A nasal oxygen inhalation mask with air flow counterflow structure

Abstract

The application relates to the field of medical devices, and discloses a nasal oxygen inhalation mask with air flow butt joint structure. The mask comprises a nasal cavity outer cover cup covering only the periphery of a nasal cavity, branch pipelines horizontally opposite on the left and right sides of the cover cup, a limiting fixing part, a side exhaust hole, a supporting framework, a gastrointestinal tube insertion port and a peripheral skirt. The branch pipelines are horizontally opposite in the cover cup to form an air flow butt joint area, and eliminate unidirectional air flow impact force. The limiting fixing part is arranged near the upper and lower center lines of the cover cup, so that the branch pipelines extend to the ears along the two sides of the face to form an ear-hanging type fixing, and no belt is needed. The side exhaust hole adopts a porous dispersion type array layout, 3-5 micropores are arranged on each side, and carbon dioxide is quickly exhausted. The supporting framework is arranged at the bottom of the cover cup to prevent collapse and extrusion of the nose. The gastrointestinal tube insertion port is in a film structure and is provided with a horizontal or cross-shaped opening, is closed in a natural state, and is unfolded to wrap the gastrointestinal tube when the tube is placed. The mask does not affect the speaking and eating of a patient, is comfortable and stable to wear, and is suitable for high-flow oxygen therapy and patients needing to be provided with gastrointestinal tubes.

Description

Technical Field

[0001] This application relates to the field of medical device technology, specifically to a nasal oxygen mask for clinical oxygen therapy. Background Technology

[0002] Oxygen therapy is a commonly used clinical treatment method to correct hypoxia, improve arterial blood oxygen partial pressure and oxygen saturation levels, and is one of the important methods for adjuvant treatment of various diseases. Currently, traditional oxygen therapy often uses oxygen cannulas and oxygen masks. However, when patients use nasal cannulas, the nasal cannula can easily rub against the nasal cavity wall after being inserted into the nasal cavity, and the oxygen sprayed at a high flow rate can also directly irritate the nasal cavity, causing discomfort. Although oxygen masks can alleviate this problem to some extent, they cover the nose and lips, causing great inconvenience for patients to speak and eat, resulting in poor patient compliance. Specifically, with traditional masks, the mask covers the area around the mouth and nose and is fixed with straps, causing a feeling of constriction and severely limiting daily activities such as eating and drinking. In addition, traditional masks also pose risks of carbon dioxide retention and can easily lead to facial pressure sores with prolonged wear.

[0003] While existing nasal oxygen delivery devices exist that only cover the nose, the branch catheters typically connect directly from both sides of the cup. This can lead to a one-way airflow after oxygen enters, causing significant impact on the patient's nasal cavity during high-flow oxygen delivery, resulting in poor comfort. Furthermore, the cup of such devices is prone to collapse and deformation during use, compressing the patient's nose and affecting wearing comfort and ventilation. In addition, existing nasal oxygen delivery devices are inconvenient to use in patients requiring simultaneous gastrointestinal tube placement, as oxygen leakage is likely after the tube is inserted, and a proper seal is difficult to guarantee.

[0004] Therefore, there is an urgent need for a new type of oxygen therapy device that can effectively supply oxygen, ensure that patients can speak and eat normally, and is comfortable and stable to wear. Summary of the Invention

[0005] (a) Technical problems to be solved In view of the above-mentioned defects of existing oxygen masks, this application provides a nasal oxygen mask, which aims to solve the following technical problems: (1) Traditional masks cover both the oral cavity and the nasal cavity at the same time, which hinders patients from speaking and eating; (2) The airflow pressure is too high when inhaling oxygen at high flow rate, resulting in poor patient compliance; (3) Due to the limited size and weight of the mask, it is easy to fall off or reverse, and prolonged strap fixation can induce facial pressure sores; (4) The dead space inside the cup is large, making it difficult to exhale carbon dioxide, which can easily cause retention or repeated inhalation of carbon dioxide; (5) The mask is easy to collapse and squeeze the nose when worn; (6) It is inconvenient for patients who need to have a gastrointestinal tube placed, and oxygen leakage is likely to occur.

[0006] (II) Technical Solution To achieve the above objectives, this application provides the following technical solution: A nasal oxygen mask includes a nasal cavity outer cup, a main tube, branch tubes, an air source connector, a limiting and fixing component, a side exhaust port, a supporting frame, a gastrointestinal tube insertion port, and an outer perimeter skirt. Its features are: 1. Nasal cavity external cup and branch tube layout The nasal cavity cup only covers the periphery of the patient's nasal cavity and does not cover the oral cavity area.

[0007] The branch tubing is horizontally positioned on the outer periphery downstream of the nostrils, located on the left and right sides of the mask cup. Its air inlets are horizontally opposite each other inside the cup, creating an airflow counter-current zone. During high-flow oxygen therapy, the airflow from the branch tubing on both sides creates a counter-current flow along the horizontal direction of the patient's face within the mask cup. This effectively eliminates the impact force of unidirectional airflow, prevents excessive gas pressure, and avoids discomfort caused by high-pressure airflow to the patient's nasal cavity, significantly improving patient compliance under high-flow oxygen therapy conditions.

[0008] 2. Limiting and fixing components Limiting and fixing components are provided on both the left and right sides. These components are positioned near the upper and lower center lines of the cup to limit and change the direction of the branch tubing, ensuring that the branch tubing extends to the patient's ear along a predetermined trajectory. The layout relationship between this device, the branch tubing, and the branch tubing interface is as follows: Structural relationship and connection method: The connection sequence is to first assemble the branch tubes on the limiting and fixing parts, and then connect the branch tubes to the air inlet of the nasal cavity cup. The air inlet extends into the inside of the nasal cavity cup. The directional relationship is that after the limiting and fixing parts lead the branch tubes out from the side of the cup, they change their direction so that they extend upward along both sides of the patient's face to the ears, forming an ear-hook fixing path.

[0009] Mechanism of action: This device defines the direction and position of the branch tubes and uses an ear-hook fixation method to make the mask fit securely on the patient's nose without the need for additional straps; at the same time, the device effectively prevents the cup from being reversed or accidentally falling off during use.

[0010] 3. Side exhaust vents The mask cup has side vents on both sides. The carbon dioxide exhaled by the patient can be quickly expelled from the mask cup through the side vents, effectively preventing carbon dioxide from being retained and re-inhaled inside the mask cup, reducing the risk of carbon dioxide retention and ensuring the patient's respiratory safety.

[0011] Furthermore, the side exhaust vents are not single, localized gas pressure relief channels, but rather employ a "multi-porous diffusion" array layout. Specifically, the multi-porous diffusion exhaust structure is located in specific areas on the left and right side walls of the nasal cavity outer cup, preferably in the middle and rear part of the cup side wall, corresponding to the lateral projection area of ​​the human nasal wing, with 3 to 5 micropores respectively. The micropores are preferably 1.2 to 1.5 times the total air intake cross-sectional area of ​​the branch pipes, and the diameter of a single pore is 2 to 5 mm.

[0012] Compared with traditional mask exhaust structures, the porous dispersion exhaust structure has unique hydrodynamic behavior, specifically manifested in the following three aspects: (1) Expiratory phase – convergence and diffusion conversion: When using a traditional mask structure, when the patient exhales gas (mainly CO2), the exhaled CO2 gas, because its density is greater than that of fresh oxygen, tends to first settle at the bottom of the cup and then find a single "low resistance point (i.e., exhaust port)" to flow out naturally, which can easily lead to CO2 re-inhalation. However, when using a porous diffusion exhaust structure, when the patient exhales gas, due to the extremely small internal volume of the cup (almost no dead space), the pressure inside the cup increases instantaneously, and the exhaled airflow is quickly converted into a fan-shaped or arc-shaped diffusion flow with an angle of about 60° to 120° relative to the side wall plane of the cup. This allows the exhaled carbon dioxide gas to flow out of the nasal cavity in a fan-shaped or arc-shaped manner, accelerating the expulsion speed and preventing the exhaled carbon dioxide gas from being re-inhaled.

[0013] (2) Inspiratory phase – negative pressure sealing and dead space flushing: At the moment of inhalation, a slight negative pressure is formed inside the cup, and fresh oxygen enters directly from the air inlet below the nostril, effectively reducing the short-circuit loss of fresh oxygen from the exhaust port and improving the actual utilization rate of oxygen. More importantly, a laminar displacement airflow is formed inside the cup from bottom to top and from inside to outside, which thoroughly removes the CO2 gas retention area in the nasal vestibule and the apex of the cup.

[0014] (3) Improved acoustic comfort and clinical applicability Clinical tests have shown that traditional large-diameter exhaust windows tend to produce a whistling sound when high-pressure airflow passes through, significantly disrupting patients' sleep. The aforementioned porous diffusion exhaust structure disperses the total energy of the airflow spectrum, causing the exhaust sound wave frequency to shift to higher frequencies and significantly attenuate. The exhaust noise is reduced by 10-15 decibels compared to a single-hole design, providing a quieter treatment environment for patients requiring long-term nighttime oxygen therapy.

[0015] 4. Supporting skeleton The support frame is located at the bottom or outer periphery of the cup, providing structural support to prevent the cup from collapsing or deforming during use. This avoids the cup compressing the patient's nose after collapsing, ensuring sufficient breathing space inside the cup and improving wearing comfort. Preferably, the support frame is located at the bottom of the cup, specifically on the midline of the bottom of the cup between the patient's nostrils, and has a straight or T-shaped structure.

[0016] 5. Gastrointestinal tube insertion site The bottom of the cup has two gastrointestinal tube insertion ports, one large and one small. The larger port is compatible with gastrointestinal tubes with an outer diameter of 12Fr to 20Fr, while the smaller port is compatible with gastrointestinal tubes with an outer diameter of 4Fr to less than 12Fr, meeting the needs of different patients. The gastrointestinal tube insertion port is characterized by its thin-film structure with a single or cross-shaped opening. This opening is naturally closed, effectively preventing oxygen leakage. When a gastrointestinal tube needs to be inserted, it is inserted through this opening. The thin film naturally unfolds and tightly wraps around the tube, preventing accidental dislodgement and effectively preventing oxygen leakage, achieving a good seal.

[0017] 6. Outer skirt hem The bra cup has a skirt around its outer perimeter. The skirt increases the contact area between the bra cup and the patient's face, distributing pressure over a larger area, which not only increases wearing comfort but also improves the fit and stability of the bra cup to the face, preventing air leakage.

[0018] In some preferred embodiments, the outer skirt and the limiting fastener are integrated into a single design. Specifically, the limiting fastener is integrated into the outer skirt, and the limiting fastener is joined to the plane of the outer skirt at a 60° to 90° angle. A branch guide limiting hole is provided in the middle of the limiting fastener. The limiting fastener acts like a small ear growing from the outer skirt; after the branch guide passes through the limiting hole, it changes the direction of its combination with the bra cup, preventing the bra cup from flipping and forming an ear-like fixing path.

[0019] Furthermore, the cup sidewall is equipped with a gas sampling interface, which is connected to an external carbon dioxide concentration monitoring device via an extension tube. This allows for real-time monitoring of the patient's exhaled carbon dioxide concentration, solving the problem of the need to wear an additional carbon dioxide monitoring nasal cannula in existing end-tidal carbon dioxide monitoring.

[0020] (III) Beneficial Effects Compared with the prior art, this application has the following significant advantages: 1. Airflow counter-current design solves the problem of high flow rate and pressure. This application places the branch tubing horizontally opposite each other on the outer periphery of the downstream of the nostril, and uses the countercurrent effect of the airflow on the left and right sides to eliminate unidirectional pressure. This effectively solves the technical problem of excessive airflow pressure during high-flow oxygen therapy, avoids the stimulation and damage of high-pressure airflow to the patient's nasal cavity, and significantly improves the patient's treatment compliance under high-flow oxygen therapy conditions.

[0021] 2. Side-mounted porous diffused exhaust structure to create a barrier against repeated inhalation. This application employs a subnasal air intake and a multi-porous diffused exhaust structure on both sides, creating a barrier against re-inhalation during the patient's continuous respiratory cycle. The horizontally opposed air intake below the nostrils prevents CO2 from sinking to the area below the nostrils and allows it to be rapidly expelled laterally through the diffused holes on the sides. This design is particularly advantageous when the patient's respiratory rate is high (e.g., >25 breaths / min), effectively avoiding the risk of CO2 re-inhalation due to delayed exhaust.

[0022] 3. Limiting fasteners enable strapless fixation. This application uses limiting and fixing components to define the direction of the branch pipes and employs an ear-loop fixing method to achieve a stable wearing of the mask, eliminating the need for additional straps and simplifying the wearing process. It also effectively prevents the mask cups from rotating backward or falling off, improving safety and convenience. The layout of the device with the branch pipes and their interfaces has been optimized to ensure smooth airflow and reliable fixation.

[0023] 4. Support frame to prevent collapse and compression The support frame at the bottom of the bra cup effectively prevents the cup from collapsing and deforming during use, avoids squeezing the patient's nose, and ensures sufficient breathing space and wearing comfort.

[0024] 5. The membrane-type gastrointestinal tube inlet achieves self-sealing. The "one large and one small" gastrointestinal tube insertion port effectively solves the compatibility problem. It adopts a thin film structure with a straight or cross-shaped opening. In its natural state, it closes to prevent oxygen leakage. When the gastrointestinal tube is inserted, it automatically unfolds and tightly wraps the tube, achieving an adaptive sealing effect of "sealing when there is no tube and wrapping when there is a tube". This facilitates clinical operation and ensures airtightness, overcoming the shortcomings of traditional masks in terms of poor sealing and cumbersome operation when inserting gastrointestinal tubes.

[0025] In summary, this application provides a nasal oxygen mask with a simple structure, complete functions, and comfortable wear, which has significant inventiveness and novelty, and has broad prospects for clinical application. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of a basic nasal oxygen mask according to this application. This demonstrates the external structure of a basic product and the connection relationships between its components. Figure 2 This is a schematic diagram of a nasal oxygen mask with a carbon dioxide sampling line according to this application. This demonstrates the external structure and component connections of a product equipped with carbon dioxide sampling and monitoring capabilities. Figure 3 This is a schematic diagram of the external structure of the cup of a nasal oxygen mask with a carbon dioxide sampling line according to this application. Figure 4 This is a schematic diagram of the internal structure of the cup of a nasal oxygen mask with a carbon dioxide sampling tube according to this application. Explanation of each mark in the diagram: 1-Nasal cavity external cup; 2-Main tube; 3-Branch tube; 4-Gas source connector; 5-Limiting and fixing component; 6-Side exhaust port; 7-Support frame; 8-Gastrointestinal tube insertion port; 9-Outer perimeter skirt; 10-Branch tube interface; 11-Gas sampling interface; 12-Extension tube; 13-Carbon dioxide monitoring connector Detailed Implementation

[0027] The specific embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0028] Example 1: Preparation Example of a Product with a Carbon Dioxide Monitoring Interface The nasal oxygen mask of this application will be further described in detail below with reference to the specific preparation process. This preparation embodiment is intended to fully disclose the technical solution of this application so that those skilled in the art can implement it, but it is not intended to limit the scope of protection of this application.

[0029] I. Material Selection The components of the nasal oxygen mask described in this application can be made of medical polymer materials, including medical-grade soft polyvinyl chloride and silicone rubber. For example... Figure 1 As shown, this embodiment uses silicone rubber to prepare the main components for illustration.

[0030] Medical-grade silicone rubber should meet the requirements of ISO 10993 series of standards for biological evaluation of medical devices and USP Class VI standards, with a cell viability rate of ≥70% in cytotoxicity tests, a sensitization index of ≤1, and no irritation.

[0031] The specific materials selected are as follows: The nasal cavity outer cup (1), outer skirt (9), thin-film gastrointestinal tube insertion port (8), and supporting skeleton (7) are all injection molded from medical-grade liquid silicone (LSR), with a Shore A hardness of 40-60 degrees, tensile strength ≥8.0MPa, tear strength ≥25kN / m, and elongation ≥600%. Medical-grade liquid silicone conforming to ISO 10993-5 and ISO 10993-10 standards is preferred. The nasal cavity outer cup (1) also integrates a branch tube interface (10), a gas sampling interface (11), and a limiting and fixing component (5). See [link to relevant documentation]. Figure 3 .

[0032] Main tube (2) and extension tube (12): medical grade silicone tubes are used. The inner diameter of the main tube (2) is 5-6 mm and the Shore A hardness is 50-60 degrees.

[0033] Branch pipe (3) Inner diameter 2.5~3mm; wall thickness 1.0~1.5mm, Shore A hardness 50~60 degrees.

[0034] Gas source connector (4) and carbon dioxide monitoring connector (13): Made of medical grade polycarbonate (PC) or polypropylene (PP) injection molding, the material should meet the ISO 10993 biocompatibility requirements.

[0035] II. Dimensional Design of Each Component Nasal external cup (1): The cup outline conforms to the outer outline of the human nose and has a triangular cup-shaped structure. The cup height (from the root of the nose to the columella) is 35-50mm, the width (between the two sides of the nostrils) is 30-45mm, and the depth (in the direction of nasal protrusion) is 15-25mm. The cup wall thickness is 1.2-2.0mm.

[0036] Outer skirt (9): Located on the outer edge of the nasal cavity cup (1), with a width of 5-10 mm and a thickness of 0.8-1.5 mm, and integrally formed with the cup. The thickness of the skirt edge gradually decreases to 0.5-0.8 mm to enhance the fit and seal with the facial skin.

[0037] Support frame (7): Located at the bottom of the cup, it has a T-shaped structure, is integrally connected to the outer circumference of the bottom of the cup, and extends outward along the depth direction of the center line of the bottom of the cup. See [link / reference]. Figure 4 .

[0038] Gastrointestinal tube insertion port (8): There are two ports, one large and one small, located on both sides of the support frame (7). The insertion port is a thin film structure with a thickness of 0.3 to 1.0 mm and is circular. The diameter of the large insertion port is 7 mm and the diameter of the small insertion port is 4 mm. The film has a straight or cross opening in the center, which is closed in its natural state due to the elasticity of the silicone.

[0039] Side ventilation holes (6): set on the left and right sides of the cup, with 3 to 5 ventilation holes on each side, and the diameter of the holes is 2 to 5 mm.

[0040] Branch pipe interface (10): It is set on the left and right sides of the cup, and the inner diameter of the interface is 4-6mm, which is compatible with the outer diameter of the branch pipe (3).

[0041] Gas sampling interface (11): Located on the left / right sides of the cup, with an inner diameter of 4-6 mm, which is compatible with the outer diameter of the extension pipe (12).

[0042] Limiting and fixing components (5): These are located on the left and right sides of the cup, near the upper and lower center lines. They are in the form of pipe clamps or slots and are used to fix and guide the direction of the branch pipes (3). The length of the device is 10-20 mm and the width is 5-10 mm.

[0043] Main pipe (2) and extension pipe (12): length 50-100cm, inner diameter 4-6mm, wall thickness 1.0-1.5mm.

[0044] Gas source connector (4): Located at the end of the main pipe (2), it is a standard conical connector (15mm taper) that is compatible with the standard interface of the oxygen supply equipment.

[0045] Carbon dioxide monitoring connector (13): Located at the end of the extension pipe (12), it is a standard tapered connector (15mm taper) that is compatible with the standard interface of the carbon dioxide monitoring equipment.

[0046] III. Molding Process (a) such as Figure 3 , 4 As shown, the nasal cavity outer cup (1), support frame (7), outer skirt (9), thin film gastrointestinal tube insertion port (8), branch pipeline interface (10) and limiting fixation component (5) are integrally formed using liquid silicone injection molding (LSR Injection Molding) process.

[0047] The specific process steps are as follows: Step 1: Mold Preparation. A precision injection mold is designed and manufactured based on the 3D model of the nasal cavity outer cup. The mold is made of S136 or NAK80 mold steel, and the cavity surface is polished to a mirror finish (Ra≤0.2μm). The mold is equipped with a zoned temperature control system. Deep hole drilling technology is used to drill crisscrossing water channels in the mold base and inserts, forming an efficient heating / cooling circuit. The mold temperature is controlled in zones from 160 to 190℃.

[0048] Step 2: Raw material pretreatment. Medical-grade liquid silica gel (LSR) is selected, consisting of component A (base polymer) and component B (crosslinking agent), with a platinum catalyst added. Components A and B are precisely mixed in a 1:1 ratio using a dynamic mixing device, with the mixing ratio deviation controlled within ±1%. The mixture undergoes degassing treatment to eliminate air bubbles in the raw material.

[0049] Step 3: Injection Molding. Inject the uniformly mixed liquid silicone into the barrel of the injection molding machine, maintaining the barrel temperature at 20–30°C. Initially, fill the cavity rapidly at a speed of 50–100 mm / s; switch to a lower speed (10–20 mm / s) towards the end of the filling, controlling the injection pressure at 5–15 MPa. After injection, perform the vulcanization and cross-linking reaction at a mold temperature of 160–190°C. A multi-stage holding pressure strategy is employed: initial holding pressure 10–15 MPa, holding time 2–3 seconds; middle holding pressure 5–10 MPa, holding time 3–5 seconds; final holding pressure 2–5 MPa, holding time 1–2 seconds. The total vulcanization time is determined based on the product wall thickness, generally 30–90 seconds.

[0050] Step 4: Demolding and Finishing. After vulcanization, open the mold and remove the product. Use a special tool to remove burrs and excess material from the gate. Check the integrity of the membrane at the gastrointestinal tube insertion site and the shape of the slotted / cross-shaped opening.

[0051] (ii) Extrusion molding of main pipe and branch pipe The main pipe (2), extension pipe (12) and branch pipe (3) are prepared using medical-grade silicone tube extrusion molding process.

[0052] The specific process steps are as follows: Step 1: Raw material preparation. Select medical-grade solid silicone (VMQ) compound.

[0053] Step 2: Extrusion Molding. Add the compounded rubber to the hopper of a single-screw extruder, controlling the extrusion temperature at 150–170℃, with the die temperature at 170±2℃. The extruded tube is cooled in a setting water bath at 30–32℃.

[0054] Step 3: Vulcanization. The extruded pipe is continuously vulcanized through a high-temperature vulcanization channel (200-250℃).

[0055] Step 4: Cutting. Cut the vulcanized silicone tube to the designed length. The main tube (2) and extension tube (12) are cut to a length of 50-100cm, and the branch tubes are cut to a length of 20-35cm.

[0056] (iii) Injection molding of gas source connector and carbon dioxide monitoring connector (13) The gas source connector (4) and carbon dioxide monitoring connector (13) are injection molded from medical-grade polycarbonate (PC) or polypropylene (PP).

[0057] The specific process steps are as follows: Step 1: Drying. Dry the PC or PP granules at 80-120℃ for 2-4 hours to remove moisture.

[0058] Step 2: Injection Molding. Add the dried granules to the injection molding machine barrel. Barrel temperature: PC 280–310℃, PP 200–230℃. Mold temperature: PC 80–100℃, PP 40–60℃. Injection pressure: 80–150 MPa, holding pressure: 50–100 MPa, cooling time: 10–30 seconds.

[0059] Step 3: Demolding and finishing. Open the mold, remove the product, and trim the gate and flash.

[0060] IV. Component Assembly The nasal oxygen mask of this application is assembled in the following order: Step 1: Connecting branch pipes to branch pipe interfaces Insert one end of each of the two branch tubes (3) into the branch tube interfaces (10) on the left and right sides of the nasal cavity cup (1), respectively, to a depth of 10-15 mm. Use medical-grade silicone rubber adhesive (such as MED ADH 4300) for bonding and fixing. Before applying the adhesive, keep the bonding surface dry and clean, and remove any grease, dust, and release agent residue. After bonding, cure at room temperature for 24 hours, or use heat curing (60-80℃, 30 minutes) to accelerate curing.

[0061] Step 2: Installation of branch pipe (3) and limiting fastener (5) Pass the branch pipe (3) through the clamp or slot of the limiting fastener (5), and use medical-grade adhesive to bond and fix the branch pipe (3) to the branch pipe interface (10).

[0062] Step 3: Connect the main pipe to the branch pipes.

[0063] The upper end of the main pipe (2) is connected to the lower ends of the two branch pipes (3) through a tee or a Y-type connector, and the connection is fixed with medical-grade adhesive. The tee or Y-type connector is injection molded from medical-grade polycarbonate.

[0064] Step 4: Install the gas source connector.

[0065] Insert the gas source connector (4) into the end of the main pipe (2) to a depth of 15-20 mm, and fix it with medical-grade adhesive to ensure that the connection is sealed and leak-proof.

[0066] Step 5: Use medical-grade adhesive to bond and fix the head end of the extension tube (12) to the gas sampling interface (11), and bond and fix the tail end of the extension tube (12) to the carbon dioxide monitoring connector (13). Step 6: Overall inspection.

[0067] After assembly, check the sealing and firmness of each connection, check the natural closure of the membrane opening at the gastrointestinal tube inlet (8), check the unobstructedness of the side vent (6), and check the guiding direction and fixing effect of the limiting fastener (5) on the branch pipeline (3).

[0068] V. Sterilization and Packaging The assembled nasal oxygen mask was sterilized using ethylene oxide (EtO). The sterilization parameters were: ethylene oxide concentration 600–800 mg / L, temperature 45–55℃, relative humidity 40–80%, and sterilization time 3–6 hours. After sterilization, a desorption process was performed to remove residual ethylene oxide, ensuring that the residual ethylene oxide level was ≤10 μg / g.

[0069] After sterilization, the nasal oxygen masks are sealed and packaged in a Class 100,000 cleanroom, individually sealed using medical-grade dialysis paper / plastic composite film bags. The packaging is labeled with the product name, specifications, production date, expiration date, sterilization method, and a "single-use" label.

[0070] VI. Performance Testing The quality of the prepared nasal oxygen masks shall be tested according to the following items: Appearance inspection: The surface of the product should be smooth, free of cracks, bubbles, impurities, and burrs, and the color should be uniform.

[0071] Dimensional inspection: The dimensions of each component should conform to the design drawings, and the tolerance of key dimensions should be controlled within ±0.2mm.

[0072] Air tightness test: Wear the mask on a standard nose model, introduce compressed air to a pressure of 5 kPa, maintain for 30 seconds, and the pressure drop should not exceed 0.5 kPa.

[0073] Biocompatibility testing: Cytotoxicity test (cell viability ≥70%), sensitization test (sensitization index ≤1), and stimulation test (no irritant reaction) were conducted in accordance with the ISO 10993 series of standards.

[0074] Sterilization effectiveness test: The sterility test shall be performed in accordance with the method of the Pharmacopoeia of the People's Republic of China, and no sterile growth should be observed.

[0075] The nasal oxygen mask prepared by the above process has a complete structure, strong connection of all components, good sealing performance, and biocompatibility that meets the requirements of medical devices, and can be mass-produced industrially.

[0076] Example 2: Real-world clinical application In actual use, medical staff connect the gas source connector (4) to the oxygen supply equipment and connect the carbon dioxide monitoring connector (13) to the carbon dioxide monitoring equipment.

[0077] Oxygen enters the two branch lines (3) on the left and right through the main tube (2), and then enters the nasal cup (1) through the branch line interface (10). Since the two branch lines (3) are horizontally opposite each other on the left and right sides of the cup, the airflow is counteracted inside the cup, eliminating unidirectional impact and making the oxygen inhaled by the patient more gentle and comfortable.

[0078] The branch tube (3) is routed around the patient's ear, and the ear-hook fixation is achieved by using the directional path defined by the limiting fixation piece (5), without the need for additional straps. After the patient wears it, the nasal cavity cup (1) only covers the nose, and the oral cavity is completely exposed, allowing the patient to speak and eat normally.

[0079] The carbon dioxide exhaled by the patient is quickly expelled from the cup through the side exhaust ports (6) on both sides, and will not remain inside the cup. During this period, the carbon dioxide monitoring device dynamically extracts the patient's exhaled gas to monitor the carbon dioxide concentration.

[0080] When a patient needs a gastrointestinal tube, the tube is inserted through the straight or cross-shaped openings of the gastrointestinal tube insertion ports (8) on both sides of the supporting frame (7). The membrane-like structure naturally unfolds and tightly wraps the gastrointestinal tube, preventing it from falling off and preventing oxygen leakage. When the gastrointestinal tube is not needed, the membrane opening remains closed due to its natural elasticity, preventing oxygen leakage.

[0081] The outer edge (9) comes into contact with the patient's facial skin, increasing the contact area, dispersing pressure, and ensuring the comfort and stability of wearing.

[0082] In high-flow-rate oxygen therapy scenarios (e.g., oxygen flow rate ≥15L / min), traditional nasal cannulas can easily irritate the nasal cavity due to excessive airflow, while traditional face masks can hinder patient communication by covering the mouth and nose. The nasal oxygen mask of this application, with its horizontally opposed airflow counteracting design of branched tubing on both sides, effectively disperses and counteracts the pressure generated by high-flow-rate airflow, ensuring patient comfort even during high-flow-rate oxygen therapy. Simultaneously, because the mouth is not covered, patients can communicate normally with medical staff and eat and drink normally, greatly improving the patient experience in high-flow-rate oxygen therapy scenarios.

[0083] Industrial applicability

[0084] The nasal oxygen mask of this application has a simple structure and low manufacturing cost. It can be mass-produced using medical-grade silicone or plastic materials through injection molding or compression molding processes. It is suitable for promotion and application in medical institutions at all levels and has good industrial practicality and market prospects.

[0085] The above figures and embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the spirit and scope of the technical solutions of this application. All such modifications or substitutions should be covered within the scope of the claims of this application and do not constitute any limitation on the scope of protection of this application.

Claims

1. A nasal oxygen mask with an airflow counter-current structure, characterized in that, include: Nasal cavity external cup (1), the nasal cavity external cup (1) only covers the periphery of the patient's nasal cavity and does not cover the oral cavity area; Branch pipe (3), the branch pipe (3) is horizontally opposed on the outer periphery downstream of the nostril and is set on the left and right sides of the cup. Its air inlet is horizontally opposed inside the cup to form an airflow collision zone. Limiting and fixing component (5), the limiting and fixing component (5) is set near the upper and lower center line of the cup, limiting and changing the direction of the branch tube (3), so that the branch tube (3) extends to the patient's ear according to the predetermined trajectory, forming an ear-hook fixing path; Side exhaust vents (6) are provided on the left and right sides of the cup, and the carbon dioxide exhaled by the patient can be quickly discharged outside the cup through the side exhaust vents. The support frame (7) is set in the bottom area or outer periphery of the cup to form a structural support for the cup and prevent the cup from collapsing and deforming during use. Gastrointestinal tube insertion port (8), the gastrointestinal tube insertion port (8) is located at the bottom of the cup, the gastrointestinal tube insertion port (8) is a thin film structure and has a single or cross opening. The opening is closed in the natural state. When the gastrointestinal tube is inserted, the opening of the thin film naturally unfolds and tightly wraps the gastrointestinal tube. Outer skirt (9), the outer skirt (9) is set on the outer periphery of the bra cup.

2. The nasal oxygen mask according to claim 1, characterized in that, The side exhaust port (6) adopts a multi-hole diffuse array layout and is set on the left and right side walls of the nasal cavity outer cup (1). Each of the two sides has 3 to 5 micro holes. The total cross-sectional area of ​​the micro holes is 1.2 to 1.5 times the total air intake cross-sectional area of ​​the branch pipe (3), and the diameter of a single hole is 2 to 5 mm.

3. The nasal oxygen mask according to claim 2, characterized in that, The porous diffused exhaust structure is located in the middle and rear part of the side wall of the cup, corresponding to the outer projection area of ​​the human nose.

4. The nasal oxygen mask according to claim 1, characterized in that, The supporting frame (7) is set at the bottom of the cup, specifically at the midline of the bottom of the cup between the patient's two nostrils, and is in the shape of a straight line or a T-shape.

5. The nasal oxygen mask according to claim 1, characterized in that, The gastrointestinal tube insertion port (8) is provided with two ports, one large and one small. The large port is compatible with gastrointestinal tubes with an outer diameter of 12Fr to 20Fr, and the small port is compatible with gastrointestinal tubes with an outer diameter of 4Fr to less than 12Fr.

6. The nasal oxygen mask according to claim 1, characterized in that, The outer skirt (9) and the limiting fastener (5) are designed as an integrated unit. The limiting fastener (5) is integrated on the outer skirt (9). The plane where the limiting fastener (5) and the outer skirt (9) are located is at a 60° to 90° angle. The limiting fastener (5) is provided with a branch conduit limiting hole in the middle.

7. The nasal oxygen mask according to claim 1, characterized in that, The cup is provided with a gas sampling interface (11) on its side wall. The sampling interface is connected to an external carbon dioxide concentration monitoring device through an extension tube (12) to monitor the carbon dioxide concentration exhaled by the patient in real time.

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