Pressure measurement system for balloon catheters

Abstract

The purpose of this invention is to provide a high-precision balloon catheter pressure measurement system. The catheter includes an outer tube and an inner tube, with an annular chamber between them forming an inflation / deflation chamber. The distal end of the outer tube is connected to the proximal end of the balloon, and the distal end of the inner tube passes through the balloon cavity and is fixed to the distal tip of the balloon. A pressure sensor is installed on the inner tube within the balloon cavity. To avoid the distortion of gas pressure signals caused by the catheter's length and curvature, which are relied upon by traditional monitoring methods, a pressure sensor is directly installed within the balloon cavity to monitor the gas pressure in real time. This avoids interference during signal transmission, provides more accurate gas pressure data, and enables more precise counterpulsation control. Simultaneously, the monitored gas pressure inside the balloon can be compared with the gas pressure inside the catheter to detect adverse events and ensure the safety of the balloon catheter during assisted blood pumping.

Description

Technical Field

[0001] This utility model relates to the field of medical device technology, specifically to a balloon catheter pressure measurement system. Background Technology

[0002] The working principle of the intra-aortic balloon counterpulsation (IABP) system is to place a balloon counterpulsation catheter in the patient's aorta via arterial puncture. An external counterpulsation pump inflates or deflates the balloon counterpulsation catheter according to the patient's electrocardiogram data. When the aortic valve closes during diastole, the counterpulsation pump inflates the balloon, generating positive pressure, increasing diastolic pressure, and increasing blood perfusion to the whole body and coronary arteries. At the beginning of systole, when the aortic valve opens, the balloon is rapidly deflated, generating negative pressure, causing a momentary drop in aortic pressure, reducing left ventricular ejection resistance (i.e., cardiac afterload), increasing cardiac output, and thus improving left ventricular ejection.

[0003] During IABP treatment, it is essential to ensure that the balloon inflation / deflation timing is synchronized with the heartbeat to optimize coronary perfusion and reduce myocardial oxygen consumption. This requires monitoring the pressure inside the balloon. Current technology uses a pressure sensor placed at the proximal end of the catheter to monitor the pressure within the catheter lumen, but this method has low measurement accuracy. Utility Model Content

[0004] The purpose of this invention is to provide a balloon catheter pressure measurement system with high measurement accuracy.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows: a balloon catheter pressure measurement system, the catheter includes an outer tube and an inner tube, and the annular chamber between the two constitutes an inflation and deflation chamber, the distal end of the outer tube is connected to the proximal end of the balloon, the distal end of the inner tube passes through the inner cavity of the balloon and is fixed to the tip of the distal end of the balloon, and a pressure sensor is provided on the inner tube in the inner cavity of the balloon.

[0006] Furthermore, the pressure sensor includes a sensing head and an optical fiber. The outer shell of the sensing head is fixed to the outer wall of the inner tube by a thin film, and the pressure-sensitive diaphragm of the sensing head is arranged to avoid contact with the thin film.

[0007] Furthermore, the pressure sensor includes a sensing head and an optical fiber. The sensing head is wrapped with a pressure-conducting gel, which is fixedly connected to the outer wall of the inner tube. The pressure is transmitted to the pressure-sensitive diaphragm of the sensing head through the gel.

[0008] Furthermore, the balloon includes a cylindrical section, a proximal conical section, and a distal conical section. A pressure sensor is installed on the inner tube corresponding to the proximal or distal conical section. A wire tube is installed in the annular cavity between the inner and outer tubes. The optical fiber passes through the wire tube and extends proximally. A thin film covers the outer periphery of the inner tube and the wire tube and fixes their positions.

[0009] Furthermore, a seal is installed at the distal end of the conduit.

[0010] Furthermore, the tip has a central hole for the inner tube to pass through, and a through hole is also provided on the tip. An optical fiber sensor is installed in the through hole, the sensing element of the optical fiber sensor is placed in the through hole, and the optical fiber extends along the through hole to the proximal end and passes through the tube.

[0011] Furthermore, a filling hole communicating with the through hole is provided on the outer wall of the tip, and gel is filled into the through hole from the filling hole.

[0012] Furthermore, the distal end of the tip is provided with an oblique hole that communicates with the through hole. The core of the oblique hole is arranged at an angle to the axis of the tip, and the included angle α is 15°-45°.

[0013] In the above scheme, to avoid the distortion of gas pressure signals caused by catheter-based gas pressure signal transmission, which is easily affected by catheter length and curvature, a pressure sensor is directly placed inside the balloon cavity to monitor the gas pressure in real time. This avoids interference during signal transmission, provides more accurate gas pressure data, and enables more precise counterpulsation control. Simultaneously, the monitored gas pressure inside the balloon can be compared with the gas pressure inside the catheter to detect adverse events and ensure the safety of the balloon catheter during assisted blood pumping. Attached Figure Description

[0014] Figure 1 A schematic diagram of the overall structure of a balloon catheter;

[0015] Figure 2 This is a schematic diagram of the internal structure of the balloon catheter in Example 1;

[0016] Figure 3 for Figure 2 Enlarged diagram of the middle section;

[0017] Figure 4 for Figure 2 Sectional view along line AA;

[0018] Figure 5 This is a schematic diagram of the internal structure of the balloon catheter in Example 2;

[0019] Figure 6 for Figure 5 Enlarged diagram of the middle section;

[0020] Figure 7 for Figure 5 Sectional view along the BB direction.

[0021] In the diagram, 10-catheter, 11-outer tube, 12-inner tube, 13-tube, 14-membrane, 20-balloon, 21-cylindrical segment, 22-proximal conical segment, 23-distal conical segment, 30-tip, 31-central hole, 32-through hole, 33-filling hole, 34-oblique hole, 40-pressure sensor, 41-sensing head, 42-optical fiber, 50-optical fiber sensor, 51-sensing element, 52-optical fiber, 60-gel. Detailed Implementation

[0022] To facilitate understanding, we first define the orientation: "proximal" or "proximal" refers to the side closest to the operator / doctor, while "distal" or "distal" refers to the side furthest from the operator / doctor, i.e., the side closest to the heart. See the attached diagram for further details. Figures 1-7 This utility model will be discussed in further detail.

[0023] See Figure 1 , Figure 2 , Figure 5 As shown, a balloon catheter pressure measurement system includes an outer tube 11 and an inner tube 12, with an annular chamber between them forming an inflation / deflation chamber. The distal end of the outer tube 11 is connected to the proximal end of the balloon 20, and the distal end of the inner tube 12 passes through the inner cavity of the balloon 20 and is fixed to the distal tip 30 of the balloon 20. A pressure sensor 40 is installed on the inner tube 12 within the inner cavity of the balloon 20. The inner tube 12 serves two purposes: supporting the balloon 20 (including during inflation and folding) and fixing it to the tip 30, providing a guidewire channel and an irrigation fluid channel. The annular chamber between the outer tube 11 and the inner tube 12 is a gas channel through which gas enters or exits the inner cavity of the balloon 20. Therefore, this channel is connected to the inner cavity of the balloon 20, and in principle, the gas pressure within the balloon 20 can be measured by measuring the gas pressure within this channel. However, this system is susceptible to distortion due to the length and curvature of the catheter 10. If the balloon 20 experiences leakage or other adverse events, the system will be unable to accurately reflect the internal gas pressure of the balloon 20. In this invention, a pressure sensor 40 is directly installed inside the balloon 20 cavity to monitor the gas pressure inside the balloon 20 cavity in real time. This avoids interference during signal transmission, provides more accurate gas pressure data, and enables more precise counterpulsation control. Simultaneously, the monitored gas pressure inside the balloon 20 can be compared with the gas pressure inside the catheter 10 to detect adverse events and ensure the safety of the balloon catheter operation.

[0024] Because the inner tube 12 has a very small diameter, a small sensor must also be selected. The pressure sensor 40 described here includes a sensing head 41 and an optical fiber 42. This type of sensor uses optical signals as the carrier for conversion and transmission, featuring high precision and high sensitivity, while avoiding electromagnetic interference affecting the patient and medical equipment. Since the balloon 20 is repeatedly inflated and deflated during the cardiac cycle, the sensing head 41 needs to withstand certain pressure and mechanical stress; therefore, the stability of the sensing head 41's position is crucial. While considering positional stability, factors such as small diameter and avoiding damage to the balloon 20 must also be taken into account. Figure 3 As shown, the outer shell of the sensing head 41 is fixed to the outer wall of the inner tube 12 by a thin film. The thin film tightly wraps the sensing head 41 around the outer circumference of the inner tube 12. The thin film and the outer wall of the inner tube 12 can also be fused together to further increase the reliability of the connection. The thin film is thin and hardly increases the outer diameter at that point. At the same time, the smooth surface of the thin film will not damage the balloon 20. To ensure the accuracy of pressure measurement by the sensing head 41, the pressure-sensitive diaphragm of the sensing head 41 is arranged to avoid interference with the sensing of gas pressure.

[0025] Another fixing method is as follows: The pressure sensor 40 includes a sensing head 41 and an optical fiber 42. The sensing head 41 is wrapped with a pressure-conducting gel. The gel is fixedly connected to the outer wall of the inner tube 12. The gel wraps the entire sensing head 41 inside. The pressure is transmitted to the pressure-sensitive diaphragm of the sensing head 41 through the gel. The sensing head 41 will not be displaced or damaged in the dynamic environment to ensure the accuracy of the signal.

[0026] For further details, please refer to [link / reference]. Figure 4The balloon 20 includes a cylindrical section 21, a proximal conical section 22, and a distal conical section 23. The outer diameter of the cylindrical section 21 is larger than the outer diameters of the proximal and distal conical sections 22 and 23. The pressure sensor 40 is mounted on the inner tube 12 corresponding to the proximal or distal conical section 22. When the balloon 20 is folded and wrapped around the outer circumference of the inner tube 12, the outer diameter of the entire balloon catheter can be minimized. Considering the installation of the optical fiber 42, a conduit 13 is provided in the annular cavity between the inner tube 12 and the outer tube 13. The optical fiber 42 passes through the conduit 13 and extends proximally. In other words, an additional conduit 13 is provided outside the inner tube 12 for the installation of the optical fiber 42. This eliminates the need to consider how to fix the optical fiber 42 to the inner tube 12, greatly reducing the difficulty of installing and fixing the optical fiber 42. At the same time, the overall routing of the optical fiber 42 is smooth, ensuring high measurement accuracy of the entire sensor. To prevent the tubing 13 from twisting within the annular cavity between the inner and outer tubes, we preferably fix the tubing 13 to the inner tube 12, and cover the outer periphery of the inner tube 12 and the tubing 13 with a membrane 14 to fix their positions. The thickness of the membrane 14 is negligible, minimizing the cross-sectional area of ​​the inner tube 12 and the tubing 13. In other words, the cross-section of the inflation / deflation channel between the inner tube 12 and the outer tube 11 is as large as possible, thereby ensuring timely inflation / deflation of the balloon 20 and improving the balloon counterpulsation effect.

[0027] Real-time monitoring and measurement of various parameters related to cardiac function, such as blood pressure, provides doctors with accurate data support, helping them to better assess patients' cardiac function and the effectiveness of IABP treatment. Figure 5 , Figure 6 , Figure 7 As shown, the tip 30 has a central hole 31 for the inner tube 12 to pass through, and a through hole 32 is also provided on the tip 30. A fiber optic sensor 50 is installed in the through hole 32. The sensing element 51 of the fiber optic sensor 50 is placed in the through hole 32, and the fiber optic line 52 extends proximally along the through hole 32 and passes through the tube 13. The real-time monitoring of blood fluid pressure by the fiber optic sensor 50 is an indispensable feature of the balloon catheter. Here, it is preferable to extend the fiber optic lines of the two sensors outward from the same tube 13 to ensure that the cross-section of the inflation / deflation channel between the inner tube 12 and the outer tube 11 is as large as possible, thereby ensuring timely inflation / deflation response of the balloon 20 and improving the balloon counterpulsation effect.

[0028] Because the tip 30 itself is very small, in order to facilitate the installation of the sensor 51, a filling hole 33 communicating with the through hole 32 is provided on the outer wall of the tip 30, and gel 60 is filled into the through hole 32 from the filling hole 33. The gel 60 can fix the position of the sensor 51 and prevent it from shifting; on the other hand, it is also used to transmit blood pressure.

[0029] Furthermore, the distal end of the tip 30 is also provided with an oblique hole 34 communicating with the through hole 32. The core of the oblique hole 34 is arranged at an angle to the axis of the tip 30, and the included angle α is 15°-45°. The setting of the oblique hole 34 can bring at least the following beneficial effects: (1) The oblique hole 34 enables the sensing element 51 to collect blood pressure data without being directly exposed to the blood, which protects the sensing element 51 and makes the output more stable and reliable; (2) The obliquely arranged oblique hole 34 can limit the position of the sensing element 51 and prevent the sensing element 51 from sliding out of the tip 30; (3) When the gel 60 is injected from the filling hole 33 into the through hole 32, excess air bubbles can be discharged from the oblique hole 34, reducing the air bubbles in the gel 60 after curing. It should be emphasized that the gel 60 here is a material that can conduct pressure and can transmit blood pressure to the sensing element 51.

[0030] Since the distal end of the tubing 13 is located inside the balloon 20, a seal is provided at the distal end of the tubing 13 to prevent gas from entering.

[0031] Finally, the embodiments listed above are preferred embodiments of this application and are not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A balloon catheter pressure measurement system, wherein the catheter (10) comprises an outer tube (11) and an inner tube (12) and the annular chamber between the two constitutes an inflation / deflation chamber, the distal end of the outer tube (11) is connected to the proximal end of the balloon (20), and the distal end of the inner tube (12) passes through the inner cavity of the balloon (20) and is fixed to the distal tip (30) of the balloon (20), characterized in that: A pressure sensor (40) is installed on the inner tube (12) inside the balloon (20).

2. The balloon catheter pressure measurement system according to claim 1, characterized in that: The pressure sensor (40) includes a sensing head (41) and an optical fiber (42). The sensing head (41) is fixed to the outer wall of the inner tube (12) by a thin film on the outer periphery of the housing. The pressure-sensitive diaphragm of the sensing head (41) is arranged to avoid the thin film.

3. The balloon catheter pressure measurement system according to claim 1, characterized in that: The pressure sensor (40) includes a sensing head (41) and an optical fiber (42). The sensing head (41) is wrapped with a pressure-conducting gel, which is fixedly connected to the outer wall of the inner tube (12). The pressure is transmitted to the pressure-sensitive diaphragm of the sensing head (41) through the gel.

4. The balloon catheter pressure measurement system according to claim 2 or 3, characterized in that: The balloon (20) includes a cylindrical section (21), a proximal conical section (22) and a distal conical section (23). A pressure sensor (40) is installed on the inner tube (12) corresponding to the proximal conical section (22) or the distal conical section (23). A wire tube (13) is installed in the annular cavity between the inner tube (12) and the outer tube (11). The optical fiber (42) passes through the wire tube (13) and extends to the proximal end. A thin film (14) covers the outer periphery of the inner tube (12) and the wire tube (13) and fixes their positions.

5. The balloon catheter pressure measurement system according to claim 4, characterized in that: The tip (30) has a central hole (31) for the inner tube (12) to pass through. The tip (30) also has a through hole (32). A fiber optic sensor (50) is installed in the through hole (32). The sensing element (51) of the fiber optic sensor (50) is placed in the through hole (32), and the fiber optic line (52) extends along the through hole (32) to the proximal end and passes through the tube (13).

6. The balloon catheter pressure measurement system according to claim 5, characterized in that: A filling hole (33) communicating with the through hole (32) is provided on the outer wall of the tip (30), and gel (60) is filled into the through hole (32) from the filling hole (33).

7. The balloon catheter pressure measurement system according to claim 6, characterized in that: The distal end of the tip (30) is also provided with an oblique hole (34) that communicates with the through hole (32). The core of the oblique hole (34) is arranged at an angle to the axis of the tip (30), and the included angle α is 15° to 45°.

8. The balloon catheter pressure measurement system according to claim 5, characterized in that: The distal end of the conduit (13) is filled with a seal.

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