Variable internal diameter endotracheal tube structure

Abstract

The application relates to the technical field of medical airway medical devices, and discloses a tracheal tube structure with variable pipe diameter, which comprises a tube body, a tail end joint is fixedly installed at one end of the tube body, a cuff is fixedly installed on the outer diameter of one side of the tube body, an arc-shaped spring tube is fixedly installed at the outer surface of the tube body and located inside the cuff, a ventilation hole is arranged at the end position of the arc-shaped spring tube on the surface of the tube body, a sealing sleeve is movably installed in the ventilation hole, an L-shaped channel is arranged in the sealing sleeve, the end of the arc-shaped spring tube is connected with the outer side end of the sealing sleeve through a connecting rod, and an inner sleeve is arranged in the tube body. The application can accurately correct the intubation angle, adapt to different tracheal pipe diameters, balance the ventilation effect, automatically stabilize the pressure, protect the tracheal mucosa, is simple to operate, has good sealing performance and reset performance, and greatly improves the safety and clinical applicability of the tracheal intubation.

Description

Technical Field

[0001] This invention relates to the field of medical airway medical device technology, specifically a variable diameter tracheal tube structure. Background Technology

[0002] Endotracheal tubes are core medical devices for establishing artificial airways in clinical anesthesia and emergency surgery. They are primarily used to provide respiratory support to patients, while also isolating the airway to prevent aspiration and leakage, ensuring respiratory safety during surgery and treatment. Currently, the conventional endotracheal tubes used clinically have a relatively simple structure, with mostly fixed diameters. Medical staff need to select the appropriate tube size based on the patient's age, body type, and tracheal diameter. However, individual differences exist in the human trachea, and some patients have special conditions such as tracheal stenosis or airway lesions. Fixed-diameter tubes are difficult to fit precisely, easily leading to problems such as insufficient fit, excessive ventilation resistance, or low ventilation efficiency, affecting clinical ventilation outcomes.

[0003] Current endotracheal tubes still have many substantial shortcomings in clinical use, and their practicality and safety need to be improved. The insertion angle of conventional tubes cannot be flexibly adjusted. In cases where the patient's glottic angle is offset or the airway structure is unique, intubation becomes significantly more difficult, easily leading to intubation failure and airway mucosal abrasion. Furthermore, the pressure of the cuff after inflation cannot be adaptively adjusted. Excessive pressure after the tube is in contact with the trachea can easily damage the tracheal mucosa, causing postoperative complications such as sore throat and airway edema. Conversely, insufficient cuff pressure can result in poor sealing, leakage, and aspiration, making it difficult to balance sealing effectiveness and airway protection.

[0004] In addition, traditional endotracheal tubes lack automatic diameter adjustment, making it impossible to adapt and adjust in real time according to the patient's actual airway condition. This results in poor clinical adaptability, and the procedures for tube positioning and structural repositioning are cumbersome, significantly impacting the convenience and safety of clinical intubation. This is due to the existing endotracheal tubes' fixed structure, poor adaptability, uncontrollable pressure, and inconvenient adjustment, among other technical limitations. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a variable-diameter endotracheal tube structure, which solves the problems of traditional endotracheal tubes having a fixed diameter, being unable to adapt to different and diseased tracheas, having difficulty adjusting the insertion angle, being difficult to insert, having uncontrollable cuff pressure that can easily damage the mucosa, and having difficulty in achieving both sealing and protection, as well as poor clinical adaptability and ease of operation.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a variable diameter endotracheal tube structure, comprising a tube body, a tail connector fixedly installed at one end of the tube body, a cuff fixedly installed on one side of the outer diameter of the tube body, an arc-shaped spring tube fixedly installed on the outer surface of the tube body inside the cuff, a vent hole opened on the surface of the tube body near the end of the arc-shaped spring tube, a sealing sleeve movably installed inside the vent hole, an L-shaped channel opened inside the sealing sleeve, the end of the arc-shaped spring tube being connected to the outer end of the sealing sleeve via a connecting rod, an inner sleeve provided inside the tube body, an air inlet chamber opened between the inner wall and the outer wall of the inner sleeve, a plurality of outer positioning rings evenly arranged on the outer diameter of the inner sleeve, the inner wall of each outer positioning ring being connected to the outer wall of the inner sleeve via four ribs, a piston movably installed inside each rib, a support rod fixedly installed on the outer end of each piston, and an outer support plate fixedly installed on the outer end of each support rod.

[0007] Preferably, a first air inlet pipe is fixedly installed on one side of the sheath, and a first airbag is fixedly installed at the end of the first air inlet pipe.

[0008] Preferably, a second air intake pipe is fixedly installed on one side of the air intake chamber, the end of the second air intake pipe extends to the outside of the duct body and a second airbag is fixedly installed thereon, and exhaust valves are fixedly installed on the outer diameter of both the second air intake pipe and the first air intake pipe.

[0009] Preferably, the inner ends of the pistons are all connected to the inner wall of the intake chamber by a first return spring.

[0010] Preferably, the inner sleeve has a core inside, and one end of the core is hinged with several snake-bone joints.

[0011] Preferably, the other end of the tube core is threadedly connected to a lead screw, an adjustment knob is fixedly installed on the outer end of the lead screw, and a positioning block is movably installed on the inner end of the lead screw.

[0012] Preferably, a traction cable is fixedly installed on one side of the inner end of the positioning block, and a plurality of second return springs are evenly fixedly installed on the outer diameter of the traction cable. An eccentric shaft is fixedly installed inside the end of the snake joint, and the end of the traction cable passes around the outer wall of the eccentric shaft and is fixedly installed on the other side of the inner end of the positioning block.

[0013] Preferably, a first one-way valve is fixedly installed inside the inner end of both the first airbag and the second airbag, and a second one-way valve is fixedly installed inside the outer end of both the first airbag and the second airbag.

[0014] Preferably, the surface of the catheter body is provided with scale lines.

[0015] Preferably, the inner diameter of the catheter body is set to 2.0mm-6.0mm, which is suitable for newborns to adolescents. Alternatively, the inner diameter of the catheter body can be set to 6.5mm-11.0mm, which is suitable for adults.

[0016] This invention provides a variable-diameter endotracheal tube structure. It has the following advantages: 1. This invention expands the diameter of the catheter body by using air pressure to drive the piston, strut and external support plate, which can adapt to human tracheas of different diameters and with lesions, flexibly adapt to various clinical use scenarios, and balance ventilation resistance and ventilation efficiency to improve ventilation effect.

[0017] 2. This invention utilizes an adjustment knob, lead screw, traction cable, and snake joint to flexibly adjust the bending angle of the catheter tip, quickly correct the insertion direction, assist the catheter in passing smoothly through the glottis, and reduce the difficulty of catheterization and the risk of catheterization failure.

[0018] 3. After the catheter diameter is expanded, the internal air pressure of the cuff will adaptively release pressure. Through the linkage structure of the arc-shaped spring tube, connecting rod, sealing sleeve and L-shaped channel, the cuff pressure is automatically balanced, and the cuff is always kept in precise fit with the trachea. This not only prevents air leakage and aspiration, but also avoids damage to the tracheal mucosa due to excessive pressure, thus improving safety. Attached Figure Description

[0019] Figure 1 This is a perspective view of the present invention; Figure 2 This is a schematic diagram of the internal structure of the sheath in this invention; Figure 3 for Figure 2 Enlarged view of point A in the middle; Figure 4 This is a schematic diagram of the inner sleeve in this invention; Figure 5 This is a frontal view of the internal structure of the inner sleeve in this invention; Figure 6 for Figure 5 Enlarged view at point B in the middle; Figure 7 This is a schematic diagram of the core structure in this invention; Figure 8 This is a schematic diagram of the internal structure of the die in this invention; Figure 9 This is a schematic diagram of the internal structure of the snake joint in this invention; Figure 10 This is a schematic diagram of the internal structure of the first airbag in this invention.

[0020] The components are as follows: 1. Tube body; 2. Tail end connector; 3. Sheath; 4. First air inlet pipe; 5. First airbag; 6. Arc-shaped spring tube; 7. Vent hole; 8. Sealing sleeve; 9. L-shaped channel; 10. Connecting rod; 11. Inner sleeve; 12. Air inlet chamber; 13. Second air inlet pipe; 14. Second airbag; 15. Exhaust valve; 16. Outer positioning ring; 17. Rib; 18. Piston; 19. First return spring; 20. Support rod; 21. Outer support plate; 22. Tube core; 23. Snake joint; 24. Lead screw; 25. Adjustment knob; 26. Traction cable; 27. Second return spring; 28. Eccentric shaft; 29. ​​Positioning block; 30. First one-way valve; 31. Second one-way valve; 32. Scale line. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0022] Please see the appendix Figure 1 - Appendix Figure 10 This invention provides a variable-diameter endotracheal tube structure, such as... Figure 1As shown, the device includes a catheter body 1, which serves as the core ventilation structure and is a key component for achieving intraoperative airway ventilation and support. The entire device is made of flexible medical material, conforming to the physiological curvature of the human trachea, allowing for smooth insertion into the patient's trachea to establish the airway. One end of the catheter body 1 is fixedly fitted with a tail connector 2, which is a connection component for external ventilation equipment. After the catheter body 1 is positioned within the patient's trachea, it can be connected to conventional clinical ventilation equipment such as ventilators and breathing bags to stably deliver ventilation airflow and ensure normal oxygen supply to the patient during surgery. A cuff 3 is fixedly installed on one side of the outer diameter of the catheter body 1. The cuff 3 is an airway sealing and protective component that, when inflated, fits tightly against the inner wall of the patient's trachea. It can effectively seal the gap between the tube body 1 and the inner wall of the trachea, avoiding gas leakage during surgery and aspiration caused by oral secretions or foreign objects entering the airway, ensuring airway tightness and ventilation safety. An arc-shaped spring tube 6 is fixedly installed on the outer surface of the tube body 1 at the position inside the cuff 3. The arc-shaped spring tube 6 has good elastic deformation capability and can adapt to the changes in air pressure inside the cuff 3, expanding and contracting outward. It is the core transmission component for realizing automatic pressure relief and stabilization of the cuff 3, and can accurately respond to pressure changes in the cuff 3. A vent hole 7 is opened on the surface of the tube body 1 near the end of the arc-shaped spring tube 6. The vent hole 7 is a communication channel between the cuff 3 and the inside of the tube body 1. With the sealing sleeve 8 and the L-shaped channel 9, the channel can be opened. The opening and closing control is used to complete the pressure relief and regulation of excess air pressure inside the sheath 3. A sealing sleeve 8 is movably installed inside the vent 7. The sealing sleeve 8 can slide within the vent 7, switching between blocking and opening the vent 7 based on the deformation of the arc-shaped spring tube 6, ensuring precise start and stop of the pressure relief structure. An L-shaped channel 9 is opened inside the sealing sleeve 8. When the sealing sleeve 8 moves outward and leaves the blocking position, it connects the internal cavity of the sheath 3 with the internal air passage of the guide tube body 1, realizing the discharge and pressure relief of high-pressure gas. Gas discharge can be stopped after pressure balance. The end of the arc-shaped spring tube 6 is connected to the outer end of the sealing sleeve 8 via a connecting rod 10. The connecting rod 10 acts as a power transmission mechanism, precisely transmitting the elastic deformation displacement of the arc-shaped spring tube 6 to the sealing sleeve 8. The dynamic sealing sleeve 8 slides synchronously, realizing automatic pressure relief control through mechanical linkage, eliminating the need for manual adjustment. The inner sleeve 11 is located inside the main body of the conduit, serving as the basic load-bearing structure for pipe diameter adjustment. Its hollow interior allows for ventilation, while the cavity between the outer and inner walls accommodates airflow, providing stable structural support and air passage space for subsequent conduit diameter expansion adjustment. An air inlet chamber 12 is formed between the inner and outer walls of the inner sleeve 11, serving as a high-pressure airflow storage and transmission chamber. It stores the gas filled into the second airbag 14, providing a stable pneumatic power source for the movement of the piston 18 and the expansion of the main body of the conduit 1. Several outer positioning rings 16 are evenly distributed on the outer diameter of the inner sleeve 11.The system can regulate the installation positions of adjusting components such as ribs 17, pistons 18, and struts 20, ensuring a uniform distribution of the overall expansion structure and more balanced force distribution during expansion of the guide tube body 1. The inner wall of the outer positioning ring 16 and the outer wall of the inner sleeve 11 are connected by four ribs 17. The ribs 17 serve as movement guides for the pistons 18, stabilizing the connection between the outer positioning ring 16 and the inner sleeve 11 while limiting the movement trajectory of the pistons 18. Pistons 18 are movably installed inside each rib 17, allowing them to slide smoothly along the inside of the rib 17 under air pressure. Strides 20 are fixedly installed on the outer ends of each piston 18, extending the power transmission force directly to the outer support plate 21, simultaneously causing the outer support plate 21 to expand and deform outwards. Each outer end is fixedly equipped with an outer support plate 21. The outer support plate 21 is a component that directly compresses the inner wall of the catheter body 1. Multiple outer support plates 21 expand outward simultaneously to evenly push the catheter body 1, achieving a stable expansion of the overall diameter of the catheter body 1, adapting to the trachea of ​​different diameters. In this embodiment, a first air inlet tube 4 is fixedly installed on one side of the cuff 3. The first air inlet tube 4 is a dedicated inflation channel for the cuff 3, which can connect the first air bag 5 and the internal cavity of the cuff 3, providing a stable airway for the inflation and sealing of the cuff 3. The first air bag 5 is fixedly installed at the end of the first air inlet tube 4. The first air bag 5 is a manually inflatable component. Medical staff can continuously inflate the cuff 3 by repeatedly pressing the first air bag 5 in conjunction with the one-way valve structure. The operation is simple and convenient, adapting to the needs of rapid clinical intubation.

[0023] Furthermore, a second air inlet pipe 13 is fixedly installed on one side of the air inlet chamber 12. The second air inlet pipe 13 is a dedicated inflation passage for the air inlet chamber 12, which can connect the second airbag 14 to the inside of the air inlet chamber 12. It delivers the high-pressure gas required for the diameter expansion adjustment of the catheter body 1. The end of the second air inlet pipe 13 extends to the outside of the catheter body 1 and is fixedly installed with the second airbag 14. The second airbag 14 is an inflation control component for diameter adjustment. Medical staff can manually press the second airbag 14 in a cycle to continuously inflate the air inlet chamber 12, drive the subsequent diameter expansion structure, and realize the diameter adjustment function. Exhaust valves 15 are fixedly installed on the outer diameter of both the second air inlet pipe 13 and the first air inlet pipe 4. The exhaust valves 15 are independent pressure relief control components. After the operation, the exhaust valves 15 of the two air passages can be opened to quickly expel the gas inside the cuff 3 and the air inlet chamber 12, allowing the device to quickly reset and facilitating the smooth removal of the catheter body 1.

[0024] Furthermore, the inner end of the piston 18 is connected to the inner wall of the air intake chamber 12 through the first return spring 19. The first return spring 19 has elastic reset capability. When the gas inside the air intake chamber 12 is discharged and the air pressure disappears, it can pull the piston 18, the support rod 20 and the outer support plate 21 to automatically retract and reset, so that the main body of the conduit 1 returns to the initial minimum pipe diameter state. The structure reset is flexible and does not require manual intervention.

[0025] Furthermore, the inner cannula 11 is provided with a core 22, which is the core load-bearing component for catheter shaping and angle adjustment. It can provide support for the flexible catheter body 1, preventing the catheter body 1 from bending and collapsing during insertion. At the same time, it supports the angle adjustment structure to realize the insertion direction correction function. One end of the core 22 is hinged with several serpentine joints 23. The multi-segment hinged serpentine joints 23 have the characteristic of flexible bending at multiple angles, which can realize the arbitrary angle fine adjustment of the front end of the catheter body 1, adapt to the different physiological angles of the patient's glottis, and assist the catheter to be accurately inserted into the airway.

[0026] Furthermore, the other end of the core 22 is threadedly connected to a lead screw 24. The lead screw 24 engages with the core 22 through a threaded meshing structure, enabling precise linear displacement transmission during rotation. This ensures the accuracy of angle adjustment and avoids over-adjustment or under-adjustment. An adjustment knob 25 is fixedly installed on the outer end of the lead screw 24. The adjustment knob 25 is a manually operated component, allowing medical personnel to directly rotate it manually to drive the lead screw 24 to rotate synchronously. This operation is convenient and labor-saving, meeting the needs of rapid adjustment during surgery. A positioning block 29 is movably installed on the inner end of the lead screw 24. The positioning block 29 serves as the fixing and transmission carrier for the traction structure and can move linearly back and forth following the rotation of the lead screw 24, thereby driving the traction cable 26 to complete the pulling action and realizing the power transmission for angle adjustment.

[0027] Furthermore, a traction cable 26 is fixedly installed on one side of the inner end of the positioning block 29. The traction cable 26 is a traction transmission component with bend adjustment. It can drive the snake joint 23 to bend in a specific direction through its own tension, accurately correcting the insertion angle of the catheter body 1. Several second return springs 27 are evenly fixedly installed on the outer diameter of the traction cable 26. The second return springs 27 are evenly distributed on the outer side of the traction cable 26. When the traction force is removed, the snake joint 23 can automatically straighten and return to its original position by its own elasticity, allowing the catheter body 1 to return to its initial straight state, which is convenient for adjustment and reuse. An eccentric shaft 28 is fixedly installed inside the end of 23. The eccentric shaft 28 can change the direction of force on the traction cable 26, converting the linear tension force into the bending moment of the snake joint 23, greatly improving the flexibility and accuracy of angle adjustment, and adapting to complex insertion angle scenarios. The end of the traction cable 26 passes around the outer wall of the eccentric shaft 28 and is fixedly installed on the other side of the inner end of the positioning block 29. This fixing structure allows the tension of the traction cable 26 to act stably on the eccentric shaft 28, ensuring that the force transmission is without deviation, making the bending action of the snake joint 23 more stable and accurate, and effectively correcting the insertion deviation angle.

[0028] Furthermore, a first one-way valve 30 is fixedly installed inside the inner end of both the first airbag 5 and the second airbag 14. The first one-way valve 30 is a one-way air intake control structure, which can ensure that outside air can smoothly enter the air passage when the airbag is pressed. A second one-way valve 31 is fixedly installed inside the outer end of both the first airbag 5 and the second airbag 14. The second one-way valve 31 and the first one-way valve 30 form a two-way sealed air intake structure, which can prevent the internal gas from leaking out when the airbag is released, and achieve a one-way continuous inflation effect.

[0029] Furthermore, the surface of the catheter body 1 is provided with scale lines 32, which can intuitively display the insertion depth of the catheter body 1. Medical staff can observe the scale in real time to accurately control the insertion position, ensure that the insertion depth of the catheter body 1 meets clinical standards, improve the accuracy of insertion positioning, and reduce the risks caused by insertion that is too deep or too shallow.

[0030] Furthermore, the inner diameter of the catheter body 1 is set to 2.0mm-6.0mm, suitable for newborns to adolescents. The inner diameter of the catheter body 1 can also be set to 6.5mm-11.0mm, suitable for adults. The inner diameter of 6.5mm is the dividing point between children's and adult specifications. It should not be lower than the ventilation safety threshold and should leave a 1-2mm elastic adjustment margin to adapt to the airway differences of different populations.

[0031] Working principle: The patient is given oxygen, anesthesia is induced, and the mouth is opened. The laryngoscope is fixed at the end of the serpentine joint 23. Lubricant is applied to the tip of the catheter body 1, and it is inserted into the patient's mouth with the smallest diameter, aligned with the glottis. The catheter body 1 is gently inserted. If the angle is off, the adjustment knob 25 is rotated to rotate the lead screw 24. The lead screw 24 engages with the end of the tube core 22, causing the positioning block 29 to move. When the positioning block 29 moves, it pulls the traction cable 26. When the traction cable 26 is pulled, the eccentric shaft 28 causes the serpentine joint 23 at the tip to bend and tighten to one side, thereby causing the end of the catheter body 1 to bend accordingly, correcting the insertion direction of the tip and assisting in passing through the glottis. The adjustment knob 25 is rotated in the opposite direction for the second repetition. The position spring 27 automatically returns to its original position. The position of the tubing body 1 is confirmed via the scale line 32. Once the predetermined position is reached, the core tube 22 is removed. At this time, the first airbag 5 is continuously and cyclically pressed. Through the action of the first one-way valve 30 and the second one-way valve 31, outside air enters the cuff 3 through the first air inlet tube 4 for inflation until the outer wall of the cuff 3 is tightly pressed against the trachea to prevent leakage and aspiration. Then, the tail connector 2 is connected to the ventilator or breathing bag. When the diameter of the tubing body 1 needs adjustment after completion, the second airbag 14 is continuously and cyclically pressed. Through the action of the internal first one-way valve 30 and the second one-way valve 31, outside air is continuously injected into the air inlet chamber 12 of the inner cannula 11. The gas inside tube 12 pushes all pistons 18 outward along the direction of the reinforcing bar 17, and drives all outer support plates 21 outward through the support rod 20, thereby expanding the diameter of the catheter body 1. This expansion adapts to tracheas of different diameters and lesions, effectively balancing ventilation resistance and efficiency. After the catheter body 1 expands, the internal space of the cuff 3 decreases and the air pressure increases. This air pressure acts on the wall of the arc-shaped spring tube 6, causing it to expand outward. The end of the arc-shaped spring tube 6 expands outward, and the sealing sleeve 8 is pulled outward through the connecting rod 10. When the sealing sleeve 8 is pulled out a section from the ventilation hole 7, the L-shaped channel 9 connects the inside of the cuff 3 with the inside of the catheter body 1. Gas is discharged into the catheter body 1 through the L-shaped channel 9 to complete the depressurization. After the pressure returns to normal, the arc-shaped spring tube 6 returns to its original shape, and the sealing sleeve 8 re-seals the vent 7. This ensures that the outer wall of the cuff 3 and the trachea are always in precise contact, while preventing damage to the tracheal mucosa due to excessive pressure. After the operation is completed, the gas in the cuff 3 and the air in the air inlet chamber 12 are discharged through the exhaust valve 15, so that the cuff 3 and the catheter body 1 return to their original shape. The catheter body 1 can then be pulled out. After the depressurization is completed, the piston 18 can be retracted and reset by the first reset spring 19. The outer positioning ring 16 plays a role in regulating and limiting the overall diameter expansion structure, ensuring that each diameter expansion and reset action is stable and uniform.

[0032] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A variable-diameter endotracheal tube structure, comprising a tube body (1), characterized in that, One end of the catheter body (1) is fixedly fitted with a tail connector (2). A cuff (3) is fixedly fitted on the outer diameter of one side of the catheter body (1). An arc-shaped spring tube (6) is fixedly fitted on the outer surface of the catheter body (1) at a position inside the cuff (3). A vent hole (7) is provided on the surface of the catheter body (1) near the end of the arc-shaped spring tube (6). A sealing sleeve (8) is movably fitted inside the vent hole (7). An L-shaped channel (9) is provided inside the sealing sleeve (8). The end of the arc-shaped spring tube (6) is connected to the sealing sleeve (8) via a connecting rod (10). The outer end is connected. The inner sleeve (11) is provided inside the main body of the conduit (1). An air inlet chamber (12) is opened between the inner wall and the outer wall of the inner sleeve (11). Several outer positioning rings (16) are evenly arranged on the outer diameter of the inner sleeve (11). The inner wall of the outer positioning ring (16) and the outer wall of the inner sleeve (11) are connected by four ribs (17). A piston (18) is movably installed inside the ribs (17). A support rod (20) is fixedly installed on the outer end of the piston (18). An outer support plate (21) is fixedly installed on the outer end of the support rod (20).

2. The variable diameter endotracheal tube structure according to claim 1, characterized in that, A first air inlet pipe (4) is fixedly installed on one side of the sheath (3), and a first airbag (5) is fixedly installed at the end of the first air inlet pipe (4).

3. The variable diameter endotracheal tube structure according to claim 2, characterized in that, A second air inlet pipe (13) is fixedly installed on one side of the air inlet chamber (12). The end of the second air inlet pipe (13) extends to the outside of the duct body (1) and a second airbag (14) is fixedly installed thereon. An exhaust valve (15) is fixedly installed on the outer diameter of both the second air inlet pipe (13) and the first air inlet pipe (4).

4. The variable diameter endotracheal tube structure according to claim 1, characterized in that, The inner ends of the pistons (18) are all connected to the inner wall of the intake chamber (12) by the first return spring (19).

5. The variable diameter endotracheal tube structure according to claim 1, characterized in that, The inner sleeve (11) is provided with a core (22), and one end of the core (22) is hinged with several snake bone joints (23).

6. The variable diameter endotracheal tube structure according to claim 5, characterized in that, The other end of the core (22) is threadedly connected to a lead screw (24). An adjustment knob (25) is fixedly installed on the outer end of the lead screw (24), and a positioning block (29) is movably installed on the inner end of the lead screw (24).

7. The variable diameter endotracheal tube structure according to claim 6, characterized in that, A traction cable (26) is fixedly installed on one side of the inner end of the positioning block (29). Several second return springs (27) are evenly fixedly installed on the outer diameter of the traction cable (26). An eccentric shaft (28) is fixedly installed inside the end of the snake joint (23). The end of the traction cable (26) passes around the outer wall of the eccentric shaft (28) and is fixedly installed on the other side of the inner end of the positioning block (29).

8. The variable diameter endotracheal tube structure according to claim 3, characterized in that, A first one-way valve (30) is fixedly installed inside the inner end of the first airbag (5) and the second airbag (14), and a second one-way valve (31) is fixedly installed inside the outer end of the first airbag (5) and the second airbag (14).

9. The variable diameter endotracheal tube structure according to claim 1, characterized in that, The surface of the catheter body (1) is provided with scale lines (32).

10. The variable diameter endotracheal tube structure according to claim 1, characterized in that, The inner diameter of the catheter body (1) is set to 2.0mm-6.0mm, which is suitable for newborns to adolescents. The inner diameter of the catheter body (1) can also be set to 6.5mm-11.0mm, which is suitable for adults.

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