A single-cycle ventilation volume optimization control system and method with oxygen concentration compensation function

Abstract

This invention discloses a single-cycle ventilation volume optimization control system and method with oxygen concentration compensation function, including a physiological ventilation parameter sensing subsystem, a ventilation volume closed-loop control subsystem, and an auxiliary ventilation execution subsystem. The physiological ventilation parameter sensing subsystem uses an oxygen concentration sensor at the junction of the fan airway and the mask airway to collect mechanical ventilation parameters and oxygen concentration, which is then input into the ventilation volume closed-loop control subsystem. The ventilation volume closed-loop control subsystem calculates the oxygen consumption for the current respiratory cycle and uses it as an independent compensation quantity to calculate the optimized auxiliary ventilation volume for the next respiratory cycle. The auxiliary ventilation execution subsystem calculates the speed adjustment increment based on an incremental PID algorithm, limits it, and then uses the underlying motor drive to achieve current loop closed-loop control. By introducing actual oxygen consumption information into the auxiliary ventilation volume optimization control process, real-time feedback adjustments are made to achieve the optimal ventilation treatment effect, effectively improving the efficiency of mechanical ventilation treatment.

Description

Technical Field

[0001] This invention relates to the field of ventilator technology, and in particular to a single-cycle ventilation volume optimization control system and method with oxygen concentration compensation function. Background Technology

[0002] Ventilators, as important medical devices that can effectively replace or assist normal physiological breathing, reduce the artificial consumption of breathing, increase lung ventilation, and improve respiratory function, are widely used in clinical medicine, home healthcare, and emergency rescue. Because the stability, safety, reliability, and accuracy of various control elements of a ventilator are crucial to the respiratory therapy process, research on ventilator ventilation control is a very important step in ventilator design.

[0003] The respiratory system is characterized by nonlinearity, time delay, and large dynamic range of parameter changes. Traditional closed-loop control methods for assisted ventilation devices have serious deficiencies in terms of accuracy, personalization, intelligence, and automation. Clinically, this manifests as severe patient-ventilator asynchrony, ventilator-associated lung injury, poor assisted ventilation effects, and many other problems. At the same time, the dozens of different ventilation modes and their complex and cumbersome personalized parameter settings also place high demands on medical staff.

[0004] In the field of assisted ventilation control technology, modeling methods are commonly used for research. Many experts and scholars both domestically and internationally have proposed various ventilator ventilation modes and control methods. Although these modes may differ in name due to patent protection or other reasons, they can ultimately be categorized into volume-controlled ventilation, pressure-controlled ventilation, and hybrid control ventilation based on their control objectives. Pressure-controlled ventilation uses airway pressure as the control objective, maintaining the inspiratory airway pressure at the set pressure level throughout the treatment process. Volume-controlled ventilation uses volume as the control objective, providing ventilation to the patient at a constant flow rate according to a set tidal volume. Hybrid control ventilation combines pressure and volume control, using different control methods for ventilation treatment in different respiratory cycles. All of the above-mentioned ventilator ventilation modes involve single control or ventilation control in different respiratory cycles. Even existing hybrid ventilation modes struggle to reconcile the conflict between spontaneous breathing and forced ventilation, namely, the intelligent switching between pressure and volume control objectives, the accuracy and time delay of preset ventilation control indicators (minute ventilations, tidal volume, etc.), and patient-ventilator asynchrony and the lung injury and increased work of breathing caused by forced ventilation. Furthermore, these ventilation methods only involve optimizing and controlling airway pressure and ventilation volume, without considering changes in oxygen content during ventilation. Clinically, various oxygen supply devices used in oxygen therapy only focus on controlling the average oxygen concentration in the airway. Currently, no intelligent algorithms or devices have been found that can use oxygen consumption information from each stage of a single respiratory cycle as a compensation to precisely regulate the single respiratory process and achieve optimized control of assisted ventilation. Therefore, research on methods and devices for optimizing and controlling single-cycle ventilation volume with oxygen concentration compensation is of great significance. Summary of the Invention

[0005] To address the shortcomings of the existing technologies, the technical problem to be solved by this patent application is how to provide a single-cycle ventilation volume optimization control system and method with oxygen concentration compensation function. This system obtains ambient oxygen concentration information stably during the two plateau phases of inhalation and exhalation, incorporates the actual oxygen consumption information of the user's breathing process into the assisted ventilation volume optimization control process, and provides real-time feedback and adjustment to achieve the best ventilation treatment effect, thereby effectively improving the efficiency of mechanical ventilation treatment.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] A single-cycle ventilation capacity optimization control system with oxygen concentration compensation function includes a physiological ventilation parameter sensing subsystem, a ventilation capacity closed-loop control subsystem, and an auxiliary ventilation execution subsystem;

[0008] The physiological ventilation parameter sensing subsystem includes an oxygen concentration sensor at the junction of the fan airway and the mask airway. This sensor collects mechanical ventilation parameters and oxygen concentration. Based on the pressure-flow rate signal waveform characteristics during respiration, the system obtains stable inspiratory plateau and end-expiratory plateau start and end times, and then calculates the inspiratory plateau pressure for the current cycle. End-expiratory plateau pressure and oxygen concentration during the inspiratory plateau and end-expiratory plateau oxygen concentration Input ventilation capacity closed-loop control subsystem;

[0009] The ventilation capacity closed-loop control subsystem calculates the oxygen consumption of the current respiratory cycle and uses it as an independent compensation quantity to calculate the optimized assisted ventilation for the next respiratory cycle.

[0010] After one respiratory cycle, the inspiratory plateau pressure of that respiratory cycle is calculated based on the physiological ventilation parameter sensing subsystem. End-expiratory plateau pressure Oxygen concentration during the inspiratory plateau Oxygen concentration at the end-expiratory plateau The oxygen consumption for the current respiratory cycle is calculated by referring to the oxygen consumption calculation formula. Then it is determined whether the oxygen consumption for the current respiratory cycle has reached the set value. If the oxygen consumption has not reached the set value, the assisted ventilation is optimized in the next respiratory cycle based on the difference. If the set value is reached, the next respiratory cycle is not interfered with.

[0011] The assisted ventilation execution subsystem combines a curve fitting model with incremental PID control. The curve fitting model obtains the predicted steady-state speed, and the incremental PID is used to calculate the adjustment amount of the solenoid valve and fan speed, and update the solenoid valve status and fan speed. By controlling the opening and closing of the expiratory valve, the expiratory valve is closed during the rising phase of inspiration and opened at the end of the plateau phase of inspiration, achieving rapid response for replenishment and deflation. Combined with speed adjustment, this quickly and efficiently reduces delay and human-machine interaction, improving user comfort.

[0012] Preferably, the oxygen concentrations at the inspiratory plateau and end-expiratory plateau are obtained by calculating the average oxygen concentrations during the inspiratory and expiratory phases, respectively. as well as .

[0013] Preferably, in the ventilation capacity closed-loop control subsystem, a respiratory cycle includes an inspiratory waiting period, an inspiratory rise period, an inspiratory plateau period, a rapid expiratory period, and an end-expiratory plateau period.

[0014] Preferably, the ventilation volume closed-loop control subsystem adopts volume control, that is, ventilation is performed at a constant flow rate according to the set tidal volume, and the inspiratory pressure changes with respiratory mechanics and the patient's inspiratory effort during the ventilation process.

[0015] The formula for calculating oxygen consumption (1) is as follows:

[0016]

[0017] in, It is oxygen consumption. It refers to the inhalation volume. It is the expiratory volume. It is the average temperature during the intake phase. It is the average temperature during the exhalation phase.

[0018] Preferably, the following method is used to optimize the assisted ventilation volume:

[0019] Oxygen consumption is treated as an independent compensation factor. The assisted ventilation volume for the next respiratory cycle is calculated based on the difference between the actual oxygen consumption and the set value. Through forced control, the inspiratory time of the next respiratory cycle is prolonged or the expiratory time is shortened to compensate for the oxygen concentration.

[0020] Preferably, the auxiliary ventilation execution subsystem calculates the speed adjustment increment based on the incremental PID algorithm, limits it, and then uses the underlying motor to achieve closed-loop control of the current loop. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a single-cycle ventilation capacity optimization control system with oxygen concentration compensation function according to the present invention.

[0022] Figure 2 This is a flowchart of the ventilation capacity closed-loop control subsystem.

[0023] Figure 3 The figure shows the fitted curves of steady-state ventilator speed and airway pressure.

[0024] Figure 4 This is a schematic diagram of the combination of curve fitting model and PID control. Detailed Implementation

[0025] The present invention will now be described in further detail with reference to the accompanying drawings. In the description of the present invention, it should be understood that directional terms such as "upper," "lower," "top," and "bottom" indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. These terms are used only for the convenience of describing the present invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the scope of protection of the present invention. The directional terms "inner" and "outer" refer to the inner or outer contours relative to the outline of each component itself.

[0026] like Figure 1As shown, a single-cycle ventilation capacity optimization control system with oxygen concentration compensation function includes a physiological ventilation parameter sensing subsystem with high-precision oxygen concentration detection function, a ventilation capacity closed-loop control subsystem with oxygen concentration compensation function, and an auxiliary ventilation execution subsystem with solenoid valves and turbine fans as the core.

[0027] The physiological ventilation parameter sensing subsystem includes an oxygen concentration sensor at the junction of the fan airway and the mask airway. This sensor collects mechanical ventilation parameters and oxygen concentration. Based on the pressure-flow rate signal waveform characteristics during respiration, the system obtains stable inspiratory plateau and end-expiratory plateau start and end times, and then calculates the inspiratory plateau pressure for the current cycle. End-expiratory plateau pressure and oxygen concentration during the inspiratory plateau and end-expiratory plateau oxygen concentration Input ventilation capacity closed-loop control subsystem;

[0028] The ventilation capacity closed-loop control subsystem calculates the oxygen consumption of the current respiratory cycle by referring to the oxygen consumption calculation formula, and uses it as an independent compensation quantity to calculate the optimized assisted ventilation for the next respiratory cycle.

[0029] The auxiliary ventilation execution subsystem calculates the speed adjustment increment based on the incremental PID algorithm, limits it, and then uses the underlying motor to achieve closed-loop control of the current loop.

[0030] In this embodiment, the oxygen concentrations at the inspiratory plateau and end-expiratory plateau are obtained by calculating the average oxygen concentrations during the inspiratory and expiratory phases, respectively. as well as .

[0031] In this embodiment, such as Figure 2 As shown, in the ventilation capacity closed-loop control subsystem, a respiratory cycle includes an inspiratory waiting period, an inspiratory rising period, an inspiratory plateau period, a rapid expiratory period, and an end-expiratory plateau period.

[0032] After one respiratory cycle, the inspiratory plateau pressure of that respiratory cycle is calculated based on the physiological ventilation parameter sensing subsystem. End-expiratory plateau pressure Oxygen concentration during the inspiratory plateau Oxygen concentration at the end-expiratory plateau The oxygen consumption for the current respiratory cycle is calculated by referring to the oxygen consumption calculation formula. Then, it is determined whether the oxygen consumption for the current respiratory cycle has reached the set value. If the oxygen consumption has not reached the set value, the assisted ventilation is optimized in the next respiratory cycle based on the difference. If the set value is reached, the next respiratory cycle is not interfered with.

[0033] In this embodiment, the ventilation volume closed-loop control subsystem adopts volume control, that is, ventilation is performed at a constant flow rate according to the set tidal volume, and the inspiratory pressure changes with respiratory mechanics and the patient's inspiratory effort during the ventilation process.

[0034] The formula for calculating oxygen consumption (1) is as follows:

[0035]

[0036] in, It is oxygen consumption. It refers to the inhalation volume. It is the expiratory volume. It is the average temperature during the intake phase. It is the average temperature during the exhalation phase.

[0037] In this embodiment, the following method is used to optimize the assisted ventilation volume:

[0038] Oxygen consumption is treated as an independent compensation factor. The assisted ventilation volume for the next respiratory cycle is calculated based on the difference between the actual oxygen consumption and the set value. Through forced control, the inspiratory time of the next respiratory cycle is prolonged or the expiratory time is shortened to compensate for the oxygen concentration.

[0039] In this embodiment, the assisted ventilation execution subsystem combines a curve fitting model with incremental PID control. The curve fitting model obtains the predicted value of the steady-state speed, and the incremental PID is used to calculate the adjustment amount of the solenoid valve and fan speed, and update the solenoid valve status and fan speed. By controlling the opening and closing of the expiratory valve, the expiratory valve is closed during the rising phase of inspiration and opened at the end of the plateau phase of inspiration, so as to achieve rapid response of replenishment and deflation. Combined with the speed adjustment, it quickly and efficiently reduces delay and human-machine interaction, and improves user comfort.

[0040] In the assisted ventilation execution subsystem, prior data is obtained by collecting measured values ​​of the ventilator's steady-state rotational speed and airway pressure. Polynomial curve fitting is employed, with the following formula: ,in, These are the coefficients of the polynomial. It is the order of the polynomial, and This is the measured airway pressure. This is the steady-state rotational speed. The current solenoid valve state and the airway pressure control target are input into a curve fitting model. The fitted curve obtained based on a set of prior data is shown below. Figure 3 As shown.

[0041] The predicted steady-state speed is obtained through a curve fitting model. Incremental PID control is then used to calculate the adjustments to the solenoid valve and fan speeds, updating the solenoid valve state and fan speed accordingly. The incremental PID formula is as follows: . It is the output (adjustment amount) at the current moment. It is the output from the previous moment. It is the error at the current moment (the difference between the set value and the actual value). It is the rate of change of error at the current moment, i.e. . These are the proportional, integral, and derivative coefficients of the PID controller, representing the proportional gain, integral gain, and derivative gain, respectively. It is the derivative of the error at the current moment, that is ,in By selecting appropriate parameters, closed-loop control of the current loop is achieved through the underlying motor drive. The fitted model is combined with PID control, as illustrated in the diagram below. Figure 4 As shown.

[0042] Specifically, to improve patient comfort when using a ventilator and reduce patient-ventilator asynchrony, the expiratory valve is closed when the patient is in the rising phase of inspiration and opened when the patient is in the rapid expiratory phase, thus achieving rapid pressure relief.

[0043] This invention also discloses a single-cycle ventilation capacity optimization control method with oxygen concentration compensation function, comprising the following steps:

[0044] S1: Provide mechanical ventilation to the patient according to the preset parameters of the ventilator;

[0045] S2: An oxygen concentration sensor is installed at the junction of the fan air duct and the mask air duct to collect mechanical ventilation parameters and oxygen concentration, and input them into the ventilation capacity closed-loop control subsystem.

[0046] S3: The ventilation capacity closed-loop control subsystem calculates the oxygen consumption of the current respiratory cycle by referring to the oxygen consumption calculation formula, and uses it as an independent compensation quantity to calculate the optimized assisted ventilation for the next respiratory cycle.

[0047] S4: The auxiliary ventilation execution subsystem calculates the speed regulation increment based on the incremental PID algorithm, and after being limited, it is driven by the underlying motor to realize the current loop closed-loop control, optimize the auxiliary ventilation volume, and compensate for the oxygen concentration.

[0048] Finally, it should be noted that those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A single-cycle ventilation capacity optimization control system with oxygen concentration compensation function, characterized in that, It includes a physiological ventilation parameter sensing subsystem, a ventilation volume closed-loop control subsystem, and an assisted ventilation execution subsystem; The physiological ventilation parameter sensing subsystem includes an oxygen concentration sensor at the junction of the fan airway and the mask airway. This sensor collects mechanical ventilation parameters and oxygen concentration. Based on the pressure-flow rate signal waveform characteristics during respiration, the system obtains stable inspiratory plateau and end-expiratory plateau start and end times, and then calculates the inspiratory plateau pressure for the current cycle. End-expiratory plateau pressure and oxygen concentration during the inspiratory plateau and end-expiratory plateau oxygen concentration Input ventilation capacity closed-loop control subsystem; The ventilation capacity closed-loop control subsystem calculates the oxygen consumption of the current respiratory cycle and uses it as an independent compensation quantity to calculate the optimized assisted ventilation for the next respiratory cycle. After one respiratory cycle, the inspiratory plateau pressure of that respiratory cycle is calculated based on the physiological ventilation parameter sensing subsystem. End-expiratory plateau pressure Oxygen concentration during the inspiratory plateau Oxygen concentration at the end-expiratory plateau The oxygen consumption for the current respiratory cycle is calculated by referring to the oxygen consumption calculation formula. Then it is determined whether the oxygen consumption for the current respiratory cycle has reached the set value. If the oxygen consumption has not reached the set value, the assisted ventilation is optimized in the next respiratory cycle based on the difference. If the set value is reached, the next respiratory cycle is not interfered with. The assisted ventilation execution subsystem combines a curve fitting model with incremental PID control. The curve fitting model obtains the predicted steady-state speed, and the incremental PID is used to calculate the adjustment amount of the solenoid valve and fan speed, and update the solenoid valve status and fan speed. By controlling the opening and closing of the expiratory valve, the expiratory valve is closed during the rising phase of inspiration and opened at the end of the plateau phase of inspiration, achieving rapid response for replenishment and deflation. Combined with speed adjustment, this quickly and efficiently reduces delay and human-machine interaction, improving user comfort.

2. The single-cycle ventilation capacity optimization control system with oxygen concentration compensation function according to claim 1, characterized in that, The oxygen concentrations at the inspiratory and end-expiratory plateaus were obtained by calculating the average oxygen concentrations during the inspiratory and expiratory phases, respectively. as well as .

3. The single-cycle ventilation capacity optimization control system with oxygen concentration compensation function according to claim 1, characterized in that, In the ventilation capacity closed-loop control subsystem, a respiratory cycle includes an inspiratory waiting period, an inspiratory rising period, an inspiratory plateau period, a rapid expiratory period, and an end-expiratory plateau period.

4. The single-cycle ventilation capacity optimization control system with oxygen concentration compensation function according to claim 1, characterized in that, The ventilation volume closed-loop control subsystem adopts volume control, that is, ventilation is performed at a constant flow rate according to the set tidal volume, and the inspiratory pressure changes with respiratory mechanics and the patient's inspiratory effort during the ventilation process. The formula for calculating oxygen consumption (1) is as follows: in, It is oxygen consumption. It refers to the inhalation volume. It is the expiratory volume. It is the average temperature during the intake phase. It is the average temperature during the exhalation phase.

5. A single-cycle ventilation capacity optimization control system with oxygen concentration compensation function according to claim 3, characterized in that, The following methods can be used to optimize assisted ventilation: Oxygen consumption is treated as an independent compensation factor. The assisted ventilation volume for the next respiratory cycle is calculated based on the difference between the actual oxygen consumption and the set value. Through forced control, the inspiratory time of the next respiratory cycle is prolonged or the expiratory time is shortened to compensate for the oxygen concentration.

6. The single-cycle ventilation capacity optimization control system with oxygen concentration compensation function according to claim 1, characterized in that, The auxiliary ventilation execution subsystem calculates the speed adjustment increment based on the incremental PID algorithm, limits it, and then uses the underlying motor to achieve closed-loop control of the current loop.

Images