Adjustable subglottic suction negative pressure control method and liquid storage system

Abstract

The invention discloses an adjustable subglottic suction negative pressure control method which comprises the following steps: setting negative pressure according to individual characteristics; the central negative pressure system is started, and the device automatically and continuously sucks and removes secretions above the air bag through negative pressure; the sucked secretions directly flow into a liquid collecting bottle arranged in the device; when a microbial specimen needs to be reserved, the central negative pressure system and the rotatable liquid outlet at the lower end of the liquid collecting bottle are closed before operation, secretions are received by a sterile container after the connector is unscrewed, the secretions are submitted for inspection and culture, and the liquid outlet is screwed again after the specimen is reserved. According to the invention, the accuracy of negative pressure setting is ensured, the initial adhesion resistance and pollution risk are reduced, the nursing efficiency is improved, the labor intensity is reduced, and the risks of mucous membrane injury, airway infection, biofilm formation and the like are obviously reduced.

Description

Technical Field

[0001] The present invention relates to the medical field, and in particular to an adjustable subglottic suction negative pressure control method and a liquid storage system. Background Art

[0002] In modern medicine, subglottic suctioning is an important method for preventing ventilator-associated pneumonia (VAP) in mechanically ventilated patients. By clearing secretions accumulated above the endotracheal tube cuff, this technique effectively reduces the risk of secretions being aspirated into the lower respiratory tract, thereby reducing the incidence of lung infections. However, existing technologies have the following shortcomings in terms of negative pressure control, secretion management, infection prevention and control, and nursing efficiency:

[0003] 1. Traditional subglottic suction devices mostly use a fixed negative pressure mode, which cannot be precisely adjusted according to individual patient differences (such as age, condition, secretion volume and mucosal tolerance). For patients with sensitive mucosa (such as the elderly or early postoperative patients), fixed high negative pressure can easily lead to airway mucosal damage, bleeding or edema; and for patients with thick secretions (such as those in the acute stage of lung infection), fixed low negative pressure may not be able to completely remove secretions due to insufficient suction, increasing the risk of biofilm formation and airway obstruction. In addition, existing devices lack effective means to monitor negative pressure changes in real time, making it difficult to intervene in time in negative pressure abnormalities caused by secretions blocking the pipeline or liquid level fluctuations.

[0004] 2. In clinical practice, collecting microbial specimens is a key step in assessing infection types and guiding antibiotic use. Traditional methods require medical staff to manually close the negative pressure system, remove the tubing, and collect secretions in a container. This process is cumbersome and prone to leakage or contamination, increasing the nursing workload and potentially contaminating specimens due to improper operation, affecting the accuracy of test results. Furthermore, secretions can adhere to and remain in the suction tubing. Traditional devices often use manual pre-flushing, which is not only time-consuming and labor-intensive, but also unstable and can easily increase the initial adhesion resistance of secretions, affecting suction efficiency.

[0005] 3. On the one hand, existing subglottic suction devices lack an effective physical barrier to prevent secretions from flowing back. When the device is accidentally tilted or the negative pressure system fails, the secretions in the collection bottle may flow back into the airway or negative pressure pipeline, increasing the risk of cross-infection. On the other hand, the inner wall of the suction pipeline is mostly made of ordinary materials, and it is difficult to completely remove the secretions after adhesion. Long-term use can easily form biofilms, which become a breeding ground for pathogens. In addition, traditional devices mostly sterilize the pipeline by regular disassembly and disinfection, which cannot achieve dynamic sterilization during the suction process, resulting in limited infection prevention and control effects.

[0006] 4. Traditional subglottic suction operations require medical staff to frequently manually adjust the negative pressure, observe the status of secretions, and deal with problems such as pipeline blockage. The nursing workload is large and the efficiency is low. At the same time, there is a lack of real-time data monitoring and transmission functions. Medical staff cannot remotely obtain the patient's suction status and physiological indicators (such as airway pressure, mucosal impedance, etc.), making it difficult to detect abnormal conditions and intervene in time. When pipeline blockage causes a sudden increase in negative pressure, if it is not handled in time, it may cause serious airway complications.

[0007] Therefore, those skilled in the art are committed to providing an adjustable subglottic suction negative pressure control method and liquid storage system that can effectively solve the above technical problems. Summary of the Invention

[0008] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is to provide a

[0009] To achieve the above object, the present invention provides an adjustable subglottic suction negative pressure control method, the method comprising the following steps:

[0010] Set negative pressure according to individual characteristics;

[0011] The negative pressure setting according to individual characteristics specifically includes injecting sterile liquid into the liquid-sealed bottle, adjusting the negative pressure level according to the liquid height, and using a distance sensor to monitor the liquid level in real time to calibrate the negative pressure; the distance sensor transmits a continuously frequency-modulated ultrasonic signal and calculates the distance using the phase difference after the signal is reflected on the liquid surface, thereby achieving dynamic calibration of the negative pressure level; thereby achieving personalized negative pressure setting and avoiding mucosal damage or incomplete secretion removal;

[0012] Turn on the central negative pressure system, and the device automatically and continuously uses negative pressure suction to remove secretions above the airbag; during the suction process, medical staff do not need to frequently perform manual operations, reducing the nursing workload; at the same time, observe the amount, color and properties of the secretions in the collection bottle. If any abnormality is found (such as bloody secretions), immediately reduce the negative pressure or suspend suction and evaluate the patient's mucosal condition.

[0013] The secretions sucked out flow directly into the collection bottle built into the device;

[0014] When collecting microbial specimens, turn off the central negative pressure system before proceeding. Unscrew the screw-down drain port at the bottom of the collection bottle to collect secretions in a sterile container for testing and culture. Retighten the drain port after collecting the specimen to avoid leakage or contamination.

[0015] Furthermore, the individual characteristics specifically include the patient's age, condition, secretion volume, and mucosal tolerance;

[0016] The negative pressure setting includes patients with less secretions (sensitive mucosa) and patients with thick secretions. The patients with less secretions are injected with liquid, and the liquid position is one-third of the scale of the liquid seal bottle to form a low negative pressure (-20 to ); When the patient with thick secretions injects liquid, the liquid position is two-thirds of the liquid seal bottle scale or full bottle; forming a medium-high negative pressure (-40 to );

[0017] The liquid seal bottle is provided with a distance measuring sensor, and the distance measuring sensor specifically includes:

[0018] By emitting a continuous frequency modulated ultrasonic signal with a frequency range of f1 to f2, the distance is calculated using the phase difference after the signal is reflected on the liquid surface in the liquid-sealed bottle, where the emitted signal is S tx , the received signal is S rx (t), the S tx The mathematical expression is:

[0019]

[0020] Among them S tx (t) represents the variation of the transmitted signal over time;

[0021] A represents the amplitude of the signal, which determines the strength of the signal;

[0022] represents the center frequency;

[0023] Δf=f2~f1 represents the frequency modulation bandwidth;

[0024] The S rx The mathematical expression of (t) is,

[0025]

[0026] Where 2πfo(tT) represents the phase change of the center frequency signal caused by the time delay T due to the propagation distance d;

[0027] It represents the core part of the FM signal, reflecting the characteristic of linear change of frequency over time (frequency increases or decreases over time). By analyzing the frequency change gradient of the reflected signal, the distance d can be solved.

[0028] φo is used to compensate for the random phase offset caused by the inherent error of the sensor hardware or the reflective surface (such as liquid level fluctuation); to ensure the benchmark consistency of the phase difference calculation; the distance sensor monitors the liquid level in the liquid seal bottle in real time to dynamically calibrate the negative pressure level to ensure the accuracy of the negative pressure setting.

[0029] Furthermore, it also includes performing Fourier transform (FFT) on the transmitted signal and the received signal, converting them into the frequency domain and extracting the phase difference of each frequency component:

[0030] Δφ(f)=φrx(f)-φtx(f)=2πfT+φ noise

[0031] Where Δφ(f) is the phase difference in the frequency domain at frequency f;

[0032] φrx(f) is the phase of the received signal at frequency f;

[0033] φtx(f) is the phase of the transmitted signal at frequency f;

[0034] f is the frequency of the ultrasonic signal;

[0035] T is the one-way time delay of ultrasonic wave from emission to reception;

[0036] φ noise is the random phase disturbance caused by environmental noise;

[0037] The phase difference of multiple frequency points in the frequency domain is fitted by the least squares method to eliminate noise interference and obtain the linear phase difference slope. The distance formula is By performing Fourier transform on the transmitted and received signals, the phase difference is extracted to calculate the liquid level, and the negative pressure level is adjusted in real time.

[0038] Furthermore, anti-interference and data transmission optimization are also included. Specifically, beamforming technology is incorporated into the sensor probe design. An array transducer focuses the main beam, suppressing multipath interference such as bottle wall reflections. Time-division multiplexing and Manchester encoding are used to package the ranging data into a fixed frame structure, which is then transmitted to the central monitoring system via Bluetooth Low Energy or a wired CAN bus. This avoids interruptions caused by wireless signal congestion or poor wired connections. These anti-interference and data transmission optimization technologies ensure the accuracy of ranging data, enabling precise calibration of negative pressure levels.

[0039] Furthermore, the automatic continuous negative pressure suction of the device to remove secretions above the airbag specifically includes:

[0040] Intelligent dynamic negative pressure regulating unit, the intelligent dynamic negative pressure regulating unit includes a pressure sensor (accuracy ), mucosal impedance detection electrodes and optical scattering sensors, dynamically adjust the negative pressure level and suction mode through fuzzy logic algorithm; used to monitor the patient's airway pressure, mucosal status and secretion viscosity in real time through multiple parameters, combined with adaptive algorithms to dynamically match the negative pressure level and suction mode, to achieve accurate removal of secretions while reducing the risk of mucosal damage.

[0041] Anti-reflux and infection control unit, used to build a sterile closed-loop suction path to prevent secretions from flowing back into the airway or environment, reducing the risk of cross-infection and biofilm formation;

[0042] The data management unit is used to track the device's operating status and patients' physiological indicators in real time, improving nursing efficiency and shortening abnormal response time.

[0043] Furthermore, the intelligent dynamic negative pressure adjustment unit includes a built-in pressure sensor and a bioelectric monitoring module, which detects the mucosal impedance value in real time through the mucosal impedance detection electrode, analyzes the secretion transmittance using an optical scattering sensor, establishes a three-dimensional mapping model based on the fuzzy logic control algorithm, and dynamically matches the negative pressure level; it can collect the patient's airway pressure, mucosal impedance value and secretion viscosity data in real time; the pressure sensor has an accuracy of Continuously monitor the negative pressure fluctuations in the suction circuit to avoid sudden pressure increases or decreases caused by secretions blocking the circuit in the traditional fixed negative pressure mode;

[0044] The microcurrent electrode (attached to the end of the suction tube) detects mucosal impedance in real time. When the impedance value is lower than the threshold (indicating the risk of mucosal edema or damage), the system automatically triggers the negative pressure reduction mechanism;

[0045] The optical scattering principle (infrared transmitting and receiving tubes) is used to analyze the transmittance of secretions, distinguishing between thin (transmittance > 60%), medium (30%-60%), and thick (<30%) states, and dynamically matching the negative pressure level.

[0046] Based on the fuzzy logic control algorithm, a three-dimensional mapping model (patient characteristics, secretion status, and negative pressure parameters) was established;

[0047] For patients with thin secretions and sensitive mucosa (such as elderly or early postoperative patients), the initial negative pressure setting is -20 to When the suction volume is detected to be <5 mL / h for three consecutive times, the machine enters the intermittent suction mode to reduce mechanical stimulation of the mucosa.

[0048] For patients with thick secretions, the initial negative pressure setting is -40 to If the suction volume is >50mL / h for 2 consecutive hours and the viscosity does not decrease, the system triggers pulse suction with a negative pressure of -40 to The frequency of the pressure dropper fluctuates at 2 Hz, which enhances the stripping effect on sticky secretions and avoids mucosal damage caused by a single high negative pressure.

[0049] Furthermore, the anti-reflux and infection control unit is provided with a pressure-sensitive double valve at the connection between the suction line and the liquid collection bottle to form a physical barrier to prevent the backflow of secretions; the inner wall of the suction tube adopts a hydrophobic environment design and integrates an ultraviolet dynamic disinfection module; a pressure-sensitive double valve is provided at the connection between the suction line and the liquid collection bottle. During normal suction, the upstream valve opens and the downstream valve closes to ensure that the secretions flow into the liquid collection bottle in one direction; when the device is accidentally tilted or the negative pressure system fails, resulting in a sudden drop in pressure, the double valves close at the same time to form a physical barrier to prevent the secretions in the liquid collection bottle from backflowing into the airway or negative pressure pipe;

[0050] The suction tube adopts a hydrophobic inner wall design and is made of medical-grade polypropylene (meets sterility standards) to reduce the adhesion and retention of secretions. It also integrates an ultraviolet dynamic disinfection module to sterilize the inner wall of the tube after each suction cycle. The liquid collection bottle adopts a gas-liquid isolation chamber structure, and secretions directly enter the liquid storage chamber through the bottom guide groove, and the upper gas is discharged through an independent filtration channel. The physical barrier (double valve) and gas-liquid isolation design provide dual protection, effectively preventing secretions from flowing back into the airway or negative pressure pipeline, reducing the risk of cross-infection. The combination of a hydrophobic environment and ultraviolet dynamic sterilization reduces secretion retention and inhibits biofilm formation, improving infection prevention and control effects, and is especially suitable for patients with low immunity.

[0051] Furthermore, the entire device is sterilely packaged, and all pipeline interfaces are sterile in design. Before the device is started, 37°C sterile saline is injected into the suction pipeline through the built-in peristaltic pump to flush the inner wall and form a moist interface; this solves the problem that traditional manual pre-flushing operations are time-consuming and prone to contamination, while reducing the initial adhesion resistance of secretions.

[0052] The data management unit uploads data to the hospital's central monitoring system in real time, including real-time negative pressure values, suction volume, secretion status operating parameters; patient physiological indicators such as mucosal impedance trend curves and airway pressure fluctuation maps; device fault warnings (such as pipeline blockage, low battery, filter membrane saturation, etc.); medical staff can remotely view the suction status of the patients in their charge through mobile terminals (such as PDAs or mobile phone APPs), and send a warning message when the system detects abnormal data (such as suction volume of 0 for 10 consecutive minutes and negative pressure >-80cmH2O, indicating pipeline blockage). The warning information is sent to the responsible nurse workstation to shorten the fault response time; digital management improves nursing efficiency, and medical staff can remotely grasp the patient's status in real time, reduce the number of bedside patrols, and shorten the response time to abnormal situations; automatic warning functions (such as pipeline blockage, negative pressure abnormalities) reduce the risk of manual monitoring omissions and improve treatment safety and medical and nursing collaboration efficiency.

[0053] Furthermore, before setting the negative pressure, the procedure also includes removing the disposable adjustable subglottic suction and fluid reservoir integrated device, confirming that the device is externally intact and that all pipes are securely connected. Sterile distilled water or saline is injected into the negative pressure liquid seal bottle through the device's water inlet, controlling the amount of water injected based on the patient's condition and suction needs. The device's external pipes are connected to the hospital's central negative pressure system interface and the subglottic suction tube interface of the patient's endotracheal tube, ensuring a tight connection with no leaks.

[0054] A liquid storage system, characterized in that it comprises:

[0055] The liquid collection bottle is used to collect the secretions sucked out. It adopts a gas-liquid isolation cabin structure inside. The secretions enter the liquid storage chamber through the bottom guide groove, and the upper gas is discharged through an independent filter channel to avoid aerosol contamination.

[0056] Liquid-sealed bottles, which form different negative pressure levels by injecting sterile liquid;

[0057] Suction tube, used to transfer secretions;

[0058] The liquid collection bottle and the liquid seal bottle are connected by a double valve, and a hydrophobic coating is provided on the inner wall of the suction pipeline to reduce the retention of secretions.

[0059] The pressure-sensitive double valve is installed at the connection between the suction line and the liquid collection bottle. It opens in one direction during normal suction and closes in the event of accidental tilt or sudden pressure drop to prevent secretions from flowing back.

[0060] Peristaltic pump: used to inject water into the suction line, pre-flushing the line and reducing the adhesion resistance of secretions;

[0061] Multi-parameter monitoring module: real-time data collection for dynamic adjustment of negative pressure.

[0062] The present invention has the following beneficial effects:

[0063] 1. According to the patient's age, condition, secretion volume and mucosal tolerance, the low or medium-high negative pressure can be accurately set by the amount of water injected into the liquid seal bottle, avoiding damage to patients with sensitive mucosa or insufficient removal of thick secretions caused by the traditional fixed negative pressure mode;

[0064] 2. By emitting continuous frequency-modulated ultrasonic signals and using phase difference to accurately calculate the liquid level, combined with Fourier transform and least squares method to eliminate noise interference, dynamic monitoring and real-time calibration of the negative pressure level are achieved to ensure the accuracy of the negative pressure setting;

[0065] 3. One-way flow during normal suction, closed in the event of accidental tilt or sudden pressure drop. The physical barrier prevents secretions from flowing back into the airway or negative pressure pipe. The hydrophobic environment on the inner wall of the suction tube reduces adhesion, ultraviolet dynamic disinfection sterilizes every cycle, and the gas-liquid isolation chamber structure of the liquid collection bottle prevents aerosol contamination.

[0066] 4. The built-in peristaltic pump injects sterile saline to automatically pre-flush the pipeline to form a wet interface, replacing manual operation and reducing initial adhesion resistance and contamination risk;

[0067] 5. Automatic continuous suction eliminates the need for frequent manual operations, simplifies the specimen collection process, improves nursing efficiency, and reduces labor intensity;

[0068] 6. Dynamic negative pressure regulation and anti-reflux design significantly reduce the risks of mucosal damage, airway infection, biofilm formation, etc., and are especially suitable for elderly, postoperative and critically ill patients. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 It is a schematic flow chart of the adjustable subglottic suction negative pressure control method of the present invention.

[0070] Figure 2 It is a schematic diagram of the liquid storage system of the present invention.

[0071] Figure 3 It is a partial structural diagram of this device. DETAILED DESCRIPTION

[0072] The present invention will be further described below with reference to the accompanying drawings and examples:

[0073] In the description of the present invention, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0074] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "installed," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0075] like Figures 1 to 3 As shown, a method for controlling the adjustable subglottic suction negative pressure comprises the following steps:

[0076] S1: Set negative pressure according to individual characteristics;

[0077] The negative pressure setting according to individual characteristics specifically includes injecting sterile liquid into the liquid-sealed bottle, adjusting the negative pressure level according to the liquid height, and using a distance sensor to monitor the liquid level in real time to calibrate the negative pressure; the distance sensor transmits a continuously frequency-modulated ultrasonic signal and calculates the distance using the phase difference after the signal is reflected on the liquid surface, thereby achieving dynamic calibration of the negative pressure level; thereby achieving personalized negative pressure setting and avoiding mucosal damage or incomplete secretion removal;

[0078] S2: The central negative pressure system is turned on, and the device automatically and continuously uses negative pressure to remove secretions above the airbag; the device specifically includes a liquid collection bottle, a liquid sealing bottle (with a rotatable liquid discharge port 105), a suction pipeline, a pressure-sensitive double valve, a multi-parameter monitoring module, and an intelligent control unit;

[0079] During the suction process, medical staff do not need to frequently perform manual operations, reducing the nursing workload; at the same time, observe the amount, color and properties of the secretions in the collection bottle. If any abnormality is found (such as bloody secretions), immediately reduce the negative pressure or suspend suction and evaluate the patient's mucosal condition.

[0080] S3: The secretions aspirated flow directly into the collection bottle built into the device;

[0081] S4: When collecting microbial specimens, turn off the central negative pressure system before proceeding. Unscrew the screw-down drain port at the bottom of the collection bottle, collect the secretions in a sterile container, and send them for testing and culture. After collecting the specimen, re-tighten the drain port to avoid leakage or contamination.

[0082] The individual characteristics specifically include the patient's age, condition, secretion volume, and mucosal tolerance;

[0083] The negative pressure setting includes patients with less secretions (sensitive mucous membranes) and patients with thick secretions. The patients with less secretions are injected with liquid, and the liquid position is one-third of the scale of the liquid seal bottle. In the present invention, a scale 102 can be set on the liquid collection bottle 100 and the liquid seal bottle 101 to form a low negative pressure (-20 to ); When the patient with thick secretions injects liquid, the liquid position is two-thirds of the liquid seal bottle scale or full bottle; forming a medium-high negative pressure (-40 to Precisely adjust the negative pressure level based on individual patient differences, preventing damage to sensitive mucosa or incomplete removal of thick secretions caused by fixed negative pressure, thereby improving treatment safety and effectiveness. Negative pressure is intuitively controlled by the amount of water in the liquid seal bottle, making operation simple and quantifiable.

[0084] The liquid seal bottle is provided with a distance measuring sensor, and the distance measuring sensor specifically includes:

[0085] By emitting a continuous frequency modulated ultrasonic signal with a frequency range of f1 to f2, the distance is calculated using the phase difference after the signal is reflected on the liquid surface in the liquid-sealed bottle, where the emitted signal is S tx , the received signal is S rx (t), the S tx The mathematical expression is:

[0086]

[0087] Among them S tx (t) represents the variation of the transmitted signal over time;

[0088] A represents the amplitude of the signal, which determines the strength of the signal;

[0089] represents the center frequency;

[0090] Δf=f2~f1 represents the frequency modulation bandwidth;

[0091] The S rx The mathematical expression of (t) is,

[0092]

[0093] Where 2πfo(tT) represents the phase change of the center frequency signal caused by the time delay T due to the propagation distance d;

[0094] It represents the core part of the FM signal, reflecting the characteristic of linear change of frequency over time (frequency increases or decreases over time). By analyzing the frequency change gradient of the reflected signal, the distance d can be solved.

[0095] φo is used to compensate for the inherent error of the sensor hardware or the random phase offset caused by the reflective surface (such as liquid level fluctuation); it ensures the baseline consistency of the phase difference calculation.

[0096] The distance measuring sensor monitors the liquid level in the liquid seal bottle in real time to dynamically calibrate the negative pressure level to ensure the accuracy of the negative pressure setting.

[0097] It also includes Fourier transform (FFT) of the transmitted and received signals, converting them to the frequency domain and extracting the phase difference of each frequency component:

[0098] Δφ(f)=φrx(f)-φtx(f)=2πfT+φ noise

[0099] Where Δφ(f) is the phase difference in the frequency domain at frequency f;

[0100] φrx(f) is the phase of the received signal at frequency f;

[0101] φtx(f) is the phase of the transmitted signal at frequency f;

[0102] f is the frequency of the ultrasonic signal;

[0103] T is the one-way time delay of ultrasonic wave from emission to reception;

[0104] φ noise is the random phase disturbance caused by environmental noise;

[0105] The phase difference of multiple frequency points in the frequency domain is fitted by the least squares method to eliminate noise interference and obtain the linear phase difference slope. The distance formula is By performing Fourier transform on the transmitted and received signals, the phase difference is extracted to calculate the liquid level, and the negative pressure level is adjusted in real time.

[0106] In the distance measurement sensor of the present invention, mathematical formulas such as Fourier transform work closely with hardware to achieve accurate distance measurement:

[0107] Taking the laser ranging sensor as an example, the hardware part mainly includes the laser, receiver and signal processing circuit. The laser emits a laser pulse, which is reflected by the target object and captured by the receiver. The received signal obtained from the hardware is a time domain signal that changes with time. In practical applications, in order to better analyze the signal characteristics and extract information related to the distance, the time domain signal is converted into a frequency domain signal using Fourier transform; for example, the received signal is sampled through the hardware circuit to obtain a series of signal values at discrete time points; these discrete data are transmitted to the signal processing chip (such as the digital signal processor DSP) and the algorithm program pre-written in the chip is used. To perform Fourier transform calculations; some high-performance ranging sensors use a dedicated digital signal processing chip (DSP), which integrates a hardware acceleration unit for the fast Fourier transform (FFT). This chip can quickly and efficiently convert the time domain signal obtained from the receiver into a frequency domain signal. Compared with pure software algorithm implementation, this effectively improves the signal processing speed and meets the ranging scenarios with high real-time requirements. Through the Fourier transform, we can clearly see the distribution of the signal at different frequencies, and then analyze the characteristics of the reflected signal, compare it with the transmitted signal, and combine it with physical constants such as the speed of light to accurately calculate the distance to the target object.

[0108] In an ultrasonic ranging sensor, the hardware's ultrasonic transducer is responsible for transmitting and receiving ultrasonic signals. Similarly, after the received ultrasonic signal undergoes preliminary processing by hardware circuits such as amplification and filtering, it is also subjected to Fourier transform analysis in a similar manner. Since ultrasonic waves are affected by various factors during propagation, the frequency characteristics of their echo signals contain information such as distance and target object material. By performing a Fourier transform on the received signal, converting it from the time domain to the frequency domain and analyzing the frequency domain characteristics, the target distance can be more accurately calculated. For example, after the hardware circuit converts the received ultrasonic echo signal into an electrical signal, it is transmitted to a microcontroller (MCU) or a dedicated signal processing chip, where the Fourier transform algorithm is executed within the chip to obtain frequency domain data, thereby achieving accurate distance measurement.

[0109] Ultrasonic phase difference ranging technology is used to achieve real-time and accurate monitoring of the liquid level in the liquid-sealed bottle, ensuring that the negative pressure level is consistent with the preset value and avoiding unstable negative pressure caused by liquid level fluctuations; combining frequency domain analysis and algorithm optimization (such as the least squares method) to effectively suppress environmental noise interference and improve data reliability.

[0110] It also includes anti-interference and data transmission optimization, specifically including the introduction of beamforming technology in the sensor probe design, focusing the main beam through an array transducer (such as four micro-probes distributed in a cross shape), suppressing multipath interference such as bottle wall reflection; using time division multiplexing (TDM) and Manchester encoding, the ranging data (phase difference, frequency, temperature compensation value, etc.) are packaged into a fixed frame structure and transmitted to the central monitoring system via low-power Bluetooth 5.2 (BLE) or wired CAN bus. Avoid interruptions caused by wireless signal congestion or poor wired contact. The anti-interference and data transmission optimization technology is used to ensure the accuracy of the ranging data to achieve precise calibration of the negative pressure level.

[0111] The automatic continuous negative pressure suction of the device to remove secretions above the airbag specifically includes:

[0112] Intelligent dynamic negative pressure regulating unit, the intelligent dynamic negative pressure regulating unit includes a pressure sensor (accuracy ), mucosal impedance detection electrodes and optical scattering sensors, dynamically adjust the negative pressure level and suction mode through fuzzy logic algorithm; used to monitor the patient's airway pressure, mucosal status and secretion viscosity in real time through multiple parameters, combined with adaptive algorithms to dynamically match the negative pressure level and suction mode, to achieve accurate removal of secretions while reducing the risk of mucosal damage.

[0113] Anti-reflux and infection control unit, used to build a sterile closed-loop suction path to prevent secretions from flowing back into the airway or environment, reducing the risk of cross-infection and biofilm formation;

[0114] The data management unit is used to track the device's operating status and patients' physiological indicators in real time, improving nursing efficiency and shortening abnormal response time.

[0115] The intelligent dynamic negative pressure adjustment unit includes a built-in pressure sensor and a bioelectric monitoring module. The device detects the mucosal impedance value in real time through the mucosal impedance detection electrode, uses an optical scattering sensor to analyze the transmittance of secretions, establishes a three-dimensional mapping model based on the fuzzy logic control algorithm, and dynamically matches the negative pressure level. It can collect the patient's airway pressure, mucosal impedance value (reflecting the health status of the mucosa) and secretion viscosity data in real time; the pressure sensor has an accuracy of Continuously monitor the negative pressure fluctuations in the suction circuit to avoid sudden pressure increases or decreases caused by secretions blocking the circuit in the traditional fixed negative pressure mode;

[0116] The microcurrent electrode (attached to the end of the suction tube) detects mucosal impedance in real time. When the impedance value is lower than the threshold (indicating the risk of mucosal edema or damage), the system automatically triggers the negative pressure reduction mechanism;

[0117] The optical scattering principle (infrared transmitting and receiving tubes) is used to analyze the transmittance of secretions, distinguishing between thin (transmittance > 60%), medium (30%-60%), and thick (<30%) states, and dynamically matching the negative pressure level.

[0118] Based on the fuzzy logic control algorithm, a three-dimensional mapping model (patient characteristics, secretion status, and negative pressure parameters) was established;

[0119] For patients with thin secretions and sensitive mucosa (such as elderly or early postoperative patients), the initial negative pressure setting is -20 to When the suction volume is detected to be <5 mL / h for three consecutive times, enter the intermittent suction mode (suction for 5 minutes, pause for 10 minutes) to reduce mechanical stimulation of the mucosa.

[0120] For patients with thick secretions (such as those in the acute phase of lung infection), the initial negative pressure setting is -40 to - If the suction volume is >50mL / h for 2 consecutive hours and the viscosity does not decrease, the system triggers pulse suction with a negative pressure of -40 to The frequency fluctuates at 2Hz, enhancing the stripping effect on sticky secretions while avoiding mucosal damage caused by a single high negative pressure. Real-time dynamic adjustment of negative pressure avoids pressure abnormalities caused by secretion blockage or mucosal sensitivity in traditional fixed modes, significantly reducing the risk of mucosal damage, bleeding, or edema. Furthermore, the suction mode automatically switches according to different secretion states (thin or thick) (such as pulsed suction to enhance the stripping effect), improving secretion removal efficiency and reducing the risk of biofilm formation.

[0121] The anti-reflux and infection control unit is provided with a pressure-sensitive double valve at the connection between the suction line and the liquid collection bottle to form a physical barrier to prevent the backflow of secretions; the inner wall of the suction tube adopts a hydrophobic environment design and integrates an ultraviolet dynamic disinfection module; a pressure-sensitive double valve is provided at the connection between the suction line and the liquid collection bottle. During normal suction, the upstream valve (close to the patient end) opens and the downstream valve (close to the negative pressure source end) closes to ensure that the secretions flow into the liquid collection bottle in one direction; when the device is accidentally tilted or the negative pressure system fails, resulting in a sudden drop in pressure, the double valves close at the same time to form a physical barrier to prevent the secretions in the liquid collection bottle from backflowing into the airway or negative pressure pipe;

[0122] The suction tube adopts a hydrophobic inner wall design (surface energy <20mN / m) and is made of medical-grade polypropylene (in compliance with sterility standards) to reduce the adhesion and retention of secretions; it also integrates an ultraviolet dynamic disinfection module (wavelength 254nm, irradiation intensity ≥10000μW·s / cm 2 The inner wall of the tube is sterilized by irradiation after each suction cycle (i.e., suction and pause period). The liquid collection bottle adopts a gas-liquid isolation chamber structure. Secretions enter the liquid storage chamber directly through the bottom guide groove, and the upper gas is discharged through an independent filtration channel (0.22μm hydrophobic filter membrane). This prevents aerosol contamination of the ward environment.

[0123] The entire device is sterilely packaged, and all pipeline interfaces are sterile in design. Before the device is started, 37°C sterile saline is injected into the suction pipeline through the built-in peristaltic pump (priming volume 5-10mL, automatically adjusted according to the length of the pipeline) to flush the inner wall and form a moist interface; this solves the problem that traditional manual pre-flushing operations are time-consuming and easy to contaminate, while reducing the initial adhesion resistance of secretions.

[0124] The data management unit uploads data to the hospital's central monitoring system in real time, including real-time negative pressure value, suction volume, secretion status operating parameters; mucosal impedance trend curve, airway pressure fluctuation map and other patient physiological indicators; device failure warning (such as pipeline blockage, low battery power, filter membrane saturation, etc.); medical staff can remotely view the suction status of the patients in charge through mobile terminals (such as PDA or mobile phone APP). When the system detects abnormal data (such as suction volume of 0 for 10 consecutive minutes and negative pressure), the system will automatically check the suction status of the patients in charge. When a warning message (such as a blocked pipeline) is sent, it will be sent to the responsible nurse workstation to shorten the fault response time.

[0125] Before setting the negative pressure, the procedure also involves removing the disposable adjustable subglottic suction and fluid reservoir integrated device, confirming that the device is externally intact and that all connections (including the central negative pressure connecting tube and subglottic suction tube) are secure. Sterile distilled water or saline solution is injected into the negative pressure liquid seal bottle through the device's water inlet 108, controlling the amount of water injected based on the patient's condition and suction needs. The device's external pipes are connected to the hospital's central negative pressure system interface and the subglottic suction tube interface of the patient's endotracheal tube. Ensure that the connections are tight and leak-free.

[0126] A liquid storage system, comprising:

[0127] S100: Liquid collection bottle, used to collect secretions sucked out, with a gas-liquid isolation chamber structure inside. The secretions enter the liquid storage chamber through the bottom guide groove, and the upper gas is discharged through an independent filter channel to avoid aerosol contamination.

[0128] S200: Liquid-sealed bottle, which forms different negative pressure levels by injecting sterile liquid (distilled water or saline);

[0129] S300: Suction line, used to transfer secretions;

[0130] S400: Pressure-sensitive double valve, installed at the connection between the suction line and the liquid collection bottle, one-way open during normal suction, and close in the event of accidental tilt or sudden pressure drop to prevent secretions from flowing back;

[0131] S500: Peristaltic pump: used to inject water (37°C sterile saline) into the suction line to pre-flush the line and reduce the adhesion resistance of secretions;

[0132] S600: Multi-parameter monitoring module: collects real-time data for dynamic negative pressure adjustment. Includes a pressure sensor (accuracy ±1 cmH2O), a bioelectric monitoring module (detects mucosal impedance), and an optical scattering sensor (analyzes secretion transmittance).

[0133] During specific implementation, it is necessary to regularly check whether the interfaces of the device are loose and whether the liquid in the liquid seal bottle is clear (if the liquid is turbid or contaminated, the device needs to be replaced in time); avoid excessive tilting or inversion of the device to prevent liquid from flowing back into the central negative pressure system or the patient's airway.

[0134] The device is disposable and must be discarded after each patient's use to avoid cross infection. If the device is damaged, the tube is blocked, or the negative pressure regulation fails, a new device must be replaced immediately. During the suction process, closely monitor the patient's vital signs and airway pressure. If the patient experiences choking, coughing, airway bleeding, or other discomfort, immediately reduce the negative pressure or stop suctioning and notify the doctor. Avoid using excessively high negative pressure for a long time (such as ) to prevent mucosal damage, dryness or bleeding.

[0135] The above describes in detail the preferred embodiments of the present invention. It should be understood that those skilled in the art can make numerous modifications and variations based on the concepts of the present invention without inventive effort. Therefore, any technical solutions that can be derived by those skilled in the art through logical analysis, reasoning, or limited experimentation based on the concepts of the present invention and the prior art should be within the scope of protection defined by the claims.

Claims

1. A method for controlling the negative pressure of subglottic suction, characterized in that: The method comprises the following steps: Set negative pressure according to individual characteristics; The negative pressure setting according to individual characteristics specifically includes injecting sterile liquid into the liquid-sealed bottle, adjusting the negative pressure level according to the liquid height, and using a distance sensor to monitor the liquid level in real time to calibrate the negative pressure; the distance sensor transmits a continuously frequency-modulated ultrasonic signal and calculates the distance using the phase difference after the signal is reflected on the liquid surface, thereby achieving dynamic calibration of the negative pressure level; Turn on the central negative pressure system, and the device automatically and continuously uses negative pressure to remove secretions above the airbag; The secretions sucked out flow directly into the collection bottle built into the device; When microbial specimens need to be collected, close the central negative pressure system before the operation. The lower end of the liquid collection bottle has a rotatable liquid discharge port. After unscrewing the interface, use a sterile container to collect the secretions and send them for inspection and culture. After collecting the specimens, tighten the liquid discharge port again.

2. The adjustable subglottic suction negative pressure control method according to claim 1, characterized in that: The individual characteristics specifically include the patient's age, condition, secretion volume, and mucosal tolerance; The negative pressure setting includes patients with less secretions and patients with thick secretions. When the patient with less secretions injects liquid, the liquid position is one-third of the liquid seal bottle scale, forming a low negative pressure; when the patient with thick secretions injects liquid, the liquid position is two-thirds of the liquid seal bottle scale or the bottle is full, forming a medium-high negative pressure; The liquid seal bottle is provided with a distance measuring sensor, and the distance measuring sensor specifically includes: By emitting a continuous frequency modulated ultrasonic signal with a frequency range of f1 to f2, the distance is calculated using the phase difference after the signal is reflected on the liquid surface in the liquid-sealed bottle, where the emitted signal is S tx , the received signal is S rx (t), the S tx The mathematical expression is: Among them S tx (t) represents the variation of the transmitted signal over time; A represents the amplitude of the signal, which determines the strength of the signal; represents the center frequency; Δf=f2~f1 represents the frequency modulation bandwidth; The S rx The mathematical expression of (t) is, Where 2πfo(tT) represents the phase change of the center frequency signal caused by the time delay T due to the propagation distance d; It represents the core part of the FM signal, reflecting the linear change of frequency over time. By analyzing the frequency change gradient of the reflected signal, the distance d can be calculated. φo is used to compensate for the inherent error of sensor hardware or the random phase offset caused by the reflective surface; The distance measuring sensor monitors the liquid level in the liquid seal bottle in real time to dynamically calibrate the negative pressure level to ensure the accuracy of the negative pressure setting.

3. The adjustable subglottic suction negative pressure control method according to claim 2, characterized in that: It also includes Fourier transform of the transmitted and received signals, converting them into the frequency domain and extracting the phase difference of each frequency component: Δφ(f)=φrx(f)-φtx(f)=2πT+φ noise Where Δφ(f) is the phase difference in the frequency domain at frequency f; φrx(f) is the phase of the received signal at frequency f; φtx(f) is the phase of the transmitted signal at frequency f; f is the frequency of the ultrasonic signal; T is the one-way time delay of ultrasonic wave from emission to reception; φ noise is the random phase disturbance caused by environmental noise; The phase difference of multiple frequency points in the frequency domain is fitted by the least squares method to eliminate noise interference and obtain the linear phase difference slope. The distance formula is By performing Fourier transform on the transmitted and received signals, the phase difference is extracted to calculate the liquid level, and the negative pressure level is adjusted in real time.

4. The adjustable subglottic suction negative pressure control method according to claim 3, characterized in that: It also includes anti-interference and data transmission optimization, specifically including the introduction of beamforming technology in the sensor probe design, focusing the main beam through an array transducer, and suppressing multipath interference such as bottle wall reflection; using time division multiplexing and Manchester encoding to package the ranging data into a fixed frame structure, and transmit it to the central monitoring system via low-power Bluetooth or wired CAN bus; the said anti-interference and data transmission optimization technology is used to ensure the accuracy of the ranging data to achieve precise calibration of the negative pressure level.

5. The adjustable subglottic suction negative pressure control method according to any one of claims 1 to 4, characterized in that: The automatic continuous negative pressure suction of the device to remove secretions above the airbag specifically includes: An intelligent dynamic negative pressure regulation unit includes a pressure sensor, a mucosal impedance detection electrode, and an optical scattering sensor, and dynamically adjusts the negative pressure level and suction mode through a fuzzy logic algorithm. It is used to monitor the patient's airway pressure, mucosal status, and secretion viscosity in real time through multiple parameters, and dynamically matches the negative pressure level and suction mode with an adaptive algorithm to achieve precise removal of secretions while reducing the risk of mucosal damage. Anti-reflux and infection control unit, used to build a sterile closed-loop suction path to prevent secretions from flowing back into the airway or environment, reducing the risk of cross-infection and biofilm formation; The data management unit is used to track the device's operating status and patients' physiological indicators in real time, improving nursing efficiency and shortening abnormal response time.

6. The adjustable subglottic suction negative pressure control method according to claim 5, characterized in that: The intelligent dynamic negative pressure adjustment unit includes a built-in pressure sensor and a bioelectric monitoring module. The device detects the mucosal impedance value in real time through a mucosal impedance detection electrode, analyzes the light transmittance of secretions using an optical scattering sensor, and establishes a three-dimensional mapping model based on a fuzzy logic control algorithm to dynamically match the negative pressure level. It can collect data on the patient's airway pressure, mucosal impedance, and secretion viscosity in real time. The pressure sensor has an accuracy of ±1 cmH2O and continuously monitors the negative pressure fluctuations in the suction circuit to avoid sudden pressure increases or decreases caused by secretions blocking the circuit in the traditional fixed negative pressure mode. The microcurrent electrode detects the mucosal impedance in real time. When the impedance value is lower than the threshold, the system automatically triggers the negative pressure reduction mechanism. Utilizes the optical scattering principle to analyze the transmittance of secretions, distinguish between thin, medium and thick states, and dynamically match the negative pressure level; Based on the fuzzy logic control algorithm, a three-dimensional mapping model is established; For patients with thin secretions and sensitive mucosa, the initial negative pressure is set to -20 to -30 cmH2O. When the suction volume is detected to be <5 mL / h for three consecutive times, intermittent suction mode is entered to reduce mechanical stimulation of the mucosa. For patients with thick secretions, the initial negative pressure is set to -40 to -60 cmH2O. If the suction volume is >50 mL / h for two consecutive hours and the viscosity does not decrease, the system triggers pulsed suction, and the negative pressure fluctuates between -40 and -60 cmH2O at a frequency of 2 Hz, enhancing the stripping effect of viscous secretions while avoiding mucosal damage caused by a single high negative pressure.

7. The adjustable subglottic suction negative pressure control method according to claim 6, characterized in that: The anti-reflux and infection control unit is provided with a pressure-sensitive double valve at the connection between the suction line and the liquid collection bottle to form a physical barrier to prevent the backflow of secretions; the inner wall of the suction tube adopts a hydrophobic environment design and integrates an ultraviolet dynamic disinfection module; a pressure-sensitive double valve is provided at the connection between the suction line and the liquid collection bottle. During normal suction, the upstream valve opens and the downstream valve closes to ensure that the secretions flow into the liquid collection bottle in one direction; when the device is accidentally tilted or the negative pressure system fails, resulting in a sudden drop in pressure, the double valves close at the same time to form a physical barrier to prevent the secretions in the liquid collection bottle from backflowing into the airway or negative pressure pipe; The suction tube adopts a hydrophobic inner wall design and is made of medical-grade polypropylene to reduce the adhesion and retention of secretions; it integrates an ultraviolet dynamic disinfection module to irradiate and sterilize the inner wall of the pipeline after each suction cycle; the liquid collection bottle adopts a gas-liquid isolation cabin structure, and the secretions enter the liquid storage chamber directly through the bottom guide groove, and the upper gas is discharged through an independent filtration channel.

8. The adjustable subglottic suction negative pressure control method according to claim 7, characterized in that: The whole device is sterile packaged, and all pipeline interfaces are sterile. Before starting the device, 37°C sterile saline is injected into the suction pipeline through the built-in peristaltic pump to flush the inner wall and form a moist interface. The data management unit uploads data to the hospital's central monitoring system in real time, including real-time negative pressure values, suction volumes, secretion status operating parameters; patient physiological indicators such as mucosal impedance trend curves and airway pressure fluctuation maps; device failure warnings; medical staff can remotely view the suction status of the patients in their charge through mobile terminals, and send warning information when the system detects abnormal data.

9. The adjustable subglottic suction negative pressure control method according to claim 1, wherein: Before setting the negative pressure, it is also necessary to take out the disposable adjustable subglottic suction and liquid storage integrated device, confirm that the appearance of the device is not damaged, and the pipelines are firmly connected; inject sterile distilled water or saline into the negative pressure liquid seal bottle through the water inlet of the device, and control the water injection volume according to the patient's condition and suction needs; connect the external pipeline of the device to the hospital central negative pressure system interface and the subglottic suction tube interface of the patient's tracheal tube.

10. A liquid storage system, characterized in that: include: The liquid collection bottle is used to collect the secretions sucked out. It adopts a gas-liquid isolation chamber structure inside. The secretions enter the liquid storage chamber through the bottom guide groove, and the upper gas is discharged through an independent filtering channel; Liquid-sealed bottles, which form different negative pressure levels by injecting sterile liquid; Suction tube, used to transfer secretions; The pressure-sensitive double valve is installed at the connection between the suction line and the liquid collection bottle. It opens in one direction during normal suction and closes in the event of accidental tilt or sudden pressure drop to prevent secretions from flowing back. Peristaltic pump: used to inject water into the suction line, pre-flushing the line and reducing the adhesion resistance of secretions; Multi-parameter monitoring module: real-time data collection for dynamic adjustment of negative pressure.

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