Speed ​​control method and device

Abstract

This application discloses a speed control method and apparatus. The method includes: acquiring a first average flow rate and a second average flow rate of a ventricular assist device (VAD), wherein the first average flow rate is the average flow rate of the VAD during a first cardiac cycle at a target speed, and the second average flow rate is the average flow rate of the VAD during a second cardiac cycle at the target speed, wherein the first cardiac cycle is later than the second cardiac cycle; determining an abnormal state of a target user based on the first and second average flow rates; and adjusting the target speed and / or the impeller's rotation direction within the housing based on the target user's abnormal state. This application determines the current user's abnormal state based on the average flow rate of the VAD during different cardiac cycles, and then adjusts the impeller's speed and / or rotation direction based on the abnormal state, thereby enabling the performance of the VAD to conform in real time to the pump flow characteristics of the user's physiological state changes.

Description

Technical Field

[0001] This application relates to the field of medical device technology, and in particular to a speed control method and device. Background Technology

[0002] Mechanical circulatory support devices, such as ventricular assist devices (VADs), can be used to provide long-term mechanical support or assistance to patients with heart failure or other heart-related diseases, helping the heart pump blood from the heart to other parts of the body.

[0003] The VAD uses non-contact bearings to allow the impeller to float within the housing during operation. Once the impeller shape is determined, the VAD's pressure-flow curve remains fixed. However, changes in the patient's physiological state require different characteristics in the pressure-flow curve. Therefore, achieving pump flow characteristics that conform to changes in the patient's physiological state is a pressing problem to be solved. Summary of the Invention

[0004] This application provides a speed control method and device that can adjust the impeller's speed and rotation direction to achieve pump flow characteristics that conform to changes in the patient's physiological state.

[0005] In a first aspect, embodiments of this application provide a speed control method applied to a ventricular assist device, the ventricular assist device including a housing and an impeller disposed within the housing; the method includes:

[0006] The first average flow rate and the second average flow rate of the ventricular assist device are obtained. The first average flow rate is the average flow rate of the ventricular assist device when it is running at the target speed during a first cardiac cycle. The second average flow rate is the average flow rate of the ventricular assist device when it is running at the target speed during a second cardiac cycle. The first cardiac cycle is later than the second cardiac cycle.

[0007] The abnormal state of the target user is determined based on the first average flow rate and the second average flow rate. The target user is a user who uses the ventricular assist device.

[0008] Adjust the target rotation speed and / or the rotation direction of the impeller within the housing according to the abnormal state of the target user.

[0009] Secondly, an embodiment of this application provides a control unit including one or more processors, wherein the one or more processors are used for:

[0010] A first average flow rate and a second average flow rate of the ventricular assist device are obtained. The first average flow rate is the average flow rate of the ventricular assist device when it is running at a target speed during a first cardiac cycle. The second average flow rate is the average flow rate of the ventricular assist device when it is running at the target speed during a second cardiac cycle. The first cardiac cycle is later than the second cardiac cycle.

[0011] The abnormal state of the target user is determined based on the first average flow rate and the second average flow rate. The target user is a user who uses the ventricular assist device.

[0012] Adjust the target rotation speed and / or the impeller's rotation direction within the housing according to the abnormal state of the target user.

[0013] Thirdly, embodiments of this application provide a ventricular assist device, the ventricular assist device comprising:

[0014] case;

[0015] An impeller disposed within the housing;

[0016] The control unit for controlling the levitation rotation of the impeller, the control unit being used for:

[0017] The first average flow rate and the second average flow rate of the ventricular assist device are obtained. The first average flow rate is the average flow rate of the ventricular assist device when it is running at the target speed during a first cardiac cycle. The second average flow rate is the average flow rate of the ventricular assist device when it is running at the target speed during a second cardiac cycle. The first cardiac cycle is later than the second cardiac cycle.

[0018] The abnormal state of the target user is determined based on the first average flow rate and the second average flow rate. The target user is a user who uses the ventricular assist device.

[0019] Adjust the target rotation speed and / or the rotation direction of the impeller within the housing according to the abnormal state of the target user.

[0020] Fourthly, embodiments of this application provide a medical device, the medical device including a processor, a memory, a communication interface, and one or more programs, the one or more programs being stored in the memory and configured to be executed by the processor, the programs including instructions for performing some or all of the steps described in the method described in the first aspect above.

[0021] Fifthly, embodiments of this application provide a computer-readable storage medium storing a computer program for electronic data interchange, wherein the computer program causes a computer to perform some or all of the steps described in the method described in the first aspect above.

[0022] Sixthly, embodiments of this application provide a computer program product, wherein the computer program product includes a non-transitory computer-readable storage medium storing a computer program, the computer program being operable to cause a computer to perform some or all of the steps described in the method described in the first aspect of embodiments of this application. The computer program product may be a software installation package.

[0023] The technical solution provided in this application obtains a first average flow rate and a second average flow rate of a ventricular assist device (VAD). The first average flow rate is the average flow rate of the VAD during a first cardiac cycle when it operates at a target speed, and the second average flow rate is the average flow rate of the VAD during a second cardiac cycle when it operates at the target speed. The first cardiac cycle is later than the second cardiac cycle. The application determines the abnormal state of a target user based on the first and second average flow rates. It then adjusts the target speed and / or the impeller's rotation direction within the housing based on the abnormal state of the target user. This application determines the current abnormal state of the user based on the average flow rate of the VAD during different cardiac cycles, and then adjusts the impeller's speed and / or rotation direction based on the abnormal state, thereby ensuring that the performance of the VAD matches the pump flow characteristics of the user's changing physiological state in real time. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of a ventricular assist system provided in an embodiment of this application;

[0026] Figure 2 This is a schematic diagram of the structure of a ventricular assist device provided in an embodiment of this application;

[0027] Figure 3 This is a schematic diagram of an impeller blade with a backward-curved blade shape provided in an embodiment of this application;

[0028] Figure 4 This is a schematic diagram of an impeller blade with a forward-curved blade shape provided in an embodiment of this application;

[0029] Figure 5 This is a schematic flowchart of a speed control method provided in an embodiment of this application;

[0030] Figure 6 This is a schematic diagram of the structure of a medical device provided in an embodiment of this application. Detailed Implementation

[0031] To help those skilled in the art better understand the technical solutions of this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the description of the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0032] The terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, software, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but also includes steps or units not listed, or other steps or units inherent to such processes, methods, products, or apparatus.

[0033] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0034] In this article, "proximal" is defined as the end closer to the operator; "distal" is defined as the end farther from the operator, that is, the end closer to the patient's heart.

[0035] In this application, "rotational speed" refers to the speed of rotation of a motor or electric motor, which is related to the speed of rotation of the rotor or impeller of the ventricular assist device and can be defined as rotational speed per minute. "Flow rate," "fluid flow rate," and "pump flow rate" refer to the volume of fluid delivered through the ventricular assist device per unit time, which can be estimated and measured in liters per minute.

[0036] The ventricular assist device of this application can be attached to the apex of the left ventricle, right ventricle, or both ventricles of the heart. The ventricular assist device may further include a centrifugal pump, axial flow pump, or magnetic levitation pump capable of delivering the entire output to the left ventricle according to pulmonary or blood circulation.

[0037] A ventricular assist device (VAD) can be attached to the heart via a ventricular connection assembly (such as a top ring, ventricular cuff, or ventricular linker). This assembly can be sutured to the heart and connected to the VAD. The other end of the VAD can be connected to the ascending aorta via an outlet tube and / or an artificial blood vessel connected to the outlet tube. This allows the VAD to effectively divert blood from the weakened ventricle and propel it into the aorta, thereby circulating it to the remainder of the patient's vascular system and providing ventricular support. This application illustrates the use of a VAD in the left ventricle as an example.

[0038] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of a ventricular assist system provided in an embodiment of this application. Figure 1 As shown, the ventricular assist system includes a ventricular assist device 100, an external controller 200, and a transmission assembly 300 connecting the ventricular assist device 100 to the external controller 200. One end of the transmission assembly 300 is connected to a motor inside the ventricular assist device 100, and the other end passes through the patient's abdominal skin to connect to the external controller 200 located outside the body. The external controller 200 is used to monitor the ventricular assist device 100, and can perform functions such as controlling and displaying data of the ventricular assist device 100, fault detection alarms, and data logging. The transmission assembly 300 may be a percutaneous cable, which may include one or more power cables and one or more communication cables.

[0039] like Figure 2 As shown, the ventricular assist device 100 includes a housing assembly with an inlet pipe and an impeller 20 for propelling fluid. The housing assembly includes a first housing and a second housing opposite to the first housing, which together form a chamber 10. The housing assembly also has a fluid inlet 14 and a fluid outlet 15 communicating with the chamber 10. The impeller 20 can levitate and rotate within the chamber 10. The rotation of the impeller 20 generates centrifugal force to transport fluid, allowing fluid to enter the chamber 10 from the fluid inlet 14 and exit from the fluid outlet 15. The levitation and rotation of the impeller 20 means that the impeller 20 does not contact the chamber wall of the chamber 10 during rotation.

[0040] The ventricular assist device 100 also includes a motor 30 and a control unit 33 for driving the impeller 20 to levitate and rotate. The second housing includes a first sidewall 11 and a second sidewall 12. The motor 30 includes a stator 31 and a rotor 32 positioned on either side of the first sidewall 11. The stator 31 is fixed to the outer side of the first sidewall 11 relative to the chamber 10, while the rotor 32 is located inside the chamber 10. Furthermore, the rotor 32 is fixedly connected to the impeller 20. When the stator 31 drives the rotor 32 to rotate within the chamber 10, the impeller 20 also rotates synchronously within the chamber 10 along with the rotor 32. The rotation of the impeller 20 can pressurize the fluid within the chamber 10, giving it greater pressure and thus achieving the fluid pressurization effect of a blood pump.

[0041] The control unit 33 can be located inside or outside the ventricular assist device 100. The control unit 33 is used to detect relevant parameters of the ventricular assist device 100 and the patient, and to control the operation of the ventricular assist device 100. For example, the control unit 33 supplies current to the motor 30 through one or more wires and detects the current through a current detection circuit (such as a phase current detection circuit); it controls the rotational speed of the ventricular assist device 100 according to received instructions. Furthermore, the control unit 33 is electrically connected to the stator 31. By controlling the magnitude and direction of the current flowing through the stator 31, the control unit can control the magnitude and direction of the magnetic force between the stator 31 and the rotor 32, thereby controlling the rotational speed and direction of the impeller 20.

[0042] The impeller 20 is annular, with the fluid inlet 14 directly opposite the inner ring of the annular impeller 20. The impeller 20 includes opposing third and fourth surfaces 22 and a flow channel 21. The flow channel 21 extends radially along the annular impeller 20 and is located between the third and fourth surfaces 23. After entering the inner ring of the impeller 20, the fluid flows out of the impeller 20 through the flow channel 21. As the impeller 20 rotates within the flow channel 21, the fluid velocity increases, resulting in a pressurization effect, and then it flows out from the fluid outlet 15.

[0043] Furthermore, the impeller 20 in this application can be a forward-curved blade impeller or a backward-curved blade impeller. For example... Figure 3 As shown, in a backward-curved blade impeller, the blade exit angle α < 90 degrees, and the bending direction of the impeller blades is opposite to the impeller rotation direction; as Figure 4 As shown, the blade exit angle α of the forward-curved blade impeller is greater than 90 degrees, and the bending direction of the impeller blades is the same as the rotation direction of the impeller.

[0044] Before the ventricular assist device 100 leaves the factory, the shape of the impeller 20 is determined, and the pressure-flow curve of the ventricular assist device 100 remains fixed. However, changes in the patient's physiological state require different characteristics of the pressure-flow curve. For example, when the patient's blood pressure is normal, a flat pressure-flow curve is needed to achieve stronger flow pulsation, which is beneficial to the health of the vascular system; when the patient has hypertension, a steep pressure-flow curve is needed to ensure that the pump flow does not decrease with increased blood pressure. After the shape of the impeller 20 is determined, the impeller 20 can rotate clockwise or counterclockwise under the control of the control unit. Depending on the characteristics of the blade angle, the impeller 20 will exhibit a flat or steep flow curve characteristic when rotating clockwise or counterclockwise.

[0045] Based on this, this application proposes a speed control method that adjusts the rotational speed and direction of the impeller 20 according to the user's current physiological state to meet the pump flow characteristics of changes in the user's current physiological state and improve user safety.

[0046] Based on the above description, this application will now be described from the perspective of method examples.

[0047] Please see Figure 5 , Figure 5 This is a flowchart illustrating a speed control method provided in an embodiment of this application, applied to, for example... Figures 1-2 The ventricular assist device 100 is shown. (As shown in the image) Figure 5 As shown, the method includes the following steps.

[0048] S510. Obtain a first average flow rate and a second average flow rate of the ventricular assist device, wherein the first average flow rate is the average flow rate of the ventricular assist device when running at a target speed during a first cardiac cycle, and the second average flow rate is the average flow rate of the ventricular assist device when running at the target speed during a second cardiac cycle, wherein the first cardiac cycle is later than the second cardiac cycle.

[0049] The ventricular assist device 100 delivers blood to a desired location by controlling the rotation of the impeller 20. When the ventricular assist device is used in the left ventricle, it pumps blood from the left ventricle to the aorta; when used in the right ventricle, it pumps blood from the right ventricle to the pulmonary artery. At a given impeller 20 rotational speed, the flow rate pumped by the ventricular assist device 100 depends on the pressure differential that the ventricular assist device 100 needs to overcome and the blood volume within the ventricle.

[0050] When a patient experiences abnormal conditions such as high afterload (i.e., elevated blood pressure) or insufficient ventricular blood volume, the pumping flow rate of the ventricular assist device 100 will decrease. This application uses changes in the pumping flow rate of the ventricular assist device 100 to determine whether the patient is currently experiencing abnormal conditions such as elevated blood pressure or insufficient ventricular blood volume. Furthermore, when an abnormal condition exists, the operation of the ventricular assist device 100 is adjusted to resolve or alleviate the abnormal condition, thereby improving patient safety.

[0051] Optionally, the method further includes: acquiring a first flow curve, wherein the first flow curve is the flow curve of the ventricular assist device when running at a target rotational speed; determining the duration between adjacent peaks in the first flow curve as a target duration; and determining the first cardiac cycle and the second cardiac cycle based on the target duration.

[0052] In this application, the control unit 33 can determine the current cardiac cycle of the target user based on the time between adjacent peaks of the flow curve of the ventricular assist device 100, and then obtain the flow rate within m cardiac cycles from the storage unit, calculate the average flow rate within the m cardiac cycles and the average flow rate within the next m cardiac cycles, where m is a positive integer greater than 1.

[0053] During operation of the ventricular assist device 100 within the patient, the pumping flow rate of the ventricular assist device 100 depends on the work it needs to do to overcome resistance and pump blood from the left ventricle to the aorta. The amount of work done by the ventricular assist device 100 can be quantified as the amount of current required to supply the motor 30; that is, the motor current corresponds to the amount of current delivered to the motor of the ventricular assist device 100 when it is operating in the patient. The load on the motor 30 varies during different phases of the patient's cardiac cycle. When the pressure gradient in the patient's heart changes, the motor current also changes to maintain a constant rotor speed. For example, when the rate of blood flow into the aorta increases (such as during cardiac contraction), the current required by the motor 30 will increase. Therefore, changes in the motor current can help characterize cardiac performance. In other words, during operation, the ventricular assist device 100 exhibits a current-flow characteristic curve, where a larger current corresponds to more work done by the ventricular assist device 100, i.e., a larger pumping flow rate.

[0054] The current of the ventricular assist device 100 can be measured by a phase current detection circuit or any other suitable means (such as a current sensor). This current-flow characteristic curve can be pre-stored in the control unit 33. Before the ventricular assist device 100 leaves the factory, it can be placed in a testing system to test the relationship between the pumping flow rate and current at different speeds, and then the current-flow characteristic curve can be stored in the control unit 33. The control unit 33 can store the detected current in real time.

[0055] Specifically, when the ventricular assist device 100 is running at the target speed, the control unit 33 acquires the current curve within a preset time period and estimates the first flow curve within the preset time period corresponding to the current curve using a pre-stored current-flow characteristic curve. This preset time period is longer than the cardiac cycle of a normal person. The duration between adjacent peaks in the first flow curve is determined as the cardiac cycle of the target user. The average flow rate within m cardiac cycles is taken as the first average flow rate, and the average flow rate within the next m cardiac cycles is taken as the second average flow rate.

[0056] S520. Determine the abnormal state of the target user based on the first average flow rate and the second average flow rate, wherein the target user is a user using the ventricular assist device.

[0057] In this application, the control unit 33 determines the change in current by comparing the magnitude of the first average flow rate and the second average flow rate, and then determines whether the target user is in an abnormal state based on the change in current. When the target user is in an abnormal state, the control unit 33 adjusts the rotation speed and / or rotation direction of the impeller 20 according to the shape of the impeller blades and the abnormal state, so as to resolve or alleviate the abnormal state while achieving pump flow characteristics that conform to the changes in the target user's physiological state.

[0058] The abnormal state may include: aortic pressure exceeding a preset value or ventricular blood volume less than a preset value, meaning the target patient may have hypertension or insufficient blood volume. When aortic pressure rises above the normal aortic pressure (preset threshold), the greater the pressure difference between the aorta and left ventricular pressure, the more work the ventricular assist device 100 needs to do. Therefore, with a constant rotational speed, the higher the aortic pressure, the less flow the ventricular assist device 100 pumps. Conversely, when the blood volume in the left ventricle is insufficient, the left ventricle cannot supply enough blood to the ventricular assist device 100, thus reducing the pumping flow rate.

[0059] Optionally, determining the abnormal state of the target user based on the first average flow rate and the second average flow rate includes: if the first average flow rate is greater than the second average flow rate, increasing the target rotation speed to a first rotation speed; if the first flow rate is greater than the second average flow rate, determining that the target user is in a first abnormal state, where the first flow rate is the flow rate of the ventricular assist device when it is running at the first rotation speed; and if the first flow rate is less than the second average flow rate, determining that the target user is in a second abnormal state.

[0060] Specifically, when the first average flow rate is greater than the second average flow rate, it indicates that the flow rate pumped by the ventricular assist device 100 has decreased, suggesting that the target user may have increased aortic pressure or insufficient blood volume. To further determine the abnormal state of the target patient, the control unit 33 can gradually increase the rotation speed of the ventricular assist device. If the flow rate pumped by the ventricular assist device 100 gradually increases, it indicates that the current target user is in an abnormal state of increased aortic pressure; if the flow rate pumped by the ventricular assist device 100 gradually decreases, it indicates that the current target user is in an abnormal state of insufficient left ventricular blood volume; if the flow rate pumped by the ventricular assist device 100 remains unchanged, the rotation speed of the ventricular assist device continues to increase, and the method described above is used to determine whether the current target user is in an abnormal state of increased aortic pressure or insufficient left ventricular blood volume.

[0061] For example, if the ventricular assist device 100 increases its rotation speed three times consecutively and the pumped flow rate remains unchanged, or if the first average flow rate is less than or equal to the second average flow rate, then the current target user is determined to be in a normal state.

[0062] S530. Adjust the target rotation speed and / or the rotation direction of the impeller within the housing according to the abnormal state of the target user.

[0063] When the target user is in an abnormal state of elevated aortic pressure, a steep pressure-flow curve is required to ensure that the pumped flow rate does not decrease as the pressure difference between the aortic and left ventricular pressures increases, thus meeting the target user's requirements for pump flow characteristics. When the target user is in an abnormal state of insufficient left ventricular blood volume, a flat pressure-flow curve is required to achieve stronger flow pulsation, which is beneficial to the health of the vascular system.

[0064] In this application, depending on the shape of the impeller blades, the impeller 20 has different pressure-flow curves when rotating clockwise and counterclockwise within the housing. When an abnormal state is detected in the target user, the pump flow characteristics of the ventricular assist device 100 can be adjusted by changing the rotation speed and / or rotation direction of the impeller 20 to resolve or alleviate the current abnormal state, thereby improving the safety of the target user.

[0065] Optionally, adjusting the target rotation speed and / or the rotation direction of the impeller within the housing according to the state of the target user includes: acquiring a first pressure-flow rate curve and a second pressure-flow rate curve, wherein the first pressure-flow rate curve is the pressure-flow rate curve when the impeller rotates in a first direction within the housing, and the second pressure-flow rate curve is the pressure-flow rate curve when the impeller rotates in a second direction within the housing, the first direction being opposite to the second direction; if the target user is in the first abnormal state, determining the rotation direction of the impeller within the housing as the second direction, and determining a first pressure difference based on the second average flow rate, the target rotation speed, and the first pressure-flow rate curve, determining a second rotation speed based on the first pressure difference, the second average flow rate, and the second pressure-flow rate curve, and adjusting the target rotation speed to the second rotation speed; if the target user is in the second abnormal state, reducing the target rotation speed while maintaining the rotation direction of the impeller within the housing as the first direction.

[0066] Before the ventricular assist device 100 leaves the factory, it can be tested in a testing system. The relationship between the pressure difference between the outlet and inlet pressures and the pump flow rate is measured when the device rotates clockwise and counterclockwise at different speeds. This involves pre-measuring multiple first pressure-flow rate curves and multiple second pressure-flow rate curves of the ventricular assist device 100. These curves are then stored in the control unit 33. When the ventricular assist device 100 is running, by acquiring the current speed, the system can find the first pressure-flow rate curve and the second pressure-flow rate characteristic curve corresponding to the target speed from the stored curves, thereby determining the speed at the desired pump flow rate characteristics.

[0067] When the ventricular assist device 100 is operating in a mode with a flatter pressure-flow curve by default, if the target user is in an abnormal state of insufficient blood volume in the left ventricle, the impeller speed is reduced to avoid suction or collapse of the left ventricle; if the target user is in an abnormal state of increased aortic pressure, the rotation direction and speed of the impeller 20 are adjusted to make the pressure-flow curve of the ventricular assist device 100 steeper, so as to accelerate the pumping of blood from the left ventricle into the aorta, thereby reducing aortic pressure.

[0068] When the ventricular assist device 100 operates with a steeper pressure-flow curve by default, if the target user is in an abnormal state of increased aortic pressure, the rotation speed of the impeller 20 is increased to accelerate the pumping of blood from the left ventricle into the aorta, thereby reducing aortic pressure. If the target user is in an abnormal state of insufficient blood volume in the left ventricle, the rotation direction and speed of the impeller 20 are adjusted to make the pressure-flow curve of the ventricular assist device 100 flatter, thereby reducing the pumping flow rate of the ventricular assist device 100 to avoid suction or collapse of the left ventricle.

[0069] The adjustment of the impeller 20's rotation direction and speed specifically includes: the control unit 33 first determines the current first pressure-flow rate curve of the ventricular assist device 100 based on the target speed, and then determines the first pressure difference from the current first pressure-flow rate curve based on the second average flow rate. From multiple second pressure-flow rate curves, a second pressure-flow rate curve that satisfies the first pressure difference and the second average flow rate is determined, and the speed corresponding to this second pressure-flow rate curve is determined as the second speed. This adjusts the impeller 20's speed to the second speed, changing the rotation direction from clockwise to counterclockwise, or vice versa.

[0070] In one example, after adjusting the target rotational speed to the second rotational speed, the method further includes: obtaining a third average flow rate and a fourth average flow rate, wherein the third average flow rate is the average flow rate of the ventricular assist device operating at the second rotational speed during a third cardiac cycle, and the fourth average flow rate is the average flow rate of the ventricular assist device operating at the second rotational speed during a fourth cardiac cycle, the fourth cardiac cycle being later than the third cardiac cycle; if the fourth average flow rate is less than or equal to the third average flow rate, reducing the second rotational speed to the third rotational speed; if the second flow rate is greater than the fourth average flow rate, maintaining the impeller rotational speed at the third rotational speed, wherein the second flow rate is the flow rate of the ventricular assist device operating at the third rotational speed; if the second flow rate is less than or equal to the fourth average flow rate, determining the rotational direction of the impeller within the housing as the first direction, and determining a second pressure difference based on the fourth average flow rate, the second rotational speed, and the second pressure-flow rate curve, and adjusting the second rotational speed based on the second pressure difference, the fourth average flow rate, and the first pressure-flow rate curve.

[0071] After adjusting the speed of impeller 20 to the second speed, or adjusting the rotation direction of impeller 20 from counterclockwise to clockwise or from clockwise to counterclockwise, this application can again obtain the change in the pumping flow of ventricular assist device 100 to determine whether the abnormal condition of increased aortic pressure or insufficient ventricular blood volume in the patient has been resolved or alleviated.

[0072] The durations of the third and fourth cardiac cycles can be less than or equal to the first cardiac cycle. After adjusting the rotation speed of the ventricular assist device 100 to the second rotation speed, the control unit 33 can calculate the third average flow rate during the third cardiac cycle and the fourth average flow rate during the fourth cardiac cycle adjacent to the third cardiac cycle. Then, it compares the third and fourth average flow rates to determine whether the target user has experienced hypovolemia or increased aortic pressure due to the adjustment of the pressure-flow curve. This problem is then addressed by adjusting the rotation speed and direction of the impeller 20.

[0073] In this application, the control unit 33 can determine whether there is an abnormal state by calculating the average flow change of the target user in real time. Then, when there is an abnormal state, the speed and / or rotation direction of the impeller 20 are adjusted according to the abnormal state, so that the performance of the ventricular assist device 100 matches the pump flow characteristics of the user's physiological state changes in real time.

[0074] Using impeller blades as Figure 4 The example shown is a forward-curving blade.

[0075] With the first direction being clockwise and the second direction being counterclockwise, assuming the impeller 20 of the ventricular assist device 100 rotates clockwise, the pressure-flow curve is flatter when the impeller 20 rotates clockwise, and steeper when the impeller 20 rotates counterclockwise. That is, the first pressure-flow curve is the pressure-flow curve of the ventricular assist device 100 at the target rotational speed when rotating clockwise, and the second pressure-flow curve is the pressure-flow curve of the ventricular assist device 100 at the target rotational speed when rotating counterclockwise. The slope of the first pressure-flow curve is less than the slope of the second pressure-flow curve.

[0076] Specifically, when the target user is in an abnormal state of insufficient left ventricular blood volume, the control unit 33 can control the reduction of the target rotation speed while maintaining the impeller 20 rotating clockwise. If the target user is in an abnormal state of increased aortic pressure, the control unit 33 adjusts the impeller 20 rotation speed to the second speed according to the first pressure-flow curve and the second pressure-flow curve, and adjusts the impeller rotation direction from clockwise to counterclockwise, so that the pressure-flow curve of the ventricular assist device 100 is steeper, meeting the pump flow characteristics of the target user.

[0077] When the target user experiences elevated aortic pressure and the rotation speed of the ventricular assist device 100 is adjusted to the second rotation speed, the control unit 33 can acquire the third and fourth average flow rates to determine whether the target user is still in an abnormal state. If the fourth average flow rate is greater than or equal to the third average flow rate, it indicates that the target user is currently in a normal state; if the fourth average flow rate is less than the third average flow rate, it indicates that the target user may currently have insufficient left ventricular blood volume. The control unit 33 can gradually reduce the rotation speed of the ventricular assist device 100 to the third rotation speed. If the pumping flow rate at the third rotation speed gradually increases, the rotation speed of the ventricular assist device 100 is maintained at the third rotation speed; if the pumping flow rate at the third rotation speed gradually decreases, it indicates that the target user's current blood volume insufficiency is serious, and the control unit 33 can readjust the rotation direction of the impeller 20 to the clockwise direction and determine the rotation speed of the impeller 20 based on the first pressure-flow curve and the second pressure-flow curve. Specifically, the first pressure-flow curve of the ventricular assist device 100 is determined based on the second rotation speed, and the second pressure difference is determined from the current first pressure-flow curve based on the fourth average flow rate. From multiple second pressure-flow curves, a second pressure-flow curve that satisfies the second pressure difference and the fourth average flow rate is determined. The rotation speed corresponding to the second pressure-flow curve is determined as the rotation speed adjusted by the ventricular assist device 100, and the rotation direction is adjusted from counterclockwise to clockwise.

[0078] With the first direction being counterclockwise and the second direction being clockwise, and assuming the impeller 20 of the ventricular assist device 100 rotates counterclockwise, the first pressure-flow rate curve is the pressure-flow rate curve of the ventricular assist device 100 at the target rotational speed when rotating counterclockwise, and the second pressure-flow rate curve is the pressure-flow rate curve of the ventricular assist device 100 at the target rotational speed when rotating clockwise. The slope of the first pressure-flow rate curve is greater than the slope of the second pressure-flow rate curve.

[0079] Specifically, when the target user is in an abnormal state of elevated aortic pressure, the control unit 33 can control the increase of the target rotation speed while maintaining the impeller 20 in a counterclockwise direction. If the target user is in an abnormal state of insufficient left ventricular blood volume, the control unit 33 adjusts the impeller 20 rotation speed to the second speed according to the first pressure-flow curve and the second pressure-flow curve, and adjusts the impeller rotation direction from counterclockwise to clockwise, so that the pressure-flow curve of the ventricular assist device 100 is flatter, meeting the pump flow characteristics of the target user.

[0080] Specifically, the control unit 33 first determines the current first pressure-flow rate curve of the ventricular assist device 100 based on the target rotational speed, and then determines the first pressure difference from the current first pressure-flow rate curve based on the second average flow rate. From multiple second pressure-flow rate curves, a second pressure-flow rate curve that satisfies the first pressure difference and the second average flow rate is determined. The rotational speed corresponding to this second pressure-flow rate curve is then determined as the second rotational speed, thereby adjusting the rotational speed of the impeller 20 to the second rotational speed, changing the rotational direction from clockwise to counterclockwise, or vice versa.

[0081] When the target user experiences left ventricular hypovolemia and the rotation speed of the ventricular assist device 100 is adjusted to the second rotation speed, the control unit 33 can acquire the third and fourth average flow rates to determine whether the target user is still in an abnormal state. If the fourth average flow rate is greater than or equal to the third average flow rate, it indicates that the target user is currently in a normal state; if the fourth average flow rate is less than the third average flow rate, it indicates that the target user's aortic pressure is currently elevated. The control unit 33 can gradually increase the rotation speed of the ventricular assist device 100 to the third rotation speed. If the pumping flow rate at the third rotation speed gradually decreases, the rotation speed of the ventricular assist device 100 is maintained at the third rotation speed; if the pumping flow rate at the third rotation speed gradually increases, it indicates that the target user's aortic pressure elevation problem is serious, and the control unit 33 can readjust the rotation direction of the impeller 20 to the counterclockwise direction and determine the rotation speed of the impeller 20 based on the first and second pressure-flow curves. Specifically, the first pressure-flow curve of the ventricular assist device 100 is determined based on the second rotation speed, and the second pressure difference is determined from the current first pressure-flow curve based on the fourth average flow rate. From multiple second pressure-flow curves, a second pressure-flow curve that satisfies the second pressure difference and the fourth average flow rate is determined. The rotation speed corresponding to the second pressure-flow curve is determined as the rotation speed adjusted by the ventricular assist device 100, and the rotation direction is adjusted from clockwise to counterclockwise.

[0082] It should be noted that the impeller blades are Figure 4 The control principle of the backward-curved blades shown is the same as that of the forward-curved blades of the impeller, but the rotation direction is exactly opposite, so it will not be elaborated here.

[0083] As can be seen, this application proposes a speed control method, which obtains a first average flow rate and a second average flow rate of a ventricular assist device (VAD). The first average flow rate is the average flow rate of the VAD during a first cardiac cycle when it operates at a target speed, and the second average flow rate is the average flow rate of the VAD during a second cardiac cycle when it operates at the target speed. The first cardiac cycle is later than the second cardiac cycle. The method determines the abnormal state of the target user based on the first and second average flow rates. It then adjusts the target speed and / or the impeller's rotation direction within the housing based on the abnormal state of the target user. This application determines the current abnormal state of the user based on the average flow rate of the VAD during different cardiac cycles, and then adjusts the impeller's speed and / or rotation direction based on the abnormal state, thereby ensuring that the performance of the VAD matches the pump flow characteristics of the user's physiological state changes in real time.

[0084] The above primarily describes the solutions of the embodiments of this application from the perspective of the method execution process. It is understood that, in order to achieve the above functions, the network device includes corresponding hardware structures and / or software modules for executing each function. Those skilled in the art should readily recognize that, in conjunction with the units and algorithm steps of the various examples described in the embodiments provided herein, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0085] For example, this application provides a control unit including one or more processors, the one or more processors being configured to: acquire a first average flow rate and a second average flow rate of a ventricular assist device, the first average flow rate being the average flow rate of the ventricular assist device operating at a target rotational speed during a first cardiac cycle, the second average flow rate being the average flow rate of the ventricular assist device operating at the target rotational speed during a second cardiac cycle, the first cardiac cycle being later than the second cardiac cycle; determine an abnormal state of a target user based on the first average flow rate and the second average flow rate, the target user being a user of the ventricular assist device; and adjust the target rotational speed and / or the rotational direction of the impeller within the housing based on the abnormal state of the target user.

[0086] For example, this application also provides a ventricular assist device, the ventricular assist device comprising:

[0087] case;

[0088] An impeller disposed within the housing;

[0089] The control unit for controlling the levitation rotation of the impeller, the control unit being used for:

[0090] The first average flow rate and the second average flow rate of the ventricular assist device are obtained. The first average flow rate is the average flow rate of the ventricular assist device when it is running at the target speed during a first cardiac cycle. The second average flow rate is the average flow rate of the ventricular assist device when it is running at the target speed during a second cardiac cycle. The first cardiac cycle is later than the second cardiac cycle.

[0091] The abnormal state of the target user is determined based on the first average flow rate and the second average flow rate. The target user is a user who uses the ventricular assist device.

[0092] Adjust the target rotation speed and / or the rotation direction of the impeller within the housing according to the abnormal state of the target user.

[0093] For example, this application also provides a medical device that includes the control unit or ventricular assist device described above.

[0094] The control unit of 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.

[0095] In embodiments of this application, the control unit may also be a chip or a chip system, such as a system on a chip (SoC).

[0096] Please see Figure 6 , Figure 6 This is a schematic diagram of the structure of a medical device provided in an embodiment of this 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 memories and configured to be executed by the one or more processors.

[0097] The above procedure includes instructions for performing the following steps:

[0098] The system acquires a first average flow rate and a second average flow rate of the ventricular assist device, wherein the first average flow rate is the average flow rate of the ventricular assist device when it operates at a target rotational speed during a first cardiac cycle, and the second average flow rate is the average flow rate of the ventricular assist device when it operates at the target rotational speed during a second cardiac cycle, wherein the first cardiac cycle is later than the second cardiac cycle; the system determines an abnormal state of a target user, wherein the target user is a user of the ventricular assist device, based on the first average flow rate and the second average flow rate; and adjusts the target rotational speed and / or the rotation direction of the impeller within the housing based on the abnormal state of the target user.

[0099] All relevant content in each scenario involved in the above method embodiments can be referenced from the functional description of the corresponding functional module, and will not be repeated here.

[0100] It should be understood that the aforementioned memory may include read-only memory and random access memory, and provides instructions and data to the processor. A portion of the memory may also include non-volatile random access memory. For example, the memory may also store information about the device type.

[0101] In the embodiments of this application, the processor of the above-described device may be a Central Processing Unit (CPU), which 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 any conventional processor, etc.

[0102] It should be understood that "at least one" in the embodiments of this application refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple.

[0103] Furthermore, unless otherwise stated, the ordinal numbers such as "first" and "second" mentioned in the embodiments of this application are used to distinguish multiple objects and are not used to limit the order, timing, priority, or importance of multiple objects. For example, "first information" and "second information" are only used to distinguish different information and do not indicate differences in the content, priority, sending order, or importance of these two types of information.

[0104] In implementation, each step of the above method can be completed by integrated logic circuits in the processor's hardware or by instructions in software. The steps of the method disclosed in the embodiments of this application can be directly manifested as execution by a hardware processor, or as a combination of hardware and software units within the processor. The software units can reside in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located in memory, and the processor executes the instructions in the memory, combining them with its hardware to complete the steps of the above method. To avoid repetition, detailed descriptions are omitted here.

[0105] This application also provides a computer storage medium storing a computer program for electronic data interchange, which causes a computer to perform some or all of the steps of any of the methods described in the above method embodiments.

[0106] This application also provides a computer program product, which includes a non-transitory computer-readable storage medium storing a computer program operable to cause a computer to perform some or all of the steps of any of the methods described in the above method embodiments. This computer program product can be a software installation package.

[0107] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0108] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0109] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage device, which may include a flash drive, ROM, RAM, disk, or optical disk, etc.

[0110] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A ventricular assist device, characterized in that, The ventricular assist device includes: case; An impeller disposed within the housing; The control unit for controlling the levitation rotation of the impeller, the control unit being used for: The first average flow rate and the second average flow rate of the ventricular assist device are obtained. The first average flow rate is the average flow rate of the ventricular assist device when it is running at the target speed during a first cardiac cycle. The second average flow rate is the average flow rate of the ventricular assist device when it is running at the target speed during a second cardiac cycle. The first cardiac cycle is earlier than the second cardiac cycle. The abnormal state of the target user is determined based on the first average flow rate and the second average flow rate. The target user is a user who uses the ventricular assist device. Obtain a first pressure-flow rate curve and a second pressure-flow rate curve. The first pressure-flow rate curve is the pressure-flow rate curve when the impeller rotates in a first direction within the housing. The second pressure-flow rate curve is the pressure-flow rate curve when the impeller rotates in a second direction within the housing. The first direction is opposite to the second direction. If the target user is in a first abnormal state, the rotation direction of the impeller in the housing is determined to be the second direction, and a first pressure difference is determined according to the second average flow rate, the target speed and the first pressure-flow curve, and a second speed is determined according to the first pressure difference, the second average flow rate and the second pressure-flow curve, and the target speed is adjusted to the second speed. If the target user is in a second abnormal state, reduce the target rotation speed and maintain the impeller's rotation direction within the housing in the first direction.

2. The ventricular assist device according to claim 1, characterized in that, In determining the abnormal state of a target user based on the first average traffic and the second average traffic, the control unit is specifically configured to: If the first average flow rate is greater than the second average flow rate, the target rotational speed is increased to the first rotational speed; If the first flow rate is greater than the second average flow rate, it is determined that the target user is in the first abnormal state, where the first flow rate is the flow rate of the ventricular assist device when it is running at the first rotation speed; If the first traffic volume is less than the second average traffic volume, the target user is determined to be in the second abnormal state.

3. The ventricular assist device according to claim 2, characterized in that, After adjusting the target speed to the second speed, the control unit is further configured to: A third average flow rate and a fourth average flow rate are obtained. The third average flow rate is the average flow rate of the ventricular assist device when it is running at the second rotation speed during a third cardiac cycle. The fourth average flow rate is the average flow rate of the ventricular assist device when it is running at the second rotation speed during a fourth cardiac cycle. The fourth cardiac cycle is later than the third cardiac cycle. If the fourth average flow rate is less than or equal to the third average flow rate, reduce the second rotation speed to the third rotation speed; If the second flow rate is greater than the fourth average flow rate, the impeller speed is maintained at the third speed, and the second flow rate is the flow rate of the ventricular assist device when it is running at the third speed; If the second flow rate is less than or equal to the fourth average flow rate, the rotation direction of the impeller within the housing is determined to be the first direction, and a second pressure difference is determined based on the fourth average flow rate, the second rotational speed, and the second pressure-flow curve. The second rotational speed is then adjusted based on the second pressure difference, the fourth average flow rate, and the first pressure-flow curve.

4. The ventricular assist device according to claim 2 or 3, characterized in that, The slope of the first pressure-flow rate curve is less than the slope of the second pressure-flow rate curve.

5. The ventricular assist device according to claim 2 or 3, characterized in that, When the blades of the impeller are forward-curved blades, the first direction is clockwise and the second direction is counterclockwise.

6. The ventricular assist device according to claim 2 or 3, characterized in that, When the blades of the impeller are backward-curved blades, the first direction is counterclockwise and the second direction is clockwise.

7. The ventricular assist device according to claim 1, characterized in that, The control unit is also used for: Obtain a first flow rate curve, which is the flow rate curve of the ventricular assist device when it is running at the target speed; The duration between adjacent peaks in the first flow curve is determined as the target duration. The first cardiac cycle and the second cardiac cycle are determined based on the target duration.

8. A control unit, characterized in that, The control unit includes one or more processors, the one or more processors being used for: A first average flow rate and a second average flow rate of the ventricular assist device are obtained. The first average flow rate is the average flow rate of the ventricular assist device when it is running at a target speed during a first cardiac cycle. The second average flow rate is the average flow rate of the ventricular assist device when it is running at the target speed during a second cardiac cycle. The first cardiac cycle is earlier than the second cardiac cycle. The abnormal state of the target user is determined based on the first average flow rate and the second average flow rate. The target user is a user who uses the ventricular assist device. Obtain a first pressure-flow rate curve and a second pressure-flow rate curve. The first pressure-flow rate curve is the pressure-flow rate curve when the impeller rotates in a first direction inside the housing. The second pressure-flow rate curve is the pressure-flow rate curve when the impeller rotates in a second direction inside the housing. The first direction is opposite to the second direction. If the target user is in a first abnormal state, the rotation direction of the impeller in the housing is determined to be the second direction, and a first pressure difference is determined according to the second average flow rate, the target speed and the first pressure-flow curve. A second speed is determined according to the first pressure difference, the second average flow rate and the second pressure-flow curve, and the target speed is adjusted to the second speed. If the target user is in a second abnormal state, reduce the target rotation speed and maintain the impeller's rotation direction within the housing in the first direction.

9. A medical device, characterized in that, The device includes a processor, a memory, and a communication interface. The memory stores one or more programs, which are executed by the processor. The one or more programs include instructions for performing steps performed by the control unit in any one of claims 1-7.

10. 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 performed by the control unit in any one of claims 1-7.

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