Monitoring method and system of ventricular assist device and computer readable storage medium

Abstract

The invention provides a monitoring method and system for a ventricular assist device and a computer readable storage medium. The monitoring method comprises the steps of judging whether an adverse event occurs in the ventricular assist device or not based on torque current of a motor of the ventricular assist device, and judging the type of the adverse event. The method has the characteristics of simplicity, feasibility and high accuracy.

Description

Technical Field

[0001] The present invention belongs to the technical field of medical devices, and specifically relates to a monitoring method and system for a ventricular assist device, and a computer-readable storage medium. Background Art

[0002] The interventional ventricular assist system uses a micro-catheter pump at the front end of the catheter to pump blood from the ventricles to the arteries, establish a ventricle-artery drainage channel, and act as an active mechanical pump, partially replacing ventricular function to achieve the purpose of blood circulation reorganization. When the interventional ventricular assist device is operating normally, its blood inlet is located in the ventricle and the blood outlet is located in the artery. However, when the interventional ventricular assist system is operating in the body for a long time, problems such as displacement, reflux, and suction may occur. The existence of these problems will have adverse consequences for patients and need to be identified in time and corresponding measures taken. Summary of the invention

[0003] The object of the present invention is to provide a monitoring method and system for a ventricular assist device, and a computer-readable storage medium, so as to timely determine whether an adverse event occurs in the ventricular assist device and to determine the type of the adverse event, so that corresponding countermeasures can be taken in a timely manner to reduce the adverse effects on patients.

[0004] To achieve the above-mentioned purpose, the present invention provides a monitoring method for a ventricular assist device, wherein the ventricular assist device includes a motor; the characteristic is that the monitoring method includes: judging whether a first type of adverse event occurs in the ventricular assist device based on the torque current of the motor, and judging the type of the first type of adverse event; the first type of adverse event includes reflux events, suction events, and aortic valve closure events.

[0005] Optionally, obtaining an actual torque current waveform curve of the motor;

[0006] In one cardiac cycle, when the actual torque current waveform curve has a first peak and a second peak, and the ratio of the peak value of the second peak to the peak value of the first peak is within a preset value range, it is determined that a regurgitation event occurs in the ventricular assist device;

[0007] The preset value range is set to 0.2-0.6.

[0008] Optionally, obtaining an actual torque current waveform curve of the motor;

[0009] In a cardiac cycle, when the actual torque current waveform curve has a first peak and a second peak, and the time difference between the first peak and the second peak is greater than a preset time, it is determined that a regurgitation event occurs in the ventricular assist device;

[0010] The preset time is set to 1 / 3 of the cardiac cycle.

[0011] Optionally, the motor has a standard torque current waveform curve;

[0012] The monitoring method comprises:

[0013] Obtaining an actual torque current waveform curve of the motor;

[0014] Whether the first type of adverse event occurs in the ventricular assist device is determined according to the actual torque current waveform curve and the standard torque current waveform curve, and the type of the first type of adverse event is determined.

[0015] Optionally, when the actual torque current waveform curve at least partially deviates from the standard current waveform curve, it is determined that the first type of adverse event occurs in the ventricular assist device. Optionally, within a cardiac cycle, when the actual torque current waveform curve has a first peak and a second peak, and the peak value of the first peak is equal to the peak value of the peak of the standard torque current waveform curve, and the ratio of the peak value of the second peak to the peak value of the peak of the standard torque current waveform curve is within a preset range, it is determined that a regurgitation event occurs in the ventricular assist device;

[0016] The preset range is set to 0.2-0.6.

[0017] Optionally, within a cardiac cycle, when the peak value of the actual torque current waveform curve is less than 0.7 times the peak value of the standard torque current waveform curve, it is determined that the ventricular assist device has a suction event or an aortic valve normally closed event.

[0018] Optionally, when the maximum absolute value of the slope of the actual torque current waveform within a preset time range is greater than 1 / 2 of the cardiac cycle, it is determined that the ventricular assist device has a suction event;

[0019] The preset time range is set to take the moment corresponding to the peak of the actual torque current waveform curve as the middle moment, and the duration of the preset time range is 1 / 10 of the cardiac cycle.

[0020] Optionally, when the maximum absolute value of the slope of the actual torque current waveform within a preset time range is not greater than 1 / 2 of the cardiac cycle, it is determined that an aortic valve normally closed event occurs in the ventricular assist device;

[0021] The preset time range is set to take the moment corresponding to the peak of the actual torque current waveform curve as the middle moment, and the duration of the preset time range is 1 / 10 of the cardiac cycle.

[0022] Optionally, the period of the standard torque current waveform curve is the same as the period time of the actual torque current waveform curve. When the trough value of the actual torque current waveform curve is equal to the trough value of the standard torque current waveform curve, and the actual torque current waveform curve deviates from the standard torque current waveform curve in time periods other than the time when the trough value occurs, it is determined that a suction event occurs in the ventricular assist device.

[0023] Optionally, the period of the standard torque current waveform curve is the same as the period time of the actual torque current waveform curve, each period has a predetermined time period, and the peak of the standard torque current waveform curve and the peak of the actual torque current waveform curve both appear within the predetermined time period;

[0024] When the actual torque current waveform curve deviates from the standard torque current waveform curve within the predetermined time period, and the actual torque current waveform curve coincides with the standard torque current waveform curve in time periods other than the predetermined time period, it is determined that the ventricular assist device has an aortic valve normally closed event.

[0025] Optionally, after determining the type of the first type of adverse event, the method further includes controlling the rotation speed of the motor according to the type of the first type of adverse event to mitigate or eliminate the first type of adverse event.

[0026] Optionally, the ventricular assist device is provided with a blood inlet and a blood outlet;

[0027] The monitoring method further includes judging whether a second type of adverse event occurs in the ventricular assist device based on the pressure waveform curve at the blood outflow outlet and the pressure waveform curve at the blood inflow inlet, and judging the type of the second type of adverse event, wherein the second type of adverse event includes a first position abnormality event and a second position abnormality event;

[0028] The first abnormal position event refers to that both the blood inlet and the blood outlet are located in the artery;

[0029] The second abnormal position event refers to that both the blood inlet and the blood outlet are located in the ventricle.

[0030] To achieve the above-mentioned purpose, the present invention also provides a monitoring system for a ventricular assist device, comprising a current acquisition element and a control unit that are communicatively connected, wherein the current acquisition element is connected to the motor of the ventricular assist device and is configured to acquire the input increase of the motor; the control unit is configured to receive the input current of the motor, and obtain the torque current of the motor based on the input increase of the motor, and execute the monitoring method of the ventricular assist device as described in any of the preceding items.

[0031] To achieve the above-mentioned purpose, the present invention also provides a computer-readable storage medium having a program stored thereon, and when the program is executed, the monitoring method of a ventricular assist device as described in any of the preceding items is executed.

[0032] Compared with the prior art, the monitoring method and system of the ventricular assist device and the computer-readable storage medium of the present invention have the following advantages:

[0033] The aforementioned monitoring method of the ventricular assist device includes: judging whether the ventricular assist device has an adverse event based on the torque current of the motor of the ventricular assist device, and judging the type of the adverse event. The method is simple, feasible and highly accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings are used to better understand the present invention and do not constitute an improper limitation of the present invention.

[0035] Figure 1 It is a schematic diagram comparing the standard torque current waveform curve of the motor of the ventricular assist device when it is placed in the left heart and the actual torque current waveform curve when various first-type adverse events occur;

[0036] Figure 2 It is a schematic diagram comparing the standard torque current waveform curve of the motor of the ventricular assist device when it is placed in the left heart and the actual torque current waveform curve when a regurgitation event occurs;

[0037] Figure 3 It is a schematic diagram of the relationship between the torque current of the motor and the flow rate of blood pumped by the ventricular assist device when the ventricular assist device placed in the left heart has regurgitation;

[0038] Figure 4 It is a schematic diagram comparing the standard torque current waveform curve of the motor of the ventricular assist device when it is placed in the left heart and the actual torque current waveform curve when a suction event occurs;

[0039] Figure 5 It is a schematic diagram comparing the standard torque current waveform curve of the motor when the ventricular assist device is placed in the left heart and the actual torque current waveform curve when the aortic valve is normally closed;

[0040] Figure 6 It is a schematic diagram of the relationship between the pressure waveform curve at the blood outflow outlet and the pressure waveform curve at the blood inflow inlet when the ventricular assist device is placed in the left heart and its position is normal;

[0041] Figure 7 It is a schematic diagram of the relationship between the pressure waveform curve at the blood outflow outlet and the pressure waveform curve at the blood inlet of the ventricular assist device when both the blood inlet and the blood outflow outlet are located in the left ventricle;

[0042] Figure 8 It is a schematic diagram of the relationship between the pressure waveform curve at the blood outflow outlet and the pressure waveform curve at the blood inlet when the blood inlet and the blood outflow outlet of the ventricular assist device are both located in the aorta. DETAILED DESCRIPTION

[0043] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the present embodiment only illustrate the basic concept of the present invention in a schematic manner, so the illustrations only show the components related to the present invention rather than drawing according to the number, shape and size of the components in the actual implementation. The type, quantity and proportion of each component in the actual implementation can be a random change, and the component layout type may also be more complicated.

[0044] In addition, each embodiment of the following description has one or more technical features, but this does not mean that the user of the present invention must implement all the technical features in any embodiment at the same time, or can only implement part or all of the technical features in different embodiments separately. In other words, under the premise that implementation is possible, those skilled in the art can selectively implement part or all of the technical features in any embodiment according to the disclosure of the present invention and according to the design specifications or implementation requirements, or selectively implement a combination of part or all of the technical features in multiple embodiments, thereby increasing the flexibility of the implementation of the present invention.

[0045] As used in this specification, the singular forms "a", "an", and "the" include plural objects, and the plural form "plurality" includes more than two objects, unless the content clearly indicates otherwise. As used in this specification, the term "or" is generally used to include the meaning of "and / or", unless the content clearly indicates otherwise, and the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection. It can be a mechanical connection or an electrical connection. It can be directly connected or indirectly connected through an intermediate medium, and it can be a connection between the internal parts of two elements or an interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0046] The ventricular assist device is applied to the left heart or the right heart. It is understood that when the ventricular assist device is applied to the left heart, the ventricular assist device crosses the aortic valve, and the blood inlet of the ventricular assist device is located in the left ventricle, and the blood outflow outlet is located in the aorta, so that the ventricular assist device can pump the blood in the left ventricle into the aorta, and achieve the purpose of reorganizing the blood supply channel of the left heart; when the ventricular assist device is applied to the right heart, the ventricular assist device crosses the pulmonary valve, and the blood inlet of the ventricular assist device is located in the right ventricle, and the blood outflow outlet is located in the pulmonary artery, so that the ventricular assist device can pump the blood in the right ventricle to the pulmonary artery, and achieve the purpose of reorganizing the blood supply channel of the right heart. The embodiment of the present invention does not specifically limit the specific type of the ventricular assist device, which can be an axial flow ventricular assist device.

[0047] When the ventricular assist device is running at a constant speed, the torque current of the motor thereon changes periodically along with the cardiac cycle of the heart, and the torque current curve of the motor is displayed as a periodic waveform during the operation of the ventricular assist device. The motor torque current directly reflects the motor load, so the motor torque current is discussed in the present invention. The motor torque current is calculated by measuring the motor stator current.

[0048] The inventors have found that when certain adverse events occur in the ventricular assist device, the torque current waveform curve of the motor changes accordingly. That is, some adverse events of the ventricular assist device can be manifested in the torque current waveform curve of the motor. In this article, adverse events that can cause changes in the torque current waveform curve of the motor are defined as Class I adverse events.

[0049] The inventors further discovered through research that different adverse events of the first type cause different changes in the torque current waveform curve of the motor.

[0050] Based on this, the present application proposes a monitoring method for a ventricular assist device, which includes: judging whether the ventricular assist device has the first type of adverse event based on the torque current of the motor, and judging the type of the first type of adverse event. More specifically, the type of the first type of adverse event is judged according to the shape of the torque current curve of the motor. The first type of adverse event includes regurgitation events, suction events, and aortic valve closure events.

[0051] For the convenience of description, the torque current waveform curve actually measured by the motor during the operation of the ventricular assist device will be referred to as the actual torque current waveform curve, and the torque current waveform curve of the motor when the first type of adverse event does not occur in the ventricular assist device will be referred to as the standard torque current waveform curve.

[0052] Furthermore, when any of the first type adverse events occurs in the ventricular assist device, the actual torque current waveform at least partially deviates from the standard torque current waveform, and depending on the specific event, the deviation between the actual torque current waveform and the standard torque current waveform may vary.

[0053] In this way, the monitoring method may specifically include: acquiring the actual torque current waveform curve in real time. And, judging whether the first type of adverse event occurs, and judging the specific type of the first type of adverse event based on the actual torque current waveform curve and the standard torque current waveform curve. That is, when the actual torque current waveform curve is the standard torque current waveform curve, it indicates that the first type of adverse event does not occur in the ventricular assist device, and when the actual torque current waveform curve at least partially deviates from the standard torque current curve, it indicates that the first type of adverse event occurs in the ventricular assist device, specifically one of the following: a regurgitation event, a suction event, and a normally closed aortic valve event.

[0054] Next, the monitoring method is introduced in further detail.

[0055] The standard torque current waveform curve is as follows: Figures 1 to 5 As shown by line 1 in FIG. 1 , it has alternating peaks and troughs. The actual torque current waveform curve varies depending on the type of adverse event that occurs in the ventricular assist device.

[0056] It should be noted that Figures 1 to 5 All torque current waveform curves are obtained after normalization based on the measured torque current of the motor when the ventricular assist device is applied to the left heart, and the peak value of the standard torque current waveform is normalized to 1.

[0057] It should also be noted that Figures 1 to 5 All torque current waveform curves have alternating peaks and troughs.

[0058] This is under ideal conditions. During the actual operation of the ventricular assist device in the human body, when the valve between the ventricle and the artery is closed, a weak water hammer effect occurs, and a small peak will appear in the torque current waveform curve when it moves from the above peak to the above trough. Figures 1 to 5 All the torque current waveform curves in the figure are waveform curves obtained after filtering after eliminating the water hammer effect when the valve is closed.

[0059] The cause of the reflux event is that the arterial pressure is greater than the ventricular pressure, and the speed of the motor of the ventricular assist device is too slow, resulting in the maximum pressure rise of the ventricular assist device being less than the pressure difference between the ventricle and the artery, and blood flows back to the ventricle. The reflux event generally occurs during the diastole period.

[0060] When the ventricular assist device is in normal operation, the blood in the ventricular assist device is in a turbulent state. When a reflux event occurs in the ventricle, the turbulence of the blood in the ventricular assist device increases significantly, thereby aggravating the energy loss of the motor. At the same time, the reverse impact of the blood aggravates the friction loss and impact loss inside the ventricular assist device, thereby reducing the efficiency of the ventricular assist device and increasing power consumption. In this case, in order to ensure that the ventricular assist device can pump enough blood, the input current of the motor of the ventricular assist device needs to be increased.

[0061] In one embodiment, whether the ventricular assist device has the reflux event is determined based only on the torque current of the motor. Specifically, the actual torque current waveform curve of the motor is obtained. When the reflux event occurs, the actual torque current waveform curve of the motor is as follows: Figure 1 and Figure 2 The shape shown by line 2 in FIG. 1 has a first wave crest and a second wave crest in one cardiac cycle T. The peak value of the second wave crest is less than the peak value of the first wave crest, and the ratio range of the peak value of the second wave crest to the peak value of the first wave crest is within a preset numerical range. The inventors found through statistics of a large amount of experimental data that the preset numerical range is set to be greater than or equal to 0.2 and less than or equal to 0.6.

[0062] In another embodiment, whether the ventricular assist device has the reflux event is determined based only on the torque current of the motor. Specifically, the actual torque current waveform curve of the motor is obtained. When the reflux event occurs, the actual torque current waveform curve of the motor is as follows: Figure 1 and Figure 2 The shape shown by line 2 in FIG. 1 has a first wave crest and a second wave crest in one cardiac cycle T. The time difference between the first wave crest and the second wave crest is greater than a preset time. The inventor has found through statistics of a large amount of experimental data that the preset time is set to 1 / 3 of the cardiac cycle, that is, the preset time is set to T / 3.

[0063] In another embodiment, whether the ventricular assist device has the reflux event is determined based on the actual torque current waveform curve and the standard torque current waveform curve. Specifically, when the reflux event occurs, the actual torque current waveform curve of the motor is as follows: Figure 1 and Figure 2The shape shown by line 2 in the figure has a first peak and a second peak in one cardiac cycle T. The peak value of the first peak is equal to the peak value of the peak of the standard torque current waveform curve, and the ratio of the peak value of the second peak to the peak value of the peak of the standard torque current waveform curve is within the preset range, that is, the ratio of the peak value of the second peak to the peak value of the peak of the standard torque current waveform curve is greater than or equal to 0.2 and less than or equal to 0.6. It should be noted that the peak value of the first peak is equal to the peak value of the peak of the standard torque current waveform curve, including both the situation where the two are completely equal and the situation where the two are approximately equal. It should be noted that the two are approximately equal means that the deviation between the two is within 20%. In addition, by comparing line 1 and line 2, it can be seen that the peak value of the second peak appears near the time when the valley value of the valley of the standard torque current waveform curve appears.

[0064] Figure 3 The figure shows the relationship between the blood flow rate pumped by the ventricular assist device and the torque current of the motor when a regurgitation event occurs. Figure 3 This can explain why the motor of the ventricular assist device has the actual torque current waveform curve shown by line 2 when the regurgitation event occurs. Figure 3 It can be seen that when the flow rate of blood pumped by the ventricular assist device is a negative value, it indicates that blood flows into the ventricular assist device from the blood outflow outlet in the artery, and further flows out from the blood inflow inlet in the ventricle, that is, a reflux event occurs in the ventricular assist device; when the flow rate of blood pumped by the ventricular assist device is a positive value, it indicates that blood enters the ventricular assist device from the blood inflow inlet in the ventricle, and then flows out from the blood outflow outlet in the artery, that is, the blood flows in the positive direction.

[0065] The larger the reflux flow, that is, when the curve of the relationship between the motor torque current and the blood pump flow moves from point 2 to point 1, the power consumption of the ventricular assist device will also be greater. In order to overcome the blood reflux, the motor of the ventricular assist device needs to do more work, that is, the torque current of the motor should increase accordingly.

[0066] When the blood flow direction in the ventricular assist device gradually changes from reverse flow to forward flow, the relationship curve between the motor torque current and the blood pump flow rate moves from point 1 to point 3 via point 2. When the flow rate of blood pumped by the ventricular assist device is zero, the torque current of the motor reaches a minimum value, and then, as the flow rate of blood flowing in the forward direction in the ventricular assist device increases, the torque current value of the motor increases accordingly.

[0067] In other words, in the process of the blood in the ventricular assist device changing from a backflow state to a forward flow state, the torque current of the motor first increases to be able to overcome the backflow, then gradually decreases as the backflow flow decreases, and finally increases as the forward flow of blood increases. In practice, the flow of the backflow blood is less than the maximum value of the flow of the forward flow blood, which makes the maximum torque current of the motor when doing work to overcome the backflow less than the torque current of the motor when the forward flow of blood reaches its maximum value. On the torque current waveform curve, the torque current of the motor when the forward flow of blood reaches its maximum value is expressed as the peak value of the first peak, and the maximum torque current of the motor when doing work to overcome the backflow is expressed as the peak value of the second peak, thereby making the actual torque current waveform curve of the motor when a backflow event occurs appear as shown in line 2.

[0068] The reason for the suction event of the ventricular assist device is that the blood inlet of the ventricular assist device is blocked, or the blood flow channel in the ventricular assist device is blocked, resulting in a flow resistance proportional to the blood flow rate of the ventricular assist device during the process of pumping blood. When a suction event occurs, the flow resistance is proportional to the flow rate of blood pumped by the ventricular assist device, that is, the greater the flow rate of blood pumped by the ventricular assist device, the greater the flow resistance and the more severe the suction event. When the flow rate of blood pumped by the ventricular assist device decreases, the flow resistance also decreases, and the suction event is alleviated. Among them, when the flow rate of blood pumped by the ventricular assist device is zero, the flow resistance is basically zero. Therefore, the actual torque current waveform curve of the motor when the ventricular assist device has a suction event is expressed as follows: Figure 1 and Figure 4 The pattern shown by line 3 in .

[0069] In one embodiment, it is determined whether the ventricular assist device has the suction event based on the actual torque current waveform curve and the standard torque current waveform curve. Specifically, it can be seen from line 3 that when a suction event occurs, the actual torque current waveform curve of the motor also has alternating peaks and troughs. Within a cardiac cycle T, when the peak value of the peak of the actual torque current waveform curve of the motor is less than 0.7 times the peak value of the peak of the standard torque current waveform curve, and the maximum value of the absolute value of the slope of the actual torque current waveform within a preset time range is greater than 1 / 2 of the cardiac cycle, it is determined that the ventricular assist device has a suction event. The preset time range is set to take the moment corresponding to the peak of the actual torque current waveform curve as the middle moment, and 1 / 10 of the cardiac cycle as the time span.

[0070] In another embodiment, it is determined whether the ventricular assist device has the suction event according to the actual torque current waveform curve and the standard torque current waveform curve. Specifically, it can be seen from line 3 that when a suction event occurs, the actual torque current waveform curve of the motor also has alternating peaks and troughs. Comparing line 3 with line 1, it is found that the period of the standard torque current waveform curve is the same as the period time of the actual torque current waveform curve. In one cardiac cycle T, the peak value of the peak of the actual torque current waveform curve of the motor is less than 0.7 times the peak value of the peak of the standard torque current waveform curve, and at the same time, the valley value of the trough of the actual torque current waveform curve is equal to the valley value of the trough of the standard torque current waveform curve, and in other time periods except the time when the valley value of the trough occurs, the actual torque current waveform curve and the standard torque current waveform curve deviate from each other, and it is determined that the ventricular assist device has a suction event.

[0071] The same cycle time of the above two waveforms is defined as follows: the actual torque current waveform and the standard torque current waveform are both periodic. In order to facilitate the comparison of the peak and valley values ​​of the above two waveforms, the actual torque current waveform is translated on the time axis so that the time range corresponding to a cardiac cycle of the actual torque current waveform and the time range corresponding to a cardiac cycle of the standard torque current waveform remain the same. The above cardiac cycle can be a complete cardiac cycle between two adjacent peaks or a complete cardiac cycle between two adjacent troughs. In other words, the standard torque current waveform is a complete cardiac cycle within the [t1, t2] time range. By translating the actual torque current waveform on the time axis, the actual torque current waveform is also a complete cardiac cycle within the [t1, t2] time range. Of course, partial deviations can be allowed if the time range remains the same.

[0072] It should be noted that the valley value of the actual torque current waveform curve is equal to the valley value of the standard torque current waveform curve, including both completely equal and approximately equal. It should be noted that approximately equal means that the deviation between the two is within 5%.

[0073] The cause of the aortic valve normally closed event is that the motor rotates too fast, which makes the ventricular assist device have a high blood pumping efficiency and makes the arterial pressure higher than the ventricular pressure. In this process, the ventricular assist device has been working under a large load, resulting in the blood pumped by it not reaching the maximum flow rate, and then causing the torque current of the motor to not reach the maximum value. In this way, when the aortic valve normally closed event occurs, the actual torque current waveform curve of the motor is expressed as Figure 1 and Figure 5The pattern shown by line 4 in .

[0074] In one embodiment, it is determined whether the ventricular assist device has the aortic valve normally closed event based on the actual torque current waveform curve and the standard torque current waveform curve. Specifically, it can be seen from line 4 that the actual torque current waveform curve also has alternating peaks and troughs. In one cardiac cycle T, the peak value of the peak of the actual torque current waveform curve of the motor is less than 0.7 times the peak value of the peak of the standard torque current waveform curve, and the maximum value of the absolute value of the slope of the actual torque current waveform within a preset time range is not greater than 1 / 2 of the cardiac cycle, and it is determined that the ventricular assist device has a suction event. The preset time range is set to take the moment corresponding to the peak of the actual torque current waveform curve as the middle moment, and 1 / 10 of the cardiac cycle as the time span.

[0075] In another embodiment, whether the ventricular assist device has the aortic valve normally closed event is determined based on the actual torque current waveform curve and the standard torque current waveform curve. Specifically, it can be seen from line 4 that the actual torque current waveform curve also has alternating peaks and troughs. Comparing line 1 with line 4, it can be found that the actual torque current waveform area and the standard current waveform area have the same time period, and each cycle has a predetermined time period, and the peak of the standard torque current waveform curve and the peak of the actual torque current waveform curve both appear in the predetermined time period. The peak value of the peak of the actual torque current waveform curve is less than 0.7 times the peak value of the peak of the standard torque current waveform curve, and the actual torque current waveform curve and the standard torque current waveform curve are separated from each other in the predetermined time period, and also overlap in other time periods except the predetermined time period.

[0076] Here, the overlap of the actual torque current waveform curve and the standard torque current waveform curve in other time periods except the predetermined time period includes the situation that the two completely overlap, and also includes the situation that the two roughly overlap. It should be noted that the two roughly overlap means that the deviation between the two is within 5%.

[0077] To further explain, the peak of the actual torque current waveform curve corresponds to time t, and the time span of the preset time range is 0.1T, then the preset time range is t-0.05T~t+0.05T. Within the above preset time range, the maximum absolute value of the slope of the actual torque current waveform is k max , then the absolute value of the above slope ranges from 0 to k max . k max The larger the value, the faster the torque current changes within the above preset time range. When a suction event occurs, k maxIf it is greater than T / 2, it means that the torque current changes quickly. The torque current changes rapidly with the load change, but due to the flow resistance caused by suction, the torque current cannot reach the maximum value. In the event of a normally closed aortic valve, k max Not greater than T / 2, indicating that the torque current changes slowly. This is because the aortic valve is normally closed, the load does not change much, and thus the torque current does not change much.

[0078] Furthermore, the monitoring method further includes: after determining the type of the first type of adverse event, controlling the rotation speed of the motor according to the type of the first type of adverse event to mitigate or eliminate the first type of adverse event.

[0079] Specifically, when the first type of adverse event is determined to be a reflux event, the reflux is eliminated by controlling the rotation speed of the motor to increase. When the first type of adverse event is determined to be a suction event, the suction is slowed down or even eliminated by controlling the rotation speed of the motor to decrease. When the first type of adverse event is determined to be an aortic valve normally closed event, the arterial pressure is reduced by controlling the rotation speed of the motor to decrease so that the aortic valve can open and close normally.

[0080] In addition, there are some adverse events in the ventricular assist device that will not cause changes in the torque current waveform curve of the motor. These adverse events can be referred to as second-category adverse events. The second-category adverse events include abnormal position events of the ventricular assist device.

[0081] There are two specific types of abnormal position events, namely, the first abnormal position event and the second abnormal position event. The first abnormal position event refers to that the blood inlet and blood outlet of the ventricular assist device are both located in the artery. The second abnormal position event refers to that the blood inlet and blood outlet of the ventricular assist device are only located in the ventricle.

[0082] When the ventricular assist device has not had an abnormal position event, the pressure at the blood inlet is equivalent to the ventricular pressure, and the pressure at the blood outlet is equivalent to the arterial pressure, and there is a great deviation between the two. When the first abnormal position event occurs in the ventricular assist device, the blood inlet and the blood outlet are both located in the artery, so that the pressure at the blood inlet is equivalent to the arterial pressure, and the pressure at the blood outlet is also equivalent to the arterial pressure, and the arterial pressures at the two places are similar, but there is a certain deviation due to the certain distance between the blood inlet and the blood outlet. When the second abnormal position event occurs in the ventricular assist device, the blood inlet and the blood outlet are both located in the ventricle, so that the pressure at the blood inlet is equivalent to the ventricular pressure, and the pressure at the blood outlet is also equivalent to the ventricular pressure, and the ventricular pressures at the two places are similar, but there is a certain deviation due to the certain distance between the blood inlet and the blood outlet.

[0083] In other words, by acquiring the pressure at the blood outflow outlet in real time to obtain the pressure waveform curve at the blood outflow outlet (such as Figures 6 to 8 5), and obtaining the pressure at the blood inlet in real time to obtain the pressure waveform curve at the blood inlet (as shown in FIG. Figures 6 to 8 6 in the figure), if the ventricular assist device does not have the abnormal position event, the pressure waveform curve at the blood outflow outlet is equivalent to the arterial pressure waveform curve, and the pressure waveform curve at the blood inlet is equivalent to the ventricular pressure waveform curve, and there is a large deviation between the two; and when the ventricular assist device has the abnormal position event, the pressure waveform curve at the blood outflow outlet and the pressure waveform curve between the blood outflow outlets are similar, and the deviation between the two is small, wherein, when the first abnormal position event occurs, the pressure waveform curve at the blood outflow outlet and the pressure waveform curve at the blood inlet are both equivalent to the arterial pressure waveform, and when the second abnormal position event occurs, the pressure waveform curve at the blood outflow outlet and the pressure waveform curve at the blood inlet are both equivalent to the ventricular pressure waveform curve.

[0084] Therefore, the monitoring method further includes: judging whether the abnormal position event occurs in the ventricular assist device based on the pressure waveform curve at the blood outflow outlet and the pressure waveform curve at the blood inflow inlet. Specifically, when there is a large deviation between the pressure waveform curve at the blood outflow outlet and the pressure waveform curve at the blood inflow inlet, it is judged that the abnormal position event does not occur in the ventricular assist device; when the pressure waveform curve at the blood outflow outlet and the pressure waveform curve at the blood inflow inlet are similar and the deviation between the two is small, it is judged that the abnormal position event occurs in the ventricular assist device.

[0085] Through statistics, it is found that when the ventricular assist device has the first position abnormal event, the peak-to-peak value of the pressure waveform curve at the blood outflow outlet and the peak-to-peak value of the pressure waveform curve at the blood inflow inlet are both less than a second preset value, and the peak-to-peak value is the difference between the peak value of the peak and the valley value of the valley of the pressure waveform curve. This is because the pressure at the blood outflow outlet and the pressure at the blood inflow inlet are both equivalent to the arterial pressure, and the arterial pressure has a small change amplitude, so both the peak-to-peak value on the pressure waveform curve is less than the preset value.

[0086] When the second position abnormality event occurs in the ventricular assist device, the trough value of the trough of the pressure waveform curve at the blood outflow outlet is less than a third preset value, and the peak-to-peak value of the pressure waveform curve at the blood outflow outlet is greater than a fourth preset value, and the peak-to-peak value is the difference between the peak value and the trough value of the pressure waveform curve. This is because the pressure at the blood outflow outlet is equivalent to the ventricular pressure, and the ventricular pressure varies greatly with the cardiac cycle, so the peak-to-peak value on the pressure waveform curve is greater than the preset value.

[0087] The second preset value is greater than the third preset value and less than the fourth preset value. In practice, the second preset value is, for example, 60 mmHg, the third preset value is, for example, 40 mmHg, and the fourth preset value is, for example, 70 mmHg. Based on this, it can be further determined whether the position abnormality event occurring in the ventricular assist device is the first position abnormality event or the second position abnormality event.

[0088] Optionally, a pressure monitoring element is provided at the blood outflow outlet of the ventricular assist device, and the pressure monitoring element is configured to monitor the pressure at the blood outflow outlet. The pressure at the blood outflow inlet can be calculated based on the pressure at the blood outflow outlet, and the specific calculation method is well known to those skilled in the art and will not be described in detail here.

[0089] Optionally, the monitoring method further comprises: after determining the type of adverse event occurring in the ventricular assist device, generating and displaying a prompt message to warn the user and medical staff. It should be understood that different adverse events correspond to different prompt messages, so that the user and medical staff can know the type of adverse event occurring according to the displayed prompt message. The prompt message can be displayed in any suitable manner such as sound, light, text, etc.

[0090] Furthermore, the present invention also provides a monitoring system for a ventricular assist device, comprising a current acquisition element and a control unit. The current acquisition element is connected to the motor and is configured to acquire the input current of the motor. The control unit is communicatively connected to the current acquisition element and is configured to receive the input current of the motor, obtain the torque current of the motor based on the input current of the motor, and execute the monitoring method as described above.

[0091] In some embodiments, the control unit uses the FOC vector control algorithm to control the motor, and based on this, the torque current of the motor is obtained. This is because the voltage, current, electromotive force, etc. on the stator of the motor are all AC quantities, and they rotate synchronously in space continuously. The essence of the FOC vector control algorithm is to use coordinate transformation to convert the motor phase current in the three-phase stationary coordinate system (i.e., the XYZ coordinate system) to a rotating coordinate system (i.e., the dq coordinate system) that is stationary relative to the rotor magnetic pole axis of the motor, so as to achieve the purpose of controlling the motor by controlling the vector size and direction in the rotating coordinate system. Those skilled in the art know that in the rotating coordinate system, the d-axis controls the magnetic flux of the rotor, the q-axis controls the torque output of the motor, and the current value of the q-axis is the torque current value of the motor.

[0092] Furthermore, the control unit is also communicatively connected with the pressure monitoring element provided on the ventricular assist device, and is configured to receive the pressure value measured by the pressure monitoring element, and obtain the pressure waveform curve at the blood outflow outlet based on the pressure value measured in real time by the pressure monitoring element. The control unit also calculates the pressure value at the blood inlet according to the pressure value measured by the pressure monitoring element, and then obtains the pressure waveform curve at the blood inlet by obtaining the pressure value at the blood inlet. The control unit also determines whether a position abnormality event occurs in the ventricular assist device based on the pressure waveform curve at the blood inlet and the pressure waveform curve at the blood outflow outlet, and determines whether the position abnormality event that occurs is the first position abnormality event or the second position abnormality event.

[0093] Optionally, the monitoring system further comprises a display element. The display element is in communication connection with the control unit. The control unit is configured to generate a prompt message when it is determined that any adverse event occurs in the ventricular assist device, and send the prompt message to the display element for display.

[0094] Furthermore, an embodiment of the present invention also provides a computer-readable storage medium, on which a program is stored, and when the program is executed, the aforementioned monitoring method is executed.

[0095] Although the present invention is disclosed as above, it is not limited thereto. Those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for monitoring a ventricular assist device, wherein the ventricular assist device comprises a motor; characterized in that: The monitoring method includes: judging whether the ventricular assist device has a first type of adverse event based on the torque current of the motor, and judging the type of the first type of adverse event; the first type of adverse event includes reflux events, suction events, and aortic valve closure events.

2. The method for monitoring a ventricular assist device according to claim 1, characterized in that: Obtaining an actual torque current waveform curve of the motor; In one cardiac cycle, when the actual torque current waveform curve has a first peak and a second peak, and the ratio of the peak value of the second peak to the peak value of the first peak is within a preset value range, it is determined that a regurgitation event occurs in the ventricular assist device; The preset value range is set to 0.2-0.

6.

3. The method for monitoring a ventricular assist device according to claim 1, characterized in that: Obtaining an actual torque current waveform curve of the motor; In a cardiac cycle, when the actual torque current waveform curve has a first peak and a second peak, and the time difference between the first peak and the second peak is greater than a preset time, it is determined that a regurgitation event occurs in the ventricular assist device; The preset time is set to 1 / 3 of the cardiac cycle.

4. The method for monitoring a ventricular assist device according to claim 1, characterized in that: The motor has a standard torque current waveform curve; The monitoring method comprises: Obtaining an actual torque current waveform curve of the motor; Whether the first type of adverse event occurs in the ventricular assist device is determined according to the actual torque current waveform curve and the standard torque current waveform curve, and the type of the first type of adverse event is determined.

5. The method for monitoring a ventricular assist device according to claim 4, characterized in that: When the actual torque current waveform curve at least partially deviates from the standard current waveform curve, it is determined that the first type of adverse event occurs in the ventricular assist device.

6. The method for monitoring a ventricular assist device according to claim 5, characterized in that: In one cardiac cycle, when the actual torque current waveform curve has a first peak and a second peak, and the peak value of the first peak is equal to the peak value of the peak of the standard torque current waveform curve, and the ratio of the peak value of the second peak to the peak value of the peak of the standard torque current waveform curve is within a preset range, it is determined that a regurgitation event occurs in the ventricular assist device; The preset range is set to 0.2-0.

6.

7. The method for monitoring a ventricular assist device according to claim 5, characterized in that: In a cardiac cycle, when the peak value of the actual torque current waveform curve is less than 0.7 times the peak value of the standard torque current waveform curve, it is determined that the ventricular assist device has a suction event or an aortic valve normally closed event.

8. The method for monitoring a ventricular assist device according to claim 7, characterized in that: When the maximum absolute value of the slope of the actual torque current waveform within a preset time range is greater than 1 / 2 of the cardiac cycle, it is determined that the ventricular assist device has a suction event; The preset time range is set to take the moment corresponding to the peak of the actual torque current waveform curve as the middle moment, and the duration of the preset time range is 1 / 10 of the cardiac cycle.

9. The method for monitoring a ventricular assist device according to claim 7, characterized in that: When the maximum absolute value of the slope of the actual torque current waveform is no greater than 1 / 2 of the cardiac cycle within a preset time range, it is determined that the ventricular assist device has an aortic valve normally closed event; The preset time range is set to take the moment corresponding to the peak of the actual torque current waveform curve as the middle moment, and the duration of the preset time range is 1 / 10 of the cardiac cycle.

10. The method for monitoring a ventricular assist device according to claim 7, characterized in that: The period of the standard torque current waveform curve is the same as the period time of the actual torque current waveform curve. When the trough value of the actual torque current waveform curve is equal to the trough value of the standard torque current waveform curve, and the actual torque current waveform curve deviates from the standard torque current waveform curve in other time periods except the time when the trough value occurs, it is determined that a suction event occurs in the ventricular assist device.

11. The method for monitoring a ventricular assist device according to claim 7, characterized in that: The period of the standard torque current waveform curve is the same as the period time of the actual torque current waveform curve, each period has a predetermined time period, and the peak of the standard torque current waveform curve and the peak of the actual torque current waveform curve both appear in the predetermined time period; When the actual torque current waveform curve deviates from the standard torque current waveform curve within the predetermined time period, and the actual torque current waveform curve coincides with the standard torque current waveform curve in time periods other than the predetermined time period, it is determined that the ventricular assist device has an aortic valve normally closed event.

12. The method for monitoring a ventricular assist device according to any one of claims 1 to 11, characterized in that: The method further includes, after determining the type of the first type of adverse event, controlling the rotation speed of the motor according to the type of the first type of adverse event to mitigate or eliminate the first type of adverse event.

13. The method for monitoring a ventricular assist device according to any one of claims 1 to 11, characterized in that: The ventricular assist device is provided with a blood inlet and a blood outlet; The monitoring method further includes judging whether a second type of adverse event occurs in the ventricular assist device based on the pressure waveform curve at the blood outflow outlet and the pressure waveform curve at the blood inflow inlet, and judging the type of the second type of adverse event, wherein the second type of adverse event includes a first position abnormality event and a second position abnormality event; The first abnormal position event refers to that both the blood inlet and the blood outlet are located in the artery; The second abnormal position event refers to that both the blood inlet and the blood outlet are located in the ventricle.

14. A monitoring system for a ventricular assist device, characterized in that: A current collecting element and a control unit are communicatively connected, wherein the current collecting element is connected to the motor of the ventricular assist device and is configured to collect an input increase of the motor; The control unit is configured to receive an input current of the motor, obtain a torque current of the motor based on the input increase of the motor, and execute a monitoring method of a ventricular assist device as described in any one of claims 1-13.

15. A computer-readable storage medium having a program stored thereon, characterized in that: When the program is executed, the monitoring method of a ventricular assist device as described in any one of claims 1-13 is performed.

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