CN117298446A

CN117298446A - Rotating speed control method and device

Info

Publication number: CN117298446A
Application number: CN202311525996.3A
Authority: CN
Inventors: 杨羽卓; 余顺周
Original assignee: Shenzhen Core Medical Technology Co Ltd
Current assignee: Shenzhen Core Medical Technology Co Ltd
Priority date: 2023-11-15
Filing date: 2023-11-15
Publication date: 2023-12-29

Abstract

The application discloses a rotating speed control method and a rotating speed control device, wherein the method comprises the following steps: acquiring a first average flow and a second average flow of the ventricular assist device, wherein the first average flow is the average flow when the ventricular assist device operates at a target rotating speed in a first cardiac cycle, and the second average flow is the average flow when the ventricular assist device operates at the target rotating speed in a second cardiac cycle, and the first cardiac cycle is later than the second cardiac cycle; determining an abnormal state of the target user according to the first average flow and the second average flow; and adjusting the target rotating speed and/or the rotating direction of the impeller in the shell according to the abnormal state of the target user. According to the method and the device, the abnormal state of the current user is judged according to the average flow of the ventricular assist device in different cardiac cycles, and then the rotating speed and/or the rotating direction of the impeller adjusted according to the abnormal state are/is judged, so that the performance of the ventricular assist device accords with the pump flow characteristics of the physiological state change of the user in real time.

Description

Rotating speed control method and device

Technical Field

The application relates to the technical field of medical equipment, in particular to a rotating speed control method and device.

Background

Mechanical circulatory support devices, such as ventricular assist devices (Ventricular Assist Devices, VAD), may be used to provide long-term mechanical support or assistance to heart failure patients or patients suffering from other heart related diseases that assist the heart in pumping blood from the heart to other parts of the body.

The VAD uses a non-contact bearing to suspend the impeller within the housing during operation. After the impeller shape is determined, the pressure flow curve of the VAD is fixed, but for the change of the physiological state of the patient, different characteristics of the pressure flow curve are required, so how to realize the pump flow characteristics according with the change of the physiological state of the patient is a problem to be solved urgently.

Disclosure of Invention

The embodiment of the application provides a rotating speed control method and a rotating speed control device, which can realize the pump flow characteristic according with the physiological state change of a patient by adjusting the rotating speed and the rotating direction of an impeller.

In a first aspect, embodiments of the present application provide a rotational speed control method applied to a ventricular assist device including a housing and an impeller disposed within the housing; the method comprises the following steps:

acquiring a first average flow and a second average flow of the ventricular assist device, wherein the first average flow is the average flow when the ventricular assist device operates at a target rotating speed in a first cardiac cycle, the second average flow is the average flow when the ventricular assist device operates at the target rotating speed in a second cardiac cycle, and the first cardiac cycle is later than the second cardiac cycle;

Determining an abnormal state of a target user according to the first average flow and the second average flow, wherein the target user is a user using the ventricular assist device;

and adjusting the target rotating speed and/or the rotating direction of the impeller in the shell according to the abnormal state of the target user.

In a second aspect, embodiments of the present application provide a control unit including one or more processors configured to:

acquiring a first average flow and a second average flow of a ventricular assist device, wherein the first average flow is an average flow when the ventricular assist device operates at a target rotating speed in a first cardiac cycle, the second average flow is an average flow when the ventricular assist device operates at the target rotating speed in a second cardiac cycle, and the first cardiac cycle is later than the second cardiac cycle;

In a third aspect, embodiments of the present application provide a ventricular assist device comprising:

a housing;

an impeller disposed within the housing;

a control unit for controlling the suspension rotation of the impeller, wherein the control unit is used for:

In a fourth aspect, embodiments of the present application provide a medical device comprising a processor, a memory, a communication interface, and one or more programs stored in the memory and configured to be executed by the processor, the programs comprising instructions for performing part or all of the steps described in the method of the first aspect above.

In a fifth aspect, embodiments of the present application provide a computer-readable storage medium storing a computer program for electronic data exchange, where the computer program causes a computer to perform some or all of the steps described in the method of the first aspect.

In a sixth aspect, embodiments of the present application provide a computer program product, wherein the computer program product comprises 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 according to the first aspect of the embodiments of the present application. The computer program product may be a software installation package.

According to the technical scheme, the first average flow and the second average flow of the ventricular assist device are obtained, wherein the first average flow is the average flow when the ventricular assist device operates at the target rotating speed in a first cardiac cycle, and the second average flow is the average flow when the ventricular assist device operates at the target rotating speed in a second cardiac cycle, and the first cardiac cycle is later than the second cardiac cycle; determining an abnormal state of the target user according to the first average flow and the second average flow; and adjusting the target rotating speed and/or the rotating direction of the impeller in the shell according to the abnormal state of the target user. According to the method and the device, the abnormal state of the current user is judged according to the average flow of the ventricular assist device in different cardiac cycles, and then the rotating speed and/or the rotating direction of the impeller adjusted according to the abnormal state are/is judged, so that the performance of the ventricular assist device accords with the pump flow characteristics of the physiological state change of the user in real time.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of a ventricular assist system according to an embodiment of the present disclosure;

FIG. 2 is a schematic diagram of a ventricular assist device according to an embodiment of the present disclosure;

FIG. 3 is a schematic view of an impeller blade according to an embodiment of the present disclosure in the shape of a backward curved blade;

FIG. 4 is a schematic view of an impeller blade according to an embodiment of the present disclosure in the shape of a forward curved blade;

fig. 5 is a flow chart of a rotational speed control method according to an embodiment of the present application;

fig. 6 is a schematic structural diagram of a medical device according to an embodiment of the present application.

Detailed Description

For better understanding of the technical solutions of the present application by those skilled in the art, the technical solutions of the embodiments of the present application are clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application, and it is apparent that the described embodiments are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by those skilled in the art without the exercise of inventive faculty, are intended to be within the scope of protection of the present application based on the description of the embodiments herein.

The terms first, second and the like in the description and in the claims of the present application and in the above-described figures, are used for distinguishing between different objects and not for describing a particular sequential order. Furthermore, the terms "comprise" and "have," as well as any variations thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, software, article, or apparatus that comprises a list of steps or elements is not limited to only those listed steps or elements but may include other steps or elements not listed or inherent to such process, method, article, or apparatus.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.

"proximal" is defined herein as the end proximal to the operator; the "distal end" is defined as the end that is remote from the operator, i.e. the end that is close to the heart of the patient.

"rotational speed" in this application refers to the rotational speed of a motor or electric machine, which is related to the rotational speed of the rotor or impeller of the ventricular assist device, and may be defined as rotational speed per minute. "flow," "fluid flow," "pumping flow" refers to the volume of fluid delivered by a ventricular assist device per unit of time, which can be estimated and measured in liters per minute.

The ventricular assist device of the present application may be attached to the apex of the left ventricle, or the right ventricle, or both ventricles of the heart. The ventricular assist device may further comprise a centrifugal pump, an axial flow pump, or a magnetic suspension pump capable of delivering the entire output to the left ventricle according to the pulmonary circulation or blood circulation.

The ventricular assist device may be attached to the heart via a ventricular connection assembly (e.g., a top ring, a ventricular cuff) that may be sutured to the heart and coupled to the ventricular assist device, and the other end of the ventricular assist device may be connected to the ascending aorta via an outlet tube and/or an artificial blood vessel connected to the outlet tube, such that the ventricular assist device may effectively divert blood from the weakened ventricle and advance it to the aorta for circulation to the remainder of the patient's vascular system, providing ventricular assist function to the patient. The present application describes a ventricular assist device as used in the left heart.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a ventricular assist system according to an embodiment of the present disclosure. As shown in fig. 1, 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 within the ventricular assist device 100 and the other end is connected through the abdominal skin of the patient to an external controller 200 disposed outside the body. The external controller 200 is used for monitoring the ventricular assist device 100, and can realize functions of controlling and displaying data, detecting faults, alarming, recording data and the like of the ventricular assist device 100. The transmission assembly 300 may be a percutaneous cable that may include one or more power supply cables, and one or more communication cables.

As shown in fig. 2, the ventricular assist device 100 includes a housing assembly having an inlet tube and an impeller 20 for propelling a fluid. The housing assembly comprises a first housing and a second housing opposite to the first housing, wherein a cavity 10 is formed by surrounding the first housing and the second housing, and a fluid inlet 14 and a fluid outlet 15 which are communicated with the cavity 10 are respectively formed in the housing assembly. The impeller 20 is capable of rotating in suspension within the chamber 10, and rotation of the impeller 20 is capable of generating centrifugal force to transport fluid so that fluid can enter the chamber 10 from the fluid inlet 14 and be output from the fluid outlet 15. Wherein a levitated rotation of the impeller 20 means that the impeller 20 is not in contact with the cavity wall of the chamber 10 when rotating.

The ventricular assist device 100 further includes a motor 30 for driving the impeller 20 to rotate in a levitated manner and a control unit 33. The second housing includes a first side wall 11, the first housing includes a second side wall 12, and the motor 30 includes a stator 31 and a rotor 32 arranged on both sides of the first side wall 11. Wherein, the stator 31 is fixed on the outer side of the first side wall 11 opposite to the chamber 10, and the corresponding rotor 32 is positioned in the chamber 10. Further, the rotor 32 is fixedly connected to the impeller 20, and when the stator 31 drives the rotor 32 to rotate in the chamber 10, the impeller 20 also rotates in synchronization with the rotor 32 in the chamber 10. The rotation of the impeller 20 can pressurize the fluid in the chamber 10, so that the fluid in the chamber 10 has a higher pressure, thereby realizing the fluid pressurizing effect of the blood pump.

The control unit 33 may be provided inside the ventricular assist device 100 or may be provided outside the ventricular assist device 100. The control unit 33 is configured to detect parameters related to the ventricular assist device 100 and the patient, and to control operation of the ventricular assist device 100, for example, the control unit 33 supplies current to the motor 30 via one or more wires and detects the current via a current detection circuit (e.g., a phase current detection circuit); the rotational speed of the ventricular assist device 100 is controlled in accordance with the received command. Further, the control unit 33 is electrically connected to the stator 31, and controls the magnitude and direction of the magnetic force between the stator 31 and the rotor 32 by controlling the magnitude and direction of the current flowing through the stator 31, thereby controlling the rotational speed and rotational direction of the impeller 20.

The impeller 20 is annular, the fluid inlet 14 faces the inner ring of the annular impeller 20, and the impeller 20 includes opposed third and fourth faces 22, 23, and a flow passage 21. The flow path 21 extends radially along the annular impeller 20, and the flow path 21 is provided between the third surface 22 and the fourth surface 23. After entering the inner ring of the impeller 20, the fluid flows out of the impeller 20 from the flow passage 21. The fluid increases in flow velocity with the rotation of the impeller 20 in the flow passage 21, thereby achieving a pressurizing effect, and then flows out of the fluid outlet 15.

Further, the impeller 20 in the present application may be a forward-curved vane impeller, a backward-curved vane impeller. As shown in fig. 3, the blade outlet angle alpha of the backward curved blade type impeller is less than 90 degrees, and the bending direction of the impeller blades is opposite to the rotation direction of the impeller; as shown in fig. 4, the blade outlet angle α of the forward-curved blade impeller is >90 degrees, and the curved direction of the impeller blades is the same as the impeller rotation direction.

After the shape of the impeller 20 is determined before shipment of the ventricular assist device 100, the pressure-flow curve of the ventricular assist device 100 is fixed, but for a change in the physiological state of the patient, a different characteristic of the pressure-flow curve is required. For example, when the blood pressure of a patient is normal, a pressure flow curve is required to be gentle so as to realize stronger flow pulsatility, thereby being beneficial to the health of a vascular system; in patients with hypertension, a steep pressure flow curve is required to achieve that an increase in blood pressure does not reduce pump flow. After the impeller 20 is shaped, the impeller 20 may be rotated clockwise or counterclockwise under control of the control unit, and the impeller 20 may exhibit a flat or steep flow curve characteristic when rotated clockwise or counterclockwise, depending on the characteristics of the blade angle.

Based on this, the present application proposes a rotational speed control method, which adjusts the rotational speed and rotational direction of the impeller 20 according to the current physiological state of the user, so as to satisfy the pump flow characteristics of the current physiological state change of the user, thereby improving the user safety.

In connection with the above description, the present application is described below from the viewpoint of a method example.

Referring to fig. 5, fig. 5 is a flowchart of a rotational speed control method according to an embodiment of the present application, which is applied to the ventricular assist device 100 shown in fig. 1-2. As shown in fig. 5, the method includes the following steps.

S510, acquiring a first average flow and a second average flow of the ventricular assist device, wherein the first average flow is the average flow when the ventricular assist device operates at a target rotating speed in a first cardiac cycle, the second average flow is the average flow when the ventricular assist device operates at the target rotating speed in a second cardiac cycle, and the first cardiac cycle is later than the second cardiac cycle.

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

When the patient is in an abnormal state such as a heavy afterload (i.e., the patient has an increased blood pressure) or insufficient ventricular blood volume, the pumping flow rate of the ventricular assist device 100 is reduced, and the present application determines whether the patient is in an abnormal state such as an increased blood pressure or insufficient ventricular blood volume according to the change of the pumping flow rate of the ventricular assist device 100. Further, when an abnormal condition exists, patient safety is improved by adjusting the operation of ventricular assist device 100 to address or mitigate the abnormal condition.

Optionally, the method further comprises: acquiring a first flow curve, wherein the first flow curve is a flow curve when the ventricular assist device operates at a target rotating speed; determining the time length between adjacent peaks in the first flow curve as a target time length; and determining the first cardiac cycle and the second cardiac cycle according to the target duration.

In the present application, the control unit 33 may determine the current cardiac cycle of the target user according to the time between the adjacent peaks of the flow curve of the ventricular assist device 100, further obtain the flow in m cardiac cycles from the storage unit, calculate the average flow in the m cardiac cycles and the average flow in the next m cardiac cycles, and m is a positive integer greater than 1.

During operation of the ventricular assist device 100 in a patient, the flow rate of pumping through the ventricular assist device 100 is dependent upon the resistance of the ventricular assist device 100 to perform work to pump blood from the left ventricle to the aorta. The amount of work done by ventricular assist device 100 can be quantified as the amount of current that needs to be provided to motor 30, i.e., the motor current corresponds to the amount of current delivered to the motor of ventricular assist device 100 when ventricular assist device 100 is operating in a patient. The load of the motor 30 may vary during different phases of the cardiac cycle of the patient's heart. When the pressure differential in the patient's heart changes, the motor current will also change to keep the rotor speed constant. For example, as the flow rate of blood into the aorta increases (e.g., during systole), the current required by motor 30 will increase. The change in motor current can therefore help characterize cardiac performance. That is, during operation of ventricular assist device 100, ventricular assist device 100 has a current-flow characteristic, wherein the greater the current, the more ventricular assist device 100 performs, i.e., the greater the pumping flow of ventricular assist device 100.

The current of ventricular assist device 100 may be measured by a phase current detection circuit provided or by any other suitable means, such as a current sensor. The current-flow characteristic curve may be stored in the control unit 33 in advance, and before the ventricular assist device 100 leaves the factory, it may be placed in a test system to test the relationship curve of the pumping flow of the ventricular assist device 100 with the current at different rotational speeds, respectively, so that the current-flow characteristic curve is stored in the control unit 33. The control unit 33 may store the detected current in real time.

Specifically, when the ventricular assist device 100 is operated at the target rotational speed, the control unit 33 obtains a current curve for a preset period of time, and then estimates a first flow rate curve for the preset period of time corresponding to the current curve using a pre-stored current-flow rate characteristic curve. The 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 in m cardiac cycles is taken as a first average flow, and the average flow in the next m cardiac cycles is taken as a second average flow.

S520, determining an abnormal state of a target user according to the first average flow and the second average flow, wherein the target user is a user using the ventricular assist device.

In this application, the control unit 33 determines the current variation by comparing the first average flow with the second average flow, and further determines whether the current target user is in an abnormal state according to the current variation. When the target user is in an abnormal state, the control unit 33 adjusts the rotational speed and/or rotational direction of the impeller 20 according to the shape of the impeller blades and the abnormal state to realize the pump flow characteristic conforming to the physiological state change of the target user while solving or alleviating the abnormal state.

Wherein the abnormal state may include: the arterial pressure exceeds the preset pressure value or the ventricular blood volume is less than the preset volume, i.e. the current target patient may have problems of increased blood pressure or insufficient volume. When the aortic pressure rises above the normal human aortic pressure (preset threshold), the greater the pressure differential between the aortic pressure and the left ventricular pressure, the more effort the ventricular assist device 100 needs to do. Thus, the greater the arterial pressure, the less the ventricular assist device 100 pumps at a constant rotational speed. When the blood volume in the left ventricle is insufficient, the left ventricle cannot supply enough blood pumped by the ventricular assist device 100, so that the pumping flow rate of the ventricular assist device 100 is reduced.

Optionally, the determining the abnormal state of the target user according to the first average flow and the second average flow includes: if the first average flow is greater than the second average flow, 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, wherein the first flow rate is the flow rate when the ventricular assist device operates at the first rotational speed; and if the first flow is smaller than the second average flow, determining that the target user is in a second abnormal state.

Specifically, when the first average flow rate is greater than the second average flow rate, indicating that the flow rate pumped by the ventricular assist device 100 is reduced, the target user may have an elevated arterial pressure or insufficient blood volume. To further determine the abnormal state of the target patient, the control unit 33 may gradually increase the rotational speed of the ventricular assist device, and the flow pumped by the ventricular assist device 100 gradually increases, indicating that the current target user is in the abnormal state of increased arterial pressure; when the flow pumped by the ventricular assist device 100 gradually decreases, it indicates that the current target user is in an abnormal state with insufficient left ventricular blood volume; the flow pumped by the ventricular assist device 100 is unchanged, the rotational speed of the ventricular assist device continues to be increased, and it is determined whether the current target user is in an abnormal state of increased arterial pressure or an abnormal state of insufficient left ventricular blood volume in accordance with the above-described method.

For example, when the ventricular assist device 100 continuously increases the rotational speed 3 times, the pumping flow rate thereof is still unchanged or the obtained first average flow rate is less than or equal to the second average flow rate, it is determined that the current target user is in a normal state.

S530, adjusting the target rotating speed and/or the rotating direction of the impeller in the shell according to the abnormal state of the target user.

When the target user is in an abnormal state of increasing the aortic pressure, the pressure flow curve required by the target user is steep, so that the pumped flow cannot be reduced when the pressure difference between the aortic pressure and the left ventricular pressure is increased, and the requirement of the target user on the pump flow characteristic is met. When the target user is in an abnormal state of insufficient left ventricular blood volume, the target user needs to have a gentle pressure flow curve so as to realize stronger flow pulsatility, and the health of a vascular system is facilitated.

In this application, the impeller 20 has different pressure flow curves as it rotates clockwise and counter-clockwise within the housing, depending on the shape of the impeller blades. When the target user is detected to be in an abnormal state, the rotation speed and/or rotation direction of the impeller 20 can be changed, so that the pump flow characteristic of the ventricular assist device 100 can solve or relieve the current abnormal state, and the safety of the target user can be improved.

Optionally, the adjusting the target rotation speed and/or the rotation direction of the impeller in the housing according to the state of the target user includes: acquiring a first pressure flow curve and a second pressure flow curve, wherein the first pressure flow curve is a pressure flow curve when the impeller rotates in a first direction in the shell, the second pressure flow curve is a pressure flow curve when the impeller rotates in a second direction in the shell, and the first direction is opposite to the second direction; if the target user is in the first abnormal state, determining that the rotation direction of the impeller in the shell is the second direction, determining a first pressure difference according to the second average flow, the target rotating speed and the first pressure flow curve, determining a second rotating speed according to the first pressure difference, the second average flow and the second pressure flow curve, and adjusting the target rotating speed to the second rotating speed; and if the target user is in the second abnormal state, reducing the target rotating speed, and maintaining the rotating direction of the impeller in the shell to be the first direction.

Before the ventricular assist device 100 is shipped, the ventricular assist device 100 may be placed in a test system for testing, and when the ventricular assist device rotates clockwise and counterclockwise, the relationship curve between the pressure difference of the outlet pressure and the inlet pressure of the ventricular assist device 100 and the pumping flow rate at different rotation speeds is measured, that is, a plurality of first pressure flow rate curves and a plurality of second pressure flow rate curves of the ventricular assist device 100 are measured in advance. The first and second pressure flow curves for the different rotational speeds are then stored in the control unit 33. When the ventricular assist device 100 is operated, the current rotation speed is obtained, so that a first pressure flow curve and a second pressure flow characteristic curve corresponding to the target rotation speed can be searched from the stored first pressure flow curves and the stored second pressure flow curves, and the rotation speed under the required pump flow characteristic can be further determined.

When the ventricular assist device 100 defaults to operate in a mode that the pressure flow curve is flatter, if the target user is in an abnormal state of insufficient left ventricular blood volume, the rotation speed of the impeller is reduced to avoid the phenomenon of pumping or collapsing of the left ventricle; if the target user is in an abnormal state in which the aortic pressure is increased, the rotation direction and the rotation 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 in the left ventricle into the aorta, thereby reducing the aortic pressure.

When the ventricular assist device 100 defaults to operate in a steeper pressure-flow curve, if the target user is in an abnormal state in which the aortic pressure increases, the rotational speed of the impeller 20 is increased to accelerate the pumping of blood in the left ventricle into the aorta, thereby reducing the aortic pressure; if the target user is in an abnormal state of insufficient left ventricular blood volume, the rotation direction and rotation speed of the impeller 20 are adjusted to make the pressure flow curve of the ventricular assist device 100 flatter, so as to reduce the pumping flow rate of the ventricular assist device 100, so as to avoid the pumping or collapsing phenomenon of the left ventricle.

The adjustment of the rotation direction and rotation speed of the impeller 20 specifically includes: the control unit 33 first determines a current first pressure flow curve of the ventricular assist device 100 based on the target rotational speed, and determines a first pressure difference from the current first pressure flow curve based on the second average flow. In the second pressure flow rate curve that satisfies the first differential pressure and the second average flow rate is determined from the plurality of second pressure flow rate curves, the rotation speed corresponding to the second pressure flow rate curve is determined as the second rotation speed, and the rotation speed of the impeller 20 is adjusted to the second rotation speed, the rotation direction is adjusted from clockwise to counterclockwise, or the rotation direction is adjusted from counterclockwise to clockwise.

In one example, after adjusting the target rotational speed to the second rotational speed, the method further includes: obtaining a third average flow and a fourth average flow, wherein the third average flow is the average flow when the ventricular assist device operates at the second rotating speed in a third cardiac cycle, and the fourth average flow is the average flow when the ventricular assist device operates at the second rotating speed in a fourth cardiac cycle, and the fourth cardiac cycle is later than the third cardiac cycle; if the fourth average flow is smaller than or equal to the third average flow, reducing the second rotating speed to a third rotating speed; if the second flow is greater than the fourth average flow, maintaining the impeller rotation speed at a third rotation speed, wherein the second flow is the flow when the ventricular assist device operates at the third rotation speed; and if the second flow is smaller than or equal to the fourth average flow, determining the rotation direction of the impeller in the shell as the first direction, determining a second pressure difference according to the fourth average flow, the second rotating speed and the second pressure flow curve, and adjusting the second rotating speed according to the second pressure difference, the fourth average flow and the first pressure flow curve.

After adjusting the rotation speed of the impeller 20 to the second rotation speed, and adjusting the rotation direction of the impeller 20 from counterclockwise to clockwise or from clockwise to counterclockwise, the present application can acquire the change of the pumping flow rate of the ventricular assist device 100 again to determine whether the abnormal state of the increase of the arterial pressure or the insufficient ventricular blood volume existing in the patient is resolved or alleviated.

Wherein the duration of the third cardiac cycle and the fourth cardiac cycle may be less than or equal to the first cardiac cycle. After adjusting the rotational speed of the ventricular assist device 100 to the second rotational speed, the control unit 33 may calculate a third average flow rate in the third cardiac cycle and a fourth average flow rate in a fourth cardiac cycle adjacent to the third cardiac cycle, and then compare the third average flow rate and the fourth average flow rate to determine whether the target user has a problem of insufficient blood volume or increased arterial pressure due to the adjustment of the pressure flow rate curve. This problem is solved by adjusting the rotational speed and rotational direction of the impeller 20 again.

In this application, the control unit 33 may determine whether an abnormal state exists by calculating the average flow change of the target user in real time, and then adjust the rotation speed and/or rotation direction of the impeller 20 according to the abnormal state when the abnormal state exists, so that the performance of the ventricular assist device 100 accords with the pump flow characteristic of the physiological state change of the user in real time.

The impeller blades are exemplified by the forward curved blades shown in fig. 4.

When the first direction is clockwise and the second direction is counterclockwise, the pressure flow curve of the impeller 20 rotating in the clockwise direction is flatter when the impeller 20 rotates in the clockwise direction, and the pressure flow curve of the impeller 20 rotating in the counterclockwise direction is steeper, i.e., the first pressure flow curve is the pressure flow curve of the ventricular assist device 100 rotating in the clockwise direction at the target rotational speed, and the second pressure flow curve is the pressure flow curve of the ventricular assist device 100 rotating in the counterclockwise direction at the target rotational speed. The slope of the first pressure flow curve is less than the slope of the second pressure flow curve.

Wherein, when the target user is in an abnormal state of insufficient left ventricular blood volume, the control unit 33 may control to decrease the target rotation speed while maintaining the impeller 20 to rotate still in the clockwise direction. If the target user is in an abnormal state in which the arterial pressure is increased, the control unit 33 adjusts the rotation speed of the impeller 20 to the second rotation speed according to the first pressure flow curve and the second pressure flow curve, and adjusts the rotation direction of the impeller from clockwise to counterclockwise, so that the pressure flow curve of the ventricular assist device 100 is steeper, and the pump flow characteristic of the target user is satisfied.

After adjusting the rotation speed of the ventricular assist device 100 to the second rotation speed when the target user is in the state that the aortic pressure increases, the control unit 33 may acquire the third average flow rate and the fourth average flow rate to determine whether the target user is still in the abnormal state. If the fourth average flow is greater than or equal to the third average flow, the current target user is in a normal state; if the fourth average flow is less than the third average flow, it indicates that the target user is currently likely to have insufficient left ventricular blood volume. The control unit 33 may gradually decrease the rotational speed of the ventricular assist device 100 to the third rotational speed, and if the pumping flow rate at the third rotational speed gradually increases, maintain the rotational speed of the ventricular assist device 100 at the third rotational speed; if the pumping flow rate at the third rotation speed gradually decreases, which means that the problem of the current hypovolemia of the target user is serious, the control unit 33 may readjust the rotation direction of the impeller 20 to the clockwise direction and determine the rotation speed of the impeller 20 according to the first pressure flow rate curve and the second pressure flow rate curve. The method comprises the following steps: a current first pressure flow curve of ventricular assist device 100 is determined based on the second rotational speed, and a second pressure differential is determined from the current first pressure flow curve based on the fourth average flow. In the second pressure flow rate curve that satisfies the second differential pressure and the fourth average flow rate is determined from the plurality of second pressure flow rate curves, the rotational speed corresponding to the second pressure flow rate curve is determined as the rotational speed adjusted by the ventricular assist device 100, and the rotational direction is adjusted from counterclockwise to clockwise.

When the first direction is counterclockwise and the second direction is clockwise, the first pressure flow rate curve is a pressure flow rate curve at the target rotational speed when the ventricular assist device 100 rotates in the counterclockwise direction when the impeller 20 of the default ventricular assist device 100 rotates in the counterclockwise direction, and the second pressure flow rate curve is a pressure flow rate curve at the target rotational speed when the ventricular assist device 100 rotates in the clockwise direction. The slope of the first pressure flow curve is greater than the slope of the second pressure flow curve.

Wherein, when the target user is in an abnormal state in which the arterial pressure is increased, the control unit 33 may control to increase the target rotation speed while maintaining the impeller 20 to rotate still in the counterclockwise direction. If the target user is in an abnormal state with insufficient left ventricular blood volume, the control unit 33 adjusts the rotation speed of the impeller 20 to the second rotation speed according to the first pressure flow curve and the second pressure flow curve, and adjusts the rotation direction of the impeller from counterclockwise to clockwise, so that the pressure flow curve of the ventricular assist device 100 is flatter, and the pump flow characteristic of the target user is satisfied.

Specifically, the control unit 33 determines a current first pressure-flow curve of the ventricular assist device 100 according to the target rotational speed, and determines a first differential pressure from the current first pressure-flow curve according to the second average flow. In the second pressure flow rate curve that satisfies the first differential pressure and the second average flow rate is determined from the plurality of second pressure flow rate curves, the rotation speed corresponding to the second pressure flow rate curve is determined as the second rotation speed, and the rotation speed of the impeller 20 is adjusted to the second rotation speed, the rotation direction is adjusted from clockwise to counterclockwise, or the rotation direction is adjusted from counterclockwise to clockwise.

After adjusting the rotational speed of the ventricular assist device 100 to the second rotational speed when the target user is in the left ventricular hypovolemia, the control unit 33 may acquire the third average flow rate and the fourth average flow rate to determine whether the target user is still in the abnormal state. If the fourth average flow is greater than or equal to the third average flow, the current target user is in a normal state; if the fourth average flow is smaller than the third average flow, the current arterial pressure of the target user is increased. The control unit 33 may gradually increase the rotational speed of the ventricular assist device 100 to the third rotational speed, and if the pumping flow rate at the third rotational speed gradually decreases, maintain the rotational speed of the ventricular assist device 100 at the third rotational speed; if the pumping flow rate at the third rotation speed gradually increases, which means that the current arterial pressure of the target user increases, the control unit 33 may readjust the rotation direction of the impeller 20 to the counterclockwise direction, and determine the rotation speed of the impeller 20 according to the first pressure flow rate curve and the second pressure flow rate curve. The method comprises the following steps: a current first pressure flow curve of ventricular assist device 100 is determined based on the second rotational speed, and a second pressure differential is determined from the current first pressure flow curve based on the fourth average flow. In the second pressure flow rate curve that satisfies the second differential pressure and the fourth average flow rate is determined from the plurality of second pressure flow rate curves, the rotational speed corresponding to the second pressure flow rate curve is determined as the rotational speed adjusted by the ventricular assist device 100, and the rotational direction is adjusted from clockwise to counterclockwise.

It should be noted that, the control principle that the impeller blade is a backward curved blade shown in fig. 4 is the same as that of the impeller blade is a forward curved blade, and the rotation directions are opposite, which is not described in detail herein.

It can be seen that the present application proposes a rotational speed control method, in which a first average flow rate of a ventricular assist device and a second average flow rate are obtained, where the first average flow rate is an average flow rate when the ventricular assist device operates at a target rotational speed in a first cardiac cycle, and the second average flow rate is an average flow rate when the ventricular assist device operates at the target rotational speed in a second cardiac cycle, and the first cardiac cycle is later than the second cardiac cycle; determining an abnormal state of the target user according to the first average flow and the second average flow; and adjusting the target rotating speed and/or the rotating direction of the impeller in the shell according to the abnormal state of the target user. According to the method and the device, the abnormal state of the current user is judged according to the average flow of the ventricular assist device in different cardiac cycles, and then the rotating speed and/or the rotating direction of the impeller adjusted according to the abnormal state are/is judged, so that the performance of the ventricular assist device accords with the pump flow characteristics of the physiological state change of the user in real time.

The foregoing description of the embodiments of the present application has been presented primarily in terms of a method-side implementation. It will be appreciated that the network device, in order to implement the above-described functions, includes corresponding hardware structures and/or software modules that perform the respective functions. Those of skill in the art will readily appreciate that the elements and algorithm steps described in connection with the embodiments disclosed herein may be embodied as hardware or a combination of hardware and computer software. Whether a function is implemented as hardware or computer software driven hardware depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

By way of example, the present application provides a control unit comprising a controller having one or more processors configured to: acquiring a first average flow and a second average flow of a ventricular assist device, wherein the first average flow is an average flow when the ventricular assist device operates at a target rotating speed in a first cardiac cycle, the second average flow is an average flow when the ventricular assist device operates at the target rotating speed in a second cardiac cycle, and the first cardiac cycle is later than the second cardiac cycle; determining an abnormal state of a target user according to the first average flow and the second average flow, wherein the target user is a user using the ventricular assist device; and adjusting the target rotating speed and/or the rotating direction of the impeller in the shell according to the abnormal state of the target user.

By way of example, the present application also provides a ventricular assist device comprising:

a housing;

an impeller disposed within the housing;

The present application also provides, for example, a medical device comprising the control unit or the ventricular assist device described above.

Wherein, the control unit of each scheme has the function of realizing the corresponding steps executed by the medical equipment in the method; the functions may be implemented by hardware, or may be implemented by hardware executing corresponding software.

In the embodiments of the present application, the control unit may also be a chip or a chip system, for example: system on chip (SoC).

Referring to fig. 6, fig. 6 is a schematic structural diagram of a medical device according to an embodiment of the present application, where 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 configured to be executed by the one or more processors.

The program includes instructions for performing the steps of:

acquiring a first average flow and a second average flow of a ventricular assist device, wherein the first average flow is an average flow when the ventricular assist device operates at a target rotating speed in a first cardiac cycle, the second average flow is an average flow when the ventricular assist device operates at the target rotating speed in a second cardiac cycle, and the first cardiac cycle is later than the second cardiac cycle; determining an abnormal state of a target user according to the first average flow and the second average flow, wherein the target user is a user using the ventricular assist device; and adjusting the target rotating speed and/or the rotating direction of the impeller in the shell according to the abnormal state of the target user.

All relevant contents of each scenario related to the above method embodiment may be cited to the functional description of the corresponding functional module, which is not described herein.

It should be appreciated that the memory described above may include read only memory and random access memory and provide 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 of the device type.

In an embodiment of the present application, the processor of the above apparatus may be a central processing unit (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. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

It should be understood that references to "at least one" in embodiments of the present application mean one or more, and "a plurality" means two or more. "and/or", describes an association relationship of an association object, and indicates that there may be three relationships, for example, a and/or B, and may indicate: a alone, a and B together, and B alone, wherein a, B may be singular or plural. The character "/" generally indicates that the context-dependent object is an "or" relationship. "at least one of" or the like means any combination of these items, including any combination of single item(s) or plural items(s). For example, at least one (one) of a, b, or c may represent: a, b, c, a-b, a-c, b-c, or a-b-c, wherein a, b, c may be single or plural.

And, unless specified to the contrary, the embodiments of the present application refer to the ordinal terms "first," "second," etc., as used to distinguish between multiple objects, and are not to be construed as limiting the order, timing, priority, or importance of the multiple objects. For example, the first information and the second information are only for distinguishing different information, and are not indicative of the difference in content, priority, transmission order, importance, or the like of the two information.

In implementation, the steps of the above method may be performed by integrated logic circuits of hardware in a processor or by instructions in the form of software. The steps of a method disclosed in connection with the embodiments of the present application may be embodied directly in a hardware processor for execution, or in a combination of hardware and software elements in the processor for execution. The software elements may be located in a random access memory, flash memory, read-only memory, programmable read-only memory or electrically erasable programmable memory, registers, etc. as well known in the art. The storage medium is located in a memory, and the processor executes instructions in the memory to perform the steps of the method described above in conjunction with its hardware. To avoid repetition, a detailed description is not provided herein.

The present application also provides a computer storage medium storing a computer program for electronic data exchange, the computer program causing a computer to execute some or all of the steps of any one of the methods described in the method embodiments above.

Embodiments of the present application also provide a computer program product comprising 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 one of the methods described in the method embodiments above. The computer program product may be a software installation package.

It should be noted that, for simplicity of description, the foregoing method embodiments are all expressed as a series of action combinations, but it should be understood by those skilled in the art that the present application is not limited by the order of actions described, as some steps may be performed in other order or simultaneously in accordance with the present application. Further, those skilled in the art will also appreciate that the embodiments described in the specification are all preferred embodiments, and that the acts and modules referred to are not necessarily required in the present application.

In the foregoing embodiments, the descriptions of the embodiments are emphasized, and for parts of one embodiment that are not described in detail, reference may be made to related descriptions of other embodiments.

Those of ordinary skill in the art will appreciate that all or a portion of the steps in the various methods of the above embodiments may be implemented by a program that instructs associated hardware, and the program may be stored in a computer readable memory, which may include: flash disk, ROM, RAM, magnetic or optical disk, etc.

The foregoing has outlined rather broadly the more detailed description of embodiments of the present application, wherein specific examples are provided herein to illustrate the principles and embodiments of the present application, the above examples being provided solely to assist in the understanding of the methods of the present application and the core ideas thereof; meanwhile, as those skilled in the art will have modifications in the specific embodiments and application scope in accordance with the ideas of the present application, the present description should not be construed as limiting the present application in view of the above.

Claims

1. A rotational speed control method, characterized by being applied to a ventricular assist device including a housing and an impeller disposed within the housing; the method comprises the following steps:

2. The method of claim 1, wherein said determining an abnormal state of a target user from said first average flow and said second average flow comprises:

if the first average flow is greater than the second average flow, 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, wherein the first flow rate is the flow rate when the ventricular assist device operates at the first rotational speed;

And if the first flow is smaller than the second average flow, determining that the target user is in a second abnormal state.

3. The method according to claim 2, wherein said adjusting the target rotational speed and/or the rotational direction of the impeller within the housing according to the state of the target user comprises:

acquiring a first pressure flow curve and a second pressure flow curve, wherein the first pressure flow curve is a pressure flow curve when the impeller rotates in a first direction in the shell, the second pressure flow curve is a pressure flow curve when the impeller rotates in a second direction in the shell, and the first direction is opposite to the second direction;

if the target user is in the first abnormal state, determining that the rotation direction of the impeller in the shell is the second direction, determining a first pressure difference according to the second average flow, the target rotating speed and the first pressure flow curve, determining a second rotating speed according to the first pressure difference, the second average flow and the second pressure flow curve, and adjusting the target rotating speed to the second rotating speed;

and if the target user is in the second abnormal state, reducing the target rotating speed, and maintaining the rotating direction of the impeller in the shell to be the first direction.

4. A method according to claim 3, wherein after adjusting the target rotational speed to the second rotational speed, the method further comprises:

obtaining a third average flow and a fourth average flow, wherein the third average flow is the average flow when the ventricular assist device operates at the second rotating speed in a third cardiac cycle, and the fourth average flow is the average flow when the ventricular assist device operates at the second rotating speed in a fourth cardiac cycle, and the fourth cardiac cycle is later than the third cardiac cycle;

if the fourth average flow is smaller than or equal to the third average flow, reducing the second rotating speed to a third rotating speed;

if the second flow is greater than the fourth average flow, maintaining the impeller rotation speed at a third rotation speed, wherein the second flow is the flow when the ventricular assist device operates at the third rotation speed;

and if the second flow is smaller than or equal to the fourth average flow, determining the rotation direction of the impeller in the shell as the first direction, determining a second pressure difference according to the fourth average flow, the second rotating speed and the second pressure flow curve, and adjusting the second rotating speed according to the second pressure difference, the fourth average flow and the first pressure flow curve.

5. The method of claim 3 or 4, wherein the slope of the first pressure flow curve is less than the slope of the second pressure flow curve.

6. The method of claim 3 or 4, wherein when the blades of the impeller are forward curved blades, the first direction is clockwise and the second direction is counter-clockwise.

7. The method of claim 3 or 4, wherein when the blades of the impeller are backward curved blades, the first direction is a counterclockwise direction and the second direction is a clockwise direction.

8. The method according to claim 1, wherein the method further comprises:

acquiring a first flow curve, wherein the first flow curve is a flow curve when the ventricular assist device operates at a target rotating speed;

determining the time length between adjacent peaks in the first flow curve as a target time length;

and determining the first cardiac cycle and the second cardiac cycle according to the target duration.

9. A control unit comprising one or more processors configured to:

10. A ventricular assist device, the ventricular assist device comprising:

a housing;

an impeller disposed within the housing;

11. A medical device 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 comprising instructions for performing the steps in the method of any of claims 1-8.

12. A computer readable storage medium storing 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 1-8.