Blood leakage rate measuring device and method and clinical actual blood flow obtaining method

Abstract

The invention discloses a blood leakage rate measuring device and method and a clinical actual blood flow obtaining method. The blood leakage rate measuring device comprises a right heart simulator filled with liquid and a pulmonary artery simulator, a second pressure sensor and a first pressure sensor are installed at the bottom in the right heart simulator and the pulmonary artery simulator, the right heart simulator is communicated with the pulmonary artery simulator through a first pipeline and a second pipeline, and an auxiliary pump is installed on the first pipeline. The right heart auxiliary catheter penetrates through the right heart simulator, the valve assembly is arranged in liquid in the right heart simulator, the end cap is arranged in liquid in the pulmonary artery simulator, a second flow sensor is installed on the outer wall of the short tube part between the right heart simulator and the pulmonary artery simulator, and a first flow sensor is installed on the outer wall of the long tube part close to the extracorporeal membrane type cavity. According to the clinical actual blood flow obtaining method, the actual blood flow of the right heart auxiliary catheter can be accurately obtained through the obtained blood leakage rate.

Description

Technical Field

[0001] This invention relates to a device and method for measuring blood leakage rate in a right ventricular assist catheter, as well as a method for obtaining actual clinical blood flow, belonging to the field of pulsatile right ventricular assist technology. Background Technology

[0002] Mechanical circulatory assist devices are medical devices that replace or assist cardiac function, provide blood perfusion, and improve hypoxia. They have become important devices for protection during high-risk percutaneous coronary intervention (PCI) and for the treatment of cardiogenic shock (CS). Percutaneous interventional ventricular assist devices (such as Impella) are commonly used mechanical circulatory assist devices. For example, the axial flow blood pump disclosed in Chinese utility model patent No. 202121863567.3, entitled "An Intra-aortic Circulation Assist Device," has an ultra-high-speed impeller as its core component. This interventional blood pump can improve the patient's hemodynamics to a certain extent, but because the high-speed rotating impeller can damage the blood, long-term use faces the risk of serious complications such as hemolysis, thrombosis, and bleeding. To address this problem, a novel pulsating auxiliary device has emerged, such as the Chinese utility model patent "A Circulation Auxiliary Device Providing Pulsating Blood Flow" with patent number 202321349312.4. This device uses the periodic movement of an extracorporeal membrane-type intracavitary diaphragm to generate pulsating characteristics in the blood, thus solving the aforementioned problem caused by the impeller and making the blood flow pattern more consistent with human physiological characteristics.

[0003] However, practical use has revealed that the valve structure of this novel pulsatile assist device creates a gap between the valve and the tube body due to valve rotation requirements. This gap leads to blood leakage, causing inconsistencies between the blood flow rate from the extracorporeal membrane cavity and the actual blood flow rate delivered to the artery, as well as between the blood flow rate into the extracorporeal membrane cavity and the actual blood flow rate into the ventricle or atrium. This significantly impacts the assessment of actual clinical blood flow, hindering effective decision-making by physicians and posing a substantial safety hazard. While the blood leakage issue can be mitigated when used as a left ventricular assist catheter to support left ventricular function, it can be addressed by measuring cardiac output using a right ventricular floating catheter placed in the right ventricular space. However, when used as a right ventricular assist catheter to support right ventricular function, the catheter structure of the novel pulsatile assist device occupies the right ventricular space, preventing the measurement of cardiac output via the right ventricular floating catheter. Therefore, the impact of the aforementioned blood leakage issue on the device's flow rate assessment remains to be addressed. Therefore, designing a device to measure the blood leakage rate of this novel pulsatile auxiliary device, as well as a method to obtain the actual clinical blood flow, are urgent problems that need to be solved. Summary of the Invention

[0004] The purpose of this invention is to provide a blood leakage rate measurement device and method for right ventricular assist catheters, as well as a method for obtaining actual clinical blood flow. The method for obtaining actual clinical blood flow can accurately obtain the actual blood flow of the right ventricular assist catheter by measuring the blood leakage rate.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A blood leakage rate measuring device is used for a right ventricular assist catheter, the right ventricular assist catheter including a short tube, one end of which is provided with an end cap and the other end is connected to one end of a long tube via a valve assembly, the other end of which is connected to an extracorporeal membrane cavity, the extracorporeal membrane cavity being used to connect to a gas supply system. The blood leakage rate measuring device includes a right heart simulator and a pulmonary artery simulator. Both simulators are filled with liquid to simulate blood. A second pressure sensor for measuring the liquid pressure is installed at the bottom of the right heart simulator, and a first pressure sensor for measuring the liquid pressure is installed at the bottom of the pulmonary artery simulator. The right heart simulator and the pulmonary artery simulator are connected by parallel first and second pipelines. An auxiliary pump is installed on the first pipeline. The auxiliary pump works in conjunction with the first pipeline to ensure that the liquid pressures in the right heart simulator and the pulmonary artery simulator meet the blood pressure requirements of the simulated right heart and pulmonary artery, respectively. A right heart auxiliary catheter penetrates the right heart simulator, and the valve assembly is placed in the liquid within the right heart simulator. An end cap is placed in the liquid within the pulmonary artery simulator. A second flow sensor is installed on the outer wall of the short tube portion between the right heart simulator and the pulmonary artery simulator. A first flow sensor is installed on the outer wall of the long tube portion near the extracorporeal membrane cavity. The auxiliary pump, the first pressure sensor, the second pressure sensor, the first flow sensor, the second flow sensor, and the gas supply system are connected to the control system.

[0006] A method for measuring blood leakage rate, implemented based on the blood leakage rate measuring device, includes the following steps: Step 1: Based on the pre-implantation location of the right ventricular assist catheter in the right heart, the fluid pressure in the right heart simulator and the pulmonary artery simulator is adjusted by the blood leakage rate measuring device to complete the simulation of the right heart and pulmonary artery environment; Step 2: Set the operating conditions of the right ventricular assist catheter through the control system, and drive the right ventricular assist catheter to perform blood drawing and blood drainage operations under the set conditions through the gas supply system. At the same time, the first fluid flow rate through the extracorporeal membrane cavity is detected by the first flow sensor and the second fluid flow rate through the short tube is detected by the second flow sensor to obtain the first fluid flow rate change curve and the second fluid flow rate change curve. Step 3: For the blood drawing and blood draining periods within a working cycle, integrate the first liquid flow rate change curve and the second liquid flow rate change curve respectively to obtain the blood leakage rate of the valve assembly during the blood drawing and blood draining periods under the set operating conditions.

[0007] A method for obtaining actual clinical blood flow, based on a flow measurement device, includes a first flow sensor mounted on the outer wall of a long tube of a right ventricular assist catheter near the extracorporeal membrane lumen. The first flow sensor is connected to a control system, which is connected to a gas supply system for supplying gas to the right ventricular assist catheter. The method for obtaining actual clinical blood flow includes the following steps: Step 1: Set the operating conditions of the right ventricular assist catheter through the control system, and obtain the blood leakage rate of the right ventricular assist catheter during the blood draw and blood expulsion periods based on the mapping database formed by the blood leakage rate measurement method. Step 2: Under the control of the control system, the right heart assist catheter is driven by the gas supply system to perform blood drawing and blood drainage operations. At the same time, the total flow rate of fluid flowing through the extracorporeal membrane cavity during the blood drawing and blood drainage periods is detected by the first flow sensor. Step 3: Based on the total fluid flow rate, obtain the actual blood flow rate of the right ventricular assist catheter during the blood draw and blood expulsion phases under clinical conditions.

[0008] The advantages of this invention are: The blood leakage rate measurement method of this invention can obtain the blood leakage rate of the valve assembly of existing right heart assist catheters (novel pulsatile assist devices) during the blood drawing and blood expulsion periods, and truly reflect the actual blood flow.

[0009] The clinical actual blood flow acquisition method of this invention takes into account the blood leakage effect of the valve assembly of existing right ventricular assist catheters during right ventricular assist. The blood leakage rate obtained by the blood leakage rate measurement method of this invention can accurately obtain the actual blood flow between the right ventricular assist catheter and the right heart during the blood draw period, as well as the actual blood flow between the catheter and the pulmonary artery during the blood expulsion period. This is of great significance for clinical guidance and can provide effective assistance to doctors' decision-making. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the structure of the blood leakage rate measuring device of the present invention.

[0011] Figure 2 This is a schematic diagram of the structure of an existing right ventricular assist catheter.

[0012] Figure 3a This is a schematic diagram of a valve assembly.

[0013] Figure 3b yes Figure 3a A left-side view diagram.

[0014] Figure 3c yes Figure 3a A top-down view.

[0015] Figure 4 This is a schematic diagram illustrating leakage of an existing right ventricular assist catheter during blood draw (the valve is in the open position).

[0016] Figure 5 This is a schematic diagram illustrating leakage during the blood-flow phase of an existing right ventricular assist catheter (with the valve closed).

[0017] Figure 6 This is a flow rate change curve obtained by the blood leakage rate measurement method of the present invention.

[0018] Figure 7 This is a schematic diagram illustrating the implementation of the method for obtaining actual clinical blood flow according to the present invention. Detailed Implementation

[0019] like Figure 1 The present invention proposes a blood leakage rate measuring device for a right heart assist catheter 10. The right heart assist catheter 10 includes a short tube 13, one end of which is provided with an end cap 12 and the other end is connected to one end of a long tube 15 via a valve assembly 11. The other end of the long tube 15 is connected to an extracorporeal membrane cavity 14, which is used to connect to a gas supply system 20.

[0020] like Figure 1The blood leakage rate measuring device of the present invention includes a right heart (right atrium or right ventricle) simulator 40 and a pulmonary artery simulator 50. Both simulators are filled with a liquid (human or animal blood, or a glycerol-water mixture, etc.) to simulate blood. A second pressure sensor 82 for measuring the internal liquid pressure is installed at the bottom of the right heart simulator 40, and a first pressure sensor 81 for measuring the internal liquid pressure is installed at the bottom of the pulmonary artery simulator 50. The right heart simulator 40 and the pulmonary artery simulator 50 are connected by parallel first pipes 61 and second pipes 62. An auxiliary pump 60 is installed on the first pipe 61. The auxiliary pump 60 works in conjunction with the first pipe 61 to ensure that the liquid pressure in the right heart simulator 40 and the pulmonary artery simulator 50 meets the blood pressure requirements of the simulated right heart and pulmonary artery, respectively. Specifically, the auxiliary pump 60 is used to allow the liquid in the right heart simulator 40 to flow into the pulmonary artery simulator 50 via the first pipe 61. 0. The second pipeline 62 is used to connect the liquid inside the pulmonary artery simulator 50 and the right heart simulator 40. Under the action of the auxiliary pump 60, the liquid inside the pulmonary artery simulator 50 flows into the right heart simulator 40. The right heart auxiliary catheter 10 passes through the right heart simulator 40 and the valve assembly 11 is placed in the liquid inside the right heart simulator 40. The end cap 12 is placed in the liquid inside the pulmonary artery simulator 50. The part from the end cap 12 to the valve assembly 11 on the right heart auxiliary catheter 10 forms a flow loop with the first pipeline 61 and the second pipeline 62 respectively. A second flow sensor 72 is installed on the outer wall of the short pipe 13 between the right heart simulator 40 and the pulmonary artery simulator 50. A first flow sensor 71 is installed on the outer wall of the long pipe 15 near the extracorporeal membrane cavity 14. The auxiliary pump 60, the first pressure sensor 81, the second pressure sensor 82, the first flow sensor 71, the second flow sensor 72, and the gas supply system 20 are connected to the control system 30.

[0021] In the actual design, the right heart simulator 40 is an open container, and the pulmonary artery simulator 50 is a closed container with adjustable internal pressure. The liquid pressure inside the right heart simulator 40 is between 5 mmHg and 15 mmHg, and the liquid pressure inside the pulmonary artery simulator 50 is between 20 mmHg and 25 mmHg.

[0022] In actual implementation, the pulmonary artery simulator 50 adjusts its internal pressure to the simulated pulmonary artery internal pressure to complete the initialization.

[0023] In this invention, the control system 30 is a well-known technology. Generally, the control system 30 includes a controller for receiving data from sensor feedback and driving and coordinating the operation of various devices and equipment.

[0024] In this invention, the first flow sensor 71 and the second flow sensor 72 are flow sensors that do not come into contact with the liquid, such as ultrasonic flow sensors, and are not limited thereto.

[0025] Based on the blood leakage rate measuring device of the present invention described above, the present invention also proposes a blood leakage rate measuring method, which includes the following steps: Step 1: Based on the pre-implantation location of the right heart (right atrium or right ventricle) of the right heart assist catheter 10, the fluid pressure in the right heart simulator 40 and the pulmonary artery simulator 50 is adjusted by the blood leakage rate measurement device of the present invention to complete the simulation of the right heart and pulmonary artery environment, that is, to establish an in vitro simulation environment that conforms to physiological conditions. Step 2: The right ventricular assist catheter 10 is set to its operating condition by the control system 30. The right ventricular assist catheter 10 is driven by the gas supply system 20 to perform blood drawing and blood drainage operations under the set conditions. During the blood drawing and blood drainage operations, the first fluid flow rate through the extracorporeal membrane cavity 14 is detected by the first flow sensor 71 and the second fluid flow rate through the short tube 13 is detected by the second flow sensor 72. The first fluid flow rate change curve and the second fluid flow rate change curve are obtained. The first and second fluid flow rate change curves are periodic pulsating curves. Step 3: For the blood drawing and blood expulsion periods within a working cycle, integrate the first fluid flow rate change curve and the second fluid flow rate change curve respectively to obtain the blood leakage rate of valve assembly 11 or right heart assist catheter under the set working conditions during the blood drawing and blood expulsion periods.

[0026] In actual implementation, the fluid pressure within the right ventricular simulator 40 and the pulmonary artery simulator 50 is regulated by initializing the internal gas pressure of the pulmonary artery simulator 50 and by driving the auxiliary pump 60. The fluid pressures within the right ventricular simulator 40 and the pulmonary artery simulator 50 are detected by the second pressure sensor 82 and the first pressure sensor 81, respectively. The fluid pressure within the right ventricular simulator 40 should be between 5 mmHg and 15 mmHg, and the fluid pressure within the pulmonary artery simulator 50 should be between 20 mmHg and 25 mmHg.

[0027] In step 3: Blood leakage rate during blood collection period = integral of the second fluid flow rate change curve during blood collection period / integral of the first fluid flow rate change curve during blood collection period; Blood leakage rate during the bleeding period = (Integral of the first fluid flow rate change curve during the bleeding period - Integral of the second fluid flow rate change curve during the bleeding period) / Integral of the first fluid flow rate change curve during the bleeding period.

[0028] For example: Combining Figure 4 and Figure 5 To understand, Figure 6The diagram shows the first and second fluid flow rate variation curves within one work cycle, where the ratio of the blood collection period to the blood expulsion period is 1:1. During the blood collection period in the first T / 2 work cycle, the first fluid flow rate variation curve is Q. a The solid line indicates the second liquid flow rate change curve, which is Q. a2 The curve indicated by the dashed line represents the change in the first fluid flow rate during the blood expulsion phase of the second work cycle (T / 2). b The solid line indicates the second liquid flow rate change curve, which is Q. b2 The curve indicated by the dashed line.

[0029] During the blood draw period of 0-T / 2, Q a2 Q was measured by the second flow sensor 72. a Q is measured by the first flow sensor 71. a and Q a2 All values ​​are negative. The blood leakage rate during the blood collection period is calculated as follows: η a = / , Similarly, during the T / 2-T timeframe of evacuation, Q b2 Q was measured by the second flow sensor 72. b Q is measured by the first flow sensor 71. b Both Qb2 and Qb2 are positive. The blood leakage rate during the bleeding period is calculated as follows: η b =( - ) / , Here, the flow rate of liquid flowing into the external membrane cavity 14 is defined as negative, and conversely, the flow rate of liquid flowing out of the external membrane cavity 14 is defined as positive.

[0030] The blood leakage rate measurement method of the present invention further includes the following steps: placing the right ventricular assist catheter 10 under different operating conditions, obtaining the blood leakage rate during the blood draw and blood expulsion periods under each operating condition, establishing a mapping between the blood leakage rate during the blood draw and blood expulsion periods and the operating conditions, and forming a mapping database, wherein: the operating conditions are composed of the working cycle T of the right ventricular assist catheter 10, the pressure parameters of the gas supply system 20 driving the extracorporeal membrane cavity 14, and the time ratio of the blood draw and blood expulsion periods.

[0031] In this invention, the pressure parameters of the gas supply system 20 driving the extracorporeal membrane cavity 14 include the positive and negative pressures supplied to the extracorporeal membrane cavity 14. The positive pressure can be set between 700 mmHg and 800 mmHg, and the negative pressure can be set above 300 mmHg. One working cycle T consists of a continuous blood drawing period and a blood expulsion period. The time ratio of the blood drawing period to the blood expulsion period can be 1:1, 1:2, 1:3, etc., and the working cycle T can be set between 0.4 s and 1.2 s.

[0032] Here, since different operating conditions directly affect the opening and closing state of valve assembly 11, the blood leakage rate of valve assembly 11 varies under different operating conditions. Therefore, it is necessary to establish a mapping database that maps the operating conditions to the blood leakage rate during the blood drawing and blood expulsion periods.

[0033] The measurement principle of the blood leakage rate measurement method of the present invention will be described in detail below.

[0034] like Figure 2 The existing right heart assist catheter 10 includes a short tube 13, one end of which is provided with an end cap 12 and the other end is connected to one end of a long tube 15 via a valve assembly 11. The other end of the long tube 15 is connected to an extracorporeal membrane cavity 14, which is used to connect to a gas supply system 20.

[0035] The extracorporeal membrane cavity 14 includes a gas chamber cover 142 with an airflow port 1420 and a blood chamber cover 141 with a bloodflow port 1410. A diaphragm 143 is clamped between the gas chamber cover 142 and the blood chamber cover 141 and then fastened and fixed. A gas chamber 1421 is formed between the diaphragm 143 and the gas chamber cover 142, and a blood chamber 1411 is formed between the diaphragm 143 and the blood chamber cover 141. Driven by the gas flowing in and out of the gas chamber 1421, the diaphragm 143 periodically bulges toward the gas chamber 1421 or the blood chamber 1411 so that the blood flow has a pulsatile quality.

[0036] The long tube 15 is divided into three parts: a slender tubular implantation section 151, a trumpet-shaped transition section 152, and a short round tubular connecting section 153 connected in sequence. The connecting section 153 is used to connect with the blood flow port 1410 of the blood cavity cover 141, and the implantation section 151 is used to connect with the valve assembly 11.

[0037] like Figure 3aThe valve assembly 11 includes a cylindrical tube 111 with a valve port 110 in the middle. A valve disc 112 is rotatably mounted inside the tube 111 via a pivot 113. The two ends of the tube 111 are a proximal port 114 for connection to a long tube 15 and a distal port 115 for connection to a short tube 13. Viewed along the axis of the pivot 113, the valve disc 112 has an inverted trapezoidal shape. When the valve disc 112 is in the closed state, viewed along the length of the tube 111, the valve disc 112 has two ends: a countersunk end 1121 and a light end 1122. The portion between the countersunk end 1121 and the light end 1122 is a sealing surface. The weight of the valve disc portion containing the countersunk end 1121 is greater than the weight of the valve disc portion containing the light end 1122, so the valve disc 112 will always be in the open state due to its own weight when not subjected to external force. When the valve disc 112 is in the open state, such as... Figure 4 The submerged end 1121 abuts against the inner wall of the tube body 111, while the lighter end 1122 is raised to the position of the valve port 110. The sealing surface of the valve disc 112 abuts against one side of the valve port 110, forming a flow opening between the valve disc 112 and the other side of the valve port 110. The proximal port 114 is connected to the flow opening, while the distal port 115 is considered not connected (due to potential blood leakage). When the valve disc 112 is in the closed state, such as Figure 5 The sealing surface blocks the valve port 110, and the near port 114 is connected to the far port 115.

[0038] In practical applications, the flow direction of blood within the right ventricular assist catheter 10 is switched by changing the opening and closing states of the valve 112 inside the catheter body 111. For example... Figure 3b , Figure 4 As shown, when the valve disc 112 is in the open state, a first leakage gap 91 still exists between the countersunk end 1121 and the inner wall of the pipe body 111. Similarly, as Figure 3c , Figure 5 When valve disc 112 is closed, a second leakage gap 92 still exists between the light end 1122 and the inner wall of the tube body 111 near the proximal port 114 of valve port 110. This is because valve disc 112 needs to rotate freely within the tube body 111, thus an unavoidable gap is necessary to ensure its rotation. However, this unavoidable gap causes varying degrees of blood leakage when flowing through valve assembly 11, affecting the assessment of the pumping flow rate of right ventricular assist catheter 10.

[0039] Furthermore, refer to Figure 4 When the gas (air or helium) in the gas chamber 1421 is extracted by the gas supply system 20 to create negative pressure, the diaphragm 143 bulges towards the gas chamber 1421, and the valve 112 is in the open state. Clinically, the blood flow rate (Q) in the right ventricle... a1The blood enters the inner lumen of the tube body 111 through the valve port 110, and then enters the blood chamber 1411 through the long tube 15, but a small amount of pulmonary artery blood (flow rate Q) is still present. a2 (equivalent to the second liquid flow rate) through the short pipe 13 and the first leakage gap 91 of the valve assembly 11 (e.g. Figure 4 (As shown by the dashed line), the long tube 15 is recirculated into the blood chamber 1411. This process is called the squeezing phase of the right ventricular assist catheter 10. Therefore, during the squeezing phase, the total flow rate Q of blood entering the blood chamber 1411 is... a (Equivalent to the first liquid flow rate) should be Q a1 +Q a2 .

[0040] Similarly, refer to Figure 5 When gas is injected into the gas chamber 1421 via the gas supply system 20 to generate positive pressure, the diaphragm 23 bulges towards the blood chamber 1411, and the valve 112 is closed under the impact of blood flow. Clinically, most of the blood in the blood chamber 1411 (flow rate Q) is released. b2 (Equivalent to a second fluid flow rate) is injected into the pulmonary artery PA through the long tube 15, the inner cavity 1110 of the valve assembly 11, the short tube 13, and the end cap 12, but a small amount of blood (flow rate Q) is still injected. b1 From the second leakage gap 92 of valve assembly 11 (e.g.) Figure 5 (As shown by the dashed line) flows into the right heart. This process is called the ejection phase of the right ventricular assist catheter 10. Therefore, during the ejection phase, the total flow rate Q of blood flowing out of the blood chamber 1411 is... b (Equivalent to the first liquid flow rate) should be Q b1 +Q b2 .

[0041] Therefore, to accurately obtain the actual clinical blood flow (or actual clinical pumping flow) of the right ventricular assist catheter 10, it is necessary to consider the flow rate of blood leaking from the first leakage gap 91 and the second leakage gap 92 of the valve assembly 11, or in other words, it is necessary to consider the blood leakage rate of the valve assembly 11 during the blood drawing and blood expulsion periods.

[0042] Therefore, the present invention designs the above-mentioned blood leakage rate measuring device and designs the blood leakage rate measuring method of the present invention for obtaining the blood leakage rate of valve assembly 11 during the blood drawing period and the blood discharge period.

[0043] In this invention, the gas supply system 20 may include a drive motor, which is connected to the piston of the piston pump via a reducer and a ball screw. The gas inlet and outlet of the piston pump are connected to the air outlet 1420 of the extracorporeal membrane cavity 14 via a trachea, for feeding or extracting gas into or out of the gas chamber 1421, so that the gas chamber 1421 generates periodic positive and negative pressure changes, thereby causing the diaphragm 143 to undergo periodic deformation, which in turn causes the volume of the blood chamber 1411 to change periodically, for blood drawing and blood drainage operations.

[0044] The right ventricular assist catheter 10 and the gas supply system 20 are existing technologies and will not be described in detail here.

[0045] refer to Figure 7 The present invention also proposes a method for obtaining actual clinical blood flow, which is based on a flow measurement device. The flow measurement device includes a first flow sensor 71, which is installed on the outer wall of the long tube 15 of the right ventricular assist catheter 10 near the extracorporeal membrane cavity 14. The first flow sensor 71 is connected to a control system 30, and the control system 30 is connected to a gas supply system 20 for supplying gas to the right ventricular assist catheter 10.

[0046] Specifically, the method for obtaining actual clinical blood flow according to the present invention includes the following steps: Step 1: Set the operating conditions of the right ventricular assist catheter 10 through the control system 30, and obtain the blood leakage rate of the right ventricular assist catheter 10 during the blood draw and blood expulsion periods based on the mapping database formed by the blood leakage rate measurement method of the present invention through the operating conditions. Step 2: Under the control of the control system 30, the right heart assist catheter 10 is driven by the gas supply system 20 to perform blood drawing and blood drainage operations. At the same time, the total flow rate of the fluid flowing through the extracorporeal membrane cavity 14 during the blood drawing and blood drainage periods is detected by the first flow sensor 71. Step 3: Based on the total fluid flow rate, obtain the actual blood flow rate of the right ventricular assist catheter 10 during the blood draw and blood expulsion phases under clinical conditions.

[0047] In step three: The actual blood flow rate Q1' during the blood draw period is obtained by the formula Q1'=Q1×(1-η1), where Q1 is the total flow rate of liquid flowing through the extracorporeal membrane cavity 14 during the blood draw period, and η1 is the blood leakage rate during the blood draw period. The actual blood flow rate Q2' during the expulsion period is obtained by the formula Q2'=Q2×(1-η2), where Q2 is the total flow rate of fluid flowing through the extracorporeal membrane cavity 14 during the expulsion period, and η2 is the blood leakage rate during the expulsion period.

[0048] Here, the actual blood flow rate Q1' during the blood draw period is the actual flow rate of blood from the right heart into the extracorporeal membrane cavity 14, and the actual blood flow rate Q2' during the blood ejection period is the actual flow rate of blood ejected from the extracorporeal membrane cavity 14 into the pulmonary artery.

[0049] For example, refer to Figure 7 During right ventricular assist, the right ventricular assist catheter 10 is implanted via the inferior vena cava (IVC), while the extracorporeal membrane chamber 14, gas supply system 20, and control system 30 are placed outside the patient's body. Inside the body, the end cap 12 is placed within the pulmonary artery (PA). The valve assembly 11 is placed in the right heart (right atrium (RA) or right ventricle (RV)). Figure 7The illustration shows the tube placed within the right atrium (RA) to control blood flow direction. The short tube 13 simultaneously penetrates both the tricuspid valve TV and the pulmonary valve PV without interfering with the normal opening and closing of either valve. The valve assembly 11 is positioned close to the edge of the tricuspid valve TV, with a distance of at least 5 mm between it and the TV valve. The valve assembly 11 is located within the active area of ​​the tricuspid valve TV, ensuring that the TV does not obstruct the valve port 110 of the valve assembly 11 during valve opening and closing. Because the short tube 13 is placed within the patient's body, a second flow sensor 72 cannot be installed; only a first flow sensor 71 is required. To ensure the accuracy of the measurement results from the first flow sensor 71, the length of the connecting section 153 should be between 50 mm and 70 mm, and its outer diameter and thickness should meet the measurement requirements of the first flow sensor 71.

[0050] In this application, "proximal" is defined as the end closer to the operator (such as a doctor or nurse), while "distal" is defined as the end further away from the operator, that is, the end closer to the patient's heart.

[0051] like Figure 7 In the diagram, PA represents the pulmonary artery, TV represents the tricuspid valve, PV represents the pulmonary valve, LA represents the left atrium, LV represents the left ventricle, RA represents the right atrium, RV represents the right ventricle, SVC represents the superior vena cava, and IVC represents the inferior vena cava.

[0052] The advantages of this invention are: The blood leakage rate measurement method of this invention can obtain the blood leakage rate of the valve assembly of existing right heart assist catheters (novel pulsatile assist devices) during the blood drawing and blood expulsion periods, and truly reflect the actual blood flow.

[0053] The clinical actual blood flow acquisition method of this invention takes into account the blood leakage effect of the valve assembly of existing right ventricular assist catheters during right ventricular assist. The blood leakage rate obtained by the blood leakage rate measurement method of this invention can accurately obtain the actual blood flow between the right ventricular assist catheter and the right heart during the blood draw period, as well as the actual blood flow between the catheter and the pulmonary artery during the blood expulsion period. This is of great significance for clinical guidance and can provide effective assistance to doctors' decision-making.

[0054] The above description describes the preferred embodiments of the present invention and the technical principles applied thereto. For those skilled in the art, any obvious changes such as equivalent transformations or simple substitutions based on the technical solutions of the present invention, without departing from the spirit and scope of the present invention, shall fall within the protection scope of the present invention.

Claims

1. A blood leakage rate measuring device for a right ventricular assist catheter, the right ventricular assist catheter comprising a short tube, one end of the short tube having an end cap and the other end connected to one end of a long tube via a valve assembly, the other end of the long tube being connected to an extracorporeal membrane cavity, the extracorporeal membrane cavity being used for connection to a gas supply system, characterized in that: The blood leakage rate measuring device includes a right heart simulator and a pulmonary artery simulator. Both simulators are filled with liquid to simulate blood. A second pressure sensor for measuring the liquid pressure is installed at the bottom of the right heart simulator, and a first pressure sensor for measuring the liquid pressure is installed at the bottom of the pulmonary artery simulator. The right heart simulator and the pulmonary artery simulator are connected by parallel first and second pipelines. An auxiliary pump is installed on the first pipeline. The auxiliary pump works in conjunction with the first pipeline to ensure that the liquid pressures in the right heart simulator and the pulmonary artery simulator meet the blood pressure requirements of the simulated right heart and pulmonary artery, respectively. A right heart auxiliary catheter penetrates the right heart simulator, and the valve assembly is placed in the liquid within the right heart simulator. An end cap is placed in the liquid within the pulmonary artery simulator. A second flow sensor is installed on the outer wall of the short tube portion between the right heart simulator and the pulmonary artery simulator. A first flow sensor is installed on the outer wall of the long tube portion near the extracorporeal membrane cavity. The auxiliary pump, the first pressure sensor, the second pressure sensor, the first flow sensor, the second flow sensor, and the gas supply system are connected to the control system.

2. The blood leak rate measuring device of claim 1, wherein, The right heart simulator is an open container, and the pulmonary artery simulator is a closed container with adjustable internal pressure. The liquid pressure inside the right heart simulator is between 5 mmHg and 15 mmHg, and the liquid pressure inside the pulmonary artery simulator is between 20 mmHg and 25 mmHg.

3. The blood leak rate measuring device of claim 1, wherein, The first flow sensor and the second flow sensor are ultrasonic flow sensors.

4. A blood leakage rate measuring method realized based on the blood leakage rate measuring device according to claim 1, characterized by, Including the following steps: Step 1: Based on the pre-implantation location of the right ventricular assist catheter in the right heart, the fluid pressure in the right heart simulator and the pulmonary artery simulator is adjusted by the blood leakage rate measuring device to complete the simulation of the right heart and pulmonary artery environment; Step 2: Set the operating conditions of the right ventricular assist catheter through the control system, and drive the right ventricular assist catheter to perform blood drawing and blood drainage operations under the set conditions through the gas supply system. At the same time, the first fluid flow rate through the extracorporeal membrane cavity is detected by the first flow sensor and the second fluid flow rate through the short tube is detected by the second flow sensor to obtain the first fluid flow rate change curve and the second fluid flow rate change curve. Step 3: For the blood drawing and blood draining periods within a working cycle, integrate the first liquid flow rate change curve and the second liquid flow rate change curve respectively to obtain the blood leakage rate of the valve assembly during the blood drawing and blood draining periods under the set operating conditions.

5. The blood leak rate measurement method of claim 4, wherein, In step 3: the blood leakage rate during the blood drawing period = integral of the second fluid flow rate change curve during the blood drawing period / integral of the first fluid flow rate change curve during the blood drawing period; the blood leakage rate during the blood expulsion period = (integral of the first fluid flow rate change curve during the blood expulsion period - integral of the second fluid flow rate change curve during the blood expulsion period) / integral of the first fluid flow rate change curve during the blood expulsion period.

6. The blood leakage rate measurement method as described in claim 4, characterized in that, The method also includes the following steps: placing the right ventricular assist catheter under different operating conditions, calculating the blood leakage rate during the blood draw and blood expulsion periods under each operating condition, establishing a mapping between the blood leakage rate during the blood draw and blood expulsion periods and the operating conditions, and forming a mapping database, wherein: the operating conditions are composed of the working cycle T of the right ventricular assist catheter, the pressure parameters of the gas supply system driving the extracorporeal membrane cavity, and the time ratio of the blood draw and blood expulsion periods.

7. A method for obtaining actual clinical blood flow, based on a flow measurement device, the flow measurement device comprising a first flow sensor, the first flow sensor being installed on the outer wall of the portion of a long tube of a right ventricular assist catheter near the extracorporeal membrane lumen, the first flow sensor being connected to a control system, the control system being connected to a gas supply system for supplying gas to the right ventricular assist catheter, characterized in that, The method for obtaining actual clinical blood flow includes the following steps: Step 1: Set the operating conditions of the right ventricular assist catheter through the control system, and obtain the blood leakage rate of the right ventricular assist catheter during the blood draw and blood expulsion periods based on the mapping database formed by the blood leakage rate measurement method of claim 6. Step 2: Under the control of the control system, the right heart assist catheter is driven by the gas supply system to perform blood drawing and blood drainage operations. At the same time, the total flow rate of fluid flowing through the extracorporeal membrane cavity during the blood drawing and blood drainage periods is detected by the first flow sensor. Step 3: Based on the total fluid flow rate, obtain the actual blood flow rate of the right ventricular assist catheter during the blood draw and blood expulsion phases under clinical conditions.

8. The method for obtaining actual clinical blood flow as described in claim 7, characterized in that, In step three: The actual blood flow rate Q1' during the blood draw period is obtained by the formula Q1'=Q1×(1-η1), where Q1 is the total flow rate of liquid flowing through the extracorporeal membrane cavity during the blood draw period, and η1 is the blood leakage rate during the blood draw period. The actual blood flow rate Q2' during the expulsion period is obtained by the formula Q2'=Q2×(1-η2), where Q2 is the total flow rate of fluid flowing through the extracorporeal membrane cavity during the expulsion period, and η2 is the blood leakage rate during the expulsion period.

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