Nitric oxide therapy device for selectively dilating pulmonary blood vessels after cardiac surgery

Abstract

This invention provides a nitric oxide therapy device for selectively dilating pulmonary blood vessels after cardiac surgery, solving the problem of insufficient output accuracy in the low-concentration range of conventional technologies. [Solution] This invention comprises a mixing chamber body 1, a nitric oxide introduction component, a carrier gas introduction component, and a concentration adjustment mechanism. The nitric oxide introduction component and the carrier gas introduction component are each connected to the mixing chamber body via introduction pipes having needle valves. The concentration adjustment mechanism comprises a concentric sleeve 8 rotatably mounted inside the mixing chamber body and a spiral guide plate 9 mounted on the outer wall of the concentric sleeve, and an adjustment handle for rotating the concentric sleeve is connected to the concentric sleeve. This invention precisely controls the gas flow rate with the needle valve and adjusts the gas mixing path in the annular mixing channel by rotating the concentric sleeve with the adjustment handle to change the angle of the spiral guide plate, thereby improving mixing uniformity and output concentration stability.

Description

Technical Field

[0001] This invention belongs to the technical field of medical devices, and specifically relates to a nitric oxide treatment device for selectively expanding pulmonary blood vessels after the perioperative period of cardiac surgery.

Background Art

[0002] Inhaled nitric oxide (iNO), as a selective pulmonary vasodilator, has important application value in the management of the perioperative period of cardiac surgery. This selectively acts on pulmonary blood vessels, reduces pulmonary artery pressure, improves the distribution of pulmonary blood flow, can avoid causing systemic hypotension, has a rapid onset of action, and a relatively low incidence of adverse reactions, so it is widely recognized in clinical practice.

[0003] According to the "Expert Consensus on the Clinical Application of Inhaled Nitric Oxide Therapy in Critical Illnesses", the dosage of iNO used in postoperative cardiac patients is usually 5 - 20 ppm to improve refractory hypoxemia. On the other hand, a dosage of 20 - 40 ppm is used to manage perioperative pulmonary hypertension and right ventricular dysfunction, and corresponding safety measures to prevent potential risks such as methemoglobinemia have already been established. Clinical studies have shown that for patients with hypoxemia after coronary artery bypass grafting (CABG), iNO is a beneficial adjuvant treatment method that can improve arterial oxygenation and shorten the mechanical ventilation time. Also, in pediatric patients with congenital heart disease (CHD), the application of iNO has been confirmed to effectively reduce the incidence of low cardiac output syndrome (LCOS) and shorten the mechanical ventilation time.

[0004] In actual clinical applications, iNO therapy relies on dedicated gas delivery devices (e.g., nitric oxide therapy devices). Such devices require precise control of the mixing ratio of nitric oxide and carrier gas (e.g., oxygen or air) to stabilize the output concentration within the target therapeutic range. However, most existing nitric oxide therapy devices achieve the gas mixing ratio by combining conventional flow control valves with electronic control systems. This mechanical structure suffers from response delays and insufficient adjustment resolution when dealing with minute flow rate changes, making it difficult to maintain stable output accuracy in the low concentration range (e.g., 5-10 ppm). Furthermore, in some devices, the influence of flow path resistance on mixing uniformity is not adequately considered in the design of the gas mixing path, which can cause instantaneous concentration fluctuations and affect the stability and reproducibility of the treatment.

[0005] Therefore, conventional technologies have certain limitations in achieving highly accurate and stable nitric oxide concentration output. At the same time, current research trends in iNO applications are shifting from simply "controlling pulmonary hypertension" to "achieving multi-organ protection in the perioperative period," such as the prevention of cardiopulmonary bypass-related acute kidney injury (AKI), which is further increasing the demand for accuracy and stability in iNO insufflation devices. [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] This invention provides a nitric oxide therapy device for selectively dilating pulmonary blood vessels after cardiac surgery, which allows for high-precision adjustment of the mixing ratio of nitric oxide and carrier gas, maintains a stable output concentration in the low-concentration range, improves the uniformity of the gas mixture, and thereby ensures the stability and reproducibility of the treatment process. [Means for solving the problem]

[0007] To achieve the above objective, this invention employs the following technical solution:

[0008] A nitric oxide therapy device for selectively dilating pulmonary blood vessels after cardiac surgery, comprising a mixing chamber body, a nitric oxide introduction component, a carrier gas introduction component, and a concentration adjustment mechanism.

[0009] The mixing chamber body has a hollow cylindrical structure, forming a gas mixing space inside, and a mixed gas outlet is provided at one end of the mixing chamber body.

[0010] The nitric oxide introduction component comprises a first introduction pipe and a first needle valve, one end of the first introduction pipe is used to connect to an external nitric oxide gas source, and the other end communicates with the inside of the mixing chamber body, and the first needle valve is provided on the first introduction pipe and is used to adjust the amount of nitric oxide flowing in.

[0011] The carrier gas introduction component comprises a second introduction pipe and a second needle valve. One end of the second introduction pipe is used to connect to an external carrier gas source, and the other end communicates with the inside of the mixing chamber body. The second needle valve is provided on the second introduction pipe and is used to adjust the amount of carrier gas flowing in.

[0012] The concentration adjustment mechanism comprises a concentric sleeve, a spiral guide plate, and an adjustment handle. The concentric sleeve is rotatably mounted inside the mixing chamber body and forms an annular mixing channel between its outer wall and the inner wall of the mixing chamber body. The spiral guide plate is mounted on the outer wall of the concentric sleeve and extends spirally along the axial direction, with its starting end located in the inlet area of ​​the first and second inlet pipes and its end pointing toward the mixed gas outlet side. The adjustment handle is electrically connected to the concentric sleeve and is used to rotate the concentric sleeve around its axis and change the angular position of the spiral guide plate relative to the inlet.

[0013] Specifically, both the first needle valve and the second needle valve have a conical valve body structure, and the fitting gap between the valve body and the valve seat is less than 0.05 mm.

[0014] Specifically, the spiral angle of the spiral guide plate is 30° to 60°, the height of the guide plate is equal to the radial width of the annular mixing channel, and the thickness of the guide plate is 0.5 mm.

[0015] The first and second inlet pipes are positioned so that their penetration points into the mixing chamber body are offset from each other by a 120° angle, and both are located in a region upstream of the starting end of the spiral guide plate.

[0016] A flow straightening grid is provided at the mixed gas outlet. The flow straightening grid consists of a plurality of parallel-arranged thin plates, with a spacing of 1 mm between the plates, and the plane of the flow straightening grid is perpendicular to the axis of the mixed gas outlet. [Effects of the Invention]

[0017] This invention provides the following beneficial effects.

[0018] 1. This invention employs a concentration adjustment mechanism combining a first needle valve, a second needle valve, a rotatable concentric sleeve, and a spiral guide plate to achieve precise control of the mixing ratio of nitric oxide and carrier gas. This structure allows for manual adjustment of the introduction flow rate while simultaneously changing the gas contact path and mixing time within the annular mixing channel. This effectively avoids problems such as response delays and insufficient adjustment resolution that can occur at low flow rates in electronically controlled systems, thereby improving the stability and reproducibility of the treatment process. This provides a reliable instrument base for conducting high-quality clinical research, such as investigating the preventive effect of iNO on acute kidney injury after cardiac surgery.

[0019] 2. This invention utilizes a conical valve body structure for the first and second needle valves, with a fitting gap of less than 0.05 mm and a stroke range of 0 to 3 mm. By combining this with a fine adjustment knob with a pitch of 0.2 mm, it enables high-resolution mechanical adjustment of the gas introduction volume in the low flow rate range. This design allows the operator to accurately control the introduction volume based on a precise scale in the low concentration therapeutic range of 5 to 10 ppm, providing a reliable adjustment base for maintaining a stable output concentration. This precision meets the dose requirement of "improvement of postoperative refractory hypoxemia at 5 to 20 ppm" as presented in the clinical consensus, ensuring that patients receive precise treatment.

[0020] 3. This invention provides a flow straightening grid consisting of multiple parallel thin plates spaced 1 mm apart at the mixed gas outlet, thereby straightening the airflow mixed by the spiral guide plate. This structure eliminates the unevenness of velocity distribution and directional turbulence during gas outflow, enabling a stable flow state for the output airflow. Combined with the constant temperature maintenance effect of the insulating jacket, this further ensures the stability of the output concentration, making it possible to keep the concentration deviation within ±0.5 ppm. The highly stable output helps to accurately evaluate the improvement effect of iNO on hemodynamic parameters (pulmonary artery pressure, cardiac output, etc.) and oxygenation function in clinical observations, and helps reduce research bias caused by insufficient accuracy of the device. [Brief explanation of the drawing]

[0021] [Figure 1] Figure 1 is an overall structural diagram of the present invention. [Figure 2] Figure 2 is an exploded view of the overall structure of the present invention. [Figure 3] Figure 3 is a schematic diagram showing the assembly structure of the concentric sleeve and spiral guide plate. [Figure 4] Figure 4 is a schematic diagram showing the structure of the flow straightening grid at the mixed gas outlet. [Modes for carrying out the invention]

[0022] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0023] As shown in FIGS. 1 to 4, the present invention provides a nitric oxide treatment device for selectively expanding pulmonary blood vessels after the perioperative period of cardiac surgery. This device is used for system analysis to assist in the clinical observation of inhaled nitric oxide (iNO) after cardiac surgery. The overall structure of the nitric oxide treatment device includes a mixing chamber body 1, a first introduction pipe 2, a first needle valve 3, a first flow rate fine adjustment knob 4, a second introduction pipe 5, a second needle valve 6, a second flow rate fine adjustment knob 7, a concentric sleeve 8, a spiral guide plate 9, an adjustment handle 10, a rectifying grid 11, and a heat preservation jacket 12. Each component cooperates to achieve high-precision mixing and stable output of nitric oxide and carrier gas in the low concentration range.

[0024] The mixing chamber body 1 has a hollow cylindrical structure and forms a sealed gas mixing space inside. One end of the mixing chamber body 1 is provided with a mixed gas outlet, and the other end is a closed end surface to ensure that the gas is discharged from the outlet after being sufficiently mixed in the chamber body. The outer wall of the mixing chamber body 1 is covered with a heat preservation jacket 12. The heat preservation jacket 12 is provided with a liquid inlet and a liquid outlet and is used to pass a constant temperature liquid to maintain the temperature inside the mixing chamber body 1 constant and avoid the influence of gas volume change caused by environmental temperature fluctuation on the accuracy of the mixing concentration.

[0025] One end of the first inlet pipe 2 is connected to an external nitric oxide gas source, and the other end penetrates the side wall of the mixing chamber body 1 and communicates with the inside of the mixing chamber body 1. The first needle valve 3 is located on the first inlet pipe 2 in close proximity to the mixing chamber body 1 and is used to control the flow rate of nitric oxide gas into the mixing chamber body 1. The first needle valve 3 employs a conical valve body structure, with a fitting gap of less than 0.05 mm between the valve body and the valve seat, a stroke range of 0 to 3 mm, and a hardened coating on the surface of the valve body to reduce wear during long-term use. The first flow rate fine adjustment knob 4 is fixedly connected to the valve stem of the first needle valve 3. The outer surface of the first flow rate fine adjustment knob 4 is marked with a scale, and each marking corresponds to a gas flow rate change of 0.1 ml / min, making it easy for the operator to precisely adjust the amount of nitric oxide introduced.

[0026] One end of the second inlet pipe 5 is connected to an external carrier gas source, and the other end similarly penetrates the side wall of the mixing chamber body 1 and communicates with the inside of the mixing chamber body 1. The second needle valve 6 is located on the second inlet pipe 5 in close proximity to the mixing chamber body 1, and its structure is identical to that of the first needle valve 3, having the same fitting gap, stroke range, and surface treatment process as a conical valve body structure. The second flow rate fine adjustment knob 7 is fixedly connected to the valve stem of the second needle valve 6, and its scale setting matches that of the first flow rate fine adjustment knob 4, and is used to adjust the carrier gas flow rate with the same degree of precision.

[0027] The concentric sleeve 8 is coaxially mounted inside the mixing chamber body 1. An annular mixing channel is formed between its outer wall and the inner wall of the mixing chamber body 1. Both ends of the concentric sleeve 8 are rotatably connected to the inner wall of the mixing chamber body 1 via self-lubricating sliding bearings. The outer ring of the bearing is an interference fit with the inner wall of the mixing chamber body 1, and the inner ring is an intermediate fit with the outer wall of the concentric sleeve 8, ensuring that the concentric sleeve 8 maintains stability during rotation and that frictional resistance is low. The helical guide plate 9 is continuously provided in a helical shape along the outer wall of the concentric sleeve 8, with its starting end facing the inlets of the first inlet pipe 2 and the second inlet pipe 5, and its end pointing towards the mixed gas outlet. The helical angle of the helical guide plate 9 is 30° to 60°, its height is equal to the radial width of the annular mixing channel, its thickness is 0.5 mm, and its surface is polished to reduce resistance during gas flow and improve mixing efficiency.

[0028] One end of the adjustment handle 10 penetrates the side wall of the mixing chamber body 1 and is fixedly connected to the outer wall of the concentric sleeve 8. A sealing gland packing is provided between the adjustment handle 10 and the side wall of the mixing chamber body 1. The gland packing is filled with a braided packing made of polytetrafluoroethylene, and a retaining nut is provided on the outside to adjust the prepressure of the packing and ensure that no gas leakage occurs during rotation adjustment. By rotating the adjustment handle 10, the concentric sleeve 8 is driven to rotate around its axis, and the circumferential angular position of the helical guide plate 9 with respect to the inlets of the first inlet pipe 2 and the second inlet pipe 5 can be adjusted. The helical guide plate 9 guides the two types of gas introduced into the annular mixing channel to proceed along the helical path, significantly extending the mixing path, increasing the turbulent effect, and promoting sufficient diffusion and uniform mixing between gas molecules. By adjusting the circumferential angle, the initial state in which the two gas flows enter the helical channel can be optimized, ensuring the smoothness of the mixing process.

[0029] The first inlet pipe 2 and the second inlet pipe 5 are positioned so that their penetration points into the mixing chamber body 1 are offset by a 120° angle, and both are located upstream of the starting end of the spiral guide plate 9. This arrangement prevents the two types of gases from directly colliding at the inlet and ensures that the gases are guided by the spiral guide plate 9 immediately after entering the annular mixing channel, thereby increasing the initial mixing efficiency.

[0030] A flow straightening grid 11 is provided at the mixed gas outlet. The flow straightening grid 11 is composed of multiple parallel-arranged thin plates, with a spacing of 1 mm between the plates, and the plane of the flow straightening grid 11 is perpendicular to the axis of the mixed gas outlet. The function of the flow straightening grid 11 is to eliminate the non-uniformity and directional turbulence of the velocity distribution during gas outflow, to make the output gas flow laminar, and to further improve the stability and reproducibility of the output concentration.

[0031] In actual use, the operator first sets the target nitric oxide concentration based on the therapeutic needs. This concentration is typically in the low concentration range of 5-10 ppm. This concentration range corresponds to the lower limit of the dose range used in clinical consensus to improve refractory hypoxemia in post-cardiac surgery patients, and at the same time, it is an important concentration window for conducting perioperative organ protection studies. Subsequently, the first flow fine adjustment knob 4 and the second flow fine adjustment knob 7 are rotated, respectively, to precisely adjust the introduction flow rates of nitric oxide and carrier gas based on the precise scales on their outer surfaces. The needle valve employs a mechanical conical valve body structure, and the combination of minute strokes and high-precision screw pairs enables stable and reproducible adjustment in the low flow rate range, avoiding the problem of nonlinear response at low flow rates in electronically controlled systems.

[0032] After two types of gas are introduced into the mixing chamber body 1, they are guided by the spiral guide plate 9 within the annular mixing channel and move forward along the spiral path. The angle of the spiral guide plate 9 can be adjusted by the adjustment handle 10, thereby changing the residence time of the gases in the channel and the mixing intensity. For example, when used in low flow rate and low concentration treatment situations, the circumferential angle between the starting end of the spiral guide plate 9 and the two inlets can be adjusted to align them, allowing the two airflows to be smoothly introduced into the spiral channel and reducing introduction fluctuations at low flow rates. When used in higher flow rate treatment situations, the angle can be adjusted to avoid direct collision between the two airflows, eliminating local turbulence and ensuring uniform mixing at high flow rates. This allows the device to adapt to the mixing needs of different clinical treatment scenarios. This mechanical adjustment method does not require reliance on sensors or feedback systems, is simple in structure, highly reliable, and suitable for the high demands for device stability in clinical environments.

[0033] The mixed gas is rectified by the rectifier grid 11, then discharged from the mixed gas outlet, sent to the subsequent transport pipeline, and finally delivered to the patient's breathing circuit. The rectifier grid 11 ensures that the velocity distribution of the output airflow is uniform and aligned in direction, avoiding deviations in concentration detection due to localized excessive or excessive flow velocities. At the same time, the insulating jacket 12 continuously maintains a constant temperature inside the mixing chamber body 1, preventing fluctuations in gas density caused by temperature changes, thereby ensuring long-term stability of the concentration output.

[0034] This invention achieves high-precision mixing and stable output in the low-concentration range of nitric oxide and carrier gas through the structural design described above. All adjustment mechanisms are manually operated mechanical structures, making operation intuitive, maintenance easy, and suitable for medical settings such as operating rooms and intensive care units where there are extremely high demands for the reliability of the equipment. The flow path design inside the mixing chamber body 1, the geometric parameters of the spiral guide plate 9, the precise fitting of the needle valve, and the rectifying action of the rectifier grid 11 all constitute a highly efficient and stable gas mixing system, ensuring that the output concentration deviation does not exceed ±0.5 ppm within the concentration range of 5 to 10 ppm. This device provides a precise and reliable administration tool for evaluating the organ-protective effects of iNO in high-risk cardiac surgery patients (e.g., reduction of the incidence of postoperative acute kidney injury), contributing to the reduction of clinical research bias caused by insufficient accuracy of the device. [Explanation of Symbols]

[0035] 1. Mixing chamber body 2 First introduction pipe 3. First needle valve 4. First flow rate fine adjustment knob 5 Second introduction pipe 6. Second needle valve 7. Second flow rate fine adjustment knob 8 Concentric Sleeves 9. Spiral Sign 10 Adjustable handle 11 Rectifier grid 12 Insulated Jackets

Claims

1. A nitric oxide therapy device for selectively dilating pulmonary blood vessels after cardiac surgery, characterized by comprising a mixing chamber body, a nitric oxide introduction component, a carrier gas introduction component, and a concentration adjustment mechanism; The mixing chamber body has a hollow structure, forming a gas mixing space inside, and a mixed gas outlet is provided at one end of the mixing chamber body; The nitric oxide introduction component comprises a first introduction tube and a first needle valve, one end of the first introduction tube used to connect to an external nitric oxide gas source and the other end communicating with the inside of the mixing chamber body, and the first needle valve provided on the first introduction tube used to adjust the amount of nitric oxide flowing in; The carrier gas introduction component comprises a second introduction pipe and a second needle valve, one end of the second introduction pipe is used to connect to an external carrier gas source, and the other end communicates with the inside of the mixing chamber body; the second needle valve is provided on the second introduction pipe and is used to adjust the amount of carrier gas flowing in; The concentration adjustment mechanism comprises a concentric sleeve, a spiral guide plate, and an adjustment handle. The concentric sleeve is rotatably mounted inside the mixing chamber body, forming an annular mixing channel between its outer wall and the inner wall of the mixing chamber body. The spiral guide plate is mounted on the outer wall of the concentric sleeve, extending spirally along the axial direction, with its starting end located in the inlet area of ​​the first and second inlet pipes, and its end pointing toward the mixed gas outlet. The adjustment handle is electrically connected to the concentric sleeve and is used to rotate the concentric sleeve around its axis, thereby changing the angular position of the spiral guide plate relative to the inlet.

2. The nitric oxide therapy device for selectively dilating pulmonary blood vessels after cardiac surgery, as described in claim 1, characterized in that both the first needle valve and the second needle valve have a conical valve body structure, the fitting gap between the valve body and the valve seat is less than 0.05 mm, and the stroke range of the valve body is 0 to 3 mm.

3. The nitric oxide therapy device for selectively dilating pulmonary vessels after cardiac surgery, as described in claim 1, characterized in that the spiral angle of the spiral guide plate is 30° to 60°, the height of the guide plate is equal to the radial width of the annular mixing channel, and the thickness of the guide plate is 0.5 mm.

4. The nitric oxide therapy device for selectively dilating pulmonary vessels after cardiac surgery, as described in claim 1, characterized in that the first and second inlet tubes are positioned at circumferential angles of 120° relative to each other at their insertion points into the mixing chamber body, and both are located in a region upstream of the starting end of the spiral guide plate.

5. The nitric oxide therapy device for selectively dilating pulmonary blood vessels after cardiac surgery, as described in claim 1, characterized in that a flow straightening grid is provided at the mixed gas outlet, the flow straightening grid consists of a plurality of parallel-arranged thin plates, the spacing between the thin plates is 1 mm, and the plane of the flow straightening grid is perpendicular to the axis of the mixed gas outlet.

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