Suction detection method and device

Abstract

The invention provides a suction detection method and device.The method comprises the steps that a first pressure value and a second pressure value are obtained, the first pressure value is the average pressure value detected by a first pressure sensor in a first period, and the second pressure value is the average pressure value detected by a second pressure sensor in the first period; if the first pressure value is reduced by the first threshold value and the target pressure difference is increased by the second threshold value, it is determined that a suction event exists in the ventricular assist device, and the target pressure difference is the difference value between the second pressure value and the first pressure value. The first pressure sensor and the second pressure sensor are arranged to detect the pressure inside and outside the inlet tube, whether a suction event exists in the current ventricular auxiliary device or not can be directly detected by comparing the pressure inside and outside the inlet tube, and the suction detection accuracy is improved.

Description

Technical Field

[0001] The present application relates to the field of medical device technology, and in particular to a suction detection method and device. Background Art

[0002] As an effective means of treating patients with heart failure, the ventricular assist device is an artificial mechanical device that draws fluid from the venous system or the heart directly into the arterial system, partially or completely replacing the work of the ventricles.

[0003] The VAD is a device that pumps blood from the left ventricle to the aorta by means of a motor-driven impeller that rotates in suspension within a housing assembly. During the operation of the VAD, it is necessary to avoid aspiration, which may occur when the unloading of the left ventricle is too high. Aspiration events can cause arrhythmias, which can further lead to tissue trauma within the left ventricle, a dangerous situation that directly affects the patient's life and health. In addition, aspiration events can lead to reduced blood flow, which may cause damage to the VAD. Summary of the invention

[0004] The embodiments of the present application provide a suction detection method and device, which can timely detect whether there is a suction event in a ventricular assist device.

[0005] In a first aspect, an embodiment of the present application provides a suction detection method, which is applied to a ventricular assist device, wherein the ventricular assist device includes a housing assembly having an inlet pipe, an impeller disposed in the housing assembly, a motor driving the impeller to rotate in suspension, and a first pressure sensor for measuring the pressure inside the inlet pipe and a second pressure sensor for measuring the pressure outside the inlet pipe; the method includes:

[0006] Acquire a first pressure value and a second pressure value, wherein the first pressure value is an average pressure value detected by the first pressure sensor in a first cycle, and the second pressure value is an average pressure value detected by the second pressure sensor in the first cycle;

[0007] If the first pressure value is less than a first threshold value and the target pressure difference is greater than a second threshold value, it is determined that a suction event occurs in the ventricular assist device, and the target pressure difference is the difference between the second pressure value and the first pressure value.

[0008] In a second aspect, an embodiment of the present application provides a ventricular assist device, the ventricular assist device comprising:

[0009] a housing assembly having an inlet pipe;

[0010] an impeller disposed within the housing assembly;

[0011] A motor driving the impeller to rotate in suspension;

[0012] a first pressure sensor for measuring the pressure within the inlet pipe;

[0013] a second pressure sensor for measuring the pressure outside the inlet pipe;

[0014] A control circuit for controlling the operation of the motor, wherein the control circuit is used to execute instructions of the steps in the method according to the first aspect of claim 1.

[0015] In a third aspect, an embodiment of the present application provides a medical device, comprising a processor, a memory, a communication interface, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the processor, and the program comprises instructions for executing some or all of the steps described in the method described in the first aspect above.

[0016] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, which stores a computer program for electronic data exchange, wherein the computer program enables a computer to execute some or all of the steps described in the method described in the first aspect above.

[0017] In a fifth aspect, an embodiment of the present application provides a computer program product, wherein the computer program product includes a non-transitory computer-readable storage medium storing a computer program, and the computer program is operable to cause a computer to execute some or all of the steps described in the method described in the first aspect of the embodiment of the present application. The computer program product may be a software installation package.

[0018] The technical solution provided by the present application obtains a first pressure value and a second pressure value, wherein the first pressure value is the average pressure value detected by the first pressure sensor in the first cycle, and the second pressure value is the average pressure value detected by the second pressure sensor in the first cycle; if the first pressure value decreases by a first threshold value and the target pressure difference increases by a second threshold value, it is determined that there is a suction event in the ventricular assist device, and the target pressure difference is the difference between the second pressure value and the first pressure value. The present application detects the pressure inside and outside the inlet tube by setting a first pressure sensor and a second pressure sensor, and can directly detect whether there is a suction event in the current ventricular assist device by comparing the pressure inside and outside the inlet tube, thereby improving the accuracy of suction detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 is a schematic diagram of a ventricular assist system provided in an embodiment of the present application;

[0021] Figure 2 is a schematic structural diagram of a ventricular assist device provided in an embodiment of the present application;

[0022] Figure 3 is a schematic diagram of another ventricular assist system provided in an embodiment of the present application;

[0023] Figure 4 is a schematic diagram of a ventricular assist device placement position provided in an embodiment of the present application;

[0024] Figure 5 It is a flow chart of a suction detection method provided in an embodiment of the present application;

[0025] Figure 6 is a schematic diagram of left ventricular pressure provided in an embodiment of the present application;

[0026] Figure 7 It is a structural schematic diagram of a medical device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0027] In order to help those skilled in the art better understand the technical solutions of the present application, the following is a clear and complete description of the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the description of the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0028] The terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, software, product, or device that includes a series of steps or units is not limited to the listed steps or units, but also includes steps or units that are not listed, or also includes other steps or units inherent to these processes, methods, products, or devices.

[0029] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0030] The medical device involved in the present application may be a ventricular assist device, such as an implantable ventricular assist device. The ventricular assist device may be used for the left heart, the right heart, or both hearts. The ventricular assist device may include at least one blood pump, which may be a magnetic levitation pump.

[0031] "Speed" as used herein refers to the rotational speed of a motor or electric machine, which is associated with the rotational speed of the rotor or impeller of a ventricular assist device, and may be defined as revolutions per minute. "Flow", "fluid flow", "pumping flow" refers to the volume of fluid delivered through the ventricular assist device per unit of time, which may be measured in liters per minute.

[0032] Patients with heart failure can use a ventricular assist device to assist the heart in completing its pumping function. The ventricular assist device can be placed in the patient's left ventricle to pump blood from the patient's left ventricle to the aorta to solve the patient's left heart failure problem; the ventricular assist device can also be placed in the patient's right ventricle to pump blood from the patient's right ventricle to the pulmonary artery to solve the patient's right heart failure problem.

[0033] The ventricular assist system of the present application may include an LVAD (left ventricular assist device), an RVAD (right ventricular assist device) or a BIVAD (biventricular assist device), which include not only a ventricular assist device implanted in the patient's body during operation, but also typically include a controller disposed outside the patient's body and connected to the ventricular assist device via a percutaneous line (transmission system). A portion of the transmission system extends outside the patient's body between the controller and the puncture site, while another portion extends into the patient's body between the puncture site and the ventricular assist device. The controller may, for example, include an integrated battery (rechargeable battery) or may be connected to a battery so that the implanted ventricular assist device may be powered by the controller via a percutaneous line. The ventricular assist device typically includes a motor having a stator and a rotor having blades. The motor of the ventricular assist device may typically be driven by power delivered by the controller, for example, generating current in the windings of the stator, which causes the rotor and its blades to rotate in order to deliver the patient's blood.

[0034] See also Figure 1 , Figure 1 A ventricular assist system is provided in an embodiment of the present application. The ventricular assist system includes a ventricular assist device 100, a controller 200, and a percutaneous cable 300 for connecting the ventricular assist device 100 to the controller 200. The proximal end of the percutaneous cable 300 extends through the skin into the ventricular assist device 100 to transmit power, information, and control signals for the operation of the ventricular assist device 100.

[0035] The ventricular assist device 100 can be implanted in the body, for example, it can be attached to the heart via a ventricular connection component (such as a top ring, a ventricular cuff, or a ventricular cuff), which can be sutured to the heart and connected to the ventricular assist device 100. The other end of the ventricular assist device 100 can be connected to the ascending aorta or the pulmonary artery via an outlet tube and / or an artificial blood vessel connected to the outlet tube, so that the ventricular assist device 100 can effectively transfer blood from the weakened ventricle and propel it to the aorta or the pulmonary artery, thereby circulating it to the rest of the patient's vascular system and providing ventricular assist function for the patient.

[0036] The controller 200 is used to monitor the ventricular assist device 100, and can realize functions such as control and data display of the ventricular assist device 100, fault detection, alarm, and data recording. For example, the controller 200 may have a touch screen display for displaying the operating data of the ventricular assist device 100, patient information, information of the ventricular assist device 100, etc. Further, the user can set the operating parameters of the ventricular assist device 100 through the controller 200.

[0037] See also Figure 2 , Figure 2 : is a schematic diagram of the structure of a ventricular assist device 100 proposed in an embodiment of the present application. The ventricular assist device 100 includes a housing assembly having an inlet pipe 50, an impeller 20 for pushing a fluid, and a motor 30 for driving the impeller 20 to rotate in suspension. The housing assembly includes a first housing and a second housing connected to the first housing, the first housing and the second housing together form a chamber 10, and the housing assembly is also provided with a fluid inlet 14 and a fluid outlet 15 connected to the chamber 10, and the fluid inlet 14 is provided on the first housing. The impeller 20 can rotate in suspension in the chamber 10, and the rotation of the impeller 20 can generate a centrifugal force for conveying the fluid, so that the fluid can enter the chamber 10 from the fluid inlet 14 and be output from the fluid outlet 15. Among them, the suspended rotation of the impeller 20 means that the impeller 20 does not contact the cavity wall of the chamber 10 when rotating.

[0038] 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. The stator 31 is fixed to the outer side of the first side wall 11 relative to the chamber 10, and the corresponding rotor 32 is located 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 synchronously with the rotor 32 in the chamber 10.

[0039] The ventricular assist device 100 further includes a control circuit 33 , which is electrically connected to the stator 31 . The control circuit 33 can control the rotation speed and suspension height of the rotor 32 by adjusting the current flowing through the stator 31 .

[0040] See also Figure 3 , Figure 3 A schematic diagram of another ventricular assist system provided in an embodiment of the present application. The ventricular assist system includes a left ventricular assist device 210, a right ventricular assist device 220, a controller 230, and a percutaneous cable 240. The left ventricular assist device 210 and the right ventricular assist device 220 are implanted in the body, and the controller 230 is disposed outside the body, and the controller 230 is connected to the left ventricular assist device 210 and the right ventricular assist device 220 via the percutaneous cable 240.

[0041] The structures of the left ventricular assist device 210 and the right ventricular assist device 220 are similar to Figure 1 The general structure of the ventricular assist device 100 is the same as that of the ventricular assist device 100, which will not be described here.

[0042] In which, the inlet tube 50 is fixed at the apex of the left ventricle. During the implantation or operation of the ventricular assist device 100, the left ventricular assist device 210 or the right ventricular assist device 220, the tube mouth of the inlet tube 50 may be too close to or adjacent to the heart tissue and cause a suction event. A suction event may occur when the fluid inlet 14 interacts with the heart tissue, causing partial or complete blockage of the inlet tube 50. Continuous suction may damage the patient's heart, impair the function of the ventricular assist device system, and cause insufficient perfusion of the patient.

[0043] Based on this, the present application sets a first pressure sensor 51 and a second pressure sensor 52 on the inlet tube 50. The first pressure sensor 51 is set on the inner surface of the inlet tube 50, and the second pressure sensor 52 is set on the outer surface of the inlet tube 50. The distances between the first pressure sensor 51 and the second pressure sensor 52 and the tube mouth of the inlet tube 50 are respectively the first distance and the second distance, and the first distance and the second distance can be set according to the length of the inlet tube 50 of the ventricular assist device 100. Specifically, the first distance and the second distance are such that when the inlet tube 50 of the ventricular assist device 100 passes through the myocardial tissue to reach the left ventricle, the first pressure sensor 51 and the second pressure sensor 52 are in the left ventricle, such as Figure 4 The first distance and the second distance can be the same or different. For example, when the inlet pipe length is 31 mm, the first distance can be set to 10 mm and the second distance can be set to 8 mm, or both the first distance and the second distance are 10 mm.

[0044] It should be noted that the first pressure sensor 51 can be set at any position on the inner surface at a first distance from the orifice of the inlet pipe 50, and the second pressure sensor 52 can be set at any position on the outer surface at a second distance from the orifice of the inlet pipe 50, and this application does not limit this.

[0045] The first pressure sensor 51 is used to measure the pressure inside the inlet tube 50, and the second pressure sensor 52 is used to measure the pressure outside the inlet tube. The first pressure sensor 51 and the second pressure sensor 52 are both electrically connected to the control circuit 33. The control circuit 33 can detect whether there is a suction event in the current ventricular assist device 100 according to the pressure values ​​fed back by the first pressure sensor 51 and the second pressure sensor 52, and then when there is a suction event, the rotation speed of the ventricular assist device 100, the left ventricular assist device 210 or the right ventricular assist device 220 can be adjusted in time to alleviate or solve the suction event.

[0046] In combination with the above description, the present application is described below from the perspective of method examples.

[0047] See also Figure 5 , Figure 5 A schematic diagram of a suction detection method provided in an embodiment of the present application is applied to Figure 1-4 The ventricular assist device shown. Figure 5 As shown, the method includes the following steps.

[0048] S510. Acquire a first pressure value and a second pressure value, where the first pressure value is an average pressure value detected by the first pressure sensor in a first period, and the second pressure value is an average pressure value detected by the second pressure sensor in the first period.

[0049] The first pressure sensor 51 is used to measure the pressure inside the inlet tube 50, and the second pressure sensor 52 is used to measure the pressure outside the inlet tube 50, that is, the left ventricular pressure. During the normal operation of the ventricular assist device 100, the pressure inside the inlet tube 50 is lower than the pressure outside the inlet tube 50, that is, the first pressure value is lower than the second pressure value, so that blood enters the ventricular assist device 100 from the left ventricle through the fluid inlet 14 of the inlet tube 50, and then is pumped to the aorta through the impeller 20 to do work.

[0050] During the operation of the ventricular assist device 100, the first pressure sensor 51 and the second pressure sensor 52 can feed back the real-time detected pressure value to the control circuit 33. The control circuit 33 can calculate the average value of the pressure detected by the first pressure sensor 51 and the second pressure sensor 52 in each first cycle to obtain the first pressure value and the second pressure value.

[0051] The first cycle is longer than the duration of the cardiac cycle. For example, the first cycle is m times the cardiac cycle, and the value of m is 5, 10, 15, 20, etc.

[0052] S520: If the first pressure value is less than a first threshold value and the target pressure difference is greater than a second threshold value, it is determined that a suction event occurs in the ventricular assist device, and the target pressure difference is the difference between the second pressure value and the first pressure value.

[0053] When the ventricular assist device 100 operates normally, the second pressure value is within the normal range of the left ventricular pressure. When the orifice of the inlet tube 50 may be too close to or adjacent to the heart tissue, the pressure inside the inlet tube 50 will decrease because the orifice of the inlet tube 50 is partially or completely blocked; when the orifice of the inlet tube 50 is partially or completely blocked, the pressure inside the inlet tube 50 decreases, and the pressure outside the inlet tube 50 remains unchanged or increases, so the pressure difference between the outside of the inlet tube 50 and the inside of the inlet tube 50 increases. Therefore, when the control circuit 33 detects that the first pressure value decreases to less than the first threshold value, and the target pressure difference increases to greater than the second threshold value, it is determined that the current ventricular assist device 100 has a suction event.

[0054] The normal left ventricular systolic pressure is 90-120 mmHg, and the diastolic pressure is 0-10 mmHg. The first threshold value can be set to 40 mmHg, and the second threshold value can be set to 20 mmHg.

[0055] In one possible example, after determining that the ventricular assist device has a suction event, the method further includes: if the second pressure value increases by a third threshold, determining that the suction event is severe.

[0056] In the ventricular systole, when the orifice of the inlet tube 50 is partially or completely blocked, the blood in the left ventricle cannot be pumped out, so that the left ventricular pressure increases, that is, the pressure outside the inlet tube 50 increases. Therefore, when the control circuit 33 detects that the first pressure value decreases by a first threshold, the target pressure difference increases by a second threshold, and the second pressure value increases by a third threshold, it is determined that a severe suction event occurs in the current ventricular assist device 100. A severe suction event may be manifested as the orifice of the inlet tube 50 may be completely blocked, so that the pumping flow rate of the ventricular assist device 100 is less than or equal to the minimum pumping flow rate, and the minimum pumping flow rate may be 0 or 1 LPM.

[0057] For example, when the control circuit 33 detects that the first pressure value decreases to less than or equal to 35 mmHg, and the second pressure value increases to greater than or equal to 160 mmHg, it is determined that a severe suction event occurs in the current ventricular assist device 100 .

[0058] The present application sets a first pressure sensor 51 and a second pressure sensor 52 in the inlet tube 50, so that the control circuit 33 can directly determine whether a suction event occurs in the current ventricular assist device 100 by comparing the first pressure value and the second pressure value in real time, thereby improving the accuracy of suction event detection.

[0059] Optionally, the method also includes: when there is a suction event in the ventricular assist device, obtaining a first flow rate, the first flow rate being the average pumping flow rate of the ventricular assist device when it operates at a target speed during the first cycle; determining a target speed step according to the first flow rate, and successively reducing the target speed by the target speed step until the target speed is less than a preset speed, or the first pressure value is equal to the first preset pressure value, and the target pressure difference is equal to a preset pressure difference, the first preset pressure value being the average pressure value detected by the first pressure sensor when the ventricular assist device operates normally, the preset pressure difference being the pressure difference between the first pressure value and the second pressure value when the ventricular assist device operates normally, and n is less than 1.

[0060] When a suction event occurs in the ventricular assist device 100, the inlet tube 50 is partially or completely blocked, and the fluid cannot smoothly enter the ventricular assist device 100 through the inlet tube 50. When the pumped fluid decreases, the ventricular assist device 100 still runs at the same speed, which will gradually reduce the pressure in the inlet tube 50, causing the suction event of the ventricular assist device 100 to become more serious. Based on this, when the control circuit 33 detects that the ventricular assist device 100 has a suction event, it can reduce the speed of the ventricular assist device 100 to increase the pressure in the inlet tube 50, thereby alleviating or resolving the suction event.

[0061] The control circuit 33 obtains the average pumping flow rate, i.e., the first flow rate, when the ventricular assist device 100 operates at the target speed in the first cycle. The target speed is the preset operating speed when the ventricular assist device 100 operates at a constant speed. The severity of the current ventricular assist device 100 suction event can be determined based on the first flow rate when the suction event occurs. The smaller the first flow rate, the more severe the suction event of the ventricular assist device 100.

[0062] Further, the control circuit 33 determines the magnitude of the speed reduction according to the first flow rate, wherein the smaller the first flow rate, the larger the target speed step to be reduced. After determining the target speed step, the control circuit 33 reduces the target speed by the target speed step, and then obtains the first pressure value and the target pressure difference of the second cycle respectively. If the first pressure value of the second cycle is still less than the first threshold value and the target pressure difference is greater than the second threshold value, the speed of the ventricular assist device 100 continues to be reduced by the target speed step. According to this method, the speed of the ventricular assist device 100 is continuously reduced until the speed of the ventricular assist device 100 is less than the preset speed, or the first pressure value is equal to the first preset pressure value, and the target pressure difference is equal to the preset pressure difference (i.e., there is no suction event in the ventricular assist device 100).

[0063] The duration of the second cycle may be the same as that of the first cycle, and the preset rotation speed may be the lowest rotation speed allowed by the ventricular assist device 100, such as the preset rotation speed is set to 2200 rpm.

[0064] In the present application, the control circuit 33 monitors in real time whether a suction event occurs during the operation of the ventricular assist device 100, and then when a suction event occurs, the rotation speed of the ventricular assist device 100 is reduced to alleviate or solve the suction problem, thereby ensuring the normal operation of the ventricular assist device 100 and the safety of the user.

[0065] In a possible example, the method also includes: if the second pressure value is less than a fourth threshold value and the first flow rate is less than a preset flow rate, determining that the flow rate in the left ventricle is insufficient; reducing the target speed to a first speed, the first speed being the minimum speed allowed by the ventricular assist device.

[0066] The preset flow rate can be set to the minimum pumping flow rate. When the rotation speed of the ventricular assist device 100 is too fast, the fluid volume pumped into the left ventricle is less than the flow volume volume pumped into the aorta by the ventricular assist device 100, and the unloading of the left ventricle is too high, resulting in insufficient flow of fluid in the left ventricle, leading to aspiration events. Therefore, when the control circuit 33 detects that the second pressure value is less than the fourth threshold value and the first flow rate is less than the preset flow rate, it is determined that the blood flow in the left ventricle is insufficient at this time, and the rotation speed of the ventricular assist device 100 is directly reduced to the minimum allowed speed to avoid increasing the damage of the ventricular assist device 100 and the user due to the aspiration event.

[0067] In an example, the method further includes: acquiring a first pressure curve and a second pressure curve, the first pressure curve being a pressure curve generated by the pressure detected by the first pressure sensor in the first cycle, and the second pressure curve being a pressure curve generated by the pressure detected by the second pressure sensor in the first cycle; determining a target cardiac cycle based on the first pressure curve and the second pressure curve; and controlling the rotation speed of the ventricular assist device in the target cardiac cycle so that a target characteristic curve is synchronized with the target cardiac cycle, the target characteristic curve being a pumping flow curve of the ventricular assist device.

[0068] After the ventricular assist device 100 is started, the control circuit 33 controls the ventricular assist device 100 to run constantly according to the preset speed, so that the blood output by the ventricular assist device 100 is relatively continuous when it is running, while the output of the natural heart is pulsating. Therefore, the ventricular assist device 100 cannot fully simulate the patient's natural cardiac cycle, that is, it is difficult to use the ventricular assist device 100 to control the pressure in the heart. In the case of reduced blood flowing into the heart, blood may be pumped out of the ventricle by the ventricular assist device 100 at a rate faster than the ventricular filling rate, which usually causes a suction event in the ventricle. At the same time, a slight mismatch between the amount of blood pumped by the ventricular assist device 100 and the amount of blood input to the heart can also cause a dangerous increase in venous pressure, resulting in life-threatening congestion in the lungs or systemic veins.

[0069] In the present application, the control circuit 33 determines the user's cardiac cycle based on the first pressure value and the second pressure value, and then controls the rotation speed of the ventricular assist device 100 based on the cardiac cycle, so that the change in the pumping flow of the ventricular assist device 100 is synchronized with the user's cardiac cycle, so as to reduce or eliminate the occurrence of adverse events in the ventricle and improve the user's life safety.

[0070] In practical applications, the cardiac cycle mainly includes systole and diastole. During the left ventricular systole phase, the aortic valve opens and the mitral valve closes, and blood flows from the left ventricle to the aorta; during the left ventricular diastole phase, the aortic valve closes and the mitral valve opens, and blood flows from the left atrium to the left ventricle. The cyclical nature of the heart's pumping will cause changes in left ventricular pressure, such as Figure 4 As shown in the figure, when the heart enters the ventricular contraction phase, the strong contraction of the ventricular muscle causes the left ventricular pressure to rise sharply. When it exceeds the left atrial pressure, the mitral valve closes, and the left ventricular pressure rises sharply but does not exceed the aortic pressure. During the time when the mitral valve and the aortic valve are both closed during the ventricular contraction phase, the pressure in the left ventricle increases sharply. When the left ventricular pressure exceeds the aortic pressure, the aortic valve is opened, and blood is ejected from the left ventricle into the aorta. The left ventricular pressure gradually decreases after reaching the peak value. When the left ventricular pressure is less than the preset value of the aortic pressure, the aortic valve closes to prevent blood from flowing back into the ventricle, and the heart enters the ventricular diastole phase. During the time when the mitral valve and the aortic valve are both closed during the ventricular diastole phase, the pressure in the left ventricle decreases sharply. When the left ventricular pressure drops below the left atrial pressure, the mitral valve is opened, and blood is ejected from the left atrium into the left ventricle. After the mitral valve opens, the volume of the left ventricle expands rapidly. At this time, the left ventricular pressure is lower than the left atrial pressure, and blood is rapidly ejected into the left ventricle. As the left ventricle fills with blood rapidly, the speed of blood flowing back from the left atrium to the left ventricle gradually slows down.

[0071] In the present application, the control circuit 33 can determine each stage of the cardiac cycle by the turning points representing the cardiac cycle change phenomenon, that is, the control circuit 33 can determine the cardiac cycle according to the pressure changes in the first pressure curve and the second pressure curve.

[0072] Wherein, determining the target cardiac cycle according to the first pressure curve and the second pressure curve includes: if the second pressure curve continues to rise and reaches the highest point within a first time length, and the rate of change of the first pressure curve within the first time length is less than a first value, then the first time length is determined as the first stage of the contraction period in the target cardiac cycle; if the second pressure curve continues to decrease within a second time length, and the first pressure curve decreases to the lowest point within the second time length, then the second time length is determined as the second stage of the contraction period in the target cardiac cycle; if the rate of change of the second pressure curve within a third time length is less than a second value, and the first pressure curve continues to increase within the third time length, then the third time length is determined as the diastole period of the target cardiac cycle.

[0073] Specifically, Figure 6 As shown, the first stage of the systolic period is from the moment A when the mitral valve closes to the moment B when the left ventricular pressure reaches the peak; the second stage of the systolic period is from the moment when the left ventricular pressure reaches the peak to the moment C when the mitral valve opens. During the diastolic period, the left ventricular pressure does not fluctuate much, that is, the rate of change of the second pressure curve during the diastolic period is small; during the diastolic period, the mitral valve opens, blood is ejected from the left atrium into the left ventricle, the blood volume in the left ventricle increases, and the blood flowing into the ventricular assist device 100 through the inlet tube 50 also increases, so that the pressure in the inlet tube 50 continues to increase and increases to the maximum point. Therefore, the rate of change of the second pressure curve is less than the second value, and the duration of the continuous increase of the first pressure curve is determined as the diastolic period of the target cardiac cycle. In the first stage of the systolic period, the mitral valve is closed, and the blood volume in the left ventricle is large at this time. The blood flowing into the ventricular assist device 100 through the inlet tube 50 can remain stable, and the left ventricular pressure increases from the minimum value to the maximum value during this period. Therefore, the duration during which the second pressure curve continues to rise and reaches the highest point and the rate of change of the first pressure curve is less than the first value is determined as the first stage of the systolic period in the target cardiac cycle. In the second stage of the systolic period, the blood volume in the left ventricle decreases to a minimum value, and the blood flowing into the ventricular assist device 100 through the inlet tube 50 also decreases, and the left ventricular pressure continues to decrease during this period. Therefore, the duration during which the second pressure curve continues to decrease and the first pressure curve decreases to the lowest point can be determined as the second stage of the systolic period in the target cardiac cycle.

[0074] For example, the first value may be set to 30 mmHg, and the second value may be set to 10 mmHg.

[0075] Wherein, controlling the rotation speed of the ventricular assist device during the target cardiac cycle so that the target characteristic curve is synchronized with the target cardiac cycle includes: in the first stage of the contraction period of the target cardiac cycle, increasing the rotation speed of the ventricular assist device to a second rotation speed, the second rotation speed being greater than the target rotation speed; in the second stage of the contraction period of the target cardiac cycle, reducing the rotation speed of the ventricular assist device to a third rotation speed, the second rotation speed being less than the target rotation speed, the second stage being later than the first stage; in the diastole period of the target cardiac cycle, reducing the rotation speed of the ventricular assist device to a fourth rotation speed, the fourth rotation speed being greater than the first rotation speed.

[0076] In the first stage of the systolic period, the blood volume in the left ventricle is relatively large, and the rotation speed of the ventricular assist device 100 can be increased to the second speed to reduce the load on the left ventricle; in the second stage of the systolic period, the blood volume in the left ventricle is reduced to the minimum value, and the rotation speed of the ventricular assist device 100 can be reduced to the third speed to prevent the ventricular assist device 100 from having a suction event or an over-suction event; in the diastolic period, the blood volume in the left ventricle continues to increase, and the rotation speed of the ventricular assist device 100 can be reduced to the fourth speed, and the device 100 can be operated constantly at the fourth speed during the diastolic period to prevent the left ventricle from being overloaded.

[0077] Among them, the greater the pumping flow rate required by the user, the greater the second speed. For example, when the target speed is 3500rpm, the second speed can be set to 4000rpm, the third speed can be set to 3000rpm, and the fourth speed can be set to 2600rpm.

[0078] It can be seen that the present application proposes a suction detection method, which obtains a first pressure value and a second pressure value, wherein the first pressure value is the average pressure value detected by the first pressure sensor in the first cycle, and the second pressure value is the average pressure value detected by the second pressure sensor in the first cycle; if the first pressure value decreases by a first threshold value and the target pressure difference increases by a second threshold value, it is determined that there is a suction event in the ventricular assist device, and the target pressure difference is the difference between the second pressure value and the first pressure value. The present application detects the pressure inside and outside the inlet tube by setting a first pressure sensor and a second pressure sensor. By comparing the pressure inside and outside the inlet tube, it can directly detect whether there is a suction event in the current ventricular assist device, thereby improving the accuracy of suction detection.

[0079] The above mainly introduces the scheme of the embodiment of the present application from the perspective of the execution process on the method side. It is understandable that in order to realize the above functions, the network device includes a hardware structure and / or software module corresponding to each function. Those skilled in the art should easily realize that, in combination with the units and algorithm steps of each example described in the embodiment provided in this article, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0080] By way of example, the present application provides a control circuit of a ventricular assist device, characterized in that the ventricular assist device comprises a housing assembly having an inlet pipe, an impeller disposed in the housing assembly, a motor driving the impeller to rotate in suspension, and a first pressure sensor for measuring the pressure inside the inlet pipe and a second pressure sensor for measuring the pressure outside the inlet pipe;

[0081] The control circuit includes one or more processors, and the one or more processors are configured to:

[0082] Acquire a first pressure value and a second pressure value, wherein the first pressure value is an average pressure value detected by the first pressure sensor in a first cycle, and the second pressure value is an average pressure value detected by the second pressure sensor in the first cycle;

[0083] If the first pressure value is less than a first threshold value and the target pressure difference is greater than a second threshold value, it is determined that a suction event occurs in the ventricular assist device, and the target pressure difference is the difference between the second pressure value and the first pressure value.

[0084] For example, the present application provides a ventricular assist device, the ventricular assist device comprising:

[0085] a housing assembly having an inlet pipe;

[0086] an impeller disposed within the housing assembly;

[0087] A motor driving the impeller to rotate in suspension;

[0088] a first pressure sensor for measuring the pressure within the inlet pipe;

[0089] a second pressure sensor for measuring the pressure outside the inlet pipe;

[0090] A control circuit for controlling the operation of the motor, wherein the control circuit is used to execute instructions for some or all of the steps described in the above method.

[0091] As an example, the present application also provides a medical device, which includes the control circuit or ventricular assist device described above.

[0092] Among them, the control circuit of each of the above schemes has the function of implementing the corresponding steps performed by the medical device in the above method; the functions can be implemented by hardware, or by hardware executing corresponding software.

[0093] In the embodiment of the present application, the control circuit 33 may also be a chip or a chip system, such as a system on chip (SoC).

[0094] See also Figure 7 , Figure 7 It is a structural diagram of a medical device provided in an embodiment of the present application, wherein the medical device comprises: one or more processors, one or more memories, one or more communication interfaces, and one or more programs; the one or more programs are stored in the memories and are configured to be executed by the one or more processors.

[0095] The above program includes instructions for performing the following steps:

[0096] Acquire a first pressure value and a second pressure value, wherein the first pressure value is an average pressure value detected by the first pressure sensor in a first period, and the second pressure value is an average pressure value detected by the second pressure sensor in the first period;

[0097] If the first pressure value is less than a first threshold value and the target pressure difference is greater than a second threshold value, it is determined that a suction event occurs in the ventricular assist device, and the target pressure difference is the difference between the second pressure value and the first pressure value.

[0098] Among them, all relevant contents of each scenario involved in the above method embodiment can be referred to the functional description of the corresponding functional module, which will not be repeated here.

[0099] It should be understood that the above-mentioned memory may include a read-only memory and a random access memory, and provide instructions and data to the processor. A portion of the memory may also include a non-volatile random access memory. For example, the memory may also store information about the device type.

[0100] In the embodiment of the present application, the processor of the above-mentioned device may be a central processing unit (CPU), and the processor may also be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0101] It should be understood that the "at least one" involved in the embodiments of the present application refers to one or more, and "plurality" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: the existence of A alone, the existence of A and B at the same time, and the existence of B alone, where A and B can be singular or plural. The character " / " generally indicates that the previous and subsequent associated objects are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, c can be single or multiple.

[0102] Furthermore, unless otherwise specified, ordinal numbers such as "first" and "second" mentioned in the embodiments of the present application are used to distinguish multiple objects, and are not used to limit the order, timing, priority or importance of multiple objects. For example, the first information and the second information are only used to distinguish different information, and do not indicate the difference in content, priority, sending order or importance of the two types of information.

[0103] In the implementation process, each step of the above method can be completed by an integrated logic circuit of hardware in a processor or an instruction in the form of software. The steps of the method disclosed in conjunction with the embodiment of the present application can be directly embodied as a hardware processor for execution, or a combination of hardware and software units in a processor for execution. The software unit can be located in a storage medium mature in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in a memory, and the processor executes the instructions in the memory, and completes the steps of the above method in conjunction with its hardware. To avoid repetition, it is not described in detail here.

[0104] An embodiment of the present application also provides a computer storage medium, wherein the computer storage medium stores a computer program for electronic data exchange, and the computer program enables a computer to execute part or all of the steps of any method recorded in the above method embodiments.

[0105] The present application also provides a computer program product, which includes a non-transitory computer-readable storage medium storing a computer program, and the computer program is operable to cause a computer to execute some or all of the steps of any method described in the above method embodiment. The computer program product may be a software installation package.

[0106] It should be noted that, for the aforementioned method embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the described order of actions, because according to the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present application.

[0107] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0108] In the several embodiments provided in the present application, it should be understood that the disclosed devices can be implemented in other ways. For example, the device embodiments described above are only schematic, such as the division of the above-mentioned units, which is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, and the indirect coupling or communication connection of devices or units can be electrical or other forms.

[0109] The units described above as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the embodiments of the present application.

[0110] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0111] If the above-mentioned integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable memory. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, which is stored in a memory and includes several instructions for a computer device (which can be a personal computer, server or TRP, etc.) to execute all or part of the steps of each embodiment method of the present application. The aforementioned memory includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, disk or optical disk and other media that can store program codes.

[0112] A person skilled in the art may understand that all or part of the steps in the various methods of the above embodiments may be completed by instructing the relevant hardware through a program, and the program may be stored in a computer-readable memory, which may include a flash drive, ROM, RAM, a magnetic disk or an optical disk, etc.

[0113] The embodiments of the present application are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. At the same time, for general technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A suction detection method, characterized in that: The invention is applied to a ventricular assist device, the ventricular assist device comprises a housing assembly having an inlet pipe, an impeller arranged in the housing assembly, a motor driving the impeller to rotate in suspension, and a first pressure sensor for measuring the pressure inside the inlet pipe and a second pressure sensor for measuring the pressure outside the inlet pipe; the method comprises: Acquire a first pressure value and a second pressure value, wherein the first pressure value is an average pressure value detected by the first pressure sensor in a first cycle, and the second pressure value is an average pressure value detected by the second pressure sensor in the first cycle; If the first pressure value is less than a first threshold value and the target pressure difference is greater than a second threshold value, it is determined that a suction event occurs in the ventricular assist device, and the target pressure difference is the difference between the second pressure value and the first pressure value.

2. The method according to claim 1, characterized in that: After determining that the ventricular assist device has a suction event, the method further includes: If the second pressure value increases by a third threshold, it is determined that the suction event is severe.

3. The method according to claim 1 or 2, characterized in that: The method further comprises: When there is a suction event in the ventricular assist device, obtaining a first flow rate, where the first flow rate is an average pumping flow rate of the ventricular assist device when it runs at a target speed in the first cycle; Determine a target speed step according to the first flow rate, and reduce the target speed by the target speed step in sequence until the target speed is less than a preset speed, or the first pressure value is equal to the first preset pressure value, and the target pressure difference is equal to the preset pressure difference, the first preset pressure value is an average pressure value detected by the first pressure sensor when the ventricular assist device operates normally, the preset pressure difference is the pressure difference between the first pressure value and the second pressure value when the ventricular assist device operates normally, and n is less than 1.

4. The method according to claim 1, characterized in that: The method further comprises: If the second pressure value is less than a fourth threshold value, and the first flow rate is less than a preset flow rate, it is determined that the flow rate in the left ventricle is insufficient; The target rotation speed is reduced to a first rotation speed, where the first rotation speed is a minimum rotation speed allowed by the ventricular assist device.

5. The method according to claim 3, characterized in that: The method further comprises: Acquire a first pressure curve and a second pressure curve, wherein the first pressure curve is a pressure curve generated by the pressure detected by the first pressure sensor in the first period, and the second pressure curve is a pressure curve generated by the pressure detected by the second pressure sensor in the first period; determining a target cardiac cycle according to the first pressure curve and the second pressure curve; The rotation speed of the ventricular assist device is controlled within the target cardiac cycle so that a target characteristic curve is synchronized with the target cardiac cycle, wherein the target characteristic curve is a pumping flow curve of the ventricular assist device.

6. The method according to claim 5, characterized in that The step of controlling the rotation speed of the ventricular assist device within the target cardiac cycle so that the target characteristic curve is synchronized with the target cardiac cycle comprises: In the first stage of the contraction phase of the target cardiac cycle, increasing the rotation speed of the ventricular assist device to a second rotation speed, wherein the second rotation speed is greater than the target rotation speed; In a second phase of the contraction period of the target cardiac cycle, reducing the rotation speed of the ventricular assist device to a third rotation speed, wherein the second rotation speed is less than the target rotation speed, and the second phase is later than the first phase; During the diastole period of the target cardiac cycle, the rotation speed of the ventricular assist device is reduced to a fourth rotation speed, wherein the fourth rotation speed is greater than the first rotation speed.

7. The method according to claim 5, characterized in that Determining a target cardiac cycle according to the first pressure curve and the second pressure curve includes: If the second pressure curve continues to rise and reaches a peak point within a first time period, and a rate of change of the first pressure curve within the first time period is less than a first value, the first time period is determined as the first stage of the contraction period in the target cardiac cycle; If the second pressure curve continues to decrease within a second time period, and the first pressure curve decreases to a lowest point within the second time period, the second time period is determined as the second stage of the contraction period in the target cardiac cycle; If the rate of change of the second pressure curve in the third time period is less than a second value, and the first pressure curve continues to increase in the third time period, the third time period is determined as the diastolic period of the target cardiac cycle.

8. A ventricular assist device, characterized in that: The ventricular assist device comprises: a housing assembly having an inlet pipe; an impeller disposed within the housing assembly; A motor driving the impeller to rotate in suspension; a first pressure sensor for measuring the pressure within the inlet pipe; A second pressure sensor for measuring the pressure outside the inlet pipe; and A control circuit for controlling the operation of the motor, wherein the control circuit is used for: Acquire a first pressure value and a second pressure value, wherein the first pressure value is an average pressure value detected by the first pressure sensor in a first cycle, and the second pressure value is an average pressure value detected by the second pressure sensor in the first cycle; If the first pressure value is less than a first threshold value and the target pressure difference is greater than a second threshold value, it is determined that a suction event occurs in the ventricular assist device, and the target pressure difference is the difference between the second pressure value and the first pressure value.

9. A medical device, characterized in that: The method comprises a processor, a memory and a communication interface, wherein the memory stores one or more programs, and the one or more programs are executed by the processor, and the one or more programs include instructions for executing the steps in the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program for electronic data exchange, wherein the computer program enables a computer to execute the steps of the method according to any one of claims 1 to 7.

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