Online calibration device and method for tidal volume of breathing machine

Abstract

The invention relates to a breathing machine tidal volume online calibration device which is composed of an inspiration pipeline calibration module, an expiration pipeline calibration module, a computer and measurement software installed in the computer. The inspiration pipeline calibration module and the expiration pipeline calibration module are respectively connected with an inspiration pipeline and an expiration pipeline of the breathing machine, are connected in parallel through a Y-shaped pipe and then are connected with the respiratory tract of a patient. In various clinical ventilation modes such as a volume control mode, a pressure control mode, a bypass flow triggering mode and a volume / pressure mixed control mode, online calibration measurement is carried out on the inhaled tidal volume and the exhaled tidal volume of the breathing machine. The online calibration device can accurately collect the tidal volume (inhaled tidal volume) conveyed to a patient by a breathing machine and the tidal volume exhaled by the patient after metabolism, and real-time online calibration of the tidal volume of the breathing machine at the stage of clinical treatment of the patient is achieved. And the calibration data precision and the clinical quality control working efficiency and effect of the breathing machine are improved, and the method is suitable for various clinical use scenes.

Description

Technical Field

[0001] The present invention relates to a ventilator calibration device in the field of medical instruments, and particularly to an on-line calibration device and calibration method for the tidal volume of a ventilator. Background Art

[0002] According to the evaluation of international authoritative institutions, the ventilator is one of the medical devices with the highest clinical risks in large-scale medical equipment used in hospitals. Therefore, the accuracy of the tidal volume output during the treatment of patients with a ventilator is directly related to the physical health and life safety of the majority of patients. Developing a scientific and reasonable quality control plan for the ventilators in use in medical institutions and regularly carrying out quality control is an effective method to ensure its clinical effectiveness and reduce medical risks. Regular metrological calibration is an important part of the preventive maintenance in quality control and is also the fundamental means to ensure the accuracy of the measured values of relevant medical equipment.

[0003] When the ventilator is used clinically to treat patients, it has the characteristic of continuous operation for a long time once it is turned on. The treatment time of patients on the ventilator is usually several days to several weeks. During the treatment process, the inhaled tidal volume, that is, the volume of gas delivered by the ventilator to the patient in one respiratory cycle, is a key parameter for evaluating the metrological performance of the ventilator; the exhaled tidal volume, that is, the volume of gas exhaled by the patient in one respiratory cycle after metabolism, is an important indicator for clinically evaluating the patient's respiratory function and oxygenation level. In order to effectively reduce the clinical risks of treating patients with a ventilator, both the inhaled tidal volume and the exhaled tidal volume need to be detected and calibrated. In addition to the volume control mode, the clinical ventilator ventilation modes also include the pressure control mode, the by-pass trigger mode, and the volume / pressure hybrid control mode, etc.

[0004] At present, all the existing ventilator tidal volume calibration methods are carried out in the non-online treatment state where the ventilator is not connected to the patient, and only the accuracy of the inspiratory tidal volume in the volume control ventilation mode of the ventilator is measured and calibrated. There is an urgent need to carry out on-line metrological calibration and quality control for the key parameter tidal volume (including inspiratory tidal volume and expiratory tidal volume) of various clinical ventilation modes (i.e., volume control mode, pressure control mode, by-pass trigger mode, etc.) during the stage when the ventilator is used to treat patients clinically, so as to effectively ensure its clinical use quality.

[0005] Such as Figure 1The figure shows a schematic diagram of the connection of each device in the current existing calibration system for the tidal volume of a ventilator. The existing calibration methods for the tidal volume of a ventilator are all carried out when the ventilator is not connected to the patient, that is, in the non-online treatment state of the ventilator. During calibration, the inspiratory pipeline 4 and the expiratory pipeline 5 of the ventilator are connected in parallel through a Y-shaped tube and then connected to the metering device 6 and the simulated lung 7. The metering device 6 is used to measure and calibrate only the relative indication error of the inspiratory tidal volume in the volume control ventilation mode of the ventilator. The existing calibration devices and calibration methods for the tidal volume of a ventilator have the following obvious deficiencies: they can only calibrate the inhaled tidal volume in the volume control ventilation mode when the ventilator is not connected to the patient; they cannot calibrate the inhaled tidal volume and the exhaled tidal volume when the ventilator is treating a patient and operating in the pressure control ventilation mode or the volume / pressure hybrid control ventilation mode. Currently, there is a lack of calibration devices and calibration methods that can be used for online calibration of the tidal volume of a ventilator.

[0006] In view of the defects existing in the above-mentioned existing technologies, through continuous research, design, repeated sample making and improvement by the inventor of the present invention, the present invention with practical value has finally been created. Summary of the Invention

[0007] The purpose of the present invention is to overcome the defects existing in the existing ventilator calibration device, and to provide a ventilator tidal volume online calibration device and calibration method with a new structure. The technical problem to be solved is to carry out online metering calibration and quality control on the key parameter tidal volume (including inspiratory tidal volume and expiratory tidal volume) for various clinical ventilation modes (i.e., volume control mode, pressure control mode, by-pass trigger mode, etc.) during the in-use stage of the ventilator treating patients, so as to effectively ensure the clinical use quality of the ventilator, and thus be more suitable for practical use.

[0008] The purpose of the present invention and the solution to its technical problems are achieved by adopting the following technical solutions. A ventilator tidal volume online calibration device proposed according to the present invention is composed of an inspiratory pipeline calibration module, an expiratory pipeline calibration module, a computer, and measurement software installed in the computer. The inspiratory pipeline calibration module and the expiratory pipeline calibration module are respectively connected to the inspiratory pipeline and the expiratory pipeline of the ventilator, and are connected in parallel through a Y-shaped tube and then connected to the patient's respiratory tract;

[0009] The intake pipeline calibration module receives the tidal volume monitoring data of the ventilator to be calibrated through the communication protocol via the USB data communication port. The intake pipeline calibration module sends the measured data of the intake pipeline, exhalation pipeline of the ventilator to be calibrated and the tidal volume monitoring data of the ventilator to be calibrated to the computer in a set data format through the WiFi communication module, and displays them in the form of waveforms and data according to the settings of the calibration personnel through the measurement software installed in the computer, and can automatically calculate the relative indication error of the inspiratory tidal volume and the relative indication error of the expiratory tidal volume. When the relative indication error of the inspiratory tidal volume or the relative indication error of the expiratory tidal volume exceeds the preset threshold, the measurement software pops up a prompt box to warn that the tidal volume of the ventilator is out of tolerance, prompting the ventilator user to check the working status of the ventilator;

[0010] The exhalation pipeline calibration module transmits the measured data of the exhalation pipeline of the ventilator to the intake pipeline calibration module through the data line via the second RS232 data communication port to the first RS232 data communication port of the intake pipeline calibration module;

[0011] Thermal diffusion mass flow sensors based on King's law are installed in both the intake pipeline calibration module and the exhalation pipeline calibration module.

[0012] Furthermore, the intake pipeline calibration module mainly consists of a first housing, a measurement pipeline, a first battery, a first control circuit board and a communication port. Among them, the measurement pipeline consists of a first intake end filter, a first module measurement pipeline intake port, a first module measurement pipeline outlet port and from the first module measurement

[0013] It consists of a first temperature measurement sensor, a first humidity measurement sensor, a first flow measurement sensor, and a first oxygen concentration measurement sensor that are installed in sequence from the intake port of the measurement pipeline to the outlet port of the measurement pipeline of the first module. The calibrated ventilator inhalation pipeline is connected to the intake port of the first module measurement pipeline through a first intake end filter. The outlet port of the first module measurement pipeline is connected to the patient through a Y-shaped tube. The air flow sent by the ventilator to the patient enters the measurement pipeline through the intake port of the first module measurement pipeline after passing through the first intake end filter and flows out from the outlet port of the first module measurement pipeline. The first ambient atmospheric pressure measurement sensor is connected to the first ambient atmospheric pressure measurement hole provided on the first housing. The volume flow rate data of the ventilator air supply flow collected by the first flow measurement sensor at a set measurement frequency, the gas temperature data collected by the first temperature measurement sensor at a set measurement frequency, the gas humidity data collected by the first humidity measurement sensor at a set measurement frequency, the gas oxygen concentration data collected by the first oxygen concentration measurement sensor at a set measurement frequency, and the ambient atmospheric pressure data collected by the first ambient atmospheric pressure measurement sensor at a set measurement frequency. The volume flow rate data of the ventilator air supply flow collected by the first flow measurement sensor, the gas temperature data collected by the first temperature measurement sensor, the gas humidity data collected by the first humidity measurement sensor, the gas oxygen concentration data collected by the first oxygen concentration measurement sensor, and the ambient atmospheric pressure data collected by the first ambient atmospheric pressure measurement sensor are transmitted to the first control circuit board through a data line and processed according to the internal algorithm to calculate the inhalation tidal volume data of the calibrated ventilator. The first battery provides energy for each electrical component in the inhalation pipeline calibration module. When the inhalation pipeline calibration module is powered on, the first power indicator light is always on. When the inhalation pipeline calibration module is powered off, the first power indicator light goes out. The inhalation pipeline calibration module receives the measurement data of the ventilator exhalation pipeline collected by the exhalation pipeline calibration module through the first RS232 data communication port. The inhalation pipeline calibration module is connected to the second RS232 data communication port of the exhalation pipeline calibration module through a data line via the first RS232 data communication port. The inhalation pipeline calibration module receives the tidal volume monitoring data of the calibrated ventilator through the USB data communication port through the communication protocol;

[0014] Further, the exhalation pipeline calibration module consists of a second housing, a measurement pipeline, a second battery, a second control circuit board, a communication port, etc. The measurement pipeline consists of a second intake end filter, a second module measurement pipeline intake port, a second module measurement pipeline outlet port, and a second temperature measurement sensor, a second humidity measurement sensor, a second flow measurement sensor, and a second oxygen concentration measurement sensor that are sequentially installed in the measurement pipeline from the second module measurement pipeline intake port to the second module measurement pipeline outlet port. When calibrating the ventilator, the patient is sequentially connected to the second intake end filter and the second module measurement pipeline intake port through a Y-shaped tube, and the second module measurement pipeline outlet port is connected to the exhalation pipeline of the ventilator to be calibrated. The patient's exhaled air flow enters the measurement pipeline through the second intake end filter and then flows out from the second module measurement pipeline outlet port. The second flow measurement sensor collects the volume flow rate data of the patient's exhaled air flow at a set measurement frequency, the second temperature measurement sensor collects the temperature data of the patient's exhaled air flow at a set measurement frequency, the second humidity measurement sensor collects the humidity data of the patient's exhaled air flow at a set measurement frequency, and the second oxygen concentration measurement sensor collects the oxygen concentration data of the patient's exhaled air flow at a set measurement frequency. The second ambient atmospheric pressure measurement sensor is connected to a second ambient atmospheric pressure measurement hole provided on the second housing and is in contact with the outside atmosphere to collect ambient atmospheric pressure data. The volume flow rate data of the patient's exhaled air flow collected by the second flow measurement sensor, the gas temperature data collected by the second temperature measurement sensor, the gas humidity data collected by the second humidity measurement sensor, the gas oxygen concentration data collected by the second oxygen concentration measurement sensor, and the ambient atmospheric pressure data of the second ambient atmospheric pressure measurement sensor are transmitted to the control second circuit board through a data line and are processed and calculated according to an internal algorithm to obtain the exhaled tidal volume data of the ventilator to be calibrated. The exhalation pipeline calibration module is transmitted to the inhalation pipeline calibration module through the second RS232 data communication port via a data line and the first RS232 data communication port. The second battery provides energy for each electrical component in the exhalation pipeline calibration module. When the exhalation pipeline calibration module is powered on, the second power indicator light is always on. When the inhalation pipeline calibration module is powered off, the second power indicator light goes out. The exhalation pipeline calibration module transmits the measured data of the ventilator exhalation pipeline to the inhalation pipeline calibration module through the second RS232 data communication port via a data line and the first RS232 data communication port of the inhalation pipeline calibration module.

[0015] Further, the data communication between the computer and the inhalation pipeline calibration module is realized by wireless communication through the WiFi communication module installed inside the inhalation pipeline calibration module. The data communication between the inhalation pipeline calibration module and the exhalation pipeline calibration module is realized by wired communication through the first RS232 data communication port and the second RS232 data communication port.

[0016] The object of the present invention and the technical problems to be solved are also achieved by the following technical solutions. A calibration method using an online calibration device for the tidal volume of a ventilator proposed according to the present invention mainly includes the following steps:

[0017] Step 1: Start the intake pipeline calibration module to collect data

[0018] After the intake pipeline calibration module receives the start calibration command sent by the computer through the internally installed WiFi communication module, on the one hand, it starts the internal data acquisition process of the first control circuit board to receive the volume flow data of the ventilator supply air flow collected by the first flow measurement sensor, the gas temperature data collected by the first temperature measurement sensor, the gas humidity data collected by the first humidity measurement sensor, the gas oxygen concentration data collected by the first oxygen concentration measurement sensor, and the ambient atmospheric pressure data collected by the first ambient atmospheric pressure measurement sensor;

[0019] Step 2: Calculate the inspiratory tidal volume data of each ventilation cycle of the ventilator to be calibrated

[0020] Calculate the inspiratory tidal volume data of each ventilation cycle of the ventilator to be calibrated through the internal algorithm formulas (1-1) and (1-2). The first control circuit board adds time series to the obtained inspiratory tidal volume data according to the calculated specific time, where:

[0021] The inspiratory tidal volume without environmental correction is calculated by formula (1-1):

[0022]

[0023] Where: Q im is the inspiratory tidal volume without environmental correction calculated by the intake pipeline calibration module; t i is the inspiratory phase duration in this ventilation cycle; f i is the volume flow data of the ventilator supply air flow collected by the first flow measurement sensor;

[0024] The inspiratory tidal volume after environmental correction is calculated by formula (1-2):

[0025]

[0026] Where: Q′ im is the inspiratory tidal volume after environmental correction; Q im is the inspiratory tidal volume without environmental correction calculated by the intake pipeline calibration module; p i is the ambient atmospheric pressure data collected by the first ambient atmospheric pressure measurement sensor; T i is the gas temperature data collected by the first temperature measurement sensor; p H2Ois the partial pressure of water vapor under saturated humidity conditions and can be obtained by looking up Table 1 corresponding to the gas temperature data T collected by the first temperature measurement sensor; i r i is the gas humidity data collected by the first humidity measurement sensor;

[0027] The saturated vapor pressure table of water under the temperature conditions of (1 - 40)°C given in Appendix B of JJG 1132 - 2017 "Thermal Gas Mass Flowmeter" is built into the internal algorithm programs of the first control circuit board and the second control circuit board for performing correction calculations on the obtained tidal volume calibration data.

[0028] Step 3: The inspiratory pipeline calibration module receives the tidal volume monitoring data of the ventilator to be calibrated

[0029] After the inspiratory pipeline calibration module receives the start calibration command sent by the computer through the internally installed WiFi communication module, it starts the internal data acquisition process of the first control circuit board and simultaneously receives the tidal volume monitoring data of the ventilator to be calibrated through the USB data communication port according to the communication protocol, and adds timing to the data according to the tidal volume monitoring data reception time.

[0030] Step 4: Start collecting data of the expiratory pipeline calibration module

[0031] On the other hand, the inspiratory pipeline calibration module sends the start calibration command to the expiratory pipeline calibration module through the first RS232 data communication port via the data line and the second RS232 data communication port;

[0032] After the expiratory pipeline calibration module receives the start calibration command sent by the inspiratory pipeline calibration module through the second RS232 data communication port, it starts the internal data acquisition process of the second control circuit board to receive the patient's expiratory airflow volume flow data collected by the second flow measurement sensor, the gas temperature data collected by the second temperature measurement sensor, the gas humidity data collected by the second humidity measurement sensor, the gas oxygen concentration data collected by the second oxygen concentration measurement sensor, and the ambient atmospheric pressure data collected by the second ambient atmospheric pressure measurement sensor;

[0033] Step 5: Calculate the expiratory tidal volume data of each ventilation cycle of the ventilator to be calibrated

[0034] Calculate the expiratory tidal volume data of each ventilation cycle of the ventilator to be calibrated through the internal algorithm formulas (1 - 3) and (1 - 4). The second control circuit board adds timing to the obtained expiratory tidal volume data according to the calculated specific time, and sends the expiratory tidal volume data to the inspiratory pipeline calibration module through the second RS232 data communication port via the data line and the first RS232 data communication port, where:

[0035] The exhaled tidal volume without environmental correction can be calculated by formula (1-3):

[0036]

[0037] Where: Q em is the exhaled tidal volume without environmental correction calculated by the exhalation pipeline calibration module; t e is the duration of the exhalation phase in this gas delivery cycle; f e is the patient's exhaled gas flow volume data collected by the second flow measurement sensor;

[0038] The exhaled tidal volume after environmental correction can be calculated by formula (1-4):

[0039]

[0040] Where: Q' em is the exhaled tidal volume after environmental correction; Q em is the inhaled tidal volume without environmental correction calculated by the exhalation pipeline calibration module; p e is the environmental atmospheric pressure data collected by the second environmental atmospheric pressure measurement sensor; T e is the gas temperature data collected by the second temperature measurement sensor; p H2O is the partial pressure of water vapor under saturated humidity conditions, which can be obtained by looking up Table 1 corresponding to the gas temperature data T collected by the second temperature measurement sensor e r e is the gas humidity data collected by the second humidity measurement sensor;

[0041] Step 6: Calculate the relative indication error of the inhaled tidal volume and the relative indication error of the exhaled tidal volume

[0042] The first control circuit board of the inhalation pipeline calibration module calculates the relative indication error of the inhaled tidal volume of the calibrated ventilator, the exhaled tidal volume data of the calibrated ventilator sent by the exhalation pipeline calibration module, and the tidal volume monitoring data of the calibrated ventilator received through the USB data communication port according to formulas (1-5) and (1-6) in chronological order, and calculates the relative indication error of the inhaled tidal volume and the relative indication error of the exhaled tidal volume of the calibrated ventilator within the same gas delivery cycle. Where:

[0043] The relative indication error of the inhaled tidal volume of the calibrated ventilator can be calculated by formula (1-5):

[0044]

[0045] Where: Δ i is the relative indication error of the inhaled tidal volume of the calibrated ventilator; Q′ im is the inhaled tidal volume after environmental correction; Qi0 It is the monitored value of the inspiratory tidal volume in the gas delivery cycle corresponding to the ventilator to be calibrated.

[0046] The relative indication error of the expiratory tidal volume of the ventilator to be calibrated can be calculated by formula (1-6):

[0047]

[0048] Where: Δ e is the relative indication error of the expiratory tidal volume of the ventilator to be calibrated; Q' em is the expiratory tidal volume after environmental correction; Q e0 is the monitored value of the expiratory tidal volume in the gas delivery cycle corresponding to the ventilator to be calibrated;

[0049] Step 7: The computer measurement software displays the calibration data, waveform diagram and warning

[0050] The inspiratory pipeline calibration module sends the data of the inspiratory tidal volume of the ventilator to be calibrated calculated by itself, the data of the expiratory tidal volume of the ventilator to be calibrated sent by the expiratory pipeline calibration module, the tidal volume monitoring data of the ventilator to be calibrated received through the USB data communication port, and the relative indication error of the inspiratory tidal volume and the relative indication error of the expiratory tidal volume calculated corresponding to the same gas delivery cycle of the ventilator to be calibrated to the computer through the internally installed WiFi communication module, and displays them in the measurement software interface in the form of data and waveform diagram. When the relative indication error of the inspiratory tidal volume and the relative indication error of the expiratory tidal volume exceed the pre-set threshold, the measurement software will automatically pop up a prompt box to remind the user of the ventilator to be calibrated to pay attention to the working state of the ventilator.

[0051] The present invention has obvious advantages and beneficial effects compared with the prior art. By means of the above technical solutions, it has at least the following advantages:

[0052] 1. The present invention can perform on-line calibration measurement of the inhaled tidal volume and exhaled tidal volume of the ventilator under various clinical ventilation modes such as volume control mode, pressure control mode, by-pass trigger mode and volume / pressure hybrid control mode during the use stage of the ventilator for treating patients, providing equipment and technical conditions for solving the problems of metrological calibration and clinical quality control during the use stage of the ventilator.

[0053] 2. The present invention provides an on-line calibration device that can accurately collect the tidal volume (inhaled tidal volume) delivered by the ventilator to the patient and the exhaled tidal volume after the patient's metabolism, and realizes the real-time on-line calibration of the tidal volume of the ventilator during the clinical treatment of patients.

[0054] 3. The present invention solves the difficult problem of ventilator tidal volume calibration under different ventilation modes by developing an algorithm, improves the accuracy of calibration data, and adapts to various clinical use scenarios.

[0055] 4. The present invention realizes the wireless transmission of calibration data from the calibration module to the computer through the WiFi module, and cooperates with the developed measurement software to realize the output display and storage of calibration data and waveforms, and can automatically calculate the relative indication error of the inhaled tidal volume and the relative indication error of the exhaled tidal volume. When the error exceeds the preset error threshold, the software pops up a prompt box to prompt the user to pay attention to checking the working state of the ventilator, improving the efficiency and effect of the clinical quality control work of the ventilator.

[0056] 5. The present invention reduces the risk of patient infection by respectively arranging filters at the calibration module of the inspiratory pipeline of the calibration device and the air inlet end of the pipeline of the inspiratory pipeline calibration module, and at the same time protects the internal measurement sensors of the device, improving the measurement accuracy of calibration data.

[0057] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present invention more obvious and understandable, the following specific preferred embodiments are given and described in detail in conjunction with the accompanying drawings. Brief Description of the Drawings

[0058] Figure 1 Schematic connection diagram of the existing calibration method and calibration system for the tidal volume of a ventilator.

[0059] Figure 2 Schematic connection diagram of the calibration system when using the present invention to calibrate the tidal volume of a ventilator online.

[0060] Figure 3 Schematic structural diagram of the inspiratory pipeline calibration module of the present invention

[0061] Figure 4 Schematic structural diagram of the expiratory pipeline calibration module of the present invention

[0062] Figure 5 Control flow and data transmission block diagram of the calibration device of the present invention

[0063] Figure 6 Data acquisition flow chart of the inspiratory pipeline calibration module of the present invention

[0064] Figure 7 Data acquisition flow chart of the expiratory pipeline calibration module of the present invention

[0065] Wherein:

[0066] 1: Inspiratory pipeline calibration module

[0067] 101: First flow measurement sensor 102: First temperature measurement sensor

[0068] 103: First humidity measurement sensor 104: First ambient atmospheric pressure measurement sensor

[0069] 105: First oxygen concentration measurement sensor 106: First ambient atmospheric pressure measurement hole

[0070] 107: First module measurement pipeline gas outlet port 108: First RS232 data communication port

[0071] 109: First control circuit board 110: WiFi communication module

[0072] 111: First battery 112: First module measurement pipeline gas inlet port 113: First inlet port filter 114: First power indicator

[0073] 115: First housing 116: USB data communication port

[0074] 2: Exhalation pipeline calibration module

[0075] 201: Second flow measurement sensor 202: Second temperature measurement sensor

[0076] 203: Second humidity measurement sensor 204: Second ambient atmospheric pressure measurement sensor 205: Second oxygen concentration measurement sensor 206: Second ambient atmospheric pressure measurement hole

[0077] 207: Second module measurement pipeline gas outlet port 208: Second RS232 data communication port

[0078] 209: Second control circuit board 210: Second battery

[0079] 211: Second module measurement pipeline gas inlet port 212: Second inlet port filter

[0080] 213: Second power indicator 214: Second housing

[0081] 3: Ventilator 4: Inspiratory pipeline

[0082] 5: Exhalation pipeline 6: Metering device

[0083] 7: Simulated lung 8: Patient

[0084] B: Online calibration device for ventilator tidal volume Detailed implementation manners

[0085] To further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following, in combination with the accompanying drawings and preferred embodiments, details the specific implementation manners, structures, methods, steps, features and their effects of an online calibration device and calibration method for ventilator tidal volume proposed according to the present invention.

[0086] Please refer to Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 As shown, the ventilator online calibration device developed to achieve the online calibration function of the ventilator needs to accurately collect the volume of gas delivered by the ventilator to the patient, i.e., the inspiratory tidal volume, in each respiratory cycle of the patient, and the volume of exhaled gas after the patient's metabolism, i.e., the expiratory tidal volume. A ventilator tidal volume online calibration device according to a preferred embodiment of the present invention mainly includes: It is mainly composed of, among which:

[0087] A ventilator tidal volume online calibration device of the present invention is composed of an inspiratory pipeline calibration module 100, an expiratory pipeline calibration module 200, a computer, and measurement software installed in the computer. The schematic connection diagram of the calibration system when calibrating the ventilator tidal volume online is as Figure 2 shown. Connect the inspiratory pipeline calibration module 100 and the expiratory pipeline calibration module 200 of the online calibration device to the inspiratory pipeline 4 and the expiratory pipeline 5 of the ventilator respectively, and connect them in parallel through a Y-shaped tube and then connect them to the respiratory tract of the patient 8.

[0088] The inspiratory pipeline calibration module 100 receives the tidal volume monitoring data of the ventilator to be calibrated through the USB data communication port 116 according to the communication protocol. The inspiratory pipeline calibration module 100 sends the measured data of the inspiratory pipeline and the expiratory pipeline of the ventilator to be calibrated and the tidal volume monitoring data of the ventilator to be calibrated to the computer in a set data format through the WiFi communication module 110, and displays them in the form of waveforms and data according to the settings of the calibration personnel through the measurement software installed in the computer, and can automatically calculate the relative indication error of the inspiratory tidal volume and the relative indication error of the expiratory tidal volume. When the relative indication error of the inspiratory tidal volume or the expiratory tidal volume exceeds the preset threshold, the measurement software pops up a prompt box to warn that the ventilator tidal volume is out of tolerance, prompting the ventilator user to pay attention to checking the working status of the ventilator;

[0089] The expiratory pipeline calibration module 200 transmits the measured data of the ventilator expiratory pipeline to the inspiratory pipeline calibration module 100 through the second RS232 data communication port 208 via a data line to the first RS232 data communication port 108 of the inspiratory pipeline calibration module 100;

[0090] As Figure 3As shown in the figure, the intake pipe calibration module 100 of the present invention mainly consists of a first housing 115, a measurement pipeline, a first battery 111, a first control circuit board 109, a communication port, and other components. Among them, the measurement pipeline is composed of a first intake end filter 113, a first module measurement pipeline intake port 112, a first module measurement pipeline outlet port 107, and a first temperature measurement sensor 102, a first humidity measurement sensor 103, a first flow measurement sensor 101, and a first oxygen concentration measurement sensor 105 that are sequentially installed in the measurement pipeline from the first module measurement pipeline intake port 112 to the first module measurement pipeline outlet port 107. When calibrating the ventilator, the intake pipe of the ventilator to be calibrated is connected to the first module measurement pipeline intake port 112 through the first intake end filter 113, and the first module measurement pipeline outlet port 107 is connected to the patient through a Y-shaped tube. The air flow sent by the ventilator to the patient enters the measurement pipeline through the first intake end filter 113 and then flows out from the first module measurement pipeline outlet port 107.

[0091] During this process, the first intake end filter 113 can filter bacteria and impurities in the air flow to reduce the risk of patient infection. The first flow rate measurement sensor 101 collects air flow volume flow rate data at a set measurement frequency. The first temperature measurement sensor 102 collects air flow temperature data at a set measurement frequency. The first humidity measurement sensor 103 collects air flow humidity data at a set measurement frequency. The first oxygen concentration measurement sensor 105 collects air flow oxygen concentration data at a set measurement frequency. The first ambient atmospheric pressure measurement sensor 104 is connected to the first ambient atmospheric pressure measurement hole 106 provided on the first housing 116 and is in contact with the outside atmosphere for collecting ambient atmospheric pressure data. The ventilator air supply air flow volume flow rate data, gas temperature data, gas humidity data, gas oxygen concentration data, and ambient atmospheric pressure data collected by the above sensors are transmitted to the first control circuit board 109 through a data line and are processed and calculated according to an internal algorithm to obtain the calibrated ventilator inspiratory tidal volume data. The first battery 111 provides energy for each electrical component in the inspiratory pipeline calibration module 100. When the inspiratory pipeline calibration module 100 is powered on, the first power indicator light 114 is constantly on. When the inspiratory pipeline calibration module 100 is powered off, the first power indicator light 114 goes out. The first inspiratory pipeline calibration module 100 receives the ventilator expiratory pipeline measurement data collected by the expiratory pipeline calibration module 200 through the first RS232 data communication port 108. The inspiratory pipeline calibration module 100 receives the tidal volume monitoring data of the ventilator to be calibrated through the USB data communication port 116 according to the communication protocol. The inspiratory pipeline calibration module 100 sends the measured data of the inspiratory pipeline and expiratory pipeline of the ventilator to be calibrated and the tidal volume monitoring data of the ventilator to be calibrated to the computer in a set data format through the WiFi communication module 110, and displays them in the form of waveforms and data according to the settings of the calibration personnel through the measurement software installed in the computer, and can automatically calculate the relative indication errors of the inspiratory tidal volume and expiratory tidal volume. When the relative indication error of the inspiratory tidal volume or expiratory tidal volume exceeds the preset threshold, the measurement software pops up a prompt box to warn that the ventilator tidal volume is out of tolerance, prompting the ventilator user to pay attention to checking the working status of the ventilator.

[0092] The schematic structural diagram of the expiratory pipeline calibration module in the ventilator online tidal volume calibration device of the present invention is as Figure 4As shown in the figure. The exhalation pipeline calibration module 200 mainly consists of a second housing 214, a measurement pipeline, a second battery 210, a second control circuit board 209, a communication port, etc. The measurement pipeline consists of a second intake end filter 212, a second module measurement pipeline intake port 211, a second module measurement pipeline outlet port 207, and a second temperature measurement sensor 202, a second humidity measurement sensor 203, a second flow measurement sensor 201, and a second oxygen concentration measurement sensor 205 that are sequentially installed in the measurement pipeline from the second module measurement pipeline intake port 211 to the second module measurement pipeline outlet port 207. When calibrating the ventilator, the patient is sequentially connected to the second intake end filter 212 and the second module measurement pipeline intake port 211 through a Y-shaped tube, and the second module measurement pipeline outlet port 207 is connected to the exhalation pipeline 5 of the ventilator to be calibrated. The patient's exhaled air flow is filtered by the second intake end filter 212 and then enters the measurement pipeline through the second module measurement pipeline intake port 211 and flows out from the second module measurement pipeline outlet port 207. During this process, the second intake end filter 212 can filter the water vapor and sputum in the patient's exhaled air flow. The second flow measurement sensor 201 collects the volume flow rate data of the patient's exhaled air flow at a set measurement frequency. The second temperature measurement sensor 202 collects the temperature data of the patient's exhaled air flow at a set measurement frequency. The

[0093] second humidity measurement sensor 203 collects the humidity data of the patient's exhaled air flow at a set measurement frequency. The second oxygen concentration measurement sensor 205 collects the oxygen concentration data of the patient's exhaled air flow at a set measurement frequency. The second ambient atmospheric pressure measurement sensor 204 is connected to a second ambient atmospheric pressure measurement hole 206 provided on the second housing 214 and is in contact with the outside atmosphere for collecting ambient atmospheric pressure data. The volume flow rate data, gas temperature data, gas humidity data, gas oxygen concentration data, and ambient atmospheric pressure data of the patient's exhaled air flow collected by the above sensors are transmitted to the second control circuit board 209 through a data line and are processed and calculated according to an internal algorithm to obtain the exhaled tidal volume data of the ventilator to be calibrated. The second battery 210 provides energy for each electrical component in the exhalation pipeline calibration module 200. When the exhalation pipeline calibration module 200 is turned on, the second power indicator light 213 is always on. When the inhalation pipeline calibration module 200 is turned off, the second power indicator light 213 is turned off. The exhalation pipeline calibration module 200 is connected to the first RS232 data communication port 108 of the inhalation pipeline calibration module 100 through a data line via the second RS232 data communication port 208, and transmits the measured data of the ventilator exhalation pipeline to the inhalation pipeline calibration module 100.

[0094] The inhalation pipeline calibration module 100 is connected to the second RS232 data communication port 208 of the exhalation pipeline calibration module 200 through a data line via the first RS232 data communication port 108.

[0095] The control flow and data transmission diagram of the on-line tidal volume calibration device for the ventilator of the present invention are as follows Figure 5 shown. The computer, as the host computer, sends instructions to control the inspiratory pipeline calibration module 100 as the main machine, and the main machine sends instructions to control the expiratory pipeline calibration module 200 as the slave machine. When actually calibrating the tidal volume of the ventilator, the expiratory pipeline calibration module 200 sends the measured data of the gas flow in the expiratory pipeline of the ventilator to be calibrated to the second control circuit 209, and calculates the expiratory tidal volume of the ventilator to be calibrated according to the internal algorithm, and sends the calculated expiratory tidal volume to the inspiratory pipeline calibration module 100. The inspiratory pipeline calibration module 100 integrates and processes the data received from the expiratory pipeline calibration module 200 and the measured data of the gas flow in the inspiratory pipeline of the ventilator to be calibrated by itself, and calculates the relative indication error of the expiratory tidal volume and the relative error of the inspiratory tidal volume according to the internal algorithm stored in the single-chip microcomputer in the first control circuit 109, and then sends the calibration result to the computer for storage and display. The data communication between the computer and the inspiratory pipeline calibration module 100 is realized by wireless communication through the WiFi communication module 110 installed inside the inspiratory pipeline calibration module 100. The data communication between the inspiratory pipeline calibration module 100 and the expiratory pipeline calibration module 200 is realized by wired communication through the first RS232 data communication port 108 and the second RS232 data communication port 208.

[0096] During actual calibration, after the inspiratory pipeline calibration module 100 and the expiratory pipeline calibration module 200 start collecting data, the inspiratory pipeline calibration module 100 will record the current collection order. The data order collected by the inspiratory pipeline calibration module 100 and the data order received from the expiratory pipeline calibration module 200 will be integrated only when they are consistent with the current collection order. When the data order received from the expiratory pipeline calibration module 200 is inconsistent with the current collection order, the inspiratory pipeline calibration module 100 will send an instruction to the expiratory pipeline calibration module 200 to request the expiratory pipeline calibration module 200 to retransmit the data collected in the current collection order, so as to ensure that data is not lost. When the computer as the host computer receives incorrect data sent by the inspiratory pipeline calibration module 100, it will also send an instruction to the inspiratory pipeline calibration module 100 to request the inspiratory pipeline calibration module 100 to retransmit the data. When using the on-line calibration device to on-line calibrate the tidal volume of the ventilator, the data collection process of the inspiratory pipeline calibration module 100 as the main machine is as follows

[0097] shown in Figure 6As shown in the figure, first, initialize each hardware in the intake pipe calibration module 100. After completing the hardware initialization, wait for the computer acting as the host computer to send a start data acquisition instruction. After receiving the start instruction, the intake pipe calibration module 100 sends a start data acquisition instruction to the exhalation pipe calibration module 200 acting as the slave. At the same time, the intake pipe calibration module 100 starts its own data acquisition after a 2 ms delay. Every 1 s after the intake pipe calibration module 100 completes its own data acquisition and successfully receives the exhalation pipe data sent by the exhalation pipe calibration module 200 acting as the slave, it transmits the above data to the single-chip microcomputer in the first control circuit board 109 for integration and data processing. The intake pipe calibration module 100 sends the processed data to the computer acting as the host computer for display and storage. If the intake pipe calibration module 100 fails to successfully receive the exhalation pipe data sent by the exhalation pipe calibration module 200 acting as the slave after completing its own data acquisition, the intake pipe calibration module 100 will send an instruction to the exhalation pipe calibration module 200 to request retransmission of the data at the current moment. If the intake pipe calibration module 100 still fails to receive the data sent by the exhalation pipe calibration module 200, the intake pipe calibration module 100 will send an error signal to the computer acting as the host computer and stop the data acquisition process.

[0098] During actual calibration, after the exhalation pipe calibration module 200 sends the collected data to the intake pipe calibration module 100, it will wait for the response of the intake pipe calibration module 100. After receiving the response from the intake pipe calibration module 100, the exhalation pipe calibration module 200 continues to send data to ensure the time consistency of the data. When the intake pipe calibration module 100 does not send an instruction or response for too long, it is determined at this time that the acquisition ends or fails, and the exhalation pipe calibration module 200 stops data acquisition. When using the online calibration device to calibrate the tidal volume of the ventilator online, the data acquisition process of the exhalation pipe calibration module 200 is as Figure 7 shown in the figure. First, initialize each hardware in the exhalation pipe calibration module 200. After completing the hardware initialization, wait for the intake pipe calibration module 100 acting as the host to send a start data acquisition instruction. When the exhalation pipe calibration module 200 receives the start instruction, it starts its own data acquisition. When the second control circuit board 209 receives the data collected by each measurement sensor, that is, when there is data caching in the program queue, if normal communication is maintained between the exhalation pipe calibration module 200 and the intake pipe calibration module 100, that is, the exhalation pipe calibration module 200 received a response from the intake pipe calibration module 100 for the data sent last time, the exhalation pipe calibration module 200 sends its own collected data to the intake pipe calibration module 100. If the exhalation pipe calibration module 200 receives a request from the intake pipe calibration module 100 to retransmit data, the exhalation pipe calibration module 200 will retransmit the data at the current moment to the intake pipe calibration module 100.

[0099] An online calibration method for the tidal volume of a ventilator in a preferred embodiment of the present invention mainly includes the following steps:

[0100] Step 1: Start the intake pipeline calibration module 100 to collect data

[0101] After the intake pipeline calibration module 100 receives the start calibration command sent by the computer through the internally installed WiFi communication module 110, on the one hand, it starts the internal data collection process of the first control circuit board 109 to receive the volume flow data of the ventilator's air supply airflow collected by the first flow measurement sensor 101, the gas temperature data collected by the first temperature measurement sensor 102, the gas humidity data collected by the first humidity measurement sensor 103, the gas oxygen concentration data collected by the first oxygen concentration measurement sensor 105, and the ambient atmospheric pressure data collected by the first ambient atmospheric pressure measurement sensor 104.

[0102] Step 2: Calculate the inspiratory tidal volume data of each ventilation cycle of the ventilator to be calibrated

[0103] Calculate the inspiratory tidal volume data of each ventilation cycle of the ventilator to be calibrated through the internal algorithm formulas (1-1) and (1-2). The first control circuit board 109 adds time series to the obtained inspiratory tidal volume data according to the calculated specific time, where:

[0104] The inspiratory tidal volume without environmental correction is calculated by formula (1-1):

[0105]

[0106] Where: Q im is the inspiratory tidal volume without environmental correction calculated by the intake pipeline calibration module (100); t i is the inspiratory phase duration in this ventilation cycle; f i is the volume flow data of the ventilator's air supply airflow collected by the first flow measurement sensor (101);

[0107] The inspiratory tidal volume after environmental correction is calculated by formula (1-2):

[0108]

[0109] Where: Q' im is the inspiratory tidal volume after environmental correction; Q im is the inspiratory tidal volume without environmental correction calculated by the intake pipeline calibration module (100); p i is the ambient atmospheric pressure data collected by the first ambient atmospheric pressure measurement sensor (104); T i is the gas temperature data collected by the first temperature measurement sensor (102); p H2Ois the partial pressure of water vapor under saturated humidity conditions, which can be obtained by looking up Table 1 corresponding to the gas temperature data T collected by the first temperature measurement sensor (102); i r i is the gas humidity data collected by the first humidity measurement sensor (103).

[0110] Appendix B of JJG 1132-2017 "Thermal Gas Mass Flowmeter" gives the saturated vapor pressure of water under the temperature conditions of (1 to 40) °C as shown in Table 1, which is built into the internal algorithm programs of the first control circuit board (109) and the second control circuit board (209) of the present invention for correcting and calculating the obtained tidal volume calibration data.

[0111] Table 1 Saturated Vapor Pressure of Water under Different Temperature Conditions

[0112]

[0113]

[0114] Step 3: The inspiratory line calibration module 100 receives the tidal volume monitoring data of the ventilator to be calibrated

[0115] After the inspiratory line calibration module 100 receives the start calibration command sent by the computer through the internally installed WiFi communication module 110, it starts the internal data acquisition process of the first control circuit board 109 and simultaneously receives the tidal volume monitoring data of the ventilator to be calibrated through the USB data communication port 116 according to the communication protocol, and adds time series to the data according to the receiving time of the tidal volume monitoring data.

[0116] Step 4: Start collecting data of the expiratory line calibration module 200

[0117] On the other hand, the inspiratory line calibration module 100 sends the start calibration command to the expiratory line calibration module 200 through the first RS232 data communication port 108 via the data line and the second RS232 data communication port 208;

[0118] After the expiratory line calibration module 200 receives the start calibration command sent by the inspiratory line calibration module 100 through the second RS232 data communication port 208, it starts the internal data acquisition process of the second control circuit board 209 to receive the patient's expiratory airflow volume flow data collected by the second flow measurement sensor 201, the gas temperature data collected by the second temperature measurement sensor 202, the gas humidity data collected by the second humidity measurement sensor 203, the gas oxygen concentration data collected by the second oxygen concentration measurement sensor 205, and the ambient atmospheric pressure data collected by the second ambient atmospheric pressure measurement sensor 204.

[0119] Step 5: Calculate the expiratory tidal volume data of each ventilation cycle of the ventilator to be calibrated

[0120] Calculate the expiratory tidal volume data for each inspiration cycle of the calibrated ventilator through the internal algorithm formulas (1-3) and (1-4). The second control circuit board 209 adds timing to the obtained expiratory tidal volume data according to the calculated specific time, and sends the expiratory tidal volume data to the inspiratory pipeline calibration module (100) through the second RS232 data communication port (208), data line, and the first RS232 data communication port 108, where:

[0121] The expiratory tidal volume without environmental correction can be calculated through formula (1-3):

[0122]

[0123] Where: Q em is the expiratory tidal volume without environmental correction calculated by the expiratory pipeline calibration module (200); t e is the expiratory phase duration in this inspiration cycle; f e is the patient expiratory airflow volume flow data collected by the second flow measurement sensor (201);

[0124] The expiratory tidal volume after environmental correction can be calculated through formula (1-4):

[0125]

[0126] Where: Q' em is the expiratory tidal volume after environmental correction; Q em is the inspiratory tidal volume without environmental correction calculated by the expiratory pipeline calibration module (200); p e is the ambient atmospheric pressure data collected by the second ambient atmospheric pressure measurement sensor (204); T e is the gas temperature data collected by the second temperature measurement sensor (202); p H2O is the partial pressure of water vapor under saturated humidity conditions, which can be obtained by looking up Table 1 corresponding to the gas temperature data T collected by the second temperature measurement sensor (202) e ; r e is the gas humidity data collected by the second humidity measurement sensor (203).

[0127] Step 6: Calculate the relative indication error of the inspiratory tidal volume and the relative indication error of the expiratory tidal volume

[0128] The first control circuit board 109 of the intake pipeline calibration module (100) calculates the data of the inspiratory tidal volume of the ventilator to be calibrated by itself according to formulas (1-5) and (1-6), receives the data of the expiratory tidal volume of the ventilator to be calibrated sent by the expiratory pipeline calibration module 200, and receives the tidal volume monitoring data of the ventilator to be calibrated through the USB data communication port 116. Then, it calculates the relative indication error of the inspiratory tidal volume and the relative indication error of the expiratory tidal volume within the same gas delivery cycle of the ventilator to be calibrated according to the time sequence. Among them:

[0129] The relative indication error of the inspiratory tidal volume of the calibrated ventilator can be calculated by formula (1-5):

[0130]

[0131] Among them: Δ i is the relative indication error of the inspiratory tidal volume of the ventilator to be calibrated; Q′ im is the inspiratory tidal volume after environmental correction; Q i0 is the monitoring value of the inspiratory tidal volume of the ventilator to be calibrated corresponding to the gas delivery cycle.

[0132] The relative indication error of the expiratory tidal volume of the ventilator to be calibrated can be calculated by formula (1-6):

[0133]

[0134] Among them: Δ e is the relative indication error of the expiratory tidal volume of the ventilator to be calibrated; Q' em is the expiratory tidal volume after environmental correction; Q e0 is the monitoring value of the expiratory tidal volume of the ventilator to be calibrated corresponding to the gas delivery cycle.

[0135] Step 7: The computer measurement software displays the calibration data, waveform diagram and warning

[0136] The intake pipeline calibration module 100 sends the data of the inspiratory tidal volume of the ventilator to be calibrated calculated by itself, the data of the expiratory tidal volume of the ventilator to be calibrated received from the expiratory pipeline calibration module 200, the tidal volume monitoring data of the ventilator to be calibrated received through the USB data communication port 116, and the relative indication error of the inspiratory tidal volume and the relative indication error of the expiratory tidal volume within the same gas delivery cycle of the ventilator to be calibrated calculated according to the time sequence to the computer. They are displayed in the measurement software interface in the form of data and waveform diagrams. When the relative indication error of the inspiratory tidal volume and the relative indication error of the expiratory tidal volume exceed the preset threshold, the measurement software will automatically pop up a prompt box to remind the user of the ventilator to be calibrated to check the working status of the ventilator.

[0137] The inspiratory pipeline calibration module 100 sends the measured data of the inspiratory pipeline, expiratory pipeline of the ventilator to be calibrated, and the tidal volume monitoring data of the ventilator to be calibrated in a set data format to the computer through the WiFi communication module 110, and displays them in the form of waveforms and data according to the settings of the calibration personnel through the measurement software installed in the computer. When the relative indication error of the inspiratory tidal volume or expiratory tidal volume exceeds the preset threshold, the measurement software pops up a prompt box to warn that the tidal volume of the ventilator is out of tolerance, reminding the ventilator user to pay attention to checking the working status of the ventilator.

[0138] Description of the respiratory phase recognition algorithm for different ventilation modes of the ventilator in the present invention:

[0139] 1. Respiratory phase recognition algorithm for volume control mode (compatible with side-stream triggering mode):

[0140] Inspiratory phase: After the inspiratory pipeline calibration module 100, which serves as the host, receives the measured data of the expiratory pipeline collected and sent by the expiratory pipeline calibration module 200, which serves as the slave, it integrates the received data with the measured data of its own inspiratory pipeline according to the time sequence. After integrating the data, the internal algorithm program of the first control circuit board 109 in the inspiratory pipeline calibration module 100 will sequentially compare the gas flow values collected by the inspiratory pipeline calibration module 100 and the expiratory pipeline calibration module 200 within 1 s. When the gas flow value of the inspiratory pipeline collected by the inspiratory pipeline calibration module 100 is greater than the opening threshold (3 L / min for adults, 1 L / min for children) and the gas flow value of the expiratory pipeline collected by the expiratory pipeline calibration module 200 is approximately 0 L / min or equal to 0 L / min, it is determined that the working state of the ventilator to be calibrated is the inspiratory phase.

[0141] Expiratory phase: When the gas flow value of the expiratory pipeline collected by the expiratory pipeline calibration module 200, which serves as the slave, minus the gas flow value of the inspiratory pipeline collected by the inspiratory pipeline calibration module 100, which serves as the host, is less than the opening threshold (3 L / min for adults, 1 L / min for children), it is determined that the working state of the ventilator to be calibrated is the expiratory phase.

[0142] Standby and shutdown: When the gas

[0143] flow value of the inspiratory pipeline collected by the inspiratory pipeline calibration module 100, which serves as the host, and the gas flow value of the expiratory pipeline collected by the expiratory pipeline calibration module 200, which serves as the slave, are both not 0 L / min, and the absolute value of the difference between the two is not greater than the opening threshold, it is determined that the ventilator to be calibrated is in the standby state at this time; when the gas flow value of the inspiratory pipeline collected by the inspiratory pipeline calibration module 100 and the gas flow value of the expiratory pipeline collected by the expiratory pipeline calibration module 200 are both 0 L / min, it is determined that the ventilator to be calibrated is in the shutdown state at this time.

[0144] 2. Respiratory phase recognition algorithm for pressure control ventilation mode:

[0145] Inspiratory phase: After the inspiratory pipeline calibration module 100, which serves as the host, receives the measured data of the expiratory pipeline collected and sent by the expiratory pipeline calibration module 200, which serves as the slave, it integrates the received data with the measured data of its own inspiratory pipeline according to the time sequence. After integrating the data, the internal algorithm program of the first control circuit board 109 in the inspiratory pipeline calibration module 100 will sequentially compare the gas flow values collected by the inspiratory pipeline calibration module 100 and the expiratory pipeline calibration module 200 within 1 s. In the data processing program, a variable FlowDefference is introduced, and it is defined that FlowDefference is equal to the gas flow value of the inspiratory pipeline collected by the inspiratory pipeline calibration module 100 minus the gas flow value of the expiratory pipeline collected by the expiratory pipeline calibration module 200. When the value of the FlowDefference variable is greater than the tidal volume calculation start threshold (3 L / min for adults, 1 L / min for children), it is determined that the working state of the calibrated ventilator is the inspiratory phase.

[0146] When the calibrated ventilator meets any of the following conditions, the inspiratory phase can be determined to end.

[0147] Condition 1: If the value of the FlowDefference variable at the next moment is less than the opposite value of the tidal volume calculation start threshold, it is directly determined at this time that the calibrated ventilator enters the expiratory phase;

[0148] Condition 2: A variable LowFlowTimeCount is introduced. If the value of the FlowDefference variable at the next moment is less than the tidal volume calculation start threshold but greater than or equal to 0, the value of the LowFlowTimeCount variable is incremented by 1. If the value of the FlowDefference variable at the next moment is greater than the tidal volume calculation start threshold, the value of the LowFlowTimeCount variable is cleared. When the value of the LowFlowTimeCount variable is greater than the maximum upper limit set by the algorithm program, it is determined at this time that the inspiratory phase of the calibrated ventilator ends, and the ventilator enters the standby state.

[0149] Expiratory phase: When the value of the FlowDefference variable is less than the tidal volume calculation start threshold (3 L / min for adults, 1 L / min for children), it is determined that the working state of the calibrated ventilator is the expiratory phase.

[0150] When the calibrated ventilator meets any of the following conditions, the expiratory phase can be determined to end.

[0151] Condition 1: If the value of the FlowDefference variable at the next moment is greater than the opposite value of the tidal volume calculation start threshold, it is directly determined at this time that the expiratory phase of the calibrated ventilator ends;

[0152] Condition 2: Introduce the variable LowFlowTimeCount. If the value of the FlowDefference variable at the next moment is greater than the tidal volume calculation start threshold but greater than or equal to 0, increment the value of the LowFlowTimeCount variable by 1. If the value of the FlowDefference variable at the next moment is less than the tidal volume calculation start threshold, reset the value of the LowFlowTimeCount variable to zero. When the value of the LowFlowTimeCount variable is greater than the maximum upper limit set by the algorithm program, it is determined that the expiratory phase of the calibrated ventilator ends, and the ventilator enters the standby state.

[0153] Standby and shutdown: When the gas flow rate value collected by the inspiratory pipeline calibration module 100 as the host and the gas flow rate value collected by the expiratory pipeline calibration module 200 as the host are both not 0 L / min, and the absolute value of the difference between the two is not greater than the start threshold, it is determined at this time that the calibrated ventilator is in the standby state; when the gas flow rate value collected by the inspiratory pipeline calibration module 100 and the gas flow rate value collected by the expiratory pipeline calibration module 200 are both 0 L / min, it is determined that the calibrated ventilator is in the shutdown state.

[0154] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments by using the disclosed technical content within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. An on-line calibration device for tidal volume of a ventilator, characterized in that: It consists of an inspiratory pipeline calibration module (100), an expiratory pipeline calibration module (200), a computer, and measurement software installed in the computer. The inspiratory pipeline calibration module (100) and the expiratory pipeline calibration module (200) are respectively connected to the inspiratory pipeline (4) and the expiratory pipeline (5) of the ventilator, and are connected in parallel through a Y-shaped tube and then connected to the respiratory tract of the patient (8); The inspiratory pipeline calibration module (100) receives the tidal volume monitoring data of the ventilator to be calibrated through the communication protocol via the USB data communication port (116). The inspiratory pipeline calibration module (100) sends the measured data of the inspiratory pipeline and the expiratory pipeline of the ventilator to be calibrated and the tidal volume monitoring data of the ventilator to be calibrated to the computer in a set data format through the WiFi communication module (110), and displays them in the form of waveforms and data according to the settings of the calibration personnel through the measurement software installed in the computer, and can automatically calculate the relative indication error of the inspiratory tidal volume and the relative indication error of the expiratory tidal volume. When the relative indication error of the inspiratory tidal volume or the relative indication error of the expiratory tidal volume exceeds the preset threshold, the measurement software pops up a prompt box to warn that the tidal volume of the ventilator is out of tolerance, prompting the ventilator user to check the working status of the ventilator; The expiratory pipeline calibration module (200) transmits the measured data of the ventilator expiratory pipeline to the inspiratory pipeline calibration module (100) through the second RS232 data communication port (208) via a data cable to the first RS232 data communication port (108) of the inspiratory pipeline calibration module (100); Thermal diffusion mass flow sensors based on King's law are installed in both the inspiratory pipeline calibration module (100) and the expiratory pipeline calibration module (200).

2. The online calibration device for tidal volume of a ventilator according to claim 1, wherein: The inspiratory pipeline calibration module (100) mainly consists of a first housing (115), a measurement pipeline, a first battery (111), a first control circuit board (109) and a communication port. Among them, the measurement pipeline consists of a first intake end filter (113), a first module measurement pipeline intake port (112), a first module measurement pipeline outlet port (107), and a first temperature measurement sensor (102), a first humidity measurement sensor (103), a first flow measurement sensor (101), and a first oxygen concentration measurement sensor (105) that are sequentially installed in the measurement pipeline from the first module measurement pipeline intake port (112) to the first module measurement pipeline outlet port (107). The inspiratory pipeline (4) of the ventilator to be calibrated is connected to the first module measurement pipeline intake port (112) through the first intake end filter (113). The first module measurement pipeline outlet port (107) is connected to the patient (8) through a Y-shaped tube. The air flow sent by the ventilator to the patient passes through the first intake end filter (113) and then enters the measurement pipeline through the first module measurement pipeline intake port (112) and flows out from the first module measurement pipeline outlet port (107). The first ambient atmospheric pressure measurement sensor (104) is connected to the first ambient atmospheric pressure measurement hole (106) provided on the first housing (116). The volume flow rate data of the air flow sent by the ventilator collected by the first flow measurement sensor (101) at a set measurement frequency, the gas temperature data collected by the first temperature measurement sensor (102) at a set measurement frequency, the gas humidity data collected by the first humidity measurement sensor (103) at a set measurement frequency, the gas oxygen concentration data collected by the first oxygen concentration measurement sensor (105) at a set measurement frequency, and the ambient atmospheric pressure data collected by the first ambient atmospheric pressure measurement sensor (104) at a set measurement frequency. The volume flow rate data of the air flow sent by the ventilator collected by the first flow measurement sensor (101), the gas temperature data collected by the first temperature measurement sensor (102), the gas humidity data collected by the first humidity measurement sensor (103), the gas oxygen concentration data collected by the first oxygen concentration measurement sensor (105), and the ambient atmospheric pressure data collected by the first ambient atmospheric pressure measurement sensor (104) are transmitted to the first control circuit board (109) through a data line and are processed and calculated according to an internal algorithm to obtain the inspiratory tidal volume data of the ventilator to be calibrated. The first battery (111) provides energy for each electrical component in the inspiratory pipeline calibration module (100). When the inspiratory pipeline calibration module (100) is powered on, the first power indicator (114) is always on. When the inspiratory pipeline calibration module (100) is powered off, the first power indicator (114) is turned off. The inspiratory pipeline calibration module (100) receives the measurement data of the expiratory pipeline of the ventilator collected by the expiratory pipeline calibration module (200) through the first RS232 data communication port (108).The inspiratory pipeline calibration module (100) is connected to the second RS232 data communication port (208) of the expiratory pipeline calibration module (200) via a data cable through the first RS232 data communication port (108). The inspiratory pipeline calibration module (100) receives the tidal volume monitoring data of the ventilator to be calibrated through the USB data communication port (116) via a communication protocol.

3. The online calibration device for tidal volume of a ventilator according to claim 1, wherein: The exhalation pipeline calibration module (200) consists of a second housing (214), a measurement pipeline, a second battery (210), a second control circuit board (209), a communication port, etc. The measurement pipeline consists of a second intake end filter (212), a second module measurement pipeline intake port (211), a second module measurement pipeline outlet port (207), and a second temperature measurement sensor (202), a second humidity measurement sensor (203), a second flow measurement sensor (201), and a second oxygen concentration measurement sensor (205) sequentially installed in the measurement pipeline from the second module measurement pipeline intake port (211) to the second module measurement pipeline outlet port (207). When calibrating the ventilator, the patient (8) is sequentially connected to the second intake end filter (212) and the second module measurement pipeline intake port (211) through a Y-shaped tube, and the second module measurement pipeline outlet port (207) is connected to the exhalation pipeline (5) of the ventilator to be calibrated. The patient's exhaled air flow enters the measurement pipeline through the second intake end filter (212) and flows out from the second module measurement pipeline outlet port (207) through the second module measurement pipeline intake port (211). The second flow measurement sensor (201) collects the volume flow rate data of the patient's exhaled air flow at a set measurement frequency. The second temperature measurement sensor (202) collects the temperature data of the patient's exhaled air flow at a set measurement frequency. The second humidity measurement sensor (203) collects the humidity data of the patient's exhaled air flow at a set measurement frequency. The second oxygen concentration measurement sensor (205) collects the oxygen concentration data of the patient's exhaled air flow at a set measurement frequency. The second ambient atmospheric pressure measurement sensor (204) is connected to a second ambient atmospheric pressure measurement hole (206) provided on the second housing (214) and is in contact with the outside atmosphere for collecting ambient atmospheric pressure data. The volume flow rate data of the patient's exhaled air flow collected by the second flow measurement sensor (201), the gas temperature data collected by the second temperature measurement sensor (202), the gas humidity data collected by the second humidity measurement sensor (203), the gas oxygen concentration data collected by the second oxygen concentration measurement sensor (205), and the ambient atmospheric pressure data of the second ambient atmospheric pressure measurement sensor (204) are transmitted to the control second circuit board (209) through a data line and processed according to an internal algorithm to calculate the exhaled tidal volume data of the ventilator to be calibrated. The exhalation pipeline calibration module (200) is transmitted to the inhalation pipeline calibration module (100) through the second RS232 data communication port (208) through a data line and the first RS232 data communication port (108). The second battery (210) provides energy for each electrical component in the exhalation pipeline calibration module (200). When the exhalation pipeline calibration module (200) is powered on, the second power indicator light (213) is always on. When the exhalation pipeline calibration module (200) is powered off, the second power indicator light (213) goes out.The exhalation pipeline calibration module (200) transmits the measured data of the ventilator exhalation pipeline collected through the second RS232 data communication port (208) to the first RS232 data communication port (108) of the inhalation pipeline calibration module (100) via a data line.

4. An online calibration device for the tidal volume of a ventilator according to any one of claims 1-3, characterized in that: Data communication between the computer and the inspiratory pipeline calibration module (100) is realized by wireless communication through the WiFi communication module (110) installed inside the inspiratory pipeline calibration module (100). Data communication between the inspiratory pipeline calibration module (100) and the expiratory pipeline calibration module (200) is realized by wired communication through the first RS232 data communication port (108) and the second RS232 data communication port (208).

5. A calibration method using a ventilator tidal volume on-line calibration device, characterized in that: Step 1: Start the inspiratory pipeline calibration module (100) to collect data After the inspiratory pipeline calibration module (100) receives the start calibration command issued by the computer through the internally installed WiFi communication module (110), on the one hand, it starts the internal data acquisition process of the first control circuit board (109) to receive the volume flow data of the ventilator's delivered gas collected by the first flow measurement sensor (101), the gas temperature data collected by the first temperature measurement sensor (102), the gas humidity data collected by the first humidity measurement sensor (103), the gas oxygen concentration data collected by the first oxygen concentration measurement sensor (105), and the ambient atmospheric pressure data collected by the first ambient atmospheric pressure measurement sensor (104); Step 2: Calculate the inspiratory tidal volume data of each gas delivery cycle of the ventilator to be calibrated Calculate the inspiratory tidal volume data for each inspiratory cycle of the calibrated ventilator through the internal algorithm formulas (1-1) and (1-2). The first control circuit board (109) adds timing to the obtained inspiratory tidal volume data according to the calculated specific time, where: The inspiratory tidal volume without environmental correction is calculated through formula (1-1): Where: Q im is the inspiratory tidal volume without environmental correction calculated by the inspiratory line calibration module (100); t i is the inspiratory phase duration in this gas delivery cycle; f i is the volume flow rate data of the ventilator gas delivery airflow collected by the first flow measurement sensor (101); The inspiratory tidal volume after environmental correction is calculated through formula (1-2): Wherein: Q' im is the inspiratory tidal volume after environmental correction; Q im is the inspiratory tidal volume without environmental correction calculated by the inspiratory pipeline calibration module (100); p i is the environmental atmospheric pressure data collected by the first environmental atmospheric pressure measurement sensor (104); T i is the gas temperature data collected by the first temperature measurement sensor (102); p H2O is the partial pressure of water vapor under saturated humidity conditions, which can be obtained by looking up Table 1 of the saturated vapor pressure of water under the temperature conditions of (1 to 40) °C given in Appendix B of JJG 1132-2017 "Thermal Gas Mass Flowmeter" corresponding to the gas temperature data T i collected by the first temperature measurement sensor (102); r i is the gas humidity data collected by the first humidity measurement sensor (103); Place the saturated vapor pressure table of water under the temperature conditions of (1 to 40) °C given in Appendix B of JJG 1132-2017 "Thermal Gas Mass Flowmeter" into the internal algorithm programs of the first control circuit board (109) and the second control circuit board (209) for correcting and calculating the obtained tidal volume calibration data; Step 3: The intake pipeline calibration module (100) receives the tidal volume monitoring data of the calibrated ventilator After the intake pipeline calibration module (100) receives the start calibration command sent by the computer through the internally installed WiFi communication module (110), it starts the internal data acquisition process of the first control circuit board (109) and simultaneously receives the tidal volume monitoring data of the calibrated ventilator through the USB data communication port (116) according to the communication protocol, and adds timing to the data according to the tidal volume monitoring data reception time; Step 4: Start collecting data of the exhalation pipeline calibration module (200) On the other hand, the intake pipeline calibration module (100) sends the start calibration command to the exhalation pipeline calibration module (200) through the first RS232 data communication port (108) via the data line and the second RS232 data communication port (208); After the exhalation pipeline calibration module (200) receives the start calibration command sent by the intake pipeline calibration module (100) through the second RS232 data communication port (208), it starts the internal data acquisition process of the second control circuit board (209) to receive the patient's exhaled gas volume flow data collected by the second flow measurement sensor (201), the gas temperature data collected by the second temperature measurement sensor (202), the gas humidity data collected by the second humidity measurement sensor (203), the gas oxygen concentration data collected by the second oxygen concentration measurement sensor (205), and the ambient atmospheric pressure data collected by the second ambient atmospheric pressure measurement sensor (204); Step 5: Calculate the expiratory tidal volume data for each expiratory cycle of the calibrated ventilator Calculate the expiratory tidal volume data for each expiratory cycle of the calibrated ventilator through the internal algorithm formulas (1-3) and (1-4). The second control circuit board (209) adds timing to the obtained expiratory tidal volume data according to the calculated specific time, and sends the expiratory tidal volume data to the intake pipeline calibration module (100) through the second RS232 data communication port (208) via the data line and the first RS232 data communication port (108), where: The expiratory tidal volume without environmental correction can be calculated through formula (1-3): Where: Q em is the expiratory tidal volume without environmental correction calculated by the expiratory airway calibration module (200); t e is the expiratory phase duration in this inspiratory-expiratory cycle; f e is the patient's expiratory airflow volume flow rate data collected by the second flow measurement sensor (201); The expiratory tidal volume after environmental correction can be calculated through formula (1-4): Where: Q' em is the tidal volume of exhaled breath after environmental correction; Q em is the tidal volume of inhaled breath calculated by the exhalation pipeline calibration module (200) without environmental correction; p e is the environmental atmospheric pressure data collected by the second environmental atmospheric pressure measurement sensor (204); T e is the gas temperature data collected by the second temperature measurement sensor (202); p H2O is the partial pressure of water vapor under saturated humidity conditions, which can be obtained by looking up Table 1 corresponding to the gas temperature data T e collected by the second temperature measurement sensor (202); r e is the gas humidity data collected by the second humidity measurement sensor (203); Step 6: Calculate the relative indication error of the inspiratory tidal volume and the relative indication error of the expiratory tidal volume The first control circuit board (109) of the intake pipe calibration module (100) calculates the calibrated ventilator's inspiratory tidal volume data by itself according to formulas (1-5) and (1-6), receives the calibrated ventilator's expiratory tidal volume data sent by the expiratory pipe calibration module (200), and receives the calibrated ventilator's tidal volume monitoring data through the USB data communication port (116). Then, it calculates the relative indication error of the inspiratory tidal volume and the relative indication error of the expiratory tidal volume within the same gas delivery cycle of the calibrated ventilator according to the time sequence. Among them: The relative indication error of the calibrated ventilator's inspiratory tidal volume can be calculated by formula (1-5): Where: Δ i is the relative indication error of the inspiratory tidal volume of the ventilator to be calibrated; Q' im is the inspiratory tidal volume after environmental correction; Q i0 is the monitored value of the inspiratory tidal volume of the ventilator to be calibrated corresponding to the gas delivery cycle; The relative indication error of the calibrated ventilator's expiratory tidal volume can be calculated by formula (1-6): Where: Δ e is the relative indication error of the exhaled tidal volume of the ventilator to be calibrated; Q' em is the exhaled tidal volume after environmental correction; Q e0 is the monitored value of the exhaled tidal volume of the ventilator to be calibrated corresponding to the gas delivery cycle; Step 7: The computer measurement software displays the calibration data, waveform diagram, and warning The intake pipe calibration module (100) sends the calibrated ventilator's inspiratory tidal volume data calculated by itself, the calibrated ventilator's expiratory tidal volume data received from the expiratory pipe calibration module (200), the calibrated ventilator's tidal volume monitoring data received through the USB data communication port (116), as well as the relative indication error of the inspiratory tidal volume and the relative indication error of the expiratory tidal volume within the same gas delivery cycle of the calibrated ventilator calculated according to the time sequence to the computer, and displays them in the form of data and waveform diagrams on the measurement software interface. When the relative indication error of the inspiratory tidal volume and the relative indication error of the expiratory tidal volume exceed the pre-set threshold, the measurement software will automatically pop up a prompt box to remind the user of the calibrated ventilator to pay attention to the working state of the ventilator.

Images