Extracorporeal circulation platform and method for simulating different physiological statuses

Abstract

The invention relates to an extracorporeal circulation platform and a method for simulating different physiological statuses, and the method comprises the steps: enabling a flow and pressure curve to be closer to a simulation target by controlling the motion curves of a valve simulation device and a servo drive device; the method comprises the following steps: building an experimental platform which takes a valve simulation device, an electromagnetic proportional valve, a compliance simulation device, a servo driving device and a heart simulation device as components, and respectively simulating valves, peripheral resistance of blood vessels, arteriovenous and left heart in vitro; physiological parameters such as pressure and flow of a simulation target and curves are obtained through medical materials such as echocardiography, and part of feature points of the physiological parameters are used as control nodes of motion curves of the valve simulation device and the servo driving device on an extracorporeal circulation platform to adjust the motion curves of the device; finally, the feature points are adjusted according to the deviation between an experimental curve and a target curve, so that different physiological states of the heart are simulated, and the accuracy of a flow field near the valve is improved.

Description

Technical field:

[0001] The present invention relates to the field of medical equipment and devices, and in particular to an extracorporeal circulation platform and a method for simulating different physiological states. Background technology:

[0002] The heart plays a major role in transporting blood in human blood circulation. Once a problem occurs in the heart, it may lead to various diseases or even death. Most of the heart simulation devices currently used are designed based on a simplified Windkessel model, which regards the valve as a one-way valve with only two states: open and closed, ignoring the process of valve opening and closing. For example, Chen Shi (Research on the Design of an Extracorporeal Circulation Simulation System with Dual Hearts and Systemic-pulmonary Circulation [D]. Suzhou University, 2018(01)) simulated the valve in the extracorporeal circulation simulation platform by using the mechanical structure's own properties. First, the valve was replaced by a flexible diaphragm, and then a valve core with holes was used to control the unidirectional flow of the internal fluid. Liu Yu (Research on the Design and Development of a Heart Extracorporeal Pulsatile Circulation Simulation System [D]. Zhejiang University, 2018(06)) realized the low-pressure opening and closing characteristics of the natural heart valve by controlling the opening and closing of the solenoid valve in the extracorporeal circulation simulation platform in order to simulate the low-pressure opening and closing characteristics of the natural heart valve.

[0003] Due to the existence of the compliance cavity and the long tube diameter, the local flow field performance generated by the valve opening and closing characteristics will be gradually offset. Therefore, the use of a one-way valve to simulate the valve has no significant effect on the measurement of physiological parameters behind the valve, but has a greater impact on the parameter measurement of the flow field near the valve. Therefore, it is necessary to design a valve simulation device with controllable speed and angle to simulate the flow field near the valve. Summary of the invention:

[0004] Based on an in-depth study of the background technology, the purpose of the present invention is to provide an extracorporeal circulation platform and a method for simulating different physiological states. The device, while satisfying the conditions of normal and different degrees of heart failure heart pumping, takes into account that heart failure states are often accompanied by the influence of symptoms such as valvular stenosis and insufficiency, so that the valve opening and opening and closing characteristics of the valve can be controlled under the conditions that the heart simulation device simulates the working conditions of a normal or heart failure heart. This can well solve the problems of inaccurate simulation of valve opening and closing characteristics and uncontrollable valve motion curves in current heart simulation systems, and provide new possibilities for heart simulation devices.

[0005] The technical solution adopted by the present invention is as follows:

[0006] The device comprises: a servo drive device (A0), a support frame (B0), a heart simulation device (C0), a fixed base (D0), a valve simulation device (E0), an electromagnetic proportional valve (G0), a support base (J), and a compliance simulation device (L0). The servo drive device (A0) is located above the heart simulation device (C0), and the relative positions of the servo drive device (A0) and the heart simulation device (C0) are fixed by the support frame (B0). The heart simulation device (C02), the valve simulation device (E01), the electromagnetic proportional valve (G01), and the compliance simulation device (L0) are sequentially connected in series by a silicone hose. Finally, the compliance simulation device (L0) is connected to the heart simulation device (C01) by the valve simulation device (E02) and the silicone hose. The heart simulation device (C0) is installed on the support base (J) by the fixed base (D0), and other components are sequentially connected and fixed to the support base (J) by an extracorporeal circulation pipeline.

[0007] Furthermore, the servo drive device (A0) comprises a servo motor (A1), a support seat (A2), a guide rail (A3), a motor adapter plate (A4), a piston (A5), a slide table (A6), a ball screw (A7), and a coupling (A8); the guide rail (A3), the slide table (A6), and the ball screw (A7) constitute a screw slide table structure; the servo motor (A1) is connected to the guide rail (A3) through the support seat (A2); the ball screw (A7) is connected to the motor shaft through the coupling (A8); the slide table (A6) and the piston (A5) are connected through threads; the rotational motion of the servo motor (A1) is converted into reciprocating motion of the slide table (A6) and the piston (A5) along the guide rail (A3) through the guide rail (A3) and the ball screw (A7); the guide rail (A3) is fixed to the support frame (B0) through the motor adapter plate (A4).

[0008] Furthermore, the heart simulation device (C0) includes a liquid storage chamber (C1) and a buffer. The buffer is composed of a buffer bottom plate (C2), a sealing ring (C3), and a spring (C4). The buffer bottom plate (C2) is threadedly connected to the piston (A5) through a nut. When the piston (A5) starts to move downward, the spring (C4) is compressed before contacting the buffer bottom plate (C2). The spring (C4) provides a portion of the kinetic energy of the buffer bottom plate (C2), thereby reducing the relative speed difference between the piston (A5) and the buffer bottom plate (C2) when they contact. When the piston (A5) starts to move upward, the spring (C4) allows the buffer bottom plate (C2) to maintain the previous movement state for a short time and then slowly rise, thereby reducing the impact of excessive acceleration of the buffer bottom plate (C2) caused by a sudden change in the movement direction of the piston (A5). The liquid storage chamber (C1) is fixed to the base (D0) is connected to a support base (J), wherein the fixed base (D0) comprises a fixed seat (D1), a rubber pad (D2), and a set screw. The liquid storage chamber (C1) and the fixed seat (D1) are separated by the rubber pad (D2) and fixed by the set screw. The fixed base (D0) is installed on the support base (J) by means of a thread, and the servo motor (A1) is driven to move the buffer so that the volume of the liquid storage chamber (C1) changes. The liquid storage chamber (C1) can be provided with more than two through holes as required for transporting fluid medium between the liquid storage chamber (C1) and an external device. As the volume changes, the fluid medium passes through the valve simulation device (E01), the electromagnetic proportional valve (G01), and the compliance simulation device (L0), and then the fluid medium is returned to the heart simulation device (C0) through the valve simulation device (E02), thereby realizing blood circulation simulation.

[0009] Furthermore, the valve simulation device (E0) comprises a valve body (E1), a steering gear (E2), a fixed end cover (E3), an upper blood vessel support seat (E4), a blood vessel fixed shell (E5), a pressure strain gauge (E6), a blood vessel tightening device (E7), a lower blood vessel support seat (E8), and a blade (E9), wherein the blade (E9) is located inside the valve body (E1) and the equivalent area of ​​the blade (E9) inside the valve body (E1) is greater than the contact area between the blade (E9) and the inlet liquid flow, the rotation speed and direction of the blade (E9) are controlled by the steering gear (E2) outside the valve body (E1) and the rotation range of the blade (E9) is limited to [0°, 90°] by the stepped surface inside the valve body (E1), the steering gear (E2) is installed on the upper blood vessel support seat (E4) through the fixed end cover (E3), and the upper blood vessel support seat (E4) and the lower blood vessel support seat (E8) are processed The stepped surface is used for positioning and the two are clamped on the valve body (E1) by bolts. The blood vessel is located inside the upper blood vessel support seat (E4) and the lower blood vessel support seat (E8). One end of the artificial blood vessel or the physiological blood vessel is fixed to the upper blood vessel support seat (E4) and the lower blood vessel support seat (E8) by a blood vessel fixing device (E7), and the other side is pressed to the upper blood vessel support seat (E4) and the lower blood vessel support seat (E8) by a blood vessel fixing shell (E5). The upper blood vessel support seat (E4) and the lower blood vessel support seat (E8) are processed with stepped holes for placing the pressure strain gauge (E6) and transmitting data to the industrial control computer (I). If only the flow field distribution near the valve is tested, the artificial blood vessel or the physiological blood vessel does not need to be clamped, and the pressure strain gauge (E6) can be sealed in the groove inside the upper blood vessel support seat (E4) and the lower blood vessel support seat (E8) by waterproof material.

[0010] Furthermore, the electromagnetic proportional valve (G0) is connected to the industrial control computer (I), and can simulate different peripheral resistances of the extracorporeal circulation experimental platform by adjusting the opening. The industrial control computer (I) can collect and process data from devices such as the pressure sensor (E6) and the flow sensor (M), and the experimental platform is powered by a DC power supply (K).

[0011] Furthermore, the compliance simulation device (L0) comprises an acrylic cavity (L1), a fixing seat (L2), an overflow valve (L3), an end cover (L4), and a clamping check valve (L5). The compliance simulation device (L0) can be divided into different areas by an acrylic plate to simulate the compliance of multiple arteries or veins in one cavity. Through holes of corresponding calibers are made on the acrylic plate used to separate the areas for liquid flow between different areas. The check valve (L5) can also be placed according to the flow of the fluid medium. The moving direction is clamped in the through hole of the acrylic plate, so that the fluid medium flows in a specified direction. In order to adjust the compliance in different areas of the acrylic cavity, the pressure in different areas of the acrylic cavity is set by the overflow valve (L3), thereby adjusting the compliance. The overflow valve (L3) is installed on the surface of the acrylic cavity (L1) through the fixing seat (L2). The pressure in different areas is adjusted by delivering gas through the air pump. When the pressure in the target area reaches the set value, the overflow valve (L3) discharges excess gas to ensure stable compliance.

[0012] The present invention also provides a control method for the above-mentioned heart simulation device, comprising the following steps:

[0013] S1: By performing feature recognition on medical images such as ultrasound cardiogram, phonocardiogram and electrocardiogram of the simulated target, the pressure curve P0=f(t) and flow curve are obtained. And determine the coordinates of the local points;

[0014] S2: Fitting the simulated target cardiac output and achieving the simulation of the target cardiac output on the experimental platform by controlling the motion curve of the servo drive device (A0);

[0015] S3: Determine the liquid volume and pressure of each chamber of the compliance simulation device (L0) according to the physiological parameters of the simulated target, such as height and weight;

[0016] S4: adjusting the opening of the electromagnetic proportional valve (G0) according to the conditions of the simulated target to simulate different peripheral resistances;

[0017] S5: Collect the data of the pressure sensor (F0) and flow sensor (M0) of the simulation device and draw the pressure curve P1=f1(t) and flow curve of the experimental platform The obtained curve is passed through the characteristic parameter t i Divide and calculate P1=f1(t) in each interval, and P0=f0(t), Deviation ΔS 1i and total deviation ∑S1;

[0018] S6: Adjust the characteristic parameter t within the medical reference value range i And get the corresponding pressure curve P2 = f2 (t) and flow curve Determine whether there is ΔS 2i <ΔS 1i or / and the case where ∑S2 < ∑S1;

[0019] S7: Consider physiological parameters under abnormal conditions, and let the characteristic parameter t i at t i ∈[t i-1 , t i+1 range for searching, to obtain the pressure curve P3 = f3(t) and the flow curve Whether there is ΔS 3i <min[ΔS 1i , ΔS 2i or / and the case where ∑S3 < min[∑S1, ∑S2].

[0020] The present invention also provides a control method for the above valve simulation device, including the following steps:

[0021] S1: Obtain the opening and closing times of the valve during the heart pumping process;

[0022] S2: Use the opening and closing times of the valve as endpoints and successively set three moving points in this interval as the fitting points for the movement of the servo motor (E2);

[0023] S3: Feedback the force and actual rotational speed received by the blade (E9) through the magnetic encoder;

[0024] S4: Calibrate the rotational speed of the blade (E9) and make the flow field near the valve simulation device (E0) conform to the actual situation by controlling the positions of the three moving points;

[0025] S5: Determine whether the installation positions of the valve body (E1) and the blade (E9) are perpendicular to the inlet central axis by comparing the torques received by the blade (E9);

[0026] The present invention has the following advantages compared with the prior art:

[0027] The present invention can simulate different heart failure situations, myocardial stress, valve opening and closing characteristics, circulatory peripheral resistance and compliance by changing the motion curve of the servo motor (A1), the spring (C4) stiffness of the buffer, the rotation curve of the servo motor (E2), the opening degree of the electromagnetic proportional valve (G0) and the pressures in each area of the compliance simulation device (L0). While accurately simulating extracorporeal circulation under different physiological states, it improves the accuracy of the flow field near the valve. Description of the Drawings:

[0028] Figure 1 It is a schematic diagram of the physiological heart simulation device of the embodiment of the present invention;

[0029] Figure 2A schematic diagram of a heart simulation device and a servo drive device according to an embodiment of the present invention;

[0030] Figure 3 An exploded view of a buffer according to an embodiment of the present invention;

[0031] Figure 4 A schematic diagram of a valve simulation device according to an embodiment of the present invention;

[0032] Figure 5 A schematic diagram of a compliance simulation device according to an embodiment of the present invention;

[0033] Figure 6 A control method for a physiological heart simulation device according to an embodiment of the present invention;

[0034] Figure 7 A valve simulation device control method according to an embodiment of the present invention;

[0035] Figure 8 It is a schematic diagram of characteristic parameters of a servo drive device and a valve simulation device;

[0036] Fig. 9 is the left ventricular piston motion curve;

[0037] Fig.10 The step resistance model and time-varying resistance model of the valve;

[0038] Figure serial number: A0-servo drive device: A01-left atrium servo drive device, A02-left ventricle servo drive device; A11, A12-servo motor; A21, A22-support seat; A31, A32-guide rail; A41, A42-motor adapter plate; A51, A52-piston; A61, A62-slide; A71, A72-ball screw; A81, A82-coupling; B0-support frame: B01-left atrium support frame, B02-left ventricular support frame; C0-heart simulation device: C01-left atrium simulation device, C02-left ventricle simulation device; C11, C12-liquid storage chamber; C21, C22-buffer bottom plate; C31, C32-sealing ring; C41, C42-spring; D0-fixed base: D01-left atrium fixed base, D02-left ventricle fixed base; D11, D12-fixed seat; D21, D22-pad; E0-valve simulation Devices: E01-tricuspid valve simulator, E02-mitral valve simulator, E03-aortic valve simulator; E11, E12, E13-valve body, E21, E22, E23-servo, E31, E32, E33-fixed end cap, E41, E42, E43-vascular upper support seat, E51, E52, E53-vascular fixed shell, E61, E62, E63-pressure sensor, E71, E72, E73-vascular tight Fixed device, E81, E82, E83-subvascular support seat, E91, E92, E93-blade; F01, F02, F03-pressure sensor; G01, G02-electromagnetic proportional valve; H-left ventricular assist device; I-industrial computer; J-support base; K-DC power supply; L0-compliance simulation device: L1-acrylic cavity, L2-fixed seat, L3-overflow valve, L4-end cover, L5-clamp-type check valve; M-flow sensor; Specific implementation method:

[0039] The present invention is further described in detail below.

[0040] In order to facilitate the understanding of the technical content of the present invention, the technical solution is further described below in conjunction with the accompanying drawings. The words "front", "back", "upper", "lower" and other words indicating directions used in the description of the present invention are all statements based on the relationship between the accompanying drawings. The purpose is to facilitate description and cannot be regarded as a limitation on the technical content of the present invention. The words "connection" and other matching relationships involved should be understood in a broad sense unless clearly defined. They can be direct matching, indirect matching, fixed connection, detachable connection, etc. Those skilled in the art can understand the implementation methods based on the purpose of the present invention.

[0041] As the attached Figure 1As shown, the physiological heart simulation device comprises a servo drive device (A0), a support frame (B0), a heart simulation device (C0), a fixed base (D0), a valve simulation device (E0), an electromagnetic proportional valve (G0), a support base (J), and a compliance simulation device (L0). The servo drive device (A0) is located above the heart simulation device (C0) and the relative positions of the servo drive device (A0) and the heart simulation device (C0) are fixed by the support frame (B0). The heart simulation device (C02), the valve simulation device (E01), the electromagnetic proportional valve (G01), and the compliance simulation device (L0) are sequentially connected in series through a silicone hose, and finally the compliance simulation device (L0) is connected to the heart simulation device (C01) through the valve simulation device (E02) and the silicone hose. The heart simulation device (C0) is installed on the support base (J) through the fixed base (D0), and other components are sequentially connected and fixed to the support base (J) through an extracorporeal circulation pipeline.

[0042] As the attached Figure 2 As shown, the servo drive device (A0) comprises a servo motor (A1), a support seat (A2), a guide rail (A3), a motor adapter plate (A4), a piston (A5), a slide table (A6), a ball screw (A7), and a coupling (A8); the guide rail (A3), the slide table (A6), and the ball screw (A7) constitute a screw slide table structure; the servo motor (A1) is connected to the guide rail (A3) through the support seat (A2); the ball screw (A7) is connected to the motor shaft through the coupling (A8); the slide table (A6) and the piston (A5) are connected through threads; the rotational motion of the servo motor (A1) is converted into reciprocating motion of the slide table (A6) and the piston (A5) along the guide rail (A3) through the guide rail (A3) and the ball screw (A7); the guide rail (A3) is fixed to the support frame (B0) through the motor adapter plate (A4).

[0043] As the attached Figure 2 and attached Figure 3As shown, the heart simulation device (C0) includes a liquid storage chamber (C1) and a buffer. The buffer is composed of a buffer bottom plate (C2), a sealing ring (C3), and a spring (C4). The buffer bottom plate (C2) is threadedly connected to the piston (A5) through a nut. When the piston (A5) starts to move downward, the spring (C4) is compressed before contacting the buffer bottom plate (C2). The spring (C4) provides a part of the kinetic energy of the buffer bottom plate (C2), so that the relative speed difference between the piston (A5) and the buffer bottom plate (C2) when they are in contact is reduced. When the piston (A5) starts to move upward, the spring (C4) allows the buffer bottom plate (C2) to maintain the previous movement state for a short time and then slowly rise, thereby reducing the influence of the sudden change in the movement direction of the piston (A5) causing excessive acceleration of the buffer bottom plate (C2). When the piston (A5) contacts the nut on the guide shaft of the buffer bottom plate (C2), the buffer bottom plate (C2) carried by the piston (A5) moves at the same speed. In order to reduce the coaxiality requirement between the buffer bottom plate (C2) and the piston (A5), two sets of complementary pits and dome cylinders are respectively made on the bottom of the piston (A5) and the surface of the buffer bottom plate (C2). Since the movement of the piston (A5) may cause the liquid storage chamber (C1) to move, in order to prevent this phenomenon from occurring, the liquid storage chamber (C1) is connected to the support base (J) through a fixed base (D0). The fixed base (D0) includes a fixed seat (D1), a rubber pad (D2), and a set screw. The fixed base (D0) is installed on the support base (J) through threads. The liquid storage chamber (C1) and the fixed base (D0) are separated by the rubber pad (D2) and fixed by the set screw. The servo motor (A1) is driven to move the buffer, so that the volume of the liquid storage chamber (C1) changes. The liquid storage chamber (C1) can be made with more than two through holes as needed for the liquid storage chamber (C1) to transport the fluid medium between the external device. Taking the left ventricular assist device (H) as an example, the left ventricular assist device (H) needs to be connected in parallel in the circuit formed between the left ventricle and the aorta for testing. The fluid medium passes through the valve simulation device (E01), the electromagnetic proportional valve (G01) and the compliance simulation device (L0) as the volume changes, and then returns to the heart simulation device (C0) through the valve simulation device (E02) to achieve blood circulation simulation. In addition, when the heart simulation device (C0) simulates the motion state or the arrhythmia state, the buffer can change the volume of the closed cavity through the elastic deformation of the spring (C4) to simulate the effect of myocardial force.

[0044] As the attached Figure 4As shown, the valve simulation device (E0) includes a valve body (E1), a steering gear (E2), a fixed end cover (E3), a blood vessel upper support seat (E4), a blood vessel fixed shell (E5), a pressure strain gauge (E6), a blood vessel tightening device (E7), a blood vessel lower support seat (E8), and a blade (E9). The blade (E9) is located inside the valve body (E1) and the equivalent area of ​​the blade (E9) inside the valve body (E1) is larger than the contact area between the blade (E9) and the inlet liquid flow. The rotation speed and direction of the blade (E9) are controlled by the steering gear (E2) outside the valve body (E1) and the rotation range of the blade (E9) is limited to [0°, 90°] by the stepped surface inside the valve body (E1). The steering gear (E2) is installed on the blood vessel upper support seat (E4) through the fixed end cover (E3). The contact surfaces of the blood vessel upper support seat (E4) and the blood vessel lower support seat (E8) are made into complementary stepped surfaces to reduce Small leakage can be positioned through the machined stepped surface and the two can be clamped on the valve body (E1) by bolts. The blood vessel is located inside the upper blood vessel support seat (E4) and the lower blood vessel support seat (E8). One end of the artificial blood vessel or the physiological blood vessel is fixed to the upper blood vessel support seat (E4) and the lower blood vessel support seat (E8) by a blood vessel fastening device (E7), and the other side is pressed to the upper blood vessel support seat (E4) and the lower blood vessel support seat (E8) by a blood vessel fixing shell (E5). The upper blood vessel support seat (E4) and the lower blood vessel support seat (E8) are machined with stepped holes for placing the pressure strain gauge (E6) and transmitting data to the industrial control computer (I). If only the flow field distribution near the valve is tested, the artificial blood vessel or the physiological blood vessel does not need to be clamped, and the pressure strain gauge (E6) can be sealed in the groove inside the upper blood vessel support seat (E4) and the lower blood vessel support seat (E8) by waterproof material.

[0045] As the attached Figure 5 As shown, the compliance simulation device (L0) includes an acrylic cavity (L1), a fixing seat (L2), an overflow valve (L3), an end cover (L4), and a clamping check valve (L5). The compliance simulation device (L0) can be divided into different areas by an acrylic plate to simulate the compliance of multiple arteries or veins in one cavity. The acrylic plate used to separate the areas is provided with through holes of corresponding calibers for liquid flow between different areas. The check valve (L5) can also be clamped in the through hole of the acrylic plate according to the flow direction of the fluid medium to make the fluid medium flow in a specified direction. In order to adjust the compliance in different areas of the acrylic cavity, the pressure in different areas of the acrylic cavity is set by the overflow valve (L3), thereby adjusting the compliance. The overflow valve (L3) is installed on the surface of the acrylic cavity (L1) through the fixing seat (L2). The pressure in different areas is adjusted by delivering gas through an air pump. When the pressure in the target area reaches the set value, the overflow valve (L3) discharges excess gas to ensure stable compliance.

[0046] like Figure 6 As shown, the present invention also provides a control method for the physiological heart simulation device.

[0047] S1: By performing feature recognition on medical images such as ultrasound cardiogram, phonocardiogram and electrocardiogram of the simulated target, the pressure curve P0=f0(t) and flow curve are obtained. In combination with the phonocardiogram and / or electrocardiogram, the key data of the local points are extracted to determine the relevant parameters of valve opening and closing, cardiac cycle and heart rate and their corresponding pressure and flow. Taking the left heart as an example, the relevant parameters of valve opening and closing include the aortic valve opening time t2, the aortic valve closing time t4, the atrioventricular valve opening time t5 and the atrioventricular valve closing time t1, and the relevant parameters of the cardiac cycle include the isovolumetric contraction period duration Δt 等容收缩期 , rapid ejection phase duration Δt 快速射血期 , slow down the ejection phase duration Δt 减慢射血期 , isovolumetric relaxation duration Δt 等容舒张期 , rapid filling period Δt 快速充盈期 , slow down the filling period Δt 减慢充盈期 and atrial contraction period Δt 心房收缩期 , the heart rate HR can be calculated from the interval between the two R waves of the electrocardiogram. In addition, the P wave duration, QRS wave duration and T wave duration of the electrocardiogram or the first heart sound, second heart sound, third heart sound and fourth heart sound of the phonocardiogram can also be used to assist in judging the opening and closing of the valve and the contraction and relaxation state of the heart. In one cycle, the various parameters need to meet the following requirements:

[0048] S2: Since blood can be approximately considered as an incompressible liquid and the heart simulation device (C0) pumps out simulated blood by changing the internal volume, the volume change of the heart simulation device (C0) should be consistent with the heart stroke volume (cardiac output), that is, the volume change is changed by setting the movement speed of the buffer bottom plate (C2). Taking the normal left ventricle as an example, the left ventricular output flow is approximately a sine wave during the systolic period and is zero during the diastolic period. The left ventricular stroke volume q(t) is determined by the target left ventricular systolic period time T 收缩 , cardiac cycle T and maximum left ventricular stroke volume q0 are calculated, where: T 收缩 =Δt 等容收缩期 +Δt 快速射血期 +Δt 减慢射血期 =t4-t1, The function expression relationship is as follows:

[0049] In order to facilitate calculation and measurement, the product of stroke volume SV and heart rate HR, namely cardiac output CO, is used as the design standard of the piston (A25) motion curve and the flow curve is obtained. The piston (A5) motion curve is then calculated based on the bottom surface area S of the buffer bottom plate (C2), or the piston (A5) motion curve is also obtained by dividing the identified ventricular volume curve by the area of ​​the piston (A5) inside the heart simulation device (C0), where: T1 = t3-t1, T2 = t4-t3, T3 = t5-t4, T4 = t7-t5+t1.

[0050] In order to enable the heart simulator (C0) to simulate various conditions, the cardiac output under various heart rate conditions of the simulated target can be fitted to obtain the relationship between cardiac output and heart rate.

[0051] Among them, HR and HR i They are fitted heart rate and specific heart rate, CO and CO i are the cardiac output at the fitted heart rate and specific heart rate, respectively. a and b are gender-related constants, which are 0.413 and 0.0017 for males and 0.418 and 0.0016 for females.

[0052] S3: Determine the liquid volume and pressure of each chamber of the compliance simulation device (L0) according to the physiological parameters of the simulated target, such as height and weight;

[0053] S4: adjusting the opening of the electromagnetic proportional valve (G0) according to the conditions of the simulated target to simulate different peripheral resistances;

[0054] S5: Collect the data of the pressure sensor (F0) and flow sensor (M0) of the simulation device and draw the pressure curve P1=f1(t) and flow curve of the experimental platform The obtained curve is passed through the characteristic parameter t i Divide and calculate P1=f1(t) in each interval, and P0=f0(t), Deviation ΔS 1i and total deviation ∑S1;

[0055] S6: Adjust the characteristic parameter t within the medical reference value range i And get the corresponding pressure curve P2 = f2 (t) and flow curve Determine whether ΔS exists 2i <ΔS 1i Or / and ∑S2<∑S1, a normal heart with a heart rate of 75 beats / min is used as the simulation target, and the characteristic parameters must meet the following requirements:

[0056] S7: Since the simulated target may have diseases or special physiological structures, adjust the characteristic parameters again to make the characteristic parameter t i At t i ∈[t i-1 , t i+1 , search to see if there is a situation where ΔS 3i < min[ΔS 1i , ΔS 2i or / and ∑S3 < min[∑S1, ∑S2]. When the characteristic parameter t i no longer changes, select this solution as the final solution.

[0057] As Figure 7 shown, the present invention also provides a control method for the valve simulation device.

[0058] S1: Obtain the opening and closing times of the valve during the heart pumping process through Method 1, including the arterial valve opening time t2, the arterial valve closing time t4, the atrioventricular valve opening time t5, and the atrioventricular valve closing time t1.

[0059] S2: Traditional valve simulation only considers the actual flow area or one-way action of the valve. In this case, the valve impedance curve only considers the opening and closing states of the valve, ignoring the influence of the movement curve of the valve from the opening state to the closing state on the flow field. Using the valve opening and closing times as endpoints, three moving points are sequentially set in this interval as the fitting points for the movement of the servo motor (E2). The initial positions of the moving points are determined according to the maximum myocardial elasticity model. The three moving points are 0.28T d , 0.53T d , and 1.3T d , where T d is the peak time of the myocardial elasticity model E(t). Taking the left ventricle as an example, the myocardial elasticity model:

[0060] where LVP(t) is the left ventricular pressure curve, LVV(t) is the left ventricular volume curve, and V0 is the volume of the left ventricle under the condition of no stress.

[0061] S3: The servo drive device (A0) reciprocates in a specified curve, enabling the fluid medium to continuously exchange between the heart simulation device (C0) and the valve simulation device (E0). The internal blades (E9) of the valve simulation device (E0) are washed by the fluid medium, resulting in a deviation between the actual rotation speed and the theoretical rotation speed of the blades (E9). Measure the force and actual rotation speed of the blades (E9) through a magnetic encoder.

[0062] S4: Calibrate the rotation speed of the blade (E9) and make the flow field near the valve simulation device (E0) conform to the actual situation by controlling the positions of the three moving points.

[0063] S5: Since the actual transmembrane pressure difference of the valve is very small, generally around 8 mmHg, by comparing the torque difference of the leaflet (E9), it is determined whether the installation position of the valve simulation device (E0) is perpendicular to the central axis of the inlet. When the torque difference is less than 5 mmHg, it is considered that the installation position is perpendicular to the central axis of the inlet.

[0064] Compared with the diaphragm check valve, this device can not only simulate the opening and flow area of ​​the heart valve under normal physiological conditions, but also can realize the conditions of valvular insufficiency and stenosis or the accelerated heart pumping speed due to excitement, exercise, etc. by adjusting the maximum movement angle and movement curve of the servo (E2).

[0065] The device can also simulate the atrium and ventricle separately, and the functions and auxiliary systems of the device cannot be understood as limiting the scope of the invention patent. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Claims

1. A physiological heart simulation device and a control method thereof, characterized in that: The device comprises: a servo drive device (A0), a support frame (B0), a heart simulation device (C0), a fixed base (D0), a valve simulation device (E0), an electromagnetic proportional valve (G0), a support base (J), and a compliance simulation device (L0). The servo drive device (A0) is located above the heart simulation device (C0), and the relative positions of the servo drive device (A0) and the heart simulation device (C0) are fixed by the support frame (B0). The heart simulation device (C02), the valve simulation device (E01), the electromagnetic proportional valve (G01), and the compliance simulation device (L0) are sequentially connected in series by a silicone hose. Finally, the compliance simulation device (L0) is connected to the heart simulation device (C01) by the valve simulation device (E02) and the silicone hose. The heart simulation device (C0) is installed on the support base (J) by the fixed base (D0), and other components are sequentially connected and fixed to the support base (J) by an extracorporeal circulation pipeline.

2. The servo drive device according to claim 1, characterized in that: The servo drive device (A0) comprises a servo motor (A1), a support seat (A2), a guide rail (A3), a motor adapter plate (A4), a piston (A5), a slide table (A6), a ball screw (A7), and a coupling (A8); the guide rail (A3), the slide table (A6), and the ball screw (A7) constitute a screw slide table structure; the servo motor (A1) is connected to the guide rail (A3) via the support seat (A2); the ball screw (A7) is connected to the motor shaft via the coupling (A8); and the rotational motion of the servo motor (A1) is converted into reciprocating motion of the slide table (A6) and the piston (A5) along the direction of the guide rail (A3) via the guide rail (A3) and the ball screw (A7).

3. The heart simulation device (C0) according to claim 1, characterized in that: The heart simulation device (C0) includes a liquid storage chamber (C1) and a buffer, wherein the buffer includes a buffer bottom plate (C2), a sealing ring (C3), and a spring (C4). The liquid storage chamber (C1) is connected to the support base (J) through a fixed base (D0), wherein the fixed base (D0) includes a fixed seat (D1), a rubber pad (D2), and a set screw. The liquid storage chamber (C1) and the fixed seat (D1) are separated by the rubber pad (D2) and fixed by the set screw. The fixed base (D0) is installed on the support base (J) by threads. The liquid storage chamber (C1) and the upper buffer bottom plate (C2) form a closed cavity by the sealing ring (C3), and the fluid medium flows between the heart simulation device (C0) and the valve simulation device (E0) as the buffer bottom plate (C2) moves.

4. The valve simulation device (E0) according to claim 1, characterized in that: The valve simulation device (E0) comprises a valve body (E1), a steering gear (E2), a fixed end cover (E3), a blood vessel upper support seat (E4), a blood vessel fixed shell (E5), a pressure strain gauge (E6), a blood vessel tightening device (E7), a blood vessel lower support seat (E8), and a blade (E9). The blade (E9) is located inside the valve body (E1) and the equivalent area of ​​the blade (E9) inside the valve body (E1) is larger than the contact area between the blade (E9) and the inlet liquid flow. The rotation speed and direction of the blade (E9) are controlled by the steering gear (E2) outside the valve body (E1) and the rotation range of the blade (E9) is limited to [0°, 90°] by the stepped surface inside the valve body (E1). The steering gear (E2) is arranged on the fixed end cover (E3) Installed on the upper support seat (E4) of the blood vessel, the upper support seat (E4) of the blood vessel and the lower support seat (E8) of the blood vessel are positioned by means of machined stepped surfaces and are clamped on the valve body (E1) by bolts, the blood vessel is located inside the upper support seat (E4) of the blood vessel and the lower support seat (E8), one end of which is fixed to the upper support seat (E4) of the blood vessel and the lower support seat (E8) of the blood vessel by means of a blood vessel fastening device (E7), and the other side is pressed to the upper support seat (E4) of the blood vessel and the lower support seat (E8) of the blood vessel by means of a blood vessel fixing shell (E5), the upper support seat (E4) of the blood vessel and the lower support seat (E8) of the blood vessel are machined with stepped holes for placing pressure strain gauges (E6) and transmitting data to an industrial computer (I).

5. The compliance simulation device (L0) according to claim 1, characterized in that: The compliance simulation device (L0) comprises an acrylic cavity (L1), a fixing seat (L2), an overflow valve (L3), an end cover (L4), and a clamping check valve (L5). The compliance simulation device (L0) is divided into different areas by an acrylic plate to simulate the compliance of multiple arteries or veins in one cavity. Fluid medium is transferred between different areas through through holes or clamping check valves (L5) made on the acrylic plate. The overflow valve (L3) is installed on the surface of the acrylic cavity (L1) through the fixing seat (L2), and the compliance is adjusted by setting the pressure of the overflow valve (L3).

6. The control method of the physiological heart simulation device (C0) according to claim 1, characterized in that: The following steps are involved: S1: By performing feature recognition on medical images such as ultrasound cardiogram, phonocardiogram and electrocardiogram of the simulated target, the pressure curve P0=f(t) and the flow curve Q0=φ(t) are obtained, and the coordinates of the local points are determined; S2: Fitting the simulated target cardiac output and achieving the simulation of the target cardiac output on the experimental platform by controlling the motion curve of the servo drive device (A0); S3: Determine the liquid volume and pressure of each chamber of the compliance simulation device (L0) according to the physiological parameters of the simulated target, such as height and weight; S4: adjusting the opening of the electromagnetic proportional valve (G0) according to the conditions of the simulated target to simulate different peripheral resistances; S5: Collect the data of the pressure sensor (F0) and flow sensor (M0) of the simulation device and draw the pressure curve P1=f1(t) and flow curve Q1=φ1(t) of the experimental platform. i Divide and calculate the deviation ΔS of P1=f1(t), Q1=φ1(t) and P0=f0(t), Q0=φ0(t) in each interval 1i and total deviation ∑S1; S6: Adjust the characteristic parameter t within the medical reference value range i And get the corresponding pressure curve P2 = f2(t) and flow curve Q2 = φ2(t), and judge whether ΔS exists 2i <ΔS 1i Or / and ∑S2<∑S1; S7: Consider the physiological parameters under abnormal conditions, and let the characteristic parameter be t i At t i ∈[t i-1 , t i+1 , search within this range to determine whether there is a situation where the pressure curve P3 = f3(t) and the flow rate curve Q3 = φ3(t) have ΔS 3i < min[ΔS 1i , ΔS 2i or / and ∑S3 < min[∑S1, ∑S2].

7. The control method of the valve simulation device according to claim 4, characterized in that: The following steps are involved: S1: Obtain the opening and closing time of the valve during the heart pumping process; S2: Taking the valve opening and closing time as endpoints and setting three moving points in this interval as fitting points of the servo (E2) motion; S3: Feedback the force and actual speed of the blade (E9) through the magnetic encoder; S4: calibrating the rotation speed of the blade (E9) and making the flow field near the valve simulation device (E0) conform to the actual situation by controlling the positions of the three moving points; S5: By comparing the torque applied to the blade (E9), determine whether the installation positions of the valve body (E1) and the blade (E9) are perpendicular to the central axis of the inlet.

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