Intelligent control anti-reflux combinable closed thoracic drainage system

Abstract

This application relates to the field of medical devices and discloses an intelligent, adjustable, anti-backflow, modular closed thoracic drainage system. The system includes a processor and electrically connected self-locking valves, a negative pressure isolation valve, a pressure sensing unit, and a negative pressure assembly. During the pre-test phase, the processor closes the patient-side self-locking valve, controls the negative pressure assembly to output test pulses, and calculates the equivalent pneumatic compliance of the measured space. Based on this, it determines the physical topology combination mode and loads the corresponding control parameter set. During continuous monitoring, the processor extracts characteristic data such as the transient rate of change of the pressure signal, pulse duration, mean, and variance. When the characteristic data meets specific conditions, the control state machine switches to the corresponding transient confirmation, suspected blockage, or backflow dislodgement state and outputs pause, clamp, or clamping commands. This system can adapt to the volume characteristics of different container combinations, effectively filter out physiological disturbances, and prevent air backflow and transient negative pressure overshoot when the tubing dislodges or becomes blocked.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, specifically to an intelligent, adjustable, anti-backflow, combinable closed thoracic drainage system. Background Technology

[0002] Closed thoracic drainage systems are commonly used medical devices in thoracic surgery, primarily used to drain accumulated air or fluid from the pleural cavity to restore negative pressure and promote lung re-expansion. In clinical practice, to meet varying drainage volumes and negative pressure adjustments, drainage systems typically employ different physical topologies, such as single-bottle, dual-bottle series, or multi-bottle combinations. The tubing length and collection container volume differ significantly across these architectures, resulting in varying aerodynamic volumetric delay characteristics throughout the fluid space.

[0003] Traditional electronic drainage devices typically have built-in fixed pressure control algorithms and adjustment parameters. These systems cannot automatically acquire information about the currently connected external piping and container structure during startup. When these fixed control parameters are applied to fluid spaces of varying volumes, the system's output suction command often fails to match the current fluid impedance and delay characteristics. This parameter mismatch can easily lead to control overshoot during the establishment of the target negative pressure, and even cause continuous pressure oscillations near the target setpoint, affecting the stability of the drainage process.

[0004] Existing equipment, during continuous operation, primarily adjusts the output of the internal negative pressure source based directly on the absolute pressure error collected by sensors. In clinical settings, there are short-term high-pressure airflow impacts caused by patient coughing, as well as sudden physical changes such as tubing narrowing due to pressure or accidental detachment. Current control logic cannot separate and identify these disturbance characteristics from a single absolute pressure value. When faced with short-term disturbances or gradual tubing blockage, the integral component within the control algorithm continuously accumulates errors and outputs a full-load suction command. This can cause transient negative pressure overshoot at the moment of tubing clearing or the end of the disturbance. Furthermore, in the event of accidental tubing detachment, the continuously operating negative pressure source exacerbates backflow of external air, increasing the risk of retrograde infection for the patient. Summary of the Invention

[0005] The technical problem solved by this invention is that existing closed thoracic drainage systems cannot automatically identify the physical topology of connecting pipes and collection containers, and the fixed control parameters are difficult to adapt to fluid spaces with different volume characteristics, and pressure oscillations are prone to occur under steady-state control.

[0006] Meanwhile, existing systems struggle to distinguish between physiological disturbances such as a patient's cough and sudden physical changes such as pipe detachment or blockage. They rely solely on error response to adjust the negative pressure source, making them prone to control overshoot, external gas backflow, and transient negative pressure overshoot caused by integral saturation during sudden changes in operating conditions.

[0007] To address the above problems, the present invention provides the following technical solution:

[0008] The first aspect of this invention provides an intelligent, adjustable, anti-backflow, combinable closed thoracic drainage system, comprising:

[0009] The processor, and the self-locking valve, the negative pressure isolation valve, the pressure sensing unit and the negative pressure assembly, which are electrically connected to the processor respectively;

[0010] A self-locking valve is installed on the patient-side drainage inlet line; a negative pressure isolation valve is installed between the negative pressure component and the space of the fluid being tested;

[0011] The processor is configured to perform the following operations:

[0012] During the pre-test phase, the self-locking valve is kept in the closed position, and the negative pressure component is controlled to output a test negative pressure pulse.

[0013] Based on the volume of gas extracted during the test negative pressure pulse and the pressure change collected by the pressure sensing unit, the equivalent aerodynamic compliance is calculated; based on the equivalent aerodynamic compliance, the physical topology combination mode is determined, and the control parameter group corresponding to the physical topology combination mode is loaded.

[0014] During the continuous monitoring period, the negative pressure component is driven to perform steady-state pressure closed-loop control based on the control parameter set;

[0015] When the characteristic data of the continuous pressure timing signal collected by the pressure sensing unit meets the set conditions, the control state machine switches to the corresponding state and outputs the control command for the self-locking valve or negative pressure component.

[0016] Preferably, the step of the processor controlling the negative pressure component to output a test negative pressure pulse and calculating the equivalent aerodynamic compliance includes:

[0017] When the negative pressure pulse test begins, the negative pressure isolation valve is opened and the negative pressure component is driven to draw in fluid. After the set time window ends, the negative pressure component stops drawing in fluid and the negative pressure isolation valve is closed, and the fluid space under test enters a pressure holding state.

[0018] Obtain the volume of gas extracted during the test negative pressure pulse, and the absolute difference between the holding pressure and the initial pressure under the pressure holding state;

[0019] The ratio of gas volume to absolute difference is defined as the equivalent aerodynamic compliance.

[0020] Based on the principles of fluid mechanics, the system will generate a corresponding pressure drop after extracting a certain amount of gas in a closed and isolated state. This scheme uses this physical response to obtain the background state of the pipeline and quantifies the volumetric delay characteristics of the fluid space through compliance numerical quantification.

[0021] Preferably, the control parameter set includes target negative pressure, safe threshold for respiratory fluctuation amplitude, physiological artifact time window, and safe output upper limit;

[0022] The steps for determining the physical topology combination mode based on equivalent aerodynamic compliance include: comparing the equivalent aerodynamic compliance with a preset topology threshold in non-volatile memory, and confirming the physical topology combination mode based on the comparison result.

[0023] By comparing the compliance value with a preset threshold, the current physical connection mode can be identified, thereby loading matching control parameters for the current volumetric delay characteristics.

[0024] In a preferred embodiment of the present invention, the feature data includes transient rate of change and pulse duration, and the step of controlling the state machine to switch to the corresponding state and output control commands includes:

[0025] When the processor calculates using a differential algorithm that the transient rate of change of the continuous pressure timing signal is greater than the preset positive transient threshold, the control state machine switches to the transient event confirmation state and controls the negative pressure component to pause.

[0026] When the continuous pressure timing signal falls back to the baseline tolerance band within the set confirmation window, and the calculated pulse duration is less than the physiological artifact time window, the control state machine is reset and steady-state pressure closed-loop control is restored.

[0027] This process separates short-term pulse characteristics to filter out pressure fluctuations caused by physiological disturbances such as coughing, and avoids negative pressure overshoot caused by conventional error follow-up compensation after the disturbance ends.

[0028] Preferably, the feature data includes the arithmetic mean and the time series variance, and the steps of controlling the state machine to switch to the corresponding state and output control commands include:

[0029] When the continuous pressure timing signal jumps to the ambient atmospheric pressure level, the processor controls the negative pressure component to pause and calculates the arithmetic mean and timing variance of the continuous pressure timing signal within the set confirmation window.

[0030] When the arithmetic mean is less than or equal to the atmospheric pressure tolerance threshold and the timing variance is less than the timing variance critical threshold, the control state machine switches to the reverse flow disconnection state; the processor bypasses the steady-state pressure closed-loop control, outputs a clamping command to the self-locking valve, and outputs an alarm signal in response to the lock-up position feedback signal.

[0031] By verifying the mean and variance characteristics, the system can confirm the low variance normal pressure condition after the pipeline detaches, and then close the front-end valve to block the reverse intrusion of external pollutants.

[0032] Preferably, the characteristic data includes amplitude data of periodic fluctuation characteristics, and the steps of controlling the state machine to switch to the corresponding state and output control commands include:

[0033] The processor extracts the amplitude data of the periodic fluctuation characteristics in the continuous pressure time-series signal;

[0034] When the amplitude data decays and remains below the safe threshold for respiratory fluctuation amplitude, the control state machine switches to a suspected occlusion state.

[0035] The processor clamps the control output of the negative pressure component at the safe output limit.

[0036] Increased fluid resistance leads to attenuation of respiratory wave amplitude. After the system detects this attenuation characteristic, it limits the upper limit of output, which can avoid integral accumulation saturation in conventional control algorithms and reduce the amplitude of the step response generated when the pipeline is cleared.

[0037] Preferably, after the tested fluid space enters the pressure holding state, the processor calculates the pressure recovery rate within the pressure holding time window;

[0038] When the pressure recovery rate does not exceed the preset leakage judgment threshold, the step of judging the physical topology combination mode based on equivalent aerodynamic compliance is executed;

[0039] When the pressure recovery rate exceeds the leakage detection threshold, the physical topology identification procedure is stopped.

[0040] Preferably, the volume of gas extracted during the test negative pressure pulse is obtained by the following method:

[0041] The instantaneous pumping flow rate detected by the flow detection element is integrated over the duration of the test negative pressure pulse;

[0042] Alternatively, the instantaneous air extraction flow rate can be calculated based on the actual rotational speed of the negative pressure component, the inlet pressure, and the pre-stored flow rate calibration relationship, and then the instantaneous air extraction flow rate can be integrated over the duration.

[0043] Preferably, during the pre-self-test phase, after the processor sends a command to the self-locking valve, it confirms that the self-locking valve is in the closed position based on the received valve position feedback signal.

[0044] The processor outputs an interface check prompt, and after receiving an interface closure confirmation signal, it controls the negative pressure component to output a test negative pressure pulse.

[0045] Preferably, the processor outputs a pulse width modulation signal to the negative pressure component, and controls the pumping flow rate during the steady-state pressure closed-loop control process by adjusting the speed of the vacuum pump motor inside the negative pressure component or the opening of the electromagnetic proportional valve.

[0046] The second aspect of this invention provides a control method for an intelligent, adjustable, anti-backflow, combinable closed thoracic drainage system, applied to the system provided in the first aspect of this invention. The method includes:

[0047] During the pre-test phase, the self-locking valve is kept in the closed position, and the negative pressure component is controlled to output a test negative pressure pulse.

[0048] The equivalent aerodynamic compliance is calculated based on the volume of gas extracted during the test negative pressure pulse and the pressure change collected by the pressure sensing unit.

[0049] The physical topology combination mode is determined based on the equivalent aerodynamic compliance, and the control parameter group corresponding to the physical topology combination mode is loaded.

[0050] During the continuous monitoring period, the negative pressure component is driven to perform steady-state pressure closed-loop control based on the control parameter set;

[0051] Acquire characteristic data of the continuous pressure time-series signal collected by the pressure sensing unit;

[0052] When the characteristic data meets the set conditions, the control state machine switches to the corresponding state and outputs the control command for the self-locking valve or negative pressure component.

[0053] This invention provides an intelligent, adjustable, anti-backflow, and combinable closed thoracic drainage system. It has the following beneficial effects:

[0054] 1. This invention determines the physical connection topology by closing the self-locking valve and outputting a test negative pressure pulse during the self-test phase, and calculating the equivalent aerodynamic compliance of the fluid space. This feature enables the system to automatically load the corresponding control parameter set based on the actual connected pipelines and collection container volume, avoiding steady-state pressure oscillations caused by fixed control parameters under different volumetric architectures, and improving the basic adaptability of the system's control closed loop.

[0055] 2. This invention acquires the arithmetic mean and time-series variance of the pressure signal during continuous monitoring, uses dual feature verification to identify tubing detachment conditions, and bypasses the conventional steady-state control logic after detachment is determined, directly driving the front-end self-locking valve to close. This feature establishes a physical isolation barrier in the abnormal situation of tubing disconnection, blocking the reverse intrusion of external air or airborne contaminants into the patient's drainage tubing.

[0056] 3. This invention distinguishes between short-term physiological disturbances such as coughing and physical states such as gradual pipeline blockage by extracting the transient rate of change and amplitude characteristics of the pressure signal. The system pauses suction upon confirming a short-term disturbance and limits the upper limit of the duty cycle output when a suspected blockage is identified. This suppresses the integral accumulation saturation of conventional control algorithms during sudden changes in operating conditions and reduces the dangerous transient negative pressure overshoot amplitude generated at the moment of pipeline unblocking or the end of the disturbance. Attached Figure Description

[0057] Figure 1 This is a schematic diagram of the system architecture according to an embodiment of the present invention;

[0058] Figure 2 This is a system control flowchart according to an embodiment of the present invention;

[0059] Figure 3 This is a timing diagram for the pre-test and pulse generation control in an embodiment of the present invention;

[0060] Figure 4 This is a logic diagram of physical topology identification and parameter loading in an embodiment of the present invention;

[0061] Figure 5 This is a schematic diagram illustrating the sensor physical isolation and continuous sampling principle of an embodiment of the present invention;

[0062] Figure 6 This is a logic diagram of signal decoupling and feature extraction in an embodiment of the present invention;

[0063] Figure 7 This is a flowchart illustrating the state machine state transition and artifact filtering logic of an embodiment of the present invention.

[0064] Figure 8 This is a flowchart illustrating the execution control and closed-loop response logic of an embodiment of the present invention.

[0065] Figure 9 This is a comparison diagram of the comprehensive response and system control effect under typical operating conditions in an embodiment of the present invention. Detailed Implementation

[0066] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0067] Example:

[0068] The technical solution of the present invention will be fully described with reference to the accompanying drawings of the embodiments.

[0069] See attached document Figure 1 , Figure 1 This is a schematic diagram of a system architecture according to an embodiment of the present invention.

[0070] This invention provides an intelligent, adjustable, anti-backflow, combinable closed thoracic drainage system, which may include: a bottle body, a control unit, a sensing unit, and a self-locking valve.

[0071] The inside of the bottle is divided into a separation chamber and a water seal chamber by a physical partition.

[0072] The separation chamber and the water seal chamber are connected through an internal fluid channel.

[0073] The top of the bottle is equipped with a chest tube interface and a multi-functional interface.

[0074] The multi-function interface includes a first multi-function interface and a second multi-function interface.

[0075] The chest tube inlet is connected to the fluid inlet of the separation chamber, used to connect the drainage inlet tubing on the patient side. The gas outlet of the separation chamber is connected to the water seal chamber through an internal fluid channel, allowing the gas that has undergone gas-liquid separation in the separation chamber to enter the water seal chamber.

[0076] The first multi-functional interface forms the serial input interface of the bottle and is connected to the fluid inlet side of the separation chamber;

[0077] The second multi-functional interface forms the series output interface of the bottle and is connected to the gas outlet side of the water seal cavity.

[0078] The first multi-function interface, the second multi-function interface, and the chest tube interface are each equipped with a removable seal to keep the interfaces not involved in the current fluid circuit closed.

[0079] In single-bottle independent operation mode, the chest tube interface is connected to the patient-side drainage input line, the first multi-functional interface is sealed by a seal, and the second multi-functional interface is connected to the suction port of the negative pressure component.

[0080] The fluid sequentially passes through the chest tube interface, separation chamber, internal fluid channel, water seal chamber, and second multi-functional interface, thereby completing gas-liquid separation, water seal isolation, and negative pressure exhaust within a single bottle.

[0081] In the dual-bottle series operation mode, the chest tube interface of the first bottle is connected to the patient-side drainage input tube, the second multi-functional interface of the first bottle is connected to the first multi-functional interface of the second bottle through a connecting tube, and the second multi-functional interface of the second bottle is connected to the suction port of the negative pressure component.

[0082] The unused first multi-functional port on the first bottle and the unused chest tube port on the second bottle are sealed with seals. The fluid flows sequentially through the first bottle, the connecting tube, and the second bottle to form a series fluid loop.

[0083] In the dual-bottle series operation mode, the second bottle connected to the negative pressure component is configured as the main control bottle, and its control unit is in working condition.

[0084] The negative pressure component of the first bottle remains in a stopped state, and its non-working fluid channel connected to the outside is kept closed to avoid mutual interference caused by the simultaneous operation of the two negative pressure components.

[0085] The control unit integrates a processor and a negative pressure component.

[0086] The negative pressure assembly includes a vacuum pump, a flow detection element, and a controllable negative pressure isolation valve located at the vacuum pump's suction inlet.

[0087] The flow sensing element is used to obtain the actual pumping flow rate during the test negative pressure pulse;

[0088] The controllable negative pressure isolation valve is used to isolate the vacuum pump from the space of the fluid being tested after the negative pressure pulse ends, so as to form a pressure holding detection time window.

[0089] In embodiments without an independent flow detection element, the processor calculates the actual pumping flow rate during the test negative pressure pulse based on the actual rotational speed of the vacuum pump, the inlet pressure, and the pre-stored pump speed-inlet pressure-flow calibration relationship.

[0090] The sensing unit is located in the gas phase pressure tapping channel between the second multi-functional interface of the main control bottle and the suction port of the negative pressure component, and is located downstream of the gas outlet of the water seal chamber. It is used to collect the real-time gas phase pressure signal before entering the negative pressure component.

[0091] The pressure tapping channel of the sensing unit is isolated from the main liquid channel to reduce the influence of drainage fluid, condensate and aerosol on the pressure detection results.

[0092] The self-locking valve is an electrically operated clamp-type self-locking valve installed on the patient-side drainage input line. The self-locking valve blocks the flow of gas and fluid by radially clamping the flexible drainage input line, and the valve body does not directly contact the drainage fluid.

[0093] The self-locking valve is preferably installed between the patient end and the tubing connection point that is prone to detachment, so that if the tubing connection point is detached, the self-locking valve can remain on the patient side and clamp the drainage inlet tubing on the patient side.

[0094] A self-locking valve has at least an open position and a locked closed position, and is equipped with a valve position feedback element.

[0095] The processor confirms whether the self-locking valve has closed based on the position signal output by the valve position feedback element.

[0096] If the self-locking valve fails to reach the locked-off position within the set response time, the processor outputs a valve execution fault alarm.

[0097] The sensing unit, the self-locking valve, and the negative pressure component each form an electrical connection channel with the processor.

[0098] The control unit also includes non-volatile memory, analog-to-digital conversion interface, timer, negative pressure component drive circuit, self-locking valve drive circuit, and human-machine interface.

[0099] Non-volatile memory is used to store parameter sets corresponding to different physical topology combination modes;

[0100] The state machine logic operation unit is formed by the processor executing the control program stored in non-volatile memory.

[0101] See attached document Figure 2 , Figure 2 This is a system control flowchart according to an embodiment of the present invention.

[0102] This invention provides a system operation control method, comprising the following steps:

[0103] S10, after the system is powered on and started, the processor performs a pre-isolation self-test. After confirming that the drainage inlet tube on the patient side has been isolated, it controls the negative pressure component to generate a test negative pressure pulse and performs a pressure holding test after the test negative pressure pulse ends.

[0104] S20, the processor reads the test negative pressure pulse response data fed back by the sensing unit, calculates the equivalent aerodynamic compliance parameters of the tested fluid space, and confirms the current physical topology combination mode of the system based on the equivalent aerodynamic compliance parameters.

[0105] After confirming the physical topology combination mode, the processor loads the state judgment parameter group and control parameter group that match the physical topology combination mode from the non-volatile memory.

[0106] S30, the system enters the real-time monitoring cycle, and the sensing unit continuously acquires the continuous pressure timing signal inside the bottle according to the set sampling frequency;

[0107] S40, the processor receives the continuous pressure timing signal and performs signal processing through a digital filtering algorithm to extract baseline drift feature data, periodic fluctuation feature data and transient pulse feature data respectively;

[0108] S50: The processor inputs the extracted feature data into the state machine logic operation unit, combines it with the preloaded threshold parameter matrix, and outputs the current fluid dynamics operating state of the system.

[0109] S60, the processor generates control instructions based on the running state output by the state machine: execute negative pressure closed-loop control under normal flow conditions;

[0110] If a blockage is suspected, limit the output of the negative pressure component and issue a maintenance prompt.

[0111] If a pipe disconnection is suspected, pause the negative pressure assembly and perform a pressure confirmation.

[0112] After confirming the tube is disconnected, a lock-off command is sent to the self-locking valve to clamp the drainage inlet tubing on the patient side, and the fluid passage of the tubing is confirmed to be blocked based on the valve position feedback.

[0113] The technical solutions included in this invention will be described in detail below with reference to specific embodiments.

[0114] See attached document Figure 3 , Figure 3 This is a timing diagram for pre-test and pulse generation control according to an embodiment of the present invention.

[0115] Step S10 in the above system operation control method mainly involves confirming the system isolation state and generating transient control signals.

[0116] To avoid fluid impact on the connection point during subsequent testing, the processor performs system self-test and pulse output operations through the following sub-steps:

[0117] S101, after the system is powered on and connected to a regulated power supply, the processor executes a pre-test program and locks the control unit in pre-isolation mode.

[0118] To reduce the risk of barotrauma caused by the transmission of test pressure waves along the drainage tubing into the patient's pleural cavity, the system is typically configured to establish a physical isolation barrier during the self-test phase.

[0119] To reduce the risk of negative pressure being transmitted to the patient's pleural cavity along the drainage inlet line, the processor first sends a pre-isolation command to the self-locking valve, causing the self-locking valve to clamp the drainage inlet line on the patient side, and confirms that the self-locking valve is in the closed position based on the valve position feedback signal.

[0120] The processor simultaneously confirms that all unused chest tube ports and multi-function ports are sealed by the seals and controls the negative pressure isolation valve to be in the closed position.

[0121] At this time, the fluid space being tested is isolated from the patient end and the external exhaust end of the negative pressure component.

[0122] The processor reads the real-time pressure signal fed back by the sensing unit and determines whether the pressure signal has exceeded the sensor limit, abnormal pulsation, or continuous drift within the set static observation time window.

[0123] A pressure change rate below the threshold of minor disturbance is only used as an auxiliary condition for judging the stability of test conditions, and is not used as the sole basis for confirming the airtightness of the tested fluid space.

[0124] The airtightness of the tested fluid space was further confirmed by the pressure recovery rate during the pressure holding phase after the test negative pressure pulse ended and the negative pressure isolation valve was closed.

[0125] The threshold for minute disturbance can be determined by continuously sampling the pressure background noise of a conventional closed pipeline under static conditions and taking the average value before it leaves the factory.

[0126] The processor outputs an interface check prompt through the human-machine interface, prompting the operator to confirm that the unused chest tube interface and multi-function interface have been sealed by the seal, and receives the interface closure confirmation signal input by the operator.

[0127] If the processor does not receive an interface closure confirmation signal or feedback on the closed position of the self-locking valve within the set timeout period, or detects that the pressure sensor has exceeded the limit or that the pressure signal continues to fluctuate abnormally, the processor will terminate the preparatory self-test program and output the corresponding interface check prompt, self-locking valve execution fault code, or pressure sensor fault code.

[0128] S102, after confirming that the system is in a pre-isolation state and the pressure sensing unit is working properly, the processor controls the negative pressure component to output a test negative pressure pulse, and after the test negative pressure pulse ends, it confirms the airtightness of the tested fluid space by pressure holding detection.

[0129] The processor retrieves the preset drive parameters from the non-volatile memory and sends pulse drive instructions to the negative pressure component.

[0130] The negative pressure component initiates the suction action within a set time window based on the received drive command.

[0131] When the negative pressure pulse test begins, the processor opens the negative pressure isolation valve and drives the vacuum pump to draw air.

[0132] When the negative pressure pulse ends, the processor stops the vacuum pump and closes the negative pressure isolation valve, allowing the tested fluid space to enter a pressure holding state.

[0133] During this process, the negative pressure component extracts a known volume of gas from the test fluid space, which is isolated from the patient, thereby establishing a pressure step change.

[0134] During the test of the negative pressure pulse, the fluid space under test is connected to the vacuum pump in a controlled fluid manner through the negative pressure isolation valve which is in the open state;

[0135] After the negative pressure pulse test ends, the negative pressure isolation valve closes, allowing the tested fluid space to enter a pressure holding state isolated from the vacuum pump.

[0136] The processor calculates the pressure recovery rate within the pressure holding time window.

[0137] When the pressure recovery rate exceeds the preset leakage detection threshold, the processor determines that the system has an unsealed interface, a leaking connecting pipe, or a valve seal failure, and stops performing physical topology identification.

[0138] The processor only uses the current negative pressure pulse response data to determine the physical topology combination mode when the pressure recovery rate does not exceed the leakage judgment threshold.

[0139] The time window is typically set between 0.1 and 0.5 seconds to ensure that an effective step excitation is generated within a short period of time.

[0140] From the perspective of fluid mechanics principles, when a certain amount of gas is forcibly extracted from a system in a closed and isolated state, the system will generate a corresponding pressure drop according to the basic gas equation, and the magnitude of this pressure drop is directly limited by the total volume of the currently connected fluid.

[0141] The system uses this physical response to obtain baseline state information of the piping architecture.

[0142] The integral formula for the total gas extracted during the duration of the negative pressure pulse is:

[0143] ;

[0144] In the formula, This indicates the volume of gas extracted from the fluid space under test during the negative pressure pulse test.

[0145] Indicates the duration of the negative pressure pulse during testing;

[0146] It represents the instantaneous pumping flow rate actually detected by the flow detection element, or the instantaneous pumping flow rate calculated based on the actual speed of the vacuum pump, the inlet pressure, and the pre-stored flow calibration relationship.

[0147] Through the above integral calculation, the processor can obtain the actual pumping volume during the test negative pressure pulse, providing basic data for the subsequent calculation of equivalent aerodynamic compliance parameters.

[0148] For the specific circuit design and driver program of the processor controlling the speed of the vacuum pump motor inside the negative pressure component or adjusting the opening of the electromagnetic proportional valve to accurately output a specific flow rate through the pulse width modulation signal, those skilled in the art can configure it according to the conventional microcontroller peripheral driver manual. Its underlying hardware control logic is a well-known technology in the field and will not be described in detail here.

[0149] See attached document Figure 4 , Figure 4 This is a logic diagram for physical topology identification and parameter loading according to an embodiment of the present invention.

[0150] For step S20 in the system operation control method, its main configuration is to enable the system to automatically sense the current physical connection status and match the corresponding safety control benchmark with less manual intervention.

[0151] The processor performs this process through the following sub-steps:

[0152] S201, the processor reads the pressure response data fed back by the sensing unit during the test negative pressure pulse output and the pressure holding phase, and calculates the equivalent aerodynamic compliance parameters of the tested fluid space.

[0153] In practice, the sensing unit collects the initial pressure before the test negative pressure pulse begins, and collects the holding pressure during the pressure holding phase after the test negative pressure pulse ends, the negative pressure isolation valve closes, and the pressure transient response has stabilized for a preset time.

[0154] The processor acquires the initial pressure before the start of the test negative pressure pulse. The holding pressure after the negative pressure pulse ends and the negative pressure isolation valve is closed. And calculate the absolute value of the pressure change. .

[0155] Because, under the same pumping volume conditions, the larger the effective gas volume of the fluid space, the smaller the resulting pressure change, the processor calculates the equivalent aerodynamic compliance parameters of the measured fluid space based on the pumping volume and pressure change. This reflects the effective volume characteristics of the current connected fluid space.

[0156] The formula for calculating the equivalent aerodynamic compliance parameter is:

[0157] ;

[0158] in:

[0159] ;

[0160] In the formula, The equivalent aerodynamic compliance parameter represents the space of the fluid being measured.

[0161] This indicates the volume of gas extracted during the test negative pressure pulse;

[0162] This indicates the pressure change obtained before and after the negative pressure pulse test while maintaining pressure.

[0163] When the range of test pressure variation is small relative to the initial absolute pressure, the equivalent aerodynamic compliance parameter can be used to characterize the effective gas volume of the system.

[0164] The effective gas volume in the dual-cylinder series operation mode is usually greater than that in the single-cylinder independent operation mode, so its equivalent aerodynamic compliance parameter is usually greater than that in the single-cylinder independent operation mode.

[0165] To prevent sensor data drift from causing calculation errors, the processor performs an validity screening of the pressure signal before calculation. If the absolute value of the collected pressure change is lower than the preset minimum effective pressure change, the processor marks the negative pressure pulse of this test as invalid and checks the actual air flow rate during the negative pressure pulse test.

[0166] If the actual air flow rate is lower than the minimum effective test flow rate, the processor will output a negative pressure component or flow detection error code; if the actual air flow rate is normal, the processor will re-execute the test negative pressure pulse.

[0167] If a valid pressure change cannot be obtained after a preset number of consecutive retests, the processor terminates the self-test program and outputs a topology identification failure code.

[0168] To eliminate the impact of interface leakage on the equivalent aerodynamic compliance calculation results, the processor calculates the pressure recovery rate within the pressure holding time window after the negative pressure isolation valve is closed.

[0169] ;

[0170] In the formula, and These represent the first and second detection times within the pressure holding time window, respectively. ;

[0171] This indicates the pressure recovery rate during the pressure holding phase.

[0172] S202, the processor performs a physical topology combination mode determination based on the calculated equivalent aerodynamic compliance parameters.

[0173] Before performing the physical topology combination mode determination, the processor first performs anomaly response interception.

[0174] If the pressure recovery rate during the pressure holding phase exceeds the leakage detection threshold, the processor determines that the system has an unsealed interface, a leaking connecting pipe, or a valve seal failure, and terminates the current topology identification.

[0175] If the actual air flow rate during the negative pressure pulse test is lower than the minimum effective test flow rate, or the pressure response setup time exceeds the preset response time limit, the processor determines that there is an abnormality in the negative pressure component, connecting pipe, or internal fluid channel, and terminates the current topology identification.

[0176] The processor only uses the equivalent aerodynamic compliance parameters to perform topology determination when the pressure recovery rate, actual pumping flow rate, and pressure response settling time are all within the corresponding allowable range.

[0177] Before performing the physical topology combination mode determination, the processor performs an exception response interception.

[0178] If the pressure recovery rate during the pressure holding phase exceeds the leakage detection threshold, the system is determined to have an unsealed interface, leaking connecting pipes, or a failed valve seal.

[0179] If the actual air flow rate during the negative pressure pulse test is lower than the minimum effective flow rate of the negative pressure component, or the pressure response settling time exceeds the preset response time limit, then it is determined that there is an abnormality in the negative pressure component, connecting pipe, or internal fluid channel, and the current data will not be used to perform topology determination.

[0180] The processor can only calculate the equivalent aerodynamic compliance parameters when the leakage rate, actual pumping flow rate, and pressure response time are all within the corresponding allowable ranges.

[0181] Under these two extreme conditions, the processor interrupts the self-test process and outputs a fault code.

[0182] The processor will calculate the equivalent aerodynamic compliance parameters. With the pre-stored first topology threshold and the second topological threshold A comparison is made, in which:

[0183] ;

[0184] When satisfied At that time, the processor determines that the system has the characteristic of effective volume of a single bottle and confirms that the system is in the single-bottle independent operation mode.

[0185] When satisfied At that time, the processor determines that the system has the effective volume characteristics of two bottles and confirms that the system is in the dual-bottle series operation mode.

[0186] When satisfied At this time, the processor does not force the determination of the physical topology combination mode, but outputs a topology uncertainty status indicator, prompting the operator to check the connection status of the multi-function interface, connecting pipe and interface seal, and re-execute the test negative pressure pulse after confirmation.

[0187] The first and second topological thresholds were determined by performing multiple negative pressure pulse tests on the standard single-bottle connection structure and the standard double-bottle connection structure to obtain the corresponding equivalent aerodynamic response distribution ranges.

[0188] A gray zone is formed between the two thresholds to accommodate manufacturing tolerances, pipe differences, and environmental changes.

[0189] S203, the processor retrieves and loads the matching threshold parameter matrix from the non-volatile memory configured inside the control unit according to the determined physical topology combination pattern.

[0190] The difference in internal fluid buffer volume between single-bottle and dual-bottle structures objectively alters the attenuation ratio and conduction delay time of intrapleural pressure fluctuations in patients.

[0191] When the system enters the pre-test procedure, the processor first loads the data from non-volatile memory applicable to both single-bottle independent operation mode and dual-bottle series operation mode. .

[0192] The topology identification parameter set is defined as follows:

[0193] ;

[0194] After confirming the physical topology combination mode, the processor loads the corresponding state judgment parameter group according to the confirmed physical topology combination mode m. and control parameter group , where m represents the single-bottle independent operation mode or the dual-bottle series operation mode.

[0195] ;

[0196] ;

[0197] In the formula, Indicates the minimum valid test traffic;

[0198] This indicates the permissible deviation of the pressure baseline relative to the target negative pressure;

[0199] This indicates the safe output limit of the negative pressure component in the corresponding physical topology combination mode;

[0200] The meanings of the remaining parameters are the same as those defined above.

[0201] Because the total fluid volume and pipeline length in the dual-bottle series mode are greater than those in the single-bottle mode, it has a stronger low-pass filtering and smoothing effect on high-frequency fluctuations in gas pressure, and the pressure transmission hysteresis is more obvious.

[0202] Therefore, the safe threshold for respiratory fluctuation amplitude invoked in dual-bottle mode The threshold value is typically set to be less than the amplitude threshold in single-bottle mode, while the physiological artifact time window threshold is...

[0203] It is then set to a relatively larger time span to accommodate the waveform characteristics after the attenuation is extended.

[0204] The processor loads the aforementioned multidimensional security thresholds into the active register of the state machine logic operation unit to complete the initialization of the underlying judgment parameters.

[0205] After initialization and configuration are complete, the processor sends an opening command to the self-locking valve and confirms that the self-locking valve has switched from the locked-closed position to the open position based on the valve position feedback signal.

[0206] After the self-locking valve opens, the patient-side drainage inlet tubing regains connection with the fluid channel inside the bottle, and the system enters a real-time continuous monitoring cycle. If the processor does not receive feedback on the self-locking valve's opening position within the set time, the system remains in a safe shutdown state and outputs a self-locking valve execution fault alarm.

[0207] See attached document Figure 5 , Figure 5 This is a schematic diagram of sensor physical isolation and continuous sampling according to an embodiment of the present invention.

[0208] Regarding step S30 in the system operation control method, this step is mainly used to acquire a continuous digital pressure signal of the fluid state inside the pipeline when the system enters the normal flow diversion state.

[0209] After the system de-isolates from self-test mode, the processor executes the following sub-steps to obtain a continuous stress timing sequence:

[0210] S301, the system uses a physical isolation structure to block the intrusion of liquid substances and maintain the stability of the gas pressure wave signal acquired by the sensing unit.

[0211] Clinical chest drainage air typically carries water vapor and aerosols containing biological tissue particles.

[0212] If liquid water or solid particles are deposited on the surface of the sensitive structure inside the sensing unit, it can easily affect the mechanical properties of the sensitive diaphragm and cause measurement baseline drift.

[0213] To solve this engineering problem, a gas phase pressure tap is set between the second multi-functional interface of the main control bottle and the suction inlet of the negative pressure component, and the sensing unit collects pressure signals through the gas phase pressure tap.

[0214] The gas phase pressure tap is located upstream of the negative pressure isolation valve, so that even after the negative pressure isolation valve is closed, the sensing unit can still detect the pressure change of the tested fluid space during the pressure holding phase.

[0215] A polytetrafluoroethylene hydrophobic and antibacterial breathable membrane is sealed between the gas phase pressure tap and the sensitive surface of the sensing unit.

[0216] The micropores of the polytetrafluoroethylene hydrophobic antibacterial breathable membrane allow gaseous molecules to pass through, while relying on the material's low surface energy properties to physically trap condensed droplets and aerosol particles.

[0217] In practical implementation, the micropore size of this breathable membrane is typically configured to be between 0.1 micrometers and 0.45 micrometers. This pore size range, combined with hydrophobic materials, can maintain the rigid transmission of gas pressure while blocking the permeation of liquid water surface tension. The pore size, thickness, and effective air-permeable area of ​​the breathable membrane are selected according to the liquid barrier requirements and the target pressure signal frequency band, enabling the breathable membrane to transmit gas phase pressure changes within the target frequency band to the sensitive surface of the sensing unit while preventing the intrusion of droplets and aerosol particles.

[0218] The pressure response delay and amplitude attenuation caused by the breathable membrane can be calibrated using a standard pressure signal during the equipment finalization stage, and compensated by the processor in the corresponding threshold parameters.

[0219] This physical isolation method allows pressure fluctuations inside the bottle to act stably on the pressure measuring surface of the sensing unit.

[0220] S302, the sensing unit performs digital conversion on the isolated analog pressure signal according to the set sampling frequency to construct a continuous pressure time-series signal for subsequent feature extraction.

[0221] The processor's internal timer drives the sensing unit by configuring a fixed sampling frequency.

[0222] Since the system needs to extract low-frequency natural respiratory cycle features and capture sudden fluid events with pulse widths in the millisecond range in subsequent logic, the sampling frequency setting needs to take into account the sampling requirements of low-frequency baseline and high-frequency transient signals.

[0223] To simultaneously cover low-frequency respiratory fluctuations and abnormal pressure changes lasting tens of milliseconds, the sensing unit first acquires pressure signals at a raw sampling frequency of no less than 200Hz, with a preferred raw sampling frequency of 500Hz.

[0224] The processor directly uses the original sampled sequence in the transient pulse feature extraction branch, and performs low-pass filtering and downsampling on the original sampled sequence in the baseline drift feature and periodic fluctuation feature extraction branches.

[0225] When the system expects to identify the shortest effective pressure pulse duration as At that time, the original sampling frequency should be such that the shortest effective pressure pulse corresponds to multiple consecutive sampling points, avoiding the complete pulse being represented by only one sampling point.

[0226] Original sampling frequency Shortest effective pressure pulse duration satisfy:

[0227] ;

[0228] in, The time resolution required by the transient pressure pulse identification algorithm is preset.

[0229] The analog-to-digital converter circuit integrated inside the sensing unit converts the continuous analog pressure waveform into a discrete digital sequence based on the sampling frequency.

[0230] The discretized mathematical expression for the constructed continuous pressure time series signal is defined as follows:

[0231] ;

[0232] ;

[0233] In the formula, Indicates the first Discrete digital pressure values ​​output by each sampling node;

[0234] Continuous output This constitutes the original continuous pressure timing signal;

[0235] These represent the gain, bias, and quantization conversion functions corresponding to the analog-to-digital conversion circuit.

[0236] This represents the simulated gas phase pressure acting on the sensitive surface of the sensing unit;

[0237] Indicates the sampling period;

[0238] Indicates the original sampling frequency;

[0239] Indicates the discrete sampling sequence number.

[0240] The generated digital sequence is written sequentially into pre-allocated consecutive memory addresses inside the microcontroller, forming a sliding time window sequence of fixed length.

[0241] To prevent extreme signals exceeding the range of the analog-to-digital converter from being generated by external impacts on the pipeline, the processor performs data out-of-bounds verification when receiving digital sequences.

[0242] If the sensor output data reaches the upper or lower limit of the analog-to-digital conversion quantization, the processor marks the sampling node as saturated data.

[0243] Saturated data must not be used for determining pressure safety status and transient abnormal status after being processed by ordinary smoothing interpolation.

[0244] When there is only a single isolated saturated sampling point, and the sampling values ​​before and after it are both within the normal range, the processor can interpolate the isolated sampling point in the non-safety feature calculation branch.

[0245] When the number of continuous saturation sampling points reaches the preset number, or when the pressure signal is continuously at the range boundary, the processor should output a pressure over-limit status or sensor fault status and stop the normal negative pressure closed-loop control.

[0246] For the flow and scheduling of continuously sampled data at the microprocessor level, those skilled in the art can configure the peripheral bus interface in conjunction with the direct memory access controller mechanism to cyclically move data to the ring buffer. The underlying data bus configuration and conventional cache management scheme are well-known technologies in the field and will not be described in detail here.

[0247] See attached document Figure 6 , Figure 6 This is a logic diagram for signal decoupling and feature extraction according to an embodiment of the present invention.

[0248] For step S40 in the system operation control method, its main configuration is to strip the slowly varying background static pressure, periodic physiological fluctuations and high-frequency sudden events mixed in the continuous pressure time sequence signal in the frequency domain and convert them into independent feature variables that can be recognized by the state machine.

[0249] The processor performs the following sub-steps to extract multidimensional hydrodynamic features:

[0250] In this embodiment, the pressure value is expressed as gauge pressure relative to the local atmospheric pressure, and the atmospheric pressure gauge pressure is defined as zero.

[0251] When the system is in negative pressure drainage mode, the pressure value is negative;

[0252] An increase in pressure value toward zero indicates a decrease in the absolute value of negative pressure, while a decrease in pressure value away from zero and toward the negative indicates an increase in the absolute value of negative pressure.

[0253] The subsequent description of pressure increase refers to the gauge pressure reading increasing and approaching zero, while pressure decrease refers to the gauge pressure reading decreasing and moving away from zero.

[0254] S401, the processor extracts the pressure baseline sequence through a low-pass digital filtering algorithm and calculates baseline drift characteristic data.

[0255] The background static pressure of a thoracic drainage system reflects the overall sealing performance and negative pressure suction status of the system.

[0256] During closed thoracic drainage, the pressure baseline within the system is affected by the patient's pleural cavity pressure, gas leakage, drainage fluid discharge, and the output of the negative pressure control component. It typically exhibits slow changes or remains relatively stable near the target negative pressure.

[0257] This fluid physics phenomenon corresponds to extremely low frequency signal components in the frequency domain.

[0258] To filter out periodic interference caused by human respiration, the processor calls a preset infinite impulse response low-pass filter algorithm to process the continuous pressure timing signal.

[0259] The cutoff frequency of this low-pass filter is typically set between 0.05 Hz and 0.1 Hz to block physiological fluctuations above this frequency.

[0260] After filtering, the continuous pressure time series signal is smoothed into a pressure baseline sequence that only reflects the slow change trend of the system static pressure.

[0261] Subsequently, the processor calculates the rate of change of the baseline sequence over time, generating baseline drift feature data.

[0262] Its difference calculation formula is defined as:

[0263] ;

[0264] In the formula, This represents the rate of change of the pressure baseline per unit time.

[0265] when When this occurs, it indicates that the pressure baseline has shifted towards atmospheric pressure.

[0266] when When this occurs, it indicates that the pressure baseline is shifting in the direction of increasing absolute negative pressure.

[0267] To accurately reflect the long-term gradual change trend of system static pressure and avoid interference from local fluctuations, the differential interval step size is... It is usually set to the total number of consecutive sampling points corresponding to 10 to 30 seconds of actual physical time.

[0268] To prevent numerical oscillations caused by step response during the initialization phase of the digital filter, the processor is equipped with delayed enable logic.

[0269] During the initial time window after system startup or data reset, the processor suspends the above differential calculation and outputs valid baseline drift characteristic data only after the filtered output converges to the actual static pressure level, thereby avoiding false drift alarms caused by algorithm transient dead zones.

[0270] S402, the processor extracts the respiratory wave sequence through a bandpass digital filtering algorithm and calculates the periodic fluctuation characteristic data within a sliding window.

[0271] The patient's spontaneous breathing will produce periodic gas dynamic fluctuations within the drainage tube.

[0272] The basic principle is that the movement of the thoracic cavity during human respiration causes periodic changes in the volume of the pleural cavity, which in turn drives the gas to move back and forth inside the closed drainage tube, forming an alternating waveform superimposed on the baseline static pressure.

[0273] The processor uses a bandpass filter algorithm to extract waveforms reflecting the physical patency of the tubing from the raw signal. Based on standard human respiratory physiological indicators, the passband frequency of this bandpass filter is typically configured to be between 0.15 Hz and 1 Hz.

[0274] After filtering, baseline static pressure and high-frequency noise are suppressed, generating a clean respiratory pressure sequence.

[0275] The processor then searches for extreme values ​​within a set sliding time window to calculate the amplitude.

[0276] The formula for calculating periodic fluctuation characteristic data is:

[0277] ;

[0278] In the formula, This represents the periodic fluctuation characteristic data extracted at the current moment, namely the peak amplitude of the respiratory wave;

[0279] Indicates the first bandpass filter. The pressure value of each node;

[0280] This represents the total number of discrete sampling points included in the sliding time window.

[0281] The actual length of the sliding time window It should be no less than the lower passband cutoff frequency of the bandpass filter. The corresponding complete cycle satisfies:

[0282] ;

[0283] When the lower passband limit of the bandpass filter is set to 0.15Hz, the sliding time window is preferably set to not less than about 6.7 seconds, and can be further set to 8 to 10 seconds to improve the completeness of the calculation of low-frequency respiratory wave amplitude.

[0284] Furthermore, if the calculated When the system approaches the lower limit of the analog-to-digital conversion quantization resolution, the processor identifies it as an effective zero reference to prevent the background ambient electrical noise from being misidentified as a weak breathing fluctuation component.

[0285] S403, the processor obtains the short-time rate of change of the original signal through a smooth differential algorithm and extracts transient pulse feature data.

[0286] Accidental detachment of tubing or violent coughing by a patient can cause pressure jumps in the fluid circuit within tens to hundreds of milliseconds.

[0287] To effectively capture such high-frequency burst events, the processor directly uses the original continuous pressure timing signal without low-pass attenuation to perform time-domain differentiation.

[0288] Since conventional direct adjacent point difference operations can significantly amplify high-frequency electrical noise in the system environment, the processor uses a multi-point smoothing center difference algorithm to calculate transient rate of change.

[0289] The calculation formula is as follows:

[0290] ;

[0291] The processor retains both the sign and the absolute value of the transient rate of change.

[0292] For typical abnormal transient disturbance events, the processor determines the absolute value of the transient rate of change. Does it exceed the general transient pressure change rate threshold?

[0293] For a suspected pipe disconnection event where negative pressure is suddenly lost and approaches atmospheric pressure, the processor determines:

[0294] ;

[0295] For abnormal events involving a sudden and excessive increase in negative pressure, the processor determines:

[0296] .

[0297] Smooth window radius Typically, a number of sampling points corresponding to actual physical time of 10 to 50 milliseconds is selected to achieve a balance between high-frequency noise filtering and effective abrupt signal preservation.

[0298] Because the calculation terms of the central difference formula include sampling points after the current time step. To meet the causality requirements of real-time computing, the processor introduces a length of [missing information] into the input data stream when executing the algorithm. The buffer group delay.

[0299] That is, when the system actually receives the node The processor only executes and outputs the data corresponding to the historical node when the data is received. The transient rate of change.

[0300] This differential calculation logic, which combines multi-point averaging factors, retains the steep rising edge characteristics of the pressure mutation signal while suppressing local glitch data caused by the sensor's background thermal noise, thus improving the data reliability of subsequent state machine judgments.

[0301] For the specific mathematical derivation of the pole placement and coefficient calculation of the above digital filters, those skilled in the art can design them based on conventional digital signal processing theory. The discretization placement method is a well-known technology in this field and will not be elaborated here.

[0302] See attached document Figure 7 , Figure 7 This is a flowchart of state machine state transition and artifact filtering logic according to an embodiment of the present invention.

[0303] For step S50 in the system operation control method, its main configuration is to classify and determine the actual operating conditions of the drainage pipeline based on the extracted multidimensional fluid dynamics features and the pre-loaded topology matching threshold, and eliminate false alarms caused by the patient's physiological movements.

[0304] The processor executes this decision logic through the following sub-steps:

[0305] The state machine includes at least the following states: initialization state, self-test state, topological uncertainty state, routine drainage state, weakened respiratory fluctuation state, suspected blockage of patient-side channel, suspected obstruction of negative pressure aspiration channel, confirmed blockage state, transient event confirmation state, cough artifact state, suspected tube dislodgement state, confirmed tube dislodgement state, system leakage fault state, negative pressure component fault state, unclassified pressure abnormality state, pressure exceeding limit state, sensor fault state, self-locking valve fault state, and safe shutdown state.

[0306] When multiple state conditions are met simultaneously within the same detection cycle, the processor enters the state with the highest security priority.

[0307] Pressure overrun, sensor malfunction, and self-locking valve malfunction have higher priority than confirmed disconnection status.

[0308] Confirming tube disconnection and unclassified abnormal pressure conditions takes priority over confirming tube blockage; confirming tube blockage takes priority over routine drainage.

[0309] The S501 processor performs a joint time window comparison of baseline drift feature data and periodic fluctuation feature data to identify normal state and progressive blockage state.

[0310] During normal closed chest drainage, the tubing remains patent and the system's suction negative pressure is in dynamic equilibrium. At this time, the fluid characteristics are characterized by stable overall static pressure and periodic airflow that rises and falls with the chest wall. The processor determines baseline drift characteristic data. Whether the absolute value is lower than the set gradual change tolerance, and at the same time judge the periodic fluctuation characteristic data. Is it greater than or equal to the safe threshold for respiratory fluctuation amplitude corresponding to the current topology pattern? If the above conditions are met, the processor determines that the system is in a normal traffic-driving state.

[0311] In practice, the above-mentioned gradual change tolerance is set based on the inherent small natural leakage rate of the system, and is usually set to no more than 5 Pa / s.

[0312] To identify this progressive pathological process, the processor performs a condition check.

[0313] When progressive narrowing occurs in the drainage inlet tube, the amplitude of the respiratory pressure wave generated in the patient's pleural cavity transmitted to the bottle side usually gradually decreases.

[0314] However, the direction of pressure baseline change is related to the location of blockage, the location of the sensing unit, and the operating state of the negative pressure component. Therefore, the processor does not require the continuous positive drift of the pressure baseline to be a condition that all blockage states must be met simultaneously.

[0315] The processor performs suspected blockage assessments of the patient-side drainage channel and the negative pressure aspiration channel, respectively.

[0316] When periodic fluctuation characteristic data The amplitude of the respiratory wave is continuously lower than the threshold corresponding to the current topology combination mode. At this time, the processor first enters the suspected blockage state of the patient-side channel and starts the blockage confirmation timer.

[0317] If this state persists for the duration of the blockage confirmation time... If the periodic fluctuation amplitude does not return to the normal range within the confirmation time, the processor will change the status from suspected blockage of the patient-side channel to confirmed blockage.

[0318] For negative pressure suction channels, when Greater than the baseline drift threshold The deviation between the pressure baseline and the target negative pressure exceeds the allowable deviation. Furthermore, when the output of the negative pressure component continues to increase or reaches the safe output limit, the processor enters a state where the negative pressure suction channel is suspected to be blocked.

[0319] If the aforementioned abnormal conditions in the negative pressure suction channel persist until the time for confirming a blockage is reached... If so, the processor will change the state to a confirmed blockage state.

[0320] During any confirmation timing period, if the periodic fluctuation amplitude, pressure baseline, or negative pressure component control output returns to the normal range, the processor clears the corresponding confirmation timer and returns to the normal drainage state.

[0321] If only the amplitude of the periodic wave decreases, while the pressure baseline remains within the target negative pressure range, the processor will not directly identify it as a complete obstruction. Instead, it will output a warning of weakened respiratory waves to avoid misjudgment caused by the patient's shallow breathing, temporary breath-holding, or other physiological states.

[0322] For negative pressure suction channels, when the pressure baseline continuously shifts towards atmospheric pressure, and the pressure deviation exceeds the baseline allowable threshold... Furthermore, when the output of the negative pressure component continues to increase or reaches the safe output limit, the processor outputs a status indicator indicating that the negative pressure suction channel is suspected to be blocked.

[0323] During any of the above confirmation timing periods, if the periodic fluctuation amplitude, pressure baseline, or negative pressure component control output returns to the normal range, the processor clears the corresponding confirmation timer and returns to the normal drainage state.

[0324] Stepwise decay is defined as the overall decreasing trend of the amplitude of periodic fluctuations over multiple consecutive sliding time windows, with the amplitude remaining below the corresponding threshold after the decrease, rather than judging solely based on the amplitude decrease within a single window.

[0325] This time window delay mechanism effectively avoids false alarms caused by the instantaneous drop in amplitude due to occasional shallow and slow breathing by the patient.

[0326] The aforementioned pipe blockage confirmation time window is typically set between 30 and 60 seconds.

[0327] If during timer operation Once the circuit returns to normal, the processor clears the timer and resets to normal ducting state to avoid logic dead zones caused by intermittent pipeline pressure.

[0328] The S502 processor monitors transient pulse characteristic data in real time and captures abnormal transient disturbance events.

[0329] Whether it's an accidental detachment of a pipe connection or a patient's violent cough, it will disrupt the system's original closed negative pressure environment or inject high-pressure airflow into the pipe, which manifests as a dramatic pressure surge within tens of milliseconds.

[0330] The processor will extract transient pulse feature data in real time. With the threshold of transient pressure change rate in the threshold parameter matrix Compare them.

[0331] when When the transient pressure change rate threshold in the corresponding direction is exceeded, the processor determines that the system has captured an abnormal transient disturbance event, records the current sampling node as the event starting point, and causes the state machine to enter the transient event confirmation state.

[0332] When the event manifests as a rapid shift of pressure towards atmospheric pressure, and When this occurs, the processor marks the event as a suspected pipe detachment event and immediately suspends the operation of the negative pressure component.

[0333] Suspending the negative pressure component is a temporary safety action during the confirmation period and is not equivalent to confirming that the pipeline has detached.

[0334] After the negative pressure component is paused, the processor continues to collect pressure signals to avoid the vacuum pump pulsation affecting the subsequent calculation of pressure mean and time series variance.

[0335] To prevent the signal from oscillating at high frequencies near the threshold, causing frequent state machine resets, the processor is configured with a hysteresis comparison algorithm in this comparison logic. To prevent the transient rate of change from repeatedly exceeding the limit near the threshold, the processor sets hysteresis turn-off thresholds for the positive transient threshold and the negative transient threshold, respectively.

[0336] The hysteresis shutdown threshold is a preset ratio of the corresponding trigger threshold and is less than the corresponding trigger threshold.

[0337] S503, the processor executes composite verification logic based on pressure recovery time, post-event pressure mean, and timing variance to filter out physiological artifacts and confirm the status of tubing detachment.

[0338] Based on the analysis of differences in fluid dynamic characteristics, the patient's cough is a physiological spasm action, and the high-pressure pulse in the abdominal cavity it generates has a clear fall-off period. The system can still restore the original dynamic balance of suction after the pulse ends.

[0339] When the pipeline detaches, the drainage system is directly connected to the external atmospheric environment. When the pipeline detaches and the fluid space where the sensing unit is located is connected to the outside atmosphere, and the negative pressure component has stopped operating, the pressure in the fluid space will approach the atmospheric pressure reference, and the original breathing pressure wave and the suction pulsation of the negative pressure component will be significantly weakened.

[0340] The processor classifies disturbance events qualitatively based on this fundamental difference.

[0341] The processor tracks abnormal transient disturbances and determines whether the real-time pressure falls within the observation window for physiological artifacts. The baseline tolerance zone was restored to the level before the event.

[0342] If the pressure recovers to the baseline tolerance band within the physiological artifact observation time window, and the periodic fluctuation characteristics corresponding to those before the event reappear after recovery, the processor determines that the event is a cough, postural change, or other short-term physiological artifact.

[0343] The processor clears the suspected disconnection status flag and gradually restores the output of the negative pressure component.

[0344] If the pressure does not return to the original baseline, the processor, while keeping the negative pressure component paused, selects the confirmation window after the event and calculates the arithmetic mean of the pressure signal within the confirmation window. and time series variance .

[0345] Arithmetic mean:

[0346] ;

[0347] Time series variance:

[0348] ;

[0349] Since this embodiment uses gauge pressure relative to atmospheric pressure, atmospheric pressure is the reference pressure. It is zero.

[0350] The processor confirms pipe detachment when the following conditions are met simultaneously:

[0351] ;

[0352] and:

[0353] ;

[0354] When using gauge pressure:

[0355] ;

[0356] The two conditions mentioned above respectively indicate that the average pressure after the event enters the atmospheric pressure tolerance zone, and that the pressure signal exhibits a low fluctuation state after the negative pressure component is suspended.

[0357] If the pressure does not return to the original baseline, but the average pressure does not enter the atmospheric pressure tolerance zone, or the timing variance does not meet the de-pipe judgment condition, the processor will not directly output the de-pipe status, but will output an unclassified pressure abnormality status indicator and maintain the negative pressure component paused, audible and visual prompts, and manual inspection status.

[0358] Time series variance critical threshold The calibration is performed based on the overall background pressure fluctuation of the entire machine under the condition that the negative pressure component is suspended.

[0359] The overall background pressure fluctuation includes pressure data fluctuations generated by the pressure sensing unit, hydrophobic and antibacterial breathable membrane, gas phase pressure tapping channel, analog-to-digital conversion circuit, and power supply noise.

[0360] The processor sets a timing variance critical threshold based on the pressure variance distribution under normal sealed state, atmospheric connection state, and static working state of the sensing unit, and sets a safety margin between the variance intervals of different states.

[0361] This composite filtering mechanism based on time and energy distribution reduces the probability of false alarms caused by artifact interference and improves the reliability of system monitoring status.

[0362] For the specific execution sequence of the state flip operations and flag suspend instructions of the underlying registers of the state machine, those skilled in the art can deploy them according to the conventional microprocessor state machine programming specifications. The software implementation method is a well-known technology in this field and will not be described in detail here.

[0363] See attached document Figure 8 , Figure 8 This is a flowchart of the execution control and closed-loop response logic according to an embodiment of the present invention.

[0364] For step S60 in the system operation control method, its main configuration is to dynamically adjust the operating parameters of the electromechanical actuators inside the system based on the current operating condition classification results output by the state machine, and output corresponding clinical prompt information.

[0365] The processor executes this closed-loop response process through the following sub-steps:

[0366] When the processor receives a normal drainage status indicator, it performs steady-state pressure closed-loop follow control.

[0367] Due to intermittent gas leakage within the pleural cavity and volume changes caused by respiration, the system needs to dynamically adjust its suction capacity to maintain the set target negative pressure.

[0368] The processor extracts the pressure baseline sequence generated in step S40 and calculates the pressure deviation between the current system static pressure and the preset target negative pressure.

[0369] Based on the pressure deviation value, the processor uses a proportional-integral-derivative (PID) control algorithm to generate a control output, thereby adjusting the drive duty cycle of the negative pressure component. The relevant discretization calculation formula is defined as follows:

[0370] ;

[0371] The processor limits the calculated control output to within the allowable output range of the negative pressure component:

[0372] ;

[0373] In the formula, Indicates the first The control output of each control cycle is used to map the duty cycle of the control level of the negative pressure component.

[0374] This embodiment specifies that when the output of the negative pressure component increases, the suction capacity of the negative pressure component is enhanced. The processor calculates the pressure deviation according to the following formula:

[0375] ;

[0376] When the current pressure baseline is higher than the target negative pressure, that is, when the absolute value of the current negative pressure is insufficient, The processor adds a negative pressure component to control the output;

[0377] When the current pressure baseline is lower than the target negative pressure, i.e., the absolute value of the negative pressure is too large, The processor reduces the negative pressure component to control the output;

[0378] This indicates the pressure deviation value from the previous control cycle;

[0379] , , These represent the proportional coefficient, integral coefficient, and derivative coefficient of the control algorithm, respectively. Their specific values ​​are tuned before the equipment leaves the factory based on the system fluid transfer function and the critical proportional coefficient method.

[0380] To prevent slight pressure fluctuations caused by minute amounts of condensation in the pipeline from triggering frequent controller oscillations, a dead-zone nonlinearity mechanism is introduced in the error calculation stage of the processor.

[0381] When the pressure deviation value When the absolute value is lower than the set pressure control tolerance (usually set to 50Pa to 80Pa), the processor forces... .

[0382] At the same time, the system is configured with anti-integral saturation logic, when the calculated result is... When the maximum physical output threshold of the negative pressure component is reached, the processor suspends the integral term accumulation operation.

[0383] To prevent the integral term from being unable to exit after being suspended in the saturation region, the processor is configured with recovery logic with conditional reverse calculation.

[0384] If the pressure deviation value in the next control cycle The sign reversal indicates that the system needs to be adjusted in the opposite direction. At this time, the processor immediately resumes the integral term operation in that direction to avoid long-term lag dead zone in the control response.

[0385] S602: When the processor receives a progressive pipe blockage status indicator, it performs safety current limiting control and maintenance prompts.

[0386] When the inner diameter of the pipe decreases, the airflow resistance increases significantly.

[0387] When the tubing becomes narrow or blocked, the original correspondence between the patient's respiratory pressure wave transmission, the bottle pressure baseline, and the negative pressure component control output is disrupted.

[0388] If the negative pressure component is adjusted according to the conventional closed-loop control logic, it may cause the negative pressure component to continue to work under abnormal fluid resistance conditions, and generate pressure overshoot when the pipeline suddenly resumes unobstructed flow.

[0389] Therefore, after receiving the confirmation of the blocked pipe status, the processor limits the control output of the negative pressure component to ensure that the actual control output meets the following requirements:

[0390] ;

[0391] In the formula, This indicates the safe output limit under the current physical topology combination mode.

[0392] The upper limit of safe output is determined during the equipment design phase based on the effective volume of the bottle, the resistance of the connecting pipe, the rated performance of the negative pressure component, and the allowable pressure overshoot range.

[0393] This can cause the negative pressure component to operate at full load, and generate overpressure when the pipeline is suddenly cleared, which may lead to a safety hazard of suction overload.

[0394] Therefore, the processor is configured to forcibly limit the control output of the negative pressure component after confirming the progressive blockage state. This keeps it below the security limit corresponding to the current topology mode.

[0395] This safety limit is typically set at 30% to 50% of the system's rated output power.

[0396] While limiting hardware power, the processor sends a tube obstruction warning code to the human-machine interface, triggering an audible and visual alarm signal. This prompts the operator to check whether the drainage tube is bent, compressed, has blood clots deposited, or has abnormal connections, in accordance with the operating procedures stipulated by the medical institution. Qualified medical personnel then decide whether to take tube maintenance measures.

[0397] During the execution of rate limiting, the processor background continuously monitors stress characteristic data.

[0398] If the baseline drift characteristics and periodic fluctuation characteristics are found to return to the safe range corresponding to the normal drainage state, it indicates that the pipeline has been cleared. The processor automatically releases the control output limit and smoothly switches back to the steady-state pressure closed-loop follow control logic.

[0399] S603: When the processor receives a confirmation of the disconnected status, it triggers a self-locking cut-off protection mechanism.

[0400] A pipe detachment means that the closed operating environment inside the system has failed and is now directly connected to the outside atmosphere.

[0401] If the negative pressure component continues to maintain negative pressure suction, it will cause unfiltered external gas to be rapidly drawn into the internal flow channel of the equipment, causing pipeline contamination.

[0402] After confirming the disconnected state, the processor keeps the negative pressure component stopped and bypasses the conventional negative pressure closed-loop control module to send a lock-up closing command to the self-locking valve drive circuit.

[0403] The self-locking valve drives the flexible drainage input line to radially close, thereby blocking the flow of gas and fluid in the patient-side drainage input line.

[0404] The processor reads the valve position feedback signal from the self-locking valve.

[0405] When the valve position feedback signal indicates that the self-locking valve has reached the locked-close position, the processor outputs a status indicating that the disconnection protection has been executed.

[0406] If the self-locking valve fails to reach the locked-off position within the set response time, the processor outputs a self-locking valve execution fault status and maintains the highest priority audible and visual alarm.

[0407] The processor writes the event occurrence time, pre-event pressure baseline, transient pressure change rate, post-event pressure mean, post-event timing variance, and self-locking valve action results into non-volatile memory.

[0408] Systems in the tube disconnection protection state are not allowed to automatically resume suction.

[0409] After reconnecting and checking the tubing, medical staff should input a manual reset confirmation command through the human-machine interface.

[0410] After the medical staff reconnected and checked the tubing, they entered a manual reset confirmation command through the human-machine interface.

[0411] After receiving the manual reset confirmation command, the processor keeps the self-locking valve in the locked and closed position and re-executes the interface closure confirmation, pressure sensing unit check, test negative pressure pulse, pressure holding check, and physical topology combination pattern recognition.

[0412] Only after the self-test passes will the processor send an opening command to the self-locking valve, and after confirming that the self-locking valve has reached the open position, it will resume the normal operation of the negative pressure component, pressure maintenance check and physical topology combination mode recognition.

[0413] The processor can only resume operation of the negative pressure component after the self-test passes again.

[0414] For the underlying driving timing of the audible and visual alarm circuit and the specific bit segment configuration of the pulse width modulation peripheral register, those skilled in the art can develop it based on conventional microcontroller hardware technical manuals. The underlying software configuration implementation is a well-known technology in this field and will not be elaborated here.

[0415] To further clarify the working mechanism and technical effect of the system operation control method described in this invention in actual clinical scenarios, the following description is based on specific numerical calculation application examples and experimental verification test data.

[0416] See attached document Figure 9 , Figure 9 This is a comparison diagram of the comprehensive response and system control effect under typical working conditions according to an embodiment of the present invention. It intuitively shows the data flow logic and waveform response characteristics of the system under various physical working conditions such as topology identification, coughing disturbance, pipeline detachment and progressive pipe blockage.

[0417] In this embodiment, the actual physical connection of the system is set as a dual-bottle series operation mode to demonstrate the entire process of dynamic parameter loading and closed-loop control.

[0418] Upon system power-up, the system enters the pre-isolation self-test phase. Since this embodiment uses a gauge pressure reference, the initial pressure is measured. Pa. The processor sends a pulse drive command to the negative pressure component, and the vacuum pump extracts a volume of fluid from the test fluid space within a 0.3s time window. mL of gas.

[0419] After the negative pressure pulse ends and the negative pressure isolation valve closes, the pressure transient response enters a stable holding period, and the holding pressure is measured. -10000Pa.

[0420] The processor calculates the absolute value of the pressure change. Pa.

[0421] Based on the equivalent aerodynamic compliance formula, the following calculations were performed: mL / Pa.

[0422] The processor retrieves the topology identification parameter set from non-volatile memory, including the preset first topology threshold. mL / Pa, second topological threshold mL / Pa. Since the calculated 0.05 mL / Pa is greater than... The processor accurately determines that the current system has the characteristics of effective volume of two bottles and confirms that it is in the dual-bottle series operation mode.

[0423] Based on this mode determination, the processor loads a set of control parameters optimized for the dual-bottle volume delay characteristics, including setting the target negative pressure. Pa, safe threshold for respiratory fluctuation amplitude Pa, physiological artifact time window s, and the upper limit of safe output .

[0424] Once the real-time continuous monitoring cycle begins, the processor calculates the pressure deviation value in real time. And drive the negative pressure component.

[0425] At a certain sampling moment, the continuous pressure timing signal experienced a sharp jump, with the pressure abruptly changing from -2000Pa to -500Pa within 50ms.

[0426] The processor uses a smooth central difference algorithm to derive the transient rate of change. Pa / s, this value is greater than the preset positive transient threshold. 10000Pa / s. The state machine then enters the transient event confirmation state and temporarily suspends the negative pressure component.

[0427] The processor continued to track the pressure trajectory within the subsequent confirmation window. The pressure signal returned to the baseline tolerance band (around -1950 Pa) 1.2 seconds after the disturbance occurred, and the periodic fluctuation characteristics with a peak of 80 Pa reappeared.

[0428] Because the pulse duration is shorter than the physiological artifact time window set in the dual-bottle mode. If the processor determines that the disturbance is a physiological artifact caused by the patient's cough, the state machine is reset and the normal steady-state pressure closed-loop follow control is restored in an incremental manner.

[0429] The system was set to experience a real pipe detachment at another time, during which the pressure would also surge but remain at the ambient atmospheric pressure level.

[0430] After the negative pressure component pauses, the processor calculates the pressure arithmetic mean within a confirmation window with a physical time length of 2 seconds. Pa, time series variance .

[0431] Retrieve the corresponding atmospheric pressure tolerance threshold Pa and the critical threshold of time series variance .

[0432] The comparison results meet the requirements. and .

[0433] The state machine's double verification is successful, confirming the reverse flow disconnection state.

[0434] The processor then bypasses the conventional control algorithm, drives the self-locking valve to perform a clamping action, and outputs the highest priority audible and visual alarm after reading the locking position feedback signal, effectively blocking the reverse intrusion of external airborne pollutants.

[0435] To verify the clinical effectiveness of the above-mentioned feature extraction and state machine joint control logic, a high-precision medical fluid simulation platform was used to conduct comparative tests on the system described in this invention and a basic constant pressure drainage system without a state machine classification algorithm.

[0436] like Figure 9 As shown in the comparative data curves, the experimental platform was configured to output a simulated thoracic airflow with a baseline pressure of -2000 Pa, a respiratory rate of 0.3 Hz, and an amplitude of 120 Pa.

[0437] exist At time s, the platform injects a high-pressure gas cloud that lasts for 1 second to simulate a single violent cough;

[0438] exist At 80 seconds, the solenoid valve is fully opened to simulate the connection end being released to the atmosphere;

[0439] Furthermore, the fluid resistance of the simulated drainage channel in the experiment increased exponentially with time, and at [a certain point in time]. The simulation of a sudden drop in resistance caused by manual dredging is performed at time s.

[0440] Test data shows that the basic constant pressure system in During the cough of s, due to the sole reliance on error response, the controller drastically increased the rotational speed to counteract the pressure rise, resulting in a negative pressure overshoot lasting approximately 6 seconds after the pulse ended, with a peak value reaching -3200 Pa, posing an engineering risk of causing tissue damage. After the tube is disconnected, the vacuum pump of the basic system continues to operate at full load, drawing in external gas at a rate of 15L / min.

[0441] In comparison, the system described in this invention... After capturing transient jumps, the negative pressure pause mechanism is immediately triggered, avoiding irrational control resistance. After confirming the recovery of variance and mean, it smoothly switches back to steady state without generating significant control overshoot.

[0442] exist After the detachment occurs, the system calculates the sustained low variance state following the detachment (corresponding to...). Figure 9 middle (The node where the prescription difference curve crosses the critical threshold red line) completes the locking and isolation of the self-locking valve within 2.5s after the disturbance occurs, and the total amount of external gas inhaled is strictly limited to within 0.2L.

[0443] Meanwhile, during the gradual pipe blockage process as fluid resistance increases, the PID controller of the basic constant pressure system experiences persistent steady-state error, causing the integral term to continuously accumulate and saturate, resulting in the control duty cycle rapidly climbing to the 100% upper limit. The moment the s-pipe was cleared, the negative pressure source operating at full load generated a dangerous transient overpressure of up to -4800Pa within the pipeline.

[0444] The system of this invention separates periodic fluctuation characteristic data through a digital filtering algorithm. When the amplitude is detected to decrease from 120Pa and remain below the set safety threshold of 60Pa, the state machine promptly switches to the suspected blockage state of the patient's side channel.

[0445] After the timer is confirmed, the processor forces the control output to be... The clamp is set at the 40% safety limit.

[0446] Test data shows that at the moment of pipeline unblocking, the maximum transient pressure overshoot of the system of the present invention is effectively limited to -2250Pa, which meets the safety tolerance standard of no more than 2500Pa for absolute negative pressure of clinical chest drainage, and significantly reduces the risk of device-induced injury caused by sudden changes in pipeline dynamic characteristics.

[0447] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A smart, adjustable, anti-backflow, combinable closed thoracic drainage system, characterized in that, include: The processor, and a self-locking valve, a negative pressure isolation valve, a pressure sensing unit, and a negative pressure assembly, which are electrically connected to the processor respectively; The self-locking valve is installed on the patient-side drainage inlet tube; The negative pressure isolation valve is disposed between the negative pressure component and the space of the fluid being tested; The processor is configured to perform the following operations: during the pre-test phase, control the self-locking valve to be in the closed position and control the negative pressure component to output a test negative pressure pulse; Based on the volume of gas extracted during the test negative pressure pulse and the pressure change collected by the pressure sensing unit, the equivalent aerodynamic compliance is calculated. Based on the equivalent aerodynamic compliance, a physical topology combination mode is determined, and a control parameter group corresponding to the physical topology combination mode is loaded. During the continuous monitoring period, the negative pressure component is driven to perform steady-state pressure closed-loop control based on the control parameter set; When the characteristic data of the continuous pressure timing signal collected by the pressure sensing unit meets the set conditions, the control state machine switches to the corresponding state and outputs the control command of the self-locking valve or the negative pressure component.

2. The intelligent adjustable anti-backflow combinable closed thoracic drainage system according to claim 1, characterized in that, The steps of the processor controlling the negative pressure component to output a test negative pressure pulse and calculating the equivalent aerodynamic compliance include: When the test negative pressure pulse begins, the negative pressure isolation valve is opened and the negative pressure assembly is driven to draw in air. After the set time window ends, the negative pressure component is controlled to stop suction and the negative pressure isolation valve is closed, and the tested fluid space enters a pressure holding state; The volume of gas extracted during the test negative pressure pulse and the absolute difference between the holding pressure and the initial pressure under the pressure holding state are obtained. The ratio of the gas volume to the absolute difference is defined as the equivalent aerodynamic compliance.

3. The intelligent adjustable anti-backflow combinable closed thoracic drainage system according to claim 1, characterized in that, The control parameter set includes target negative pressure, safe threshold for respiratory fluctuation amplitude, physiological artifact time window, and safe output upper limit; The step of determining the physical topology combination mode based on the equivalent aerodynamic compliance includes: The equivalent aerodynamic compliance is compared with a preset topology threshold in the non-volatile memory, and the physical topology combination mode is confirmed based on the comparison result.

4. The intelligent adjustable anti-backflow combinable closed thoracic drainage system according to claim 3, characterized in that, The characteristic data includes transient rate of change and pulse duration. The steps of the control state machine switching to the corresponding state and outputting control commands include: When the processor calculates using a differential algorithm that the transient rate of change of the continuous pressure timing signal is greater than a preset positive transient threshold, it controls the state machine to switch to the transient event confirmation state and controls the negative pressure component to pause. When the continuous pressure timing signal falls back to the baseline tolerance band within the set confirmation window, and the calculated pulse duration is less than the physiological artifact time window, the state machine is reset and the steady-state pressure closed-loop control is restored.

5. The intelligent adjustable anti-backflow combinable closed thoracic drainage system according to claim 3, characterized in that, The feature data includes an arithmetic mean and a time series variance. The steps of the control state machine switching to the corresponding state and outputting control commands include: When the continuous pressure timing signal jumps to the ambient atmospheric pressure level, the processor controls the negative pressure component to pause, and calculates the arithmetic mean and timing variance of the continuous pressure timing signal within a set confirmation window; When the arithmetic mean is less than or equal to the atmospheric pressure tolerance threshold and the time series variance is less than the time series variance critical threshold, the state machine is controlled to switch to the reverse flow disconnection state. The processor bypasses the steady-state pressure closed-loop control, outputs a clamping command to the self-locking valve, and outputs an alarm signal in response to the lock-up position feedback signal.

6. The intelligent adjustable anti-backflow combinable closed thoracic drainage system according to claim 3, characterized in that, The characteristic data includes amplitude data of periodic fluctuation characteristics, and the steps of the control state machine switching to the corresponding state and outputting control commands include: The processor extracts the amplitude data of the periodic fluctuation characteristics in the continuous pressure time-series signal; When the amplitude data decays and remains below the safe threshold for respiratory fluctuation amplitude, the state machine is controlled to switch to a suspected blockage state. The processor clamps the control output of the negative pressure component at the upper limit of the safe output.

7. The intelligent adjustable anti-backflow combinable closed thoracic drainage system according to claim 2, characterized in that, After the tested fluid space enters a pressure holding state, the processor calculates the pressure recovery rate within the pressure holding time window. When the pressure recovery rate does not exceed the preset leakage determination threshold, the step of determining the physical topology combination mode based on the equivalent aerodynamic compliance is executed; When the pressure recovery rate exceeds the leakage determination threshold, the physical topology identification program is stopped.

8. The intelligent adjustable anti-backflow combinable closed thoracic drainage system according to claim 2, characterized in that, The volume of gas extracted during the test negative pressure pulse was obtained in the following way: The instantaneous pumping flow rate detected by the flow detection element is integrated over the duration of the test negative pressure pulse; Alternatively, the instantaneous air extraction flow rate can be calculated based on the actual rotational speed of the negative pressure component, the inlet pressure, and the pre-stored flow rate calibration relationship, and the instantaneous air extraction flow rate can be integrated over the duration.

9. The intelligent adjustable anti-backflow combinable closed thoracic drainage system according to claim 1, characterized in that, During the pre-test phase, after the processor sends a command to the self-locking valve, it confirms that the self-locking valve is in the closed position based on the received valve position feedback signal. The processor outputs an interface check prompt, and after receiving an interface closure confirmation signal, it controls the negative pressure component to output the test negative pressure pulse.

10. The intelligent adjustable anti-backflow combinable closed thoracic drainage system according to claim 1, characterized in that, The processor outputs a pulse width modulation signal to the negative pressure component, and controls the pumping flow rate during the steady-state pressure closed-loop control process by adjusting the speed of the vacuum pump motor inside the negative pressure component or the opening of the electromagnetic proportional valve.

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