, and so on.

[0044] For example, the sensor 50 can be a Hall sensor, an eddy current sensor, a distance sensor, etc.

[0045] Combined with the above description, the present application will be described from the perspective of method examples below.

[0046] Please refer to Figure 3 ,Figure 3 FIG. 1 is a schematic flow chart of a speed control method provided by an embodiment of the present application, which is applied to a ventricular assist device 100 as shown in Figure 1 - Figure 2 FIG. 2. As shown in Figure 3 FIG. 3, the method includes the following steps.

[0047] S310. Obtain a target flow pulsation index, where the target flow pulsation index is the pulsation index of the pumping flow when the ventricular assist device operates in a first cycle.

[0048] The control unit 33 can control the rotational speed of the rotor 13 to generate the blood flow velocity required by the patient. The required blood flow velocity can be selected to provide the required assist function for the patient's heart. For example, the blood flow velocity can be selected to partially assist the blood circulation function of the patient's heart. Or, the blood flow velocity can be selected to completely replace the blood circulation function of the patient's heart. According to the relationship between the speed and the blood flow velocity through the ventricular assist device 100, the rotational speed of the rotor 13 can be controlled to at least partially control the blood flow velocity from the inlet 14 to the outlet 15.

[0049] In addition to generating blood flow at an ideal speed, a pulsatile blood flow pattern may also be required. The pulsatile pattern needs to include relatively high and relatively low blood flow velocities. Such a pulsatile pattern may be required to augment or replace the patient's weak pulse, especially those patients with a relatively small natural cardiac output compared to the volumetric flow rate of the ventricular assist device 100. In addition, it may be desirable for the pulsatile pattern to produce a physiological response similar to the natural pulsatile blood flow pattern and / or blood pressure from a healthy heart. Such a physiological response may be significantly different from the response of the ventricular assist device 100 operating at a constant speed. The pulsatile circulation of blood can reduce blood stasis in the ventricles, help exercise the aortic valve, improve flushing distal to atherosclerotic lesions, increase coronary and / or end-organ perfusion, reduce the risk of ventricular suction, reduce the propensity for diseases associated with reduced pulsatility, such as arteriovenous malformations, and increase myocardial recovery.

[0050] Therefore, the control unit 33 can periodically detect the pumping condition of the ventricular assist device 100. When the current pumping flow rate of the ventricular assist device 100 cannot meet the patient's needs, the pumping flow rate of the ventricular assist device 100 can be changed by switching the speed operation mode of the ventricular assist device 100 to meet the patient's needs.

[0051] After the ventricular assist device 100 is started, the control unit 33 can first control the ventricular assist device 100 to operate at a constant speed with a target speed. The target speed is set within the speed range allowed by the ventricular assist device 100. For example, the target speed can be within the range of 2200 RPM to 4300 RPM. Medical staff can turn on the speed pulsation function on the controller 200 (such as clicking or turning on the pulsation control button on the controller 200), or turn on the speed pulsation function when it is detected that the pulsation index of the pumping flow of the ventricular assist device 100 is less than a preset threshold. The controller 200 can generate a corresponding target operation instruction and send it to the control unit 33. The target operation instruction can carry the pulsation mode of the impeller speed and the parameters of the pulsation mode (for example, pulsation period, speed pulsation amplitude, etc.). In response to the target operation instruction, the control unit 33 can control the impeller 20 to operate at the speed of the pulsation mode to generate a pulsating pumping flow.

[0052] During the operation of the ventricular assist device 100, the control unit 33 can detect the pulsation index of the pumping flow of the ventricular assist device 100 in real time. Specifically, record the flow peak value Lmax pumped by the ventricular assist device 100 in each first period, and the flow valley value Lmin pumped by the ventricular assist device 100 adjacent to the flow peak value, and calculate the average pumping flow Lave between the flow peak value Lmax and the flow valley value Lmin. Then calculate the pulsation index of the pumping flow of the ventricular assist device 100, and the pulsation index PI = (Lmax - Lmin) / Lave. Since the change in the pumping flow of the ventricular assist device 100 is synchronized with the user's cardiac cycle, the pulsation index of the pumping flow of the ventricular assist device 100 can be used to characterize the pulsation index of the user's heart. If the calculated target flow pulsation index PI is less than the preset threshold, it is determined that the pumping flow of the current ventricular assist device 100 does not meet the user's flow demand, which may cause abnormal problems such as ventricular fibrillation, aspiration, overload, and arrhythmia in the patient.

[0053] Among them, the first period can be set to 2 min, 5 min, 8 min, 10 min, etc.

[0054] S320. If the target flow pulsation index is less than or equal to the first threshold, control the operation of the ventricular assist device using the first speed mode.

[0055] Due to the patient's own physiological pulsation, the blood flow into and out of the ventricle is pulsatile. That is, the blood flow pumped out by the left ventricle reaches the lowest during the diastolic phase of the cardiac cycle and the highest during the systolic phase of the cardiac cycle. When the ventricular assist device 100 continuously operates at a constant speed or at the current speed of the ventricular assist device 100, and the pumping flow rate of the ventricular assist device 100 does not match the current patient demand. For example, when the speed is too fast, suction occurs, and when the speed is too slow, ventricular overload occurs. The control unit 33 can adjust the speed mode of the ventricular assist device 100 according to the magnitude of the current target flow pulsation index, so as to adjust the pumping flow rate of the ventricular assist device 100 by adjusting the speed of the ventricular assist device 100.

[0056] In this application, the speed of the ventricular assist device 100 can include: a constant speed mode and a pulsatile mode, and the pulsatile mode includes a square wave pulsatile mode and a sine wave pulsatile mode. The first speed mode can be a sine wave pulsatile mode or a square wave pulsatile mode.

[0057] Among them, the first threshold value can be pre-stored in the control unit 33 or the controller 200, and the first threshold value can be obtained from clinical experiments. For example, the first threshold value can be set to 50 or 30. For example, when the first threshold value is 50, if the actual pulsation index of the patient is less than the first threshold value and the difference is not large, speed pulsation is triggered, indicating that the patient's blood flow pulsation is slightly poor, the pumping flow rate of the current ventricular assist device 100 does not match the patient demand and the difference is large, resulting in possible problems such as arrhythmia, suction, and overload. The first speed mode can be a square wave pulsatile mode. For example, when the first threshold value is 30, if the actual pulsation index of the patient is less than the first threshold value, it indicates that the patient's blood flow pulsation is poor, and there is a risk of complications such as bleeding, thrombosis, and right heart failure. The first speed mode can be a sine wave pulsatile mode; triggering speed pulsation can make the pumping flow rate of the current ventricular assist device 100 match the patient demand and reduce the risk of complications such as bleeding, thrombosis, and right heart failure.

[0058] For example, after the ventricular assist device 100 is started, the control unit 33 can control the rotor 13 to operate at a constant speed at the target speed. During the process of the ventricular assist device 100 operating at a constant speed at the target speed, the control unit 33 can detect the target flow pulsation index in real time. If the first threshold value is 30, when the target flow pulsation index is less than 30, it is considered that the patient's blood flow pulsation is poor and there is a risk of complications such as bleeding, thrombosis, and right heart failure. At this time, the control unit 33 can switch the speed mode of the ventricular assist device 100 from the constant speed mode to the sine wave pulsatile mode. The sine wave mode speed realizes sine speed control according to the set amplitude and pulsation rate, so as to generate a sine flow pulsation by using the sine wave mode and generate a flow pulsation closer to the physiological law of the patient's heart.

[0059] If the first threshold is 50, when the target flow pulsation index is less than 50, it is considered that the blood flow pulsatility of the patient is slightly poor, the pumping flow pulsatility of the current ventricular assist device 100 does not match the patient's needs, the difference is small and no serious damage is caused to the patient. At this time, the control unit 33 can switch the speed mode of the ventricular assist device 100 from the constant speed mode to the square wave pulsation mode. The square wave mode adjusts the speed periodically, so that the square wave flow pulsation can be generated by using the square wave mode, and the pulsation is relatively gentle to increase the flow pulsatility without increasing the patient's heart load.

[0060] Further, if the target flow pulsation index is greater than the first threshold, such as greater than 30 or 50, the constant speed mode is continued to be used for operation.

[0061] S330. If the target flow pulsation index is greater than the first threshold and less than the second threshold, the second speed mode is used to control the operation of the ventricular assist device.

[0062] Among them, the second speed mode can be the square wave pulsation mode or the constant speed mode. The second threshold can be pre-stored in the control unit 33 or the controller 200. The second threshold is greater than the first threshold. According to clinical experiments, the second threshold can be set to 50 or 70. When the first threshold is 30 and the second threshold is 50, the second speed mode is the square wave pulsation mode; when the first threshold is 30 and the second threshold is 70, the second speed mode is the constant speed mode.

[0063] During the operation of the ventricular assist device 100 in the first speed mode, the control unit 33 detects the target pulsation flow index in real time. If the target flow pulsation index changes from less than the first threshold to greater than the first threshold and less than the second threshold, it can be considered that the pumping flow of the current ventricular assist device 100 is slightly different from or matches the patient's needs. Then, the control unit 33 can switch the speed mode of the ventricular assist device 100 from the first speed mode to the second speed mode and operate in the square wave mode or the constant speed mode.

[0064] For example, the first threshold is 30, and the second threshold is 50. When the ventricular assist device 100 is operating in the sinusoidal wave pulsation mode, if the target flow pulsation index is detected to be greater than 30 and less than 50, it is considered that the current pumping flow of the ventricular assist device 100 still does not match the patient's needs, but the difference is small and does not cause harm to the patient. The control unit 33 can switch the speed mode of the ventricular assist device 100 from the sinusoidal wave pulsation mode to the square wave pulsation mode. The square wave pulsation mode has a smaller pulsation rate than the sinusoidal wave pulsation mode, so that a certain pulsation can be achieved by using the square wave pulsation mode, which can reduce the risk of thrombosis. Further, if the target flow pulsation index of the ventricular assist device 100 is still less than 30, the sinusoidal wave pulsation mode is continued to be used to control the operation of the ventricular assist device 100. If the target flow pulsation index is greater than 50, the constant speed mode is used for operation.

[0065] For example, when the first threshold is 50 and the second threshold is 70, when the ventricular assist device 100 is operating in the square wave pulsation mode, if it is detected that the target flow pulsation index is greater than 50 and less than 70, it indicates that the current ventricular assist device 100 matches the patient's needs, and the control unit 33 can switch the speed mode of the ventricular assist device 100 to the constant speed mode, so that the heart pulsation is still acceptable and meets the patient's needs. Furthermore, if it is detected that the target flow pulsation is still greater than 30 but less than 50, the control unit 33 can continue to operate in the square wave mode. If the target flow pulsation index of the ventricular assist device 100 decreases and is less than 30, the sine wave pulsation mode is used to control the operation of the ventricular assist device 100.

[0066] In the present application, the control unit 33 determines the current pumping flow of the ventricular assist device 100 through the target flow pulsation index, and then determines the speed mode based on the comparison between the target flow pulsation index and the threshold value, so that the cardiac output of the ventricular assist device is more in line with the physiological laws of the heart, reducing the probability of complications such as bleeding, thrombosis, right heart failure, etc. caused by low blood flow pulsation.

[0067] In the present application, the method further includes: after controlling the ventricular assist device to operate in the first speed mode for a second cycle, controlling the ventricular assist device to operate in the target speed for a first cycle; and calculating the target flow pulsation index of the ventricular assist device in the first cycle.

[0068] Among them, when the ventricular assist device 100 operates in a pulsatile mode, after the ventricular assist device 100 operates in the pulsatile mode for a second cycle, the control unit 33 controls the ventricular assist device 100 to operate at a constant speed in a first cycle at a target speed, and calculates the target flow pulsation index of the ventricular assist device 100 during this first cycle, and determines the speed mode to be used in the subsequent second cycle according to the target flow pulsation index. That is to say, the second cycle is the operation period of the speed mode, and the first cycle is the selection period for determining the speed mode. The control unit takes the second cycle and the first cycle as a cycle and continuously repeats this cycle.

[0069] Exemplarily, when the first threshold is 30, the second threshold is 50, and after the ventricular assist device 100 operates in a sine wave pulsatile mode in the second cycle, if the target flow pulsation index in this first cycle is still less than 30, continue to use the sine wave pulsatile mode to operate in the second cycle, and determine the speed mode to be used in the next cycle according to the target flow pulsation index in the next first cycle; if the target flow pulsation index in this first cycle is greater than or equal to 30 and less than 50, use a square wave pulsatile mode to operate in the second cycle within this cycle, and determine the speed mode to be used in the next cycle according to the target flow pulsation index in the next first cycle; if the target flow pulsation index in this first cycle is greater than or equal to 50, use a constant speed mode to operate in the second cycle within this cycle, and determine the speed mode to be used in the next cycle according to the target flow pulsation index in the next first cycle.

[0070] The second cycle can be set to 20 min, 30 min, 40 min, 1 h, etc.

[0071] Therefore, the control methods for the speed mode of the ventricular assist device 100 in two adjacent cycle periods include: switching from a constant speed mode to a sine wave pulsatile mode, switching from a constant speed mode to a square wave pulsatile mode, continuously being in a constant speed mode, continuously being in a sine wave pulsatile mode, continuously being in a square wave pulsatile mode, switching from a sine wave pulsatile mode to a square wave pulsatile mode, switching from a sine wave pulsatile mode to a constant speed mode, switching from a square wave pulsatile mode to a constant speed mode, and switching from a square wave pulsatile mode to a sine wave pulsatile mode.

[0072] By switching between the above several speed modes, the ventricular assist device 100 makes the cardiac output of the ventricular assist device more in line with the physiological laws of the heart, and reduces the probability of complications such as bleeding, thrombosis, and right heart failure that may be caused by low blood flow pulsation.

[0073] Some parameters affecting physiological phenomena include pulse pressure and blood pressure change rate. For example, for the ventricular assist device 100, the pulsatile pressure and time change of blood pressure are affected by the angular velocity of the rotor. Therefore, by generating a pump speed mode including a period of relatively high speed and a period of relatively low speed, the ventricular assist device 100 can be selectively controlled to generate pulsatile blood flow.

[0074] In the embodiment of the present application, the square wave pulsation mode is as follows: increasing the speed of the ventricular assist device from the target speed to the first speed, and operating at the first speed for the first duration; reducing the speed of the ventricular assist device from the first speed to the target speed; operating at the target speed for the second duration; reducing the speed of the ventricular assist device from the target speed to the second speed; operating at the second speed for the third duration; increasing the speed of the ventricular assist device from the second speed to the target speed; and operating at the target speed for the second duration.

[0075] The control unit 33 operates the square wave pulsation mode to run at the speed as Figure 4 shown. The square wave pulsation mode includes a first part with a relatively high speed to generate a relatively high blood pressure, a second part with a relatively low speed to generate a relatively low blood pressure, and a transition part between the first part and the second part. The transition part generates an expected pressure change rate in the patient's circulatory system, such as simulating the pressure change rate of a natural physiological pulse, and generates an expected physiological effect related to the pressure change rate. The first part, the transition part, the second part, and the transition part form a cycle of the square wave pulsation mode.

[0076] Among them, the first part, the second part, and the transition part all have a predetermined duration. After determining that the ventricular assist device 100 operates in the square wave pulsation mode, the rotor 13 rapidly rises from the target speed w0 to the first speed w1 at time t0. In the first part 410, the rotor 13 rotates at the first speed w1 for the first duration (from time t0 to time t1). At time t1, the speed of the rotor 13 rapidly drops from the first speed w1 to the transition part 420, generating a step transition. In the transition part 420, the rotor 13 rotates at the target speed w0 for the second duration, and the transition time is from time t1 to time t2. At time t2, the speed of the rotor 13 rapidly drops from the target speed w0 to the second part 430. In the second part 430, the rotor 13 rotates at the second speed w2 for the third duration (from time t2 to time t3). At time t3, the speed of the rotor 13 rapidly rises from the second speed w2 to the transition part 440, generating a step transition. In the transition part 440, the rotor 13 rotates at the target speed w0 for the second duration, and the transition time is from time t3 to time t4. Thus, from time t0 - t4 is a cycle of the square wave pulsation. By continuously cycling this cycle, the control unit 33 can achieve the blood flow pulsation of the patient. Among them, the rapid rise of the speed of the rotor 13 can be as fast as the rapid drop, such as a linear change, or a curve change to simulate the pressure change in a natural cardiac cycle.

[0077] Exemplarily, the second duration may be greater than the first duration and / or the third duration. The first duration and the second duration may be the same or different (Figure 4 The first duration and the second duration are the same (the same in the middle). The first duration and the second duration are in the range of 10s - 20s. By setting the duration of running at the target speed to be relatively large, the balance between speed pulsation and power consumption reduction can be achieved.

[0078] For example, the second duration is greater than or equal to the sum of the first duration and the third duration. For example, the second duration is twice the first duration, or the second duration is twice the third duration. By increasing the duration of running at the target speed, the power consumption of the ventricular assist device can be reduced, while improving the performance efficiency of the ventricular assist device, thrombosis problems caused by increased temperature due to increased power consumption can be avoided.

[0079] For example, the first speed difference between the first speed and the target speed and the second speed difference between the target speed and the second speed can be the same. For example, the first speed difference and the second speed difference can be set to 500 RPM, 800 RPM, 1000 RPM, etc. The first speed difference and the second speed difference can also be different. For example, the first speed difference is set to 500 RPM and the second speed difference is set to 1000 RPM; or, the first speed difference is set to 300 RPM and the second speed difference is set to 8000 RPM, and so on.

[0080] Among them, the first duration, the second duration, the third duration, the first speed difference, and the second speed difference can be set by medical staff on the external controller 200, or the default values stored in the control unit 33 can be used. This application does not make any limitations here.

[0081] In the embodiment of this application, the sine wave pulsation mode is: controlling the ventricular assist device to run at a speed with a sine curve waveform having an amplitude of the target amplitude and a period of the target period from the target speed.

[0082] The period of the square wave pulsation mode is relatively long and is quite different from the natural cardiac cycle of the patient. When the patient has problems such as arrhythmia and aspiration, the control unit 33 can use the sine wave pulsation mode that is closer to the patient's cardiac cycle to operate.

[0083] The control unit 33 operates the sine wave pulsation mode to run at the speed as Figure 5 shown. The sine wave pulsation mode is a sine curve waveform with a target period and a target amplitude. The target amplitude and the target period can be set by medical staff on the external controller 200, or the default values stored in the control unit 33 can be used. This application does not make any limitations here.

[0084] Specifically, after determining that the ventricular assist device 100 operates in a sinusoidal pulsation mode, the rotor 13 rises from the target speed w0 to the speed w3 in a sinusoidal curve during the time period from T0 to T1; during the time period from T1 to T2, the rotor 13 descends from the speed w3 to the speed w4 in a sinusoidal curve; during the time period from T2 to T3, the rotor 13 rises from the speed w4 to the target speed w0 in a sinusoidal curve. Wherein, the time period from T0 to T3 constitutes one cycle of the sinusoidal pulsation mode. The control unit 33 can continuously cycle this cycle in the second cycle to operably pulsate the speed of the ventricular assist device 100, thereby realizing blood flow pulsation.

[0085] Exemplarily, the target amplitude is the difference between the speed w3 and the target speed w0, or the difference between the target speed w0 and the speed w4. The target amplitude can be equal to the first speed difference and / or the second speed difference. For example, the target amplitude is set to 500 RPM, 800 RPM, 1000 RPM, etc. The target amplitude can also be different from the first speed difference and / or the second speed difference.

[0086] Exemplarily, the target period is within the range of (0, 1 s). The ventricular assist device 100 can be operated at a speed with a frequency of 200 sinusoidal waves per minute, or 100 sinusoidal waves per minute, or 75 sinusoidal waves per minute.

[0087] Among them, the constant speed mode is to maintain operation at the target speed.

[0088] In this application, after the ventricular assist device 100 is started, the control unit 33 first controls the ventricular assist device 100 to operate at a constant speed in the constant speed mode. During the operation, if it is detected that the pulsation index of the pumping flow rate of the ventricular assist device 100 is less than the first threshold, then the pulsation mode is switched to control the ventricular assist device 100 to operate in the second cycle. After operating in the pulsation mode in the second cycle, it is controlled to operate in the first cycle in the constant speed mode. If the pulsation index of the pumping flow rate measured in the first cycle is still less than the second threshold, then it still operates in the pulsation mode in the second cycle; if the pulsation index of the pumping flow rate measured in the first cycle is still greater than or equal to the second threshold, then the pulsation mode is stopped, and the ventricular assist device 100 is controlled to operate in the constant speed mode until it is detected that the pulsation index of the pumping flow rate is less than the first threshold, and then it is automatically switched to the pulsation mode. The control unit 33 can further achieve the switching between pulsation modes according to the further subdivision of the pulsation index of the pumping flow rate, with sinusoidal or square wave pulsation.

[0089] It can be seen that the present application proposes a speed control method, which obtains a target flow pulsation index, and the target flow pulsation index is the pulsation index of the pumping flow when the ventricular assist device operates in the first cycle. If the target flow pulsation index is less than or equal to the first threshold, the first speed mode is used to control the operation of the ventricular assist device. If the target flow pulsation index is greater than the first threshold and less than the second threshold, the second speed mode is used to control the operation of the ventricular assist device. By comparing the target flow pulsation index with the preset threshold, the present application determines the flow demand of the current ventricular assist device, and then adjusts the speed mode of the ventricular assist device according to the flow demand, so that the cardiac output of the ventricular assist device is more in line with the physiological law of the heart, and reduces the probability of complications such as bleeding, thrombosis, and right heart failure that may be caused by low blood flow pulsation.

[0090] The above mainly introduces the solution of the embodiment of the present application from the perspective of the execution process of the method side. It can be understood that in order for the network device to implement the above functions, it includes the corresponding hardware structure and / or software module for executing each function. Those skilled in the art should easily realize that, combining the units and algorithm steps of each example described in the embodiments provided in this article, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a certain function is executed in the way of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present application.

[0091] Exemplarily, the present application embodiment also provides a control unit of a ventricular assist device, and the control unit includes one or more processors, and the one or more processors are used for:

[0092] Obtain a target flow pulsation index, where the target flow pulsation index is the pulsation index of the pumping flow when the ventricular assist device operates in the first cycle;

[0093] If the target flow pulsation index is less than or equal to the first threshold, use the first speed mode to control the operation of the ventricular assist device;

[0094] If the target flow pulsation index is greater than the first threshold and less than the second threshold, use the second speed mode to control the operation of the ventricular assist device.

[0095] Exemplarily, the present application embodiment also provides a ventricular assist device, and the ventricular assist device includes:

[0096] A housing;

[0097] An impeller disposed in the housing;

[0098] A motor for driving the impeller to rotate in suspension;

[0099] The control unit connected to the motor, which is configured to perform some or all of the steps described in the method above.

[0100] Exemplarily, the present application further provides a medical device, which includes the control unit or the ventricular assist device described above.

[0101] Among them, the control unit in each of the above solutions has the function of implementing the corresponding steps performed by the medical device in the above method; the function can be implemented by hardware or by hardware executing corresponding software.

[0102] In an embodiment of the present application, the control unit can also be a chip or a chip system, for example: a system on chip (SoC).

[0103] Please refer to Figure 6 , Figure 6 which is a schematic structural diagram of a medical device provided by an embodiment of the present application. The medical device includes: one or more processors, one or more memories, one or more communication interfaces, and one or more programs; the one or more programs are stored in the memory and are configured to be executed by the one or more processors.

[0104] The above program includes instructions for performing the following steps:

[0105] Obtain a target flow pulsation index, where the target flow pulsation index is the pulsation index of the pumping flow when the ventricular assist device operates in a first cycle;

[0106] If the target flow pulsation index is less than or equal to a first threshold, control the operation of the ventricular assist device using a first speed mode;

[0107] If the target flow pulsation index is greater than the first threshold and less than a second threshold, control the operation of the ventricular assist device using a second speed mode.

[0108] Among them, all relevant contents of each scenario involved in the above method embodiment can be cited to the function description of the corresponding functional module, and will not be repeated here.

[0109] It should be understood that the above memory may include a read-only memory and a random access memory, and provide instructions and data to the processor. A part of the memory may also include a non-volatile random access memory. For example, the memory may also store information about the device type.

[0110] In an embodiment of the present application, the processor of the above device may be a Central Processing Unit (CPU), and the processor may also be other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0111] It should be understood that the "at least one" involved in the embodiments of the present application refers to one or more, and "a plurality" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone, where A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects before and after. "At least one (item)" or its similar expression refers to any combination of these items, including any combination of single item (item) or plural items (items). For example, at least one (item) of a, b, or c can represent: a, b, c, a - b, a - c, b - c, or a - b - c, where a, b, c can be single or multiple.

[0112] Also, unless otherwise stated, the ordinal numbers such as "first" and "second" mentioned in the embodiments of the present application are used to distinguish multiple objects and are not used to limit the order, timing, priority, or importance of multiple objects. For example, the first information and the second information are only used to distinguish different information, rather than indicating differences in the content, priority, sending order, or importance of these two pieces of information, etc.

[0113] In the implementation process, each step of the above method can be completed by the integrated logic circuit in the hardware of the processor or the instructions in the form of software. The steps of the method disclosed in combination with the embodiments of the present application can be directly implemented by the execution of the hardware processor, or completed by the combination of the hardware and software units in the processor. The software unit can be located in mature storage media in the art such as random access memory, flash memory, read-only memory, programmable read-only memory, or electrically erasable programmable memory, registers, etc. This storage media is located in the memory, and the processor executes the instructions in the memory and combines its hardware to complete the steps of the above method. To avoid repetition, it will not be described in detail here.

[0114] The embodiments of the present application also provide a computer storage medium, where the computer storage medium stores a computer program for electronic data exchange, and the computer program enables the computer to execute part or all of the steps of any method recorded in the above method embodiments.

[0115] An embodiment of the present application also provides a computer program product. The computer program product includes a non-transitory computer-readable storage medium storing a computer program. The computer program is operable to cause a computer to execute some or all of the steps of any one of the methods described in the foregoing method embodiments. The computer program product may be a software installation package.

[0116] It should be noted that, for the foregoing method embodiments, for simplicity of description, they are all expressed as a series of action combinations. However, those skilled in the art should know that the present application is not limited by the described action sequence, because according to the present application, some steps may be performed in other sequences or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to the present application.

[0117] In the above embodiments, the descriptions of the various embodiments have their own emphases. For the parts not detailed in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0118] In several embodiments provided by the present application, it should be understood that the disclosed device can be implemented in other ways. For example, the device embodiments described above are only illustrative. For example, the above division of units is only a logical function division. In actual implementation, there may be other division methods. 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 displayed or discussed coupling or direct coupling or communication connection to each other can be through some interfaces. The indirect coupling or communication connection of the device or unit can be in an electrical or other form.

[0119] The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they may be located in one place, or may be distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment of the present application.

[0120] In addition, the functional units in the various embodiments of the present application can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit. The above integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

[0121] If the above integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable memory. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a memory and includes several instructions for causing a computer device (which can be a personal computer, a server, or a TRP, etc.) to execute all or part of the steps of the methods in various embodiments of this application. The aforementioned memory includes various media that can store program codes, such as USB flash drives, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), mobile hard disks, magnetic disks, or optical discs.

[0122] Those of ordinary skill in the art can understand that all or part of the steps in the various methods of the above embodiments can be completed by instructing relevant hardware through a program. This program can be stored in a computer-readable memory, and the memory can include: flash drives, ROM, RAM, magnetic disks, or optical discs, etc.

[0123] The above has introduced the embodiments of this application in detail. Specific examples are used in this article to elaborate on the principles and implementation manners of this application. The description of the above embodiments is only used to help understand the method and its core idea of this application; at the same time, for those of ordinary skill in the art, according to the idea of this application, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to this application.

Claims

1. A speed control method, characterized in that, Applied to a ventricular assist device, the method includes: Obtaining a target flow pulsation index, where the target flow pulsation index is the pulsation index of the pumping flow when the ventricular assist device operates within a first cycle; If the target flow pulsation index is less than or equal to a first threshold, controlling the operation of the ventricular assist device using a first speed mode; If the target flow pulsation index is greater than the first threshold and less than a second threshold, controlling the operation of the ventricular assist device using a second speed mode.

2. The method according to claim 1, wherein The first speed mode is any one of a sine wave pulsation mode and a square wave pulsation mode.

3. The method according to claim 1, wherein The first speed mode is any one of a square wave pulsation mode and a constant speed mode.

4. The method according to claim 2 or 3, characterized in that The square wave pulsation mode is as follows: Increasing the speed of the ventricular assist device from a target speed to a first speed, Operating at the first speed for a first duration; Decreasing the speed of the ventricular assist device from the first speed to the target speed; Operating at the target speed for a second duration; Decreasing the speed of the ventricular assist device from the target speed to a second speed; Operating at the second speed for a third duration; Increasing the speed of the ventricular assist device from the second speed to the target speed; Operating at the target speed for the second duration.

5. The method according to claim 4, wherein The second duration is greater than the first duration and / or the third duration.

6. The method according to claim 4, wherein The first duration is greater than or equal to the sum of the first duration and the third duration.

7. The method according to claim 4, characterized in that, The first speed difference and the second speed difference are the same or different. The first speed difference is the difference between the first speed and the target speed, and the second speed difference is the difference between the target speed and the second speed.

8. The method according to any one of claims 4 to 7, characterized in that The sine wave pulsation mode is as follows: Controlling the ventricular assist device to operate at a speed with a sine curve waveform having an amplitude of a target amplitude and a period of a target period from the target speed.

9. The method according to claim 8, wherein The target amplitude is equal to the first speed difference and / or the second speed difference.

10. The method according to claim 8, wherein The target period is within the range of (0, 1 s).

11. The method according to claim 3, wherein The constant speed mode is to maintain operation at the target speed.

12. The method according to claim 4, wherein The method further includes: After controlling the ventricular assist device to operate in the first speed mode for a second cycle, controlling the ventricular assist device to operate at the target speed for a first cycle; Calculating the target flow pulsation index of the ventricular assist device within the first cycle.

13. A control unit of a ventricular assist device, characterized in that, The control unit includes one or more processors, and the one or more processors are configured to: Obtain a target flow pulsation index, where the target flow pulsation index is the pulsation index of the pumping flow when the ventricular assist device operates within a first cycle; If the target flow pulsation index is less than or equal to a first threshold, control the operation of the ventricular assist device using a first speed mode; If the target flow pulsation index is greater than the first threshold and less than a second threshold, control the operation of the ventricular assist device using a second speed mode.

14. A ventricular assist device, characterized in that, The ventricular assist device includes: A housing; An impeller disposed within the housing; A motor for driving the impeller to rotate in a suspended manner; The control unit connected to the motor, and the control unit is configured to execute the steps in the method according to any one of claims 1 - 12.

15. A medical device, characterized in that, Comprising a processor, a memory, and a communication interface, the memory storing one or more programs, and the one or more programs being executed by the processor, the one or more programs including instructions for performing the steps in the method according to any one of claims 1-12.

16. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program for electronic data exchange, wherein the computer program causes a computer to perform the steps of the method according to any one of claims 1-12.

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