Speed regulation system for modular intra-aortic axial flow pump

Abstract

The application discloses a rotating speed regulation system for a modular intra-aortic axial flow pump. The system comprises a flow detection device, a controller and a blood pump driver. The flow detection device is connected with the controller and is used for measuring the descending aorta flow. The axial flow blood pump of the modular intra-aortic axial flow pump is connected with the controller via the blood pump driver, and the blood pump driver is used for driving the axial flow blood pump to operate. The controller is used for executing relevant steps to adjust the rotating speed of the axial flow blood pump to the optimal rotating speed operation. The application can accurately regulate the rotating speed of the axial flow blood pump of the modular intra-aortic axial flow pump, so that the axial flow blood pump always operates at the optimal rotating speed, thereby exerting the best blood flow hemodynamic support effect and minimizing the additional harm to the patient.

Description

Technical Field

[0001] This invention relates to a speed control system and method for a modular intra-aortic axial flow pump, belonging to the field of ventricular assist device control technology. Background Technology

[0002] Unlike classic implantable circulatory support devices, percutaneous mechanical circulatory support devices are mainly used in the treatment of cardiogenic shock and high-risk PCI patients. Due to their advantages such as minimal invasiveness, rapid initiation, and simple operation, they are becoming increasingly widely used in clinical practice.

[0003] The Modular Intra-aortic Axial-flow pump is a newly emerging percutaneous mechanical circulatory support device. It is a system composed of multiple axial-flow pumps. Each axial-flow pump operates at a low speed, resulting in a large cumulative flow and minimal damage to the blood. During operation, the axial-flow pumps are connected in parallel within the descending aorta, collectively providing hemodynamic support. The blood accelerated by the axial-flow pumps propels naturally flowing blood towards peripheral organs such as the kidneys, thereby reducing cardiac afterload, increasing cardiac output, and creating a pressure gradient across the aorta, further enhancing blood perfusion to peripheral organs like the kidneys.

[0004] Studies have shown that axial flow pumps operating at low speeds provide superior hemodynamic support within the aorta compared to high speeds. This is because at high speeds, the increased transpump pressure differential causes blood to flow backwards, re-entering the pump and undergoing secondary acceleration. Furthermore, the complex blood flow around the pump can generate turbulence, which can increase the burden on the heart and hinder recovery in high-risk PCI patients. On the other hand, the definition of low and high speeds for axial flow pumps varies depending on the degree of cardiac dysfunction in patients. In other words, the afterload relief effect and optimal pump speed differ for modular intra-aortic axial flow pumps. Therefore, precisely controlling the speed of modular intra-aortic axial flow pumps to achieve optimal hemodynamic support is crucial for clinical application, but currently, no relevant technical data is publicly available.

[0005] Therefore, designing a method to regulate the speed of an axial flow blood pump so that it operates at the optimal speed to prevent excessive speed from increasing the burden on the heart and to avoid secondary acceleration that could damage the blood is an urgent problem to be solved. Summary of the Invention

[0006] The application aims to provide a rotating speed regulation system and method for a modular intra-aortic axial flow pump, which can precisely regulate the rotating speed of the axial flow blood pump of the modular intra-aortic axial flow pump, so that the pump always operates at the optimal rotating speed, thereby exerting the best hemodynamic support effect and minimizing the additional harm to the patient.

[0007] In order to achieve the above-mentioned purpose, the application adopts the following technical solutions:

[0008] A rotating speed regulation system for a modular intra-aortic axial flow pump, comprising a flow detection device, a controller and a blood pump driver, wherein:

[0009] The flow detection device is connected with the controller, and the flow detection device is used to measure the descending aorta flow by using the ultrasonic Doppler principle;

[0010] Each axial flow blood pump of the modular intra-aortic axial flow pump is connected with the controller via the blood pump driver, and the blood pump driver is used to drive the axial flow blood pump to operate in a pulse width modulation mode;

[0011] The controller is used to perform the following steps to adjust the rotating speed of the axial flow blood pump to the optimal rotating speed: determining the initial rotating speed n0 of the axial flow blood pump; starting to increase the rotating speed according to the rotating speed adjustment step Δn, until the judgment condition one is not met, and then entering the next step; starting to reduce the rotating speed based on the dichotomy, until the judgment condition two is met, and then no longer reducing the rotating speed; and determining the current rotating speed as the optimal rotating speed of the axial flow blood pump.

[0012] A rotating speed regulation method for a modular intra-aortic axial flow pump, comprising the following steps:

[0013] 1) setting the relationship between the pump cumulative flow and the rotating speed, and the rotating speed adjustment step Δn;

[0014] 2) initializing the counting parameters i and j;

[0015] 3) determining the initial rotating speed n0 of the axial flow blood pump;

[0016] 4) measuring the descending aorta flow Q0 of the axial flow blood pump after the axial flow blood pump stably operates at the initial rotating speed n0 for a preset time;

[0017] 5) increasing the rotating speed of the axial flow blood pump according to the rotating speed adjustment step Δn, and recording the increased rotating speed as n i ;

[0018] 6) determining the pump cumulative flow Q i of the axial flow blood pump when the axial flow blood pump operates at the rotating speed n pi based on the relationship between the pump cumulative flow and the rotating speed;

[0019] 7) Measure the axial flow blood pump at rotating speed n i Descending aortic flow Q i ;

[0020] 8) Determine the size relationship of Q i , Q i-1 , and Q pi : if Q i > Q i-1 and Q i > Q pi , then i is added by 1 and return to 5); otherwise, record Q i-1 as the maximum flow in the descending aortic flow measured before the axial flow blood pump starts to reduce the rotating speed, and enter 9);

[0021] 9) Reduce the rotating speed of the axial flow blood pump by dichotomy, and the reduced rotating speed is recorded as n ij ;

[0022] 10) Determine the pumped-up flow Q ij of the axial flow blood pump at rotating speed n pij based on the relationship between the pumped-up flow and the rotating speed;

[0023] 11) Measure the descending aortic flow Q ij of the axial flow blood pump at rotating speed n ij after stable operation for a preset time;

[0024] 12) Determine the size relationship of Q ij , Q i-1 , and Q pij : if Q ij > Q i-1 and Q ij > Q pij , then determine n ij as the optimal rotating speed of the axial flow blood pump, and drive the axial flow blood pump to operate continuously at the optimal rotating speed; otherwise, j is added by 1 and return to 9).

[0025] The advantages of the present application are:

[0026] The present application can determine the pumped-up flow without additional sensors, and accurately control the rotating speed of the axial flow blood pump, so that the axial flow blood pump is adjusted to the optimal rotating speed based on the patient's physical condition to achieve the best hemodynamic support effect, thereby preventing the heart from being overloaded due to the excessively high rotating speed, avoiding the damage to blood caused by secondary acceleration, and minimizing the additional harm to the patient. The present application has high control precision, and the control process is gentle without sudden increase or decrease, which is friendly to the patient. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1is a component block diagram of a rotational speed regulating system for a modular intra-aortic axial flow pump according to the present application.

[0028] Figure 2 is a scatter plot of the cumulative flow through the pump versus the rotational speed of the modular intra-aortic axial flow pump.

[0029] Figure 3 is Figure 2 is a result plot after linear fitting of the scatter plot. DETAILED DESCRIPTION

[0030] As shown in Figure 1 , the present application proposes a rotational speed regulating system for a modular intra-aortic axial flow pump, comprising a flow detection device 10, a controller 20 and a blood pump driver 30, wherein:

[0031] The flow detection device 10 is connected to the controller 20, and the flow detection device 10 is configured to measure the descending aortic flow by using the ultrasonic Doppler principle;

[0032] Each axial flow blood pump 40 in the modular intra-aortic axial flow pump is connected to the controller 20 via the blood pump driver 30, and the blood pump driver 30 is configured to provide a corresponding voltage to the axial flow blood pump 40 based on the rotational speed calculated by the controller 20, so as to drive the axial flow blood pump 40 to operate in a pulse width modulation (PWM) mode;

[0033] The controller 20 is configured to adjust the rotational speed of the axial flow blood pump 40 to an optimal rotational speed by performing the following steps: determining an initial rotational speed n0 of the axial flow blood pump 40; starting to increase the rotational speed from the initial rotational speed n0 according to a rotational speed adjustment step Δn, until a first judgment condition is not met, and then starting to decrease the rotational speed; starting to decrease the rotational speed based on a bisection method, until a second judgment condition is met, and then no longer decreasing the rotational speed; and determining the current rotational speed as the optimal rotational speed of the axial flow blood pump 40 in the modular intra-aortic axial flow pump, so that each axial flow blood pump 40 continuously operates at the optimal rotational speed.

[0034] In actual implementation, the first judgment condition is whether the descending aortic flow measured when the axial flow blood pump 40 operates at the current rotational speed is greater than both the descending aortic flow measured when the axial flow blood pump 40 operates at the previous rotational speed and the calculated current cumulative flow through the pump, and the second judgment condition is whether the descending aortic flow measured when the axial flow blood pump 40 operates at the current rotational speed is greater than both the maximum flow among the descending aortic flows measured before the axial flow blood pump 40 starts to decrease the rotational speed and the calculated current cumulative flow through the pump, wherein the descending aortic flow measured when the axial flow blood pump 40 operates before the axial flow blood pump 40 starts to decrease the rotational speed is recorded as the maximum flow.

[0035] As shown in Figure 1The controller 20 comprises a processing module 201, a setting module 202 and a storage module 203, the processing module 201 is connected with the setting module 202, the storage module 203, the flow detection device 10 and the blood pump driver 30, wherein:

[0036] The setting module 202 is used for setting the regulation parameters, the regulation parameters comprise the relationship between the cumulative flow through the pump and the rotation speed and the rotation speed adjustment step Δn;

[0037] The storage module 203 is used for storing the regulation parameters, the descending aortic flow data received by the processing module 201 from the flow detection device 10 and the rotation speed data and the cumulative flow through the pump data calculated by the processing module 201, and these parameters and data are used for calling by the processing module 201;

[0038] The processing module 201 is used for calculating the rotation speed and the cumulative flow through the pump, and adjusting the rotation speed used for driving the axial flow blood pump 40 to run, so that the axial flow blood pump 40 finally runs at the optimal rotation speed, wherein the optimal rotation speed is determined according to the judgment condition one and the judgment condition two, in the manner that the rotation speed of the axial flow blood pump 40 is first gradually increased based on the rotation speed adjustment step Δn, and then gradually reduced based on the dichotomy.

[0039] In application, the detection area of the flow detection device 10 is located in front of the modular intra-aortic axial flow pump, that is, the blood flows through the detection area of the flow detection device 10 first and then flows through the modular intra-aortic axial flow pump. The reason for placing it in this position is that the blood flow is more stable at this position than at other positions, and it is more convenient to realize accurate measurement.

[0040] In running, the flow detection device 10 measures the descending aortic flow in real time, the controller 20 adjusts the rotation speed of the axial flow blood pump 40 in the manner of first increasing and then decreasing based on the regulation parameters, the descending aortic flow data and the like, through the blood pump driver 30, so that the axial flow blood pump 40 finally runs at the optimal rotation speed, thereby preventing the heart burden from being increased due to the too high rotation speed, avoiding the damage to the blood caused by the secondary acceleration and the like.

[0041] The application further provides a rotation speed regulation method for the modular intra-aortic axial flow pump, which is used for controlling and adjusting the rotation speed of each axial flow blood pump 40 in the modular intra-aortic axial flow pump, wherein the rotation speed of each axial flow blood pump 40 is consistent. Figure 1 It can be understood that the rotation speed regulation method comprises the following steps:

[0042] 1) setting the relationship between the cumulative flow through the pump (i.e. the cumulative blood flow through all the axial flow blood pumps 40 in the descending aorta) and the rotation speed (i.e. the rotation speed of each axial flow blood pump 40) and the rotation speed adjustment step Δn through the setting module 202;

[0043] 2) initialize the counting parameters i, j, i.e. let i = 1, j = 1, i = 1, 2, 3, …, j = 1, 2, 3, …;

[0044] 3) determine the initial rotation speed n0of the axial flow blood pump 40;

[0045] 4) measure the descending aortic flow Q0of the axial flow blood pump 40 running at the initial rotation speed n0for a preset time (usually 2 s) by the flow detection device 10;

[0046] 5) increase the rotation speed by the rotation speed adjustment step Δn for the current rotation speed of the axial flow blood pump 40, and the increased rotation speed is denoted as n i , i.e. , wherein n i is the rotation speed after the increase of Δn, n i-1 is the rotation speed of the axial flow blood pump 40 before the increase of Δn (i.e. the last rotation speed of the axial flow blood pump 40), and i represents the number of times of increasing the rotation speed;

[0047] 6) determine the pumped flow Q i of the axial flow blood pump 40 running at the rotation speed n pi based on the relationship between the pumped flow and the rotation speed;

[0048] 7) measure the descending aortic flow Q i of the axial flow blood pump 40 running at the rotation speed n i by the flow detection device 10;

[0049] 8) judge the size relationship of Q i , Q i-1 and Q pi : if Q i > Q i-1 and Q i > Q pi , then i is increased by 1, and return to 5), which indicates that the cardiac output is increased and the accelerated blood by the pump does not undergo secondary acceleration when the rotation speed of the axial flow blood pump 40 is increased to n i , i.e. the increase of the rotation speed plays a positive role in the ventricular assistance, and the rotation speed of the axial flow blood pump 40 can be further increased; otherwise, if Q i ≤ Q i-1 or Q i ≤ Q pi , then Q i-1 is recorded as the maximum flow in the descending aortic flow measured before the axial flow blood pump 40 starts to decrease the rotation speed (the maximum descending aortic flow), and enter 9), which indicates that the cardiac output is decreased or the accelerated blood by the pump undergoes secondary acceleration when the rotation speed of the axial flow blood pump 40 is increased to n i , i.e. the increase of the current rotation speed plays a reverse role in the ventricular assistance, and the rotation speed of the axial flow blood pump 40 needs to be decreased;

[0050] 9) Reduce the rotational speed of the axial flow blood pump 40 by dichotomy, and the reduced rotational speed is denoted as n ij , where j represents the number of times of reducing the rotational speed, and n i0 is the rotational speed of the axial flow blood pump 40 before the reduction. i , that is, n i0 = n i ;

[0051] 10) Based on the relationship between the flow rate through the pump and the rotational speed, determine the flow rate Q ij through the pump when the axial flow blood pump 40 runs at the rotational speed n pij .

[0052] 11) Measure the flow rate Q ij in the descending aorta when the axial flow blood pump 40 runs at the rotational speed n ij for a preset time (usually 2s) by the flow rate detection device 10.

[0053] 12) Determine the size relationship of Q ij , Q i-1 , and Q pij : if Q ij > Q i-1 and Q ij > Q pij , it means that the flow rate in the descending aorta when the rotational speed of the axial flow blood pump 40 is reduced to n ij is larger than the maximum flow rate in the descending aorta before the reduction, and the accelerated blood through the pump does not have secondary acceleration, and the current rotational speed is the best for the auxiliary effect of the system on the heart, so the n ij is determined as the optimal rotational speed of the axial flow blood pump 40, and the axial flow blood pump 40 is driven to run continuously at the optimal rotational speed, and the process ends; otherwise, if Q ij ≤ Q i-1 or Q ij ≤ Q pij , j is increased by 1, and the process returns to 9), which means that when the rotational speed of the axial flow blood pump 40 is reduced to n ij , the cardiac output is still smaller than the maximum cardiac output before the reduction, or the accelerated blood through the pump still has secondary acceleration, and the rotational speed of the axial flow blood pump 40 needs to be further reduced.

[0054] In actual implementation, whenever the controller 20 or the processing module 201 changes the rotational speed of the axial flow blood pump 40, the controller 20 or the processing module 201 sends relevant instructions to the blood pump driver 30 to drive the axial flow blood pump 40 to change the rotational speed via the blood pump driver 30.

[0055] Here, the above-mentioned rotational speed control method of the application is mainly realized by the controller 20 or the processing module 201.

[0056] In actual implementation, after the axial flow blood pump 40 operates at the optimal rotating speed for a period of time, preferably, the rotating speed regulating method of the present application needs to be performed again so that the axial flow blood pump 40 can timely adjust its optimal rotating speed according to the change of the patient's physical condition, thereby reducing the damage to the patient to the minimum.

[0057] Preferably, the relationship between the pump cumulative flow and the rotating speed satisfies the following formula:

[0058]

[0059] In the formula, Q p is the pump cumulative flow of all the axial flow blood pumps 40 in the modular intra-aortic axial flow pump, k is a proportional coefficient, n is the rotating speed of the axial flow blood pump 40, and b is a constant term. The proportional coefficient k and the constant term b are obtained by linear fitting of the scatter data obtained based on the CFD calculation method (a well-known finite volume method) and in-vitro test.

[0060] Correspondingly, in the present application, Q pi is the pump cumulative flow when the axial flow blood pump 40 operates at the rotating speed n i , and Q pij is the pump cumulative flow when the axial flow blood pump 40 operates at the rotating speed n ij .

[0061] Specifically, a numerical simulation model of the modular intra-aortic axial flow pump working in the descending aorta of a patient is established, the pump cumulative flow data of the axial flow blood pump 40 at different rotating speeds are calculated based on the CFD calculation method, and after the data accuracy is verified by in-vitro test experiments, the data are plotted on the rotating speed-pump cumulative flow coordinate system. Then, the measured scatter data are linearly fitted into a straight line, and the slope and intercept of the straight line are used to calculate k and b.

[0062] For example: Figure 2 A scatter data graph of the pump cumulative flow and the rotating speed obtained based on the CFD calculation method is shown. It should be noted that in this example, the modular intra-aortic axial flow pump contains three axial flow blood pumps, i.e., the pump cumulative flow represents the sum of the flows through the three axial flow blood pumps. In order to show clearly, the horizontal coordinate unit is set to (x 10 4 rpm). It can be seen from Figure 2 that the distribution of the scatter data presents a straight line, and the scatter data are distributed near the straight line. Figure 3 Figure 2 ​The result graph after linear fitting of the shown scattered data, the fitting result is a slanted line, through calculation can get k, b value. Through verification, the fitting correlation coefficient γ is 0.9997, the fitting precision is high, meets the requirements. In other words, in actual application, according to the actual speed of the axial flow blood pump 40, based on the above formula, the cumulative flow through the pump can be obtained, so that it is not necessary to additionally set a sensor.

[0063] In actual implementation, the initial speed n0 of the axial flow blood pump 40 is determined by the following steps:

[0064] The descending aortic flow Q before the axial flow blood pump 40 is started is measured by the flow detection device 10 I ;

[0065] According to the relationship between the cumulative flow through the pump and the speed and the descending aortic flow Q I , the initial speed n0 is calculated based on the following formula:

[0066]

[0067] In the formula, k and b are respectively the proportional coefficient and the constant term in the relationship between the cumulative flow through the pump and the speed.

[0068] Of course, it is also possible to set a value for the initial speed n0 according to experience, which is not limited.

[0069] In the present application, the dichotomy is implemented based on the following formula:

[0070]

[0071] In the formula, n ij is the speed reduced by dichotomy, n i(j-1) is the speed of the axial flow blood pump 40 before the speed is reduced by dichotomy (i.e. the last speed of the axial flow blood pump 40), Δn is the speed adjustment step (set according to clinical experience), i and j are natural numbers, and n i0 is regarded as n i , i.e. n i0 = n i .

[0072] In actual implementation, the axial flow blood pump 40 changes the speed under the driving of the pulse width modulation (PWM) mode. In other words, the processing module 201 drives the axial flow blood pump 40 to change the speed by the blood pump driver 30 in the PWM mode.

[0073] Specifically, the PWM method is a widely used technology, which can be well used to control the rotating speed of the motor (axial flow blood pump). The greater the duty cycle, the greater the ratio of high level in a cycle, and the faster the rotating speed of the motor. Therefore, by outputting different analog voltages through the PWM, the motor can reach different output rotating speeds.

[0074] The present application has the advantages of:

[0075] The present application can determine the cumulative flow through the pump without additionally setting a sensor, and can accurately control the rotating speed of the axial flow blood pump, so that the axial flow blood pump is adjusted to the optimal rotating speed based on the patient's physical condition to operate, and the best hemodynamic support effect is achieved, thereby preventing the heart burden from being increased due to the too high rotating speed, avoiding the damage to the blood caused by secondary acceleration, and minimizing the additional harm to the patient. The present application has high control precision, and the control process is gentle, without sudden increase or decrease, which is friendly to the patient.

[0076] The above describes the preferred embodiment of the present application and the technical principles used thereby, and for those skilled in the art, any equivalent transformation, simple replacement, etc. based on the technical solution of the present application without departing from the spirit and scope of the present application, all belong to the protection scope of the present application.

Claims

1. A speed control system for a modular intra-aortic axial flow pump, characterized in that, Includes a flow detection device, a controller, and a blood pump driver, wherein: The flow detection device is connected to the controller, and the flow detection device is used to measure the descending aortic flow using the ultrasonic Doppler principle; Each axial flow blood pump of the modular intra-aortic axial flow pump is connected to the controller via the blood pump driver, and the blood pump driver is used to drive the axial flow blood pump to operate in a pulse width modulation manner; The controller is used to perform the following steps to adjust the rotational speed of the axial flow blood pump to the optimal speed: determine the initial rotational speed n0 of the axial flow blood pump; increase the rotational speed according to the speed adjustment step size Δn until the first judgment condition is not met, and then proceed to the next step; decrease the rotational speed based on the binary search method until the second judgment condition is met, and then stop decreasing the rotational speed; the current rotational speed is determined as the optimal speed of the axial flow blood pump. The first judgment condition is: whether the descending aortic flow rate measured by the axial flow blood pump at the current speed is greater than the descending aortic flow rate measured by the axial flow blood pump at the previous speed and the calculated current pump-accumulated flow rate. The second judgment condition is: whether the descending aortic flow rate measured when the axial flow blood pump is running at the current speed is simultaneously greater than the maximum flow rate of the descending aortic flow rate measured before the axial flow blood pump starts to reduce its speed and the calculated current pump-accumulated flow rate.

2. The speed control system for a modular intra-aortic axial flow pump as described in claim 1, characterized in that, The controller includes a processing module, a setting module, and a storage module. The processing module is connected to the setting module, the storage module, the flow detection device, and the blood pump driver, wherein: The setting module is used to set control parameters, which include the relationship between the pump's accumulated flow rate and the rotational speed, and the rotational speed adjustment step size Δn. The storage module is used to store the control parameters, the aortic flow data received by the processing module from the flow detection device, and the rotational speed data and pump-accumulated flow data calculated by the processing module. The processing module is used to calculate the rotational speed, the cumulative flow rate after pumping, and adjust the rotational speed used to drive the axial flow blood pump so that the axial flow blood pump can eventually run continuously at the optimal rotational speed. The optimal rotational speed is determined according to the first judgment condition and the second judgment condition by first gradually increasing the rotational speed of the axial flow blood pump based on the rotational speed adjustment step size Δn, and then gradually decreasing the rotational speed of the axial flow blood pump based on the bisection method.

3. The speed control system for a modular intra-aortic axial flow pump as described in claim 1, characterized in that, The speed control system for the modular intra-aortic axial flow pump is implemented by the following speed control method, which includes the following steps: 1) Set the relationship between the pump's cumulative flow rate and the rotational speed, and the rotational speed adjustment step size Δn; 2) Initialize the counting parameters i and j; 3) Determine the initial rotational speed n0 of the axial flow blood pump; 4) Measure the aortic flow rate Q0 after the axial flow blood pump has been running stably at its initial speed n0 for a preset time; 5) For the current speed of the axial flow blood pump, increase the speed by a speed adjustment step size Δn, and record the increased speed as n. i ; 6) Based on the relationship between the accumulated flow rate and the rotational speed, determine the rotational speed n of the axial flow blood pump. i Pump-accumulated flow rate Q during operation pi ; 7) Measure the axial flow blood pump at a rotational speed n. i Reduced aortic flow Q during operation i ; 8) Determine Q i With Q i-1 Q pi Size relationship: If Q i Q i-1 And Q i Q pi If i is positive, then i is incremented by 1 and 5 is returned; otherwise, Q is incremented by 1. i-1 Record the maximum flow rate in the descending aorta measured before the axial flow pump begins to reduce its speed, and proceed to step 9). 9) Reduce the rotational speed of the axial flow blood pump using the dichotomy method, and denot the reduced rotational speed as n. ij ; 10) Based on the relationship between the pump's accumulated flow rate and rotational speed, determine the rotational speed n of the axial flow blood pump. ij Pump-accumulated flow rate Q during operation pij ; 11) Measure the axial flow blood pump at a rotational speed n ij Reduced aortic flow Q after stable operation for a preset time ij ; 12) Determine Q ij With Q i-1 Q pij Size relationship: If Q ij Q i-1 And Q ij Q pij Then n ij The optimal speed of the axial flow blood pump is determined, and the axial flow blood pump is driven to run continuously at this optimal speed; Conversely, if j is not positive, increment j by 1 and return 9.

4. The speed control system for a modular intra-aortic axial flow pump as described in claim 3, characterized in that, The relationship between the pump's cumulative flow rate and rotational speed satisfies the following formula: In the formula, Q p The cumulative flow rate of all axial flow pumps in the modular aortic axial flow pump is given by k, which is the proportionality coefficient, n, which is the rotational speed of the axial flow pump, and b, which is a constant term. k and b are obtained by linear fitting of scatter data obtained from CFD calculations and in vitro tests.

5. The speed control system for a modular intra-aortic axial flow pump as described in claim 4, characterized in that, The initial rotational speed n0 of the axial flow blood pump is determined by the following steps: Measure the descending aortic flow Q before the axial flow blood pump is started. I ; Based on the relationship between the pump's accumulated flow rate and rotational speed, and the aortic flow rate Q... I The initial rotational speed n0 is calculated based on the following formula: In the formula, k and b are the proportionality coefficient and constant term in the relationship between the pump's cumulative flow rate and rotational speed, respectively.

6. The speed control system for a modular intra-aortic axial flow pump as described in claim 3, characterized in that, The bisection method is implemented based on the following formula: In the formula, n ij To determine the reduced rotational speed using the bisection method, n i(j-1) The axial flow blood pump operates at its operating speed before the speed is reduced by the binary method, where Δn is the speed adjustment step size, and i and j are natural numbers.

7. The speed control system for a modular intra-aortic axial flow pump as described in claim 3, characterized in that, The axial flow blood pump operates by changing its rotation speed under pulse width modulation.

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