Tidal volume measuring system for anaesthesia machine pipeline

Abstract

The invention discloses a tidal volume measuring system for an anaesthesia machine pipeline, and the tidal volume measuring system comprises a near-end detection assembly, a differential pressure sensor, a differential amplifier and a microprocessor, the near-end detection assembly comprises an external flow sensor, and the external flow sensor is arranged on a tracheal catheter; the external flow sensor is arranged in the tracheal catheter and used for converting gas flow energy in the tracheal catheter into the pressure difference between the pressure high end and the pressure low end of the external flow sensor, and the pressure difference sensor is used for converting the pressure difference between the pressure high end and the pressure low end into a pressure difference electric signal. And the microprocessor is used for obtaining the gas flow in the tracheal catheter according to the electric signal output by the differential amplifier. The external flow sensor is arranged in the tracheal catheter, the flow energy of the gas in the tracheal catheter is directly detected, the actual tidal volume of a patient can be reflected more truly, interference caused by the volume change of a pipeline is avoided, and therefore the measurement error is remarkably reduced, and the gas flow measurement accuracy is improved.

Description

Technical Field

[0001] This application relates to the field of tidal volume measurement technology, specifically to a tidal volume measurement system for anesthesia machine tubing. Background Technology

[0002] Tidal volume refers to the amount of air inhaled or exhaled during each breath at rest. In mechanical ventilation, accurately setting and monitoring tidal volume is a key factor in ensuring effective respiratory support and preventing ventilator-associated lung injury. Doctors will adjust the tidal volume appropriately based on the patient's specific condition and weight to achieve the best therapeutic outcome.

[0003] In current anesthesia machine designs, most flow sensors are housed inside the machine. This layout can trigger a series of events during respiration. When a patient breathes, the pressure inside the tubing increases significantly. This pressure change affects the tubing, causing it to expand. For example, a common telescopic tube will elongate when pressure increases. To compensate for the interference in flow measurement caused by changes in pipeline volume, compliance calculations are typically used. However, this compensation method has significant limitations, and its error value is often too high. Due to the complexity of pressure changes during respiration and the diversity of pipeline characteristics, compliance calculations are difficult to accurately reflect actual conditions, leading to a large deviation between the final tidal volume measurement result and the true value. Summary of the Invention

[0004] To address the technical problems in the prior art, this application provides a tidal volume measurement system for anesthesia machine tubing.

[0005] The tidal volume measurement system for anesthesia machine tubing provided in this application adopts the following technical solution: A tidal volume measurement system for an anesthesia machine tubing, the anesthesia machine tubing including an endotracheal tube for connecting to the user's airway, the tidal volume measurement system including a proximal detection component, a differential pressure sensor, a differential amplifier, and a microprocessor, the proximal detection component including an external flow sensor disposed on the endotracheal tube, the external flow sensor being used to convert the gas flow energy in the endotracheal tube into a pressure difference between the high and low pressure ends of the external flow sensor, the two ends of the differential pressure sensor being respectively connected to the high and low pressure ends, and being used to convert the pressure difference between the high and low pressure ends into a differential pressure electrical signal, the input end of the differential amplifier being electrically connected to the differential pressure sensor, the microprocessor being electrically connected to the output end of the differential amplifier, and being used to obtain the gas flow rate in the endotracheal tube based on the electrical signal output by the differential amplifier.

[0006] By adopting the above technical solution, an external flow sensor is placed on the endotracheal tube to directly detect the gas flow energy within the tube. This more accurately reflects the patient's actual respiratory gas flow rate (i.e., tidal volume), avoiding interference caused by changes in tube volume, thus significantly reducing measurement errors and improving the accuracy of tidal volume measurement. Furthermore, this application eliminates the reliance on complex and error-prone compliance calculations. The external flow sensor converts gas flow energy into a pressure difference, which is then transmitted to the microprocessor via a differential pressure sensor and differential amplifier to directly determine the gas flow rate within the endotracheal tube. This simplifies the measurement process, reduces potential errors introduced by intermediate steps, and improves the overall reliability of the tidal volume measurement system.

[0007] Preferably, the proximal detection component further includes a first trachea and a second trachea, one end of the first trachea being connected to the high-pressure end and the other end of the first trachea being connected to one end of the differential pressure sensor, one end of the second trachea being connected to the low-pressure end and the other end of the second trachea being connected to the other end of the differential pressure sensor.

[0008] By adopting the above technical solution, the first air tube is encapsulated with gas, which can transmit the pressure at the high end to one end of the differential pressure sensor. Similarly, the second air tube is encapsulated with gas, which can transmit the pressure at the low end to the other end of the differential pressure sensor. The arrangement of the first and second air tubes achieves effective pressure transmission.

[0009] Preferably, the differential amplifier includes a differential amplification module and a voltage follower module. The input terminal of the differential amplification module is electrically connected to the differential pressure sensor, and the output terminal of the differential amplification module is electrically connected to the microprocessor. The voltage follower module is electrically connected to the differential amplification module and is used to provide a reference voltage for the differential amplification module.

[0010] By employing the above technical solution, the differential amplifier module amplifies the differential pressure signal from the differential pressure sensor, enhancing signal strength and reducing signal attenuation and interference during transmission. This allows the microprocessor to receive a clearer and more accurate signal, thereby enabling more precise calculation of gas flow within the endotracheal tube. The voltage follower module provides a stable reference voltage for the differential amplifier module. This helps the differential amplifier module maintain stable amplification performance under different operating conditions, ensuring that the amplified signal has good linearity and stability.

[0011] Preferably, the anesthesia machine tubing further includes a Y-connector, an expiratory bronchus, and an inspiratory bronchus. The first interface of the Y-connector is connected to the endotracheal tube, the second interface of the Y-connector is connected to one end of the expiratory bronchus, the third interface of the Y-connector is connected to one end of the inspiratory bronchus, the other end of the expiratory bronchus is connected to the air inlet of the anesthesia machine, and the other end of the inspiratory bronchus is connected to the air outlet of the anesthesia machine. The tidal volume measurement system for the anesthesia machine tubing further includes a built-in detection component, which includes a built-in expiratory flow sensor and a built-in inspiratory flow sensor. The built-in expiratory flow sensor and the built-in inspiratory flow sensor are respectively disposed in the expiratory bronchus and the inspiratory bronchus, and are used to detect the gas flow rate in the expiratory bronchus and the inspiratory bronchus.

[0012] By adopting the above technical solution, the gas flow rate in the expiratory bronchus and the inspiratory bronchus can be measured respectively by the built-in expiratory flow sensor and the built-in inspiratory flow sensor, thereby improving the accuracy of tidal volume detection results.

[0013] Preferably, the microprocessor is also electrically connected to both the built-in expiratory flow sensor and the built-in inspiratory flow sensor.

[0014] By adopting the above technical solution, the microprocessor can integrate the detection results of the built-in expiratory flow sensor, the built-in inspiratory flow sensor, and the external flow sensor.

[0015] Preferably, when the gas flow rate in the expiratory or inspiratory bronchus detected by the built-in expiratory flow sensor or the built-in inspiratory flow sensor obtained by the microprocessor is greater than a preset flow rate value, the microprocessor uses the gas flow rate in the expiratory or inspiratory bronchus detected by the built-in expiratory flow sensor or the built-in inspiratory flow sensor as the output value of the gas flow rate. When the gas flow rate in the expiratory or inspiratory bronchus detected by the built-in expiratory flow sensor or the built-in inspiratory flow sensor obtained by the microprocessor is less than the preset flow rate value, the microprocessor uses the gas flow rate in the endotracheal tube obtained according to the electrical signal output by the differential amplifier as the output value of the expiratory or inspiratory flow rate.

[0016] By adopting the above technical solution, the high sensitivity advantage of the external flow sensor is fully utilized in low-flow scenarios. Because it can accurately detect extremely small gas flow velocities, the gas flow rate within the endotracheal tube, measured by the sensor, processed by a differential amplifier, and calculated by a microprocessor, significantly improves the accuracy of low-flow measurements, providing reliable data for monitoring subtle changes in patient respiration during clinical anesthesia. In high-flow scenarios, the built-in expiratory or inspiratory flow sensor, with its stable measurement performance, provides accurate flow data to the system promptly when the external flow sensor exceeds its detection range, ensuring high-precision gas flow measurement across the entire flow range.

[0017] Preferably, the external flow sensor includes a housing, a first pipe, a second pipe, a first flow sensor, and a second flow sensor. The housing has a first through hole and a second through hole at its two ends. The first through hole is used to connect with a section of the endotracheal tube that connects to the user's airway. The second through hole is used to connect with a section of the endotracheal tube that connects to the first interface of the Y-type connector. One end of the first pipe is connected to the first through hole, and the other end of the first pipe is connected to the other end of the second pipe. The inner diameter of the second pipe is larger than the inner diameter of the first pipe. The first pipe and the second pipe have a first notch and a second notch, respectively. The first flow sensor is disposed in the first notch and is used to convert the gas flow energy in the first pipe into a pressure difference between the high and low pressure ends of the first flow sensor. The second flow sensor is disposed in the second notch and is used to convert the gas flow energy in the second pipe into a pressure difference between the high and low pressure ends of the second flow sensor. The number of differential pressure sensors is two, namely a first differential pressure sensor and a second differential pressure sensor; the number of differential amplifiers is two, namely a first differential amplifier and a second differential amplifier. The two ends of the first differential pressure sensor are respectively connected to the high pressure end and the low pressure end of the first flow sensor, and are used to convert the pressure difference between the high pressure end and the low pressure end of the first flow sensor into a differential pressure electrical signal. The two ends of the second differential pressure sensor are respectively connected to the high pressure end and the low pressure end of the second flow sensor, and are used to convert the pressure difference between the high pressure end and the low pressure end of the second flow sensor into a differential pressure electrical signal. The input terminal of the first differential amplifier is electrically connected to the first differential pressure sensor, and the microprocessor is electrically connected to the output terminal of the first differential amplifier. The microprocessor is used to obtain the gas flow rate in the first pipeline based on the electrical signal output by the first differential amplifier. The input terminal of the second differential amplifier is electrically connected to the second differential pressure sensor, and the microprocessor is electrically connected to the output terminal of the second differential amplifier. The microprocessor is used to obtain the gas flow rate in the second pipeline based on the electrical signal output by the second differential amplifier.

[0018] By adopting the above technical solution, when the gas flow rate is high, the second flow sensor installed in the second pipe is preferentially selected to obtain the proximal flow rate value; while when the gas flow rate is low, the first flow sensor installed in the first pipe is selected to obtain the proximal flow rate value. This design allows the patient's tidal volume to be obtained using an external flow sensor in both low and high flow rate scenarios. Because the external flow sensor is closer to the patient than the traditional built-in sensor, it can more directly sense the state of the patient's exhaled and inhaled gases, thereby significantly improving the accuracy of tidal volume detection results.

[0019] Preferably, when the gas flow rate in the expiratory or inspiratory bronchus detected by the built-in expiratory flow sensor or the built-in inspiratory flow sensor obtained by the microprocessor is greater than a preset flow rate value, the microprocessor will use the gas flow rate in the first tube obtained based on the electrical signal output by the first differential amplifier as the output value of the gas flow rate. When the gas flow rate in the expiratory or inspiratory bronchus detected by the built-in expiratory flow sensor or the built-in inspiratory flow sensor obtained by the microprocessor is less than the preset flow rate value, the microprocessor will use the gas flow rate in the first tube obtained based on the electrical signal output by the second differential amplifier as the output value of the gas flow rate.

[0020] By adopting the above technical solution, the state of the patient's exhaled and inhaled gases can be perceived more directly, thereby significantly improving the accuracy of tidal volume detection results.

[0021] Preferably, the external flow sensor further includes a partition plate, which is fixed inside the housing. A third through hole is provided on the partition plate, and the other end of the first pipe is connected to one side of the third through hole, and the other end of the second pipe is connected to the other side of the third through hole.

[0022] By adopting the above technical solution, the partition provides a stable installation support structure for the first and second pipes. It is fixed inside the housing, and through a third through-hole, precise connection between the first and second pipes is achieved. This design greatly facilitates the pipe installation process, making the assembly of the entire external flow sensor more efficient and accurate.

[0023] Preferably, the inner diameter of the second pipe is twice the inner diameter of the first pipe.

[0024] In summary, this application includes at least one of the following beneficial technical effects: 1. This application places an external flow sensor on the endotracheal tube to directly detect the gas flow energy within the tube, providing a more accurate reflection of the patient's actual respiratory gas flow (i.e., tidal volume). This avoids interference caused by changes in tube volume, significantly reducing measurement errors and improving the accuracy of tidal volume measurement. Furthermore, this application eliminates the reliance on complex and error-prone compliance calculations. The external flow sensor converts gas flow energy into a pressure difference, which is then transmitted to the microprocessor via a differential pressure sensor and differential amplifier to directly determine the gas flow rate within the endotracheal tube. This simplifies the measurement process, reduces potential errors introduced by intermediate steps, and improves the overall reliability of the tidal volume measurement system. 2. In low-flow scenarios, the high sensitivity of the external flow sensor is fully utilized. Because it can accurately detect extremely small gas velocities, the gas flow rate within the endotracheal tube, measured by the external flow sensor, processed by a differential amplifier, and calculated by a microprocessor, significantly improves the accuracy of low-flow measurements, providing reliable data for monitoring subtle respiratory changes in patients during clinical anesthesia. In high-flow scenarios, the built-in expiratory or inspiratory flow sensor, with its stable measurement performance, provides accurate flow data to the system promptly when the external flow sensor exceeds its detection range, ensuring high-precision tidal volume measurement across the entire flow range. 3. When the gas flow rate is high, the second flow sensor 215, located in the second conduit 213, is preferentially used to obtain the proximal flow rate value; while when the gas flow rate is low, the first flow sensor 214, located in the first conduit 212, is used to obtain the proximal flow rate value. This design allows the patient's tidal volume to be obtained using an external flow sensor in both low and high flow rate scenarios. Because the external flow sensor is closer to the patient than the traditional built-in sensor, it can more directly sense the state of the patient's exhaled and inhaled gases, thereby significantly improving the accuracy of the tidal volume detection results. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the tidal volume measurement system for anesthesia machine tubing provided in Embodiment 1 of this application; Figure 2 yes Figure 1 Schematic diagram of the circuit structure of a differential amplifier; Figure 3 yes Figure 1 A flowchart illustrating the detection method of the tidal volume measurement system in the tubing of a central anesthesia machine; Figure 4This is a schematic diagram showing the relationship between output voltage and time when there is a positive flow velocity inside the endotracheal tube; Figure 5 This is a schematic diagram showing the relationship between output voltage and time when there is a reverse flow velocity inside the endotracheal tube. Figure 6 This is a schematic diagram of the tidal volume measurement system for anesthesia machine tubing provided in Embodiment 2 of this application; Figure 7 yes Figure 6 A magnified view of a portion of region A in the middle; Explanation of reference numerals in the attached drawings: 1. Anesthesia machine tubing; 11. Endotracheal tube; 12. Y-connector; 13. Expiratory bronchus; 14. Inspiratory bronchus; 2. Proximal detection assembly; 21. External flow sensor; 211. Housing; 2111. First through-hole; 2112. Second through-hole; 212. First conduit; 213. Second conduit; 214. First flow sensor; 215. Second flow sensor; 216. Partition; 2161. Third through-hole; 22. First trachea; 23. Second trachea; 3. Differential pressure sensor; 3a. First differential pressure sensor; 3b. Second differential pressure sensor; 4. Differential amplifier; 41. Differential amplifier module; 42. Voltage follower module; 4a. First differential amplifier; 4b. Second differential amplifier; 5. Microprocessor; 6. Built-in detection assembly; 61. Built-in expiratory flow sensor; 62. Built-in inspiratory flow sensor. Detailed Implementation

[0026] The following is in conjunction with the appendix Figures 1-7 This application will be described in further detail.

[0027] In related technologies, the anesthesia machine tubing 1 includes an endotracheal tube 11 for connecting to the user's airway.

[0028] This application discloses a tidal volume measurement system for anesthesia machine tubing.

[0029] Example 1 Reference Figure 1The tidal volume measurement system for the anesthesia machine tubing 1 includes a proximal detection component 2, a differential pressure sensor 3, a differential amplifier 4, and a microprocessor 5. The proximal detection component 2 includes an external flow sensor 21, which is installed on the endotracheal tube 11 and converts the gas flow energy within the endotracheal tube 11 into a pressure difference between its high and low pressure ends. The differential pressure sensor 3 is connected to both the high and low pressure ends, respectively, and converts the pressure difference into a differential pressure electrical signal. The input of the differential amplifier 4 is electrically connected to the differential pressure sensor 3, and the microprocessor 5 is electrically connected to the output of the differential amplifier 4, and calculates the gas flow rate within the endotracheal tube 11 based on the electrical signal output by the differential amplifier 4. In this embodiment, the external flow sensor 21 is specifically a Y-Piece flow sensor.

[0030] The technical advantages of the above-mentioned solution are as follows: This application places an external flow sensor 21 on the endotracheal tube 11 to directly detect the gas flow energy within the endotracheal tube 11, which can more accurately reflect the patient's actual respiratory gas flow rate (i.e., tidal volume), avoid interference caused by changes in tube volume, thereby significantly reducing measurement errors and improving the accuracy of tidal volume measurement. Simultaneously, this application no longer relies on complex and error-prone compliance calculations. The external flow sensor 21 converts the gas flow energy into a pressure difference, which is then transmitted to the microprocessor 5 via the differential pressure sensor 3 and differential amplifier 4, directly yielding the gas flow rate within the endotracheal tube 11. This simplifies the measurement process, reduces errors that may be introduced by intermediate steps, and improves the reliability of the entire tidal volume measurement system.

[0031] Specifically, please refer to Figure 1 The proximal detection component 2 further includes a first trachea 22 and a second trachea 23. One end of the first trachea 22 is connected to the high-pressure end, and the other end is connected to one end of the differential pressure sensor 3. One end of the second trachea 23 is connected to the low-pressure end, and the other end is connected to the other end of the differential pressure sensor 3. In this embodiment, the first trachea 22 is encapsulated with gas, which can transmit the pressure from the high-pressure end to one end of the differential pressure sensor 3. Similarly, the second trachea 23 is encapsulated with gas, which can transmit the pressure from the low-pressure end to the other end of the differential pressure sensor 3. The effective transmission of pressure is achieved through the arrangement of the first trachea 22 and the second trachea 23.

[0032] Specifically, please refer to Figure 1 and Figure 2The differential amplifier 4 includes a differential amplification module 41 and a voltage follower module 42. The input terminal of the differential amplification module 41 is electrically connected to the differential pressure sensor 3, and the output terminal of the differential amplification module 41 is electrically connected to the microprocessor 5. The voltage follower module 42 is electrically connected to the differential amplification module 41 and provides a reference voltage for the differential amplification module 41. The differential amplification module 41 amplifies the differential pressure signal from the differential pressure sensor 3, enhancing the signal strength and reducing signal attenuation and interference during transmission. This allows the microprocessor 5 to receive a clearer and more accurate signal, thereby more accurately calculating the gas flow rate within the endotracheal tube 11. The voltage follower module 42 provides a stable reference voltage to the differential amplification module 41. This helps the differential amplification module 41 maintain stable amplification performance under different operating conditions, ensuring that the amplified signal has good linearity and stability. Because in practical applications, signal stability is crucial to the accuracy of measurement results, a stable reference voltage can avoid signal distortion caused by voltage fluctuations and improve the reliability of the entire measurement system.

[0033] In this embodiment, as Figure 2 As shown, the differential pressure sensor 3 converts the pressure difference between the high-pressure end and the low-pressure end into a differential pressure electrical signal. Since the voltage range of the differential pressure electrical signal is extremely small, it needs to pass through the differential amplifier module 41 to obtain a voltage. This voltage requires a reference voltage provided by the voltage follower module 42 to boost the voltage of the differential amplifier module 41 to 2000mV. If the pressure difference between the high-pressure end and the low-pressure end is 0, the output voltage of the differential amplifier module 41 is 2000mV, and this 2000mV voltage is taken as the zero point. When the output voltage is greater than 2000mV, it indicates that there is a positive flow rate within the endotracheal tube 11 (e.g., during exhalation). Figure 4 When the output voltage is less than 2000mV, it indicates that there is a reverse flow velocity inside the endotracheal tube 11 (e.g., during inhalation, such as...). Figure 5 This allows for the acquisition of flow rates ranging from -20 L / min to 20 L / min. Furthermore, by adjusting the differential amplifier's amplification factor, analog signals ranging from 300 mV to 3000 mV are provided to the microcontroller. This also increases the resolution of the flow rate.

[0034] Specifically, please refer to Figure 1 and Figure 3The anesthesia machine tubing 1 further includes a Y-connector 12, an expiratory bronchus 13, and an inspiratory bronchus 14. The first interface of the Y-connector 12 is connected to the endotracheal tube 11, the second interface of the Y-connector 12 is connected to one end of the expiratory bronchus 13, and the third interface of the Y-connector 12 is connected to one end of the inspiratory bronchus 14. The other end of the expiratory bronchus 13 is connected to the air inlet of the anesthesia machine, and the other end of the inspiratory bronchus 14 is connected to the air outlet of the anesthesia machine. It should be understood that the Y-connector 12 is a standard accessory for anesthetics and has the function of controlling gas flow. When a patient exhales, the second interface of the Y-connector 12 is open, and the third interface is closed. When a patient inhales, the third interface of the Y-connector 12 is open, and the second interface is closed, thereby achieving gas flow control. The specific structure of the Y-connector 12 is prior art and will not be described further in this application.

[0035] The tidal volume measurement system for the anesthesia machine tubing 1 also includes a built-in detection component 6. The built-in detection component 6 includes a built-in expiratory flow sensor 61 and a built-in inspiratory flow sensor 62. The built-in expiratory flow sensor 61 and the built-in inspiratory flow sensor 62 are respectively disposed in the expiratory bronchus 13 and the inspiratory bronchus 14, and are used to detect the gas flow rate within the expiratory bronchus 13 and the inspiratory bronchus 14. By using the built-in expiratory flow sensor 61 and the built-in inspiratory flow sensor 62 to measure the gas flow rate within the expiratory bronchus 13 and the inspiratory bronchus 14, the accuracy of the tidal volume measurement results can be improved.

[0036] Specifically, please refer to Figure 1 and Figure 3 The microprocessor 5 is also electrically connected to both the built-in expiratory flow sensor 61 and the built-in inspiratory flow sensor 62. Thus, the microprocessor 5 can integrate the detection results from the built-in expiratory flow sensor 61, the built-in inspiratory flow sensor 62, and the external flow sensor 21. Since the external flow sensor 21 is very sensitive, it can detect very small gas flow velocities, which is beneficial for small flow rate measurements. However, when the airflow velocity is high, it will exceed the detection range of the external flow sensor 21. In this case, the gas flow rate value can be obtained through either the built-in expiratory flow sensor 61 or the built-in inspiratory flow sensor 62, thereby ensuring high-precision gas flow rate measurement across the entire flow range.

[0037] Specifically, please refer to Figure 1 and Figure 3When the gas flow rate detected by the built-in expiratory flow sensor 61 or the built-in inspiratory flow sensor 62 in the expiratory bronchus 13 or the inspiratory bronchus 14, as obtained by the microprocessor 5, is greater than a preset flow rate value, the microprocessor 5 uses the gas flow rate detected by the built-in expiratory flow sensor 61 or the built-in inspiratory flow sensor 62 in the expiratory bronchus 13 or the inspiratory bronchus 14 as the output value of the gas flow rate. When the gas flow rate detected by the built-in expiratory flow sensor 61 or the built-in inspiratory flow sensor 62 in the expiratory bronchus 13 or the inspiratory bronchus 14, as obtained by the microprocessor 5, is less than the preset flow rate value, the microprocessor 5 uses the gas flow rate in the tracheal tube 11 obtained according to the electrical signal output by the differential amplifier 4 as the output value of the expiratory flow rate or the inspiratory flow rate.

[0038] In this embodiment, the high sensitivity of the external flow sensor is fully utilized in low-flow scenarios. Because it can accurately detect extremely small gas velocities, the gas flow rate within the endotracheal tube, measured by the external sensor, processed by a differential amplifier, and calculated by a microprocessor, significantly improves the accuracy of low-flow measurements, providing reliable data for monitoring subtle respiratory changes in patients during clinical anesthesia. In high-flow scenarios, the built-in expiratory or inspiratory flow sensor, with its stable measurement performance, provides accurate flow data to the system promptly when the external flow sensor exceeds its detection range, ensuring high-precision gas flow measurement across the entire flow range. Through an intelligent flow data switching mechanism, the system can automatically select the most suitable sensor data as the output based on the real-time flow rate. This dual-insurance measurement method effectively avoids measurement errors caused by the performance limitations of a single sensor under specific flow conditions, greatly enhancing the reliability of the tidal volume measurement system under different operating conditions. This ensures that the anesthesia machine can continuously, stably, and accurately monitor the patient's respiratory status, providing medical personnel with stable and reliable monitoring data.

[0039] Example 2 Please see Figure 6 and Figure 7 The main structure of Example 2 is the same as that of Example 1, except that the structure of the external flow sensor 21 and the number of differential pressure sensor 3 and differential amplifier 4 are different.

[0040] The external flow sensor 21 includes a housing 211, a first pipe 212, a second pipe 213, a first flow sensing element 214, and a second flow sensing element 215. The housing 211 has a first through hole 2111 and a second through hole 2112 at its two ends. The first through hole 2111 is used to connect with a section of the endotracheal tube 11 that connects to the user's airway. The second through hole 2112 is used to connect with a section of the endotracheal tube 11 that connects to the first interface of the Y-type connector 12. One end of the first pipe 212 is connected to the first through hole 2111, and the other end of the first pipe 212 is connected to the other end of the second pipe 213. One end is connected, the inner diameter of the second pipe 213 is larger than the inner diameter of the first pipe 212, the first pipe 212 and the second pipe 213 are respectively provided with a first notch and a second notch, the first flow sensor 214 is disposed in the first notch and is used to convert the gas flow energy in the first pipe 212 into the pressure difference between the pressure high end and the pressure low end of the first flow sensor 214, and the second flow sensor 215 is disposed in the second notch and is used to convert the gas flow energy in the second pipe 213 into the pressure difference between the pressure high end and the pressure low end of the second flow sensor 215. The differential pressure sensor 3 is provided in pairs, namely a first differential pressure sensor 3a and a second differential pressure sensor 3b. Similarly, the differential amplifier 4 is provided in pairs, namely a first differential amplifier 4a and a second differential amplifier 4b. The two ends of the first differential pressure sensor 3a are connected to the high-pressure end and the low-pressure end of the first flow sensor 214, respectively, and are used to convert the pressure difference between the high-pressure end and the low-pressure end of the first flow sensor 214 into a differential pressure electrical signal. The two ends of the second differential pressure sensor 3b are connected to the high-pressure end and the low-pressure end of the second flow sensor 215, respectively, and are used to convert the pressure difference between the high-pressure end and the low-pressure end of the second flow sensor 215 into a differential pressure electrical signal. The pressure difference between the high and low pressure ends is converted into a differential pressure electrical signal; the input terminal of the first differential amplifier 4a is electrically connected to the first differential pressure sensor 3a, the microprocessor 5 is electrically connected to the output terminal of the first differential amplifier 4a, and is used to obtain the gas flow rate in the first pipe 212 based on the electrical signal output by the first differential amplifier 4a; the input terminal of the second differential amplifier 4b is electrically connected to the second differential pressure sensor 3b, the microprocessor 5 is electrically connected to the output terminal of the second differential amplifier 4b, and is used to obtain the gas flow rate in the second pipe 213 based on the electrical signal output by the second differential amplifier 4b.

[0041] In this embodiment, since the inner diameter of the second pipe 213 is larger than the inner diameter of the first pipe 212, the cross-sectional area of ​​the second pipe 213 is larger than that of the first pipe 212. Based on the principle of fluid mechanics, under the same flow rate, the cross-sectional area is inversely proportional to the flow velocity. Therefore, the gas flow velocity in the second pipe 213 is greater than that in the first pipe 212. Thus, when the flow rate is large, the gas flow velocity in the first pipe 212 exceeds the detection threshold of the first flow sensor 214, resulting in inaccurate detection results. However, the gas flow velocity in the second pipe 213 is smaller and will not exceed the detection threshold of the second flow sensor 215.

[0042] In practical applications, when the gas flow rate is high, the second flow sensor 215, located within the second conduit 213, is preferentially used to obtain the proximal flow rate value; while when the gas flow rate is low, the first flow sensor 214, located within the first conduit 212, is used to obtain the proximal flow rate value. This design allows for the acquisition of the patient's tidal volume using an external flow sensor in both low and high flow rate scenarios. Because the external flow sensor is closer to the patient than a traditional built-in sensor, it can more directly sense the state of the patient's exhaled and inhaled gases, thereby significantly improving the accuracy of tidal volume detection results.

[0043] Specifically, please refer to Figure 6 and Figure 7 When the gas flow rate detected by the built-in expiratory flow sensor 61 or the built-in inspiratory flow sensor 62 in the expiratory bronchus 13 or the inspiratory bronchus 14, as obtained by the microprocessor 5, is greater than a preset flow rate value, the microprocessor 5 uses the gas flow rate in the first tube 212 obtained from the electrical signal output by the first differential amplifier 4a as the output value of the gas flow rate. When the gas flow rate detected by the built-in expiratory flow sensor 61 or the built-in inspiratory flow sensor 62 in the expiratory bronchus 13 or the inspiratory bronchus 14, as obtained by the microprocessor 5, is less than the preset flow rate value, the microprocessor 5 uses the gas flow rate in the first tube 212 obtained from the electrical signal output by the second differential amplifier 4b as the output value of the gas flow rate. This design allows the patient's tidal volume to be obtained using an external flow sensor in both low-flow and high-flow scenarios. Because the external flow sensor is closer to the patient than the traditional built-in sensor, it can more directly sense the state of the patient's exhaled and inhaled gases, thereby significantly improving the accuracy of the tidal volume detection results.

[0044] Specifically, please refer to Figure 6 and Figure 7The external flow sensor 21 also includes a partition 216, which is fixed inside the housing 211. The partition 216 has a third through hole 2161. The other end of the first pipe 212 communicates with one side of the third through hole 2161, and the other end of the second pipe 213 communicates with the other side of the third through hole 2161. In this embodiment, the partition 216 provides a stable installation support structure for the first pipe 212 and the second pipe 213. It is fixed inside the housing 211, and through the third through hole 2161, precise connection between the first pipe 212 and the second pipe 213 is achieved. This design greatly facilitates the pipe installation process, making the assembly of the entire external flow sensor more efficient and accurate.

[0045] Please refer to [link / reference] first. Figure 6 and Figure 7 The inner diameter of the second pipe 213 is twice that of the first pipe 212. This design, which precisely adapts to different flow rates, ensures that the entire external flow sensor maintains good measurement performance across the entire flow range. Whether it's the large flow of gas produced by a patient's deep breathing or the small flow of gas corresponding to shallow breathing, the system can accurately detect tidal volume, greatly enhancing the adaptability and reliability of the tidal volume measurement system and providing a solid foundation for accurate monitoring of the patient's respiratory status during clinical anesthesia.

[0046] The technical effects of the technical solution provided in this application include: (1) By placing an external flow sensor 21 on the endotracheal tube 11, the gas flow energy within the endotracheal tube 11 can be directly detected, which can more accurately reflect the actual respiratory gas flow rate (i.e., tidal volume) of the patient, avoid interference caused by changes in the tube volume, thereby significantly reducing measurement errors and improving the accuracy of tidal volume measurement. At the same time, this application no longer relies on complex and error-prone compliance calculations. The gas flow energy is converted into pressure difference by the external flow sensor 21, and then transmitted to the microprocessor 5 through the differential pressure sensor 3 and differential amplifier 4, directly obtaining the gas flow rate within the endotracheal tube 11, simplifying the measurement process, reducing errors that may be introduced by intermediate links, and improving the reliability of the entire tidal volume measurement system; (2) In low-flow scenarios, the high sensitivity of the external flow sensor is fully utilized. Because it can accurately detect extremely small gas flow velocities, the gas flow rate in the endotracheal tube measured by it, processed by the differential amplifier and calculated by the microprocessor, can greatly improve the accuracy of low-flow measurement and provide reliable data for monitoring subtle respiratory changes in patients during clinical anesthesia. In high-flow scenarios, the built-in expiratory or inspiratory flow sensor, with its stable measurement performance, can provide accurate flow data to the system in a timely manner when the external flow sensor exceeds its detection range, ensuring high-precision gas flow measurement across the entire flow range; (3) When the gas flow rate is high, the second flow sensor 215, located in the second pipe 213, is preferentially used to obtain the proximal flow rate value; while when the gas flow rate is low, the first flow sensor 214, located in the first pipe 212, is used to obtain the proximal flow rate value. This design allows the patient's tidal volume to be obtained using an external flow sensor in both low and high flow rate scenarios. Since the external flow sensor is closer to the patient than the traditional built-in sensor, it can more directly sense the state of the patient's exhaled and inhaled gases, thereby significantly improving the accuracy of the tidal volume detection results.

[0047] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Any other corresponding changes and modifications made based on the technical concept of this application should be included within the scope of protection of this application.

Claims

1. A tidal volume measurement system for an anesthesia machine tubing, the anesthesia machine tubing (1) including an endotracheal tube (11) for connecting to the user's airway, characterized in that: The tidal volume measurement system for the anesthesia machine tubing (1) includes a proximal detection component (2), a differential pressure sensor (3), a differential amplifier (4), and a microprocessor (5). The proximal detection component (2) includes an external flow sensor (21), which is installed on the tracheal tube (11) and is used to convert the gas flow energy in the tracheal tube (11) into a pressure difference between the high and low pressure ends of the external flow sensor (21). The two ends of the differential pressure sensor (3) are connected to the high pressure end and the low pressure end respectively, and are used to convert the pressure difference between the high pressure end and the low pressure end into a differential pressure electrical signal. The input end of the differential amplifier (4) is electrically connected to the differential pressure sensor (3), and the microprocessor (5) is electrically connected to the output end of the differential amplifier (4) and is used to obtain the gas flow rate in the tracheal tube (11) based on the electrical signal output by the differential amplifier (4).

2. The tidal volume measurement system for anesthesia machine tubing according to claim 1, characterized in that: The proximal detection component (2) further includes a first trachea (22) and a second trachea (23). One end of the first trachea (22) is connected to the high pressure end, and the other end of the first trachea (22) is connected to one end of the differential pressure sensor (3). One end of the second trachea (23) is connected to the low pressure end, and the other end of the second trachea (23) is connected to the other end of the differential pressure sensor (3).

3. The tidal volume measurement system for anesthesia machine tubing according to claim 1, characterized in that: The differential amplifier (4) includes a differential amplifier module (41) and a voltage follower module (42). The input terminal of the differential amplifier module (41) is electrically connected to the differential pressure sensor (3), and the output terminal of the differential amplifier module (41) is electrically connected to the microprocessor (5). The voltage follower module (42) is electrically connected to the differential amplifier module (41) and is used to provide a reference voltage for the differential amplifier module (41).

4. The tidal volume measurement system for anesthesia machine tubing according to claim 1, characterized in that: The anesthesia machine tubing (1) also includes a Y-type connector (12), an expiratory bronchus (13), and an inspiratory bronchus (14). The first interface of the Y-type connector (12) is connected to the tracheal tube (11), the second interface of the Y-type connector (12) is connected to one end of the expiratory bronchus (13), the third interface of the Y-type connector (12) is connected to one end of the inspiratory bronchus (14), the other end of the expiratory bronchus (13) is connected to the air inlet of the anesthesia machine, and the other end of the inspiratory bronchus (14) is connected to the air outlet of the anesthesia machine. The tidal volume measurement system for the anesthesia machine tubing (1) also includes a built-in detection component (6), which includes a built-in expiratory flow sensor (61) and a built-in inspiratory flow sensor (62). The built-in expiratory flow sensor (61) and the built-in inspiratory flow sensor (62) are respectively disposed in the expiratory bronchus (13) and the inspiratory bronchus (14) and are used to detect the gas flow in the expiratory bronchus (13) and the inspiratory bronchus (14).

5. The tidal volume measurement system for anesthesia machine tubing according to claim 4, characterized in that: The microprocessor (5) is also electrically connected to both the built-in expiratory flow sensor (61) and the built-in inspiratory flow sensor (62).

6. The tidal volume measurement system for anesthesia machine tubing according to claim 5, characterized in that: When the gas flow rate in the expiratory bronchus (13) or the inspiratory bronchus (14) detected by the built-in expiratory flow sensor (61) or the built-in inspiratory flow sensor (62) obtained by the microprocessor (5) is greater than the preset flow rate value, the microprocessor (5) uses the gas flow rate in the expiratory bronchus (13) or the inspiratory bronchus (14) detected by the built-in expiratory flow sensor (61) or the built-in inspiratory flow sensor (62) as the output value of the gas flow rate. When the gas flow rate in the expiratory bronchus (13) or the inspiratory bronchus (14) detected by the built-in expiratory flow sensor (61) or the built-in inspiratory flow sensor (62) obtained by the microprocessor (5) is less than the preset flow rate value, the microprocessor (5) uses the gas flow rate in the tracheal tube (11) obtained according to the electrical signal output by the differential amplifier (4) as the output value of the expiratory flow rate or the inspiratory flow rate.

7. The tidal volume measurement system for anesthesia machine tubing according to claim 5, characterized in that: The external flow sensor (21) includes a housing (211), a first pipe (212), a second pipe (213), a first flow sensor (214), and a second flow sensor (215). The housing (211) has a first through hole (2111) and a second through hole (2112) at its two ends. The first through hole (2111) is used to connect with a section of the endotracheal tube (11) that connects to the user's airway. The second through hole (2112) is used to connect with a section of the endotracheal tube (11) that connects to the first interface of the Y-type connector (12). One end of the first pipe (212) is connected to the first through hole (2111), and the other end of the first pipe (212) is connected to the second through hole (215). The other end of the pipe (213) is connected. The inner diameter of the second pipe (213) is larger than the inner diameter of the first pipe (212). The first pipe (212) and the second pipe (213) are respectively provided with a first notch and a second notch. The first flow sensor (214) is disposed in the first notch and is used to convert the gas flow energy in the first pipe (212) into the pressure difference between the high pressure end and the low pressure end of the first flow sensor (214). The second flow sensor (215) is disposed in the second notch and is used to convert the gas flow energy in the second pipe (213) into the pressure difference between the high pressure end and the low pressure end of the second flow sensor (215). The number of differential pressure sensors (3) is two, namely the first differential pressure sensor (3a) and the second differential pressure sensor (3b), and the number of differential amplifiers (4) is two, namely the first differential amplifier (4a) and the second differential amplifier (4b). The two ends of the first differential pressure sensor (3a) are respectively connected to the high pressure end and the low pressure end of the first flow sensor (214), and are used to convert the pressure difference between the high pressure end and the low pressure end of the first flow sensor (214) into a differential pressure electrical signal. The two ends of the second differential pressure sensor (3b) are respectively connected to the high pressure end and the low pressure end of the second flow sensor (215), and are used to convert the pressure difference between the high pressure end and the low pressure end of the second flow sensor (215) into a differential pressure electrical signal. The input terminal of the first differential amplifier (4a) is electrically connected to the first differential pressure sensor (3a), and the microprocessor (5) is electrically connected to the output terminal of the first differential amplifier (4a) and is used to obtain the gas flow rate in the first pipe (212) according to the electrical signal output by the first differential amplifier (4a). The input terminal of the second differential amplifier (4b) is electrically connected to the second differential pressure sensor (3b), and the microprocessor (5) is electrically connected to the output terminal of the second differential amplifier (4b) and is used to obtain the gas flow rate in the second pipe (213) according to the electrical signal output by the second differential amplifier (4b).

8. The tidal volume measurement system for anesthesia machine tubing according to claim 7, characterized in that: When the gas flow rate in the expiratory bronchus (13) or the inspiratory bronchus (14) detected by the built-in expiratory flow sensor (61) or the built-in inspiratory flow sensor (62) obtained by the microprocessor (5) is greater than the preset flow rate value, the microprocessor (5) uses the gas flow rate in the first pipe (212) obtained according to the electrical signal output by the first differential amplifier (4a) as the output value of the gas flow rate. When the gas flow rate in the expiratory bronchus (13) or the inspiratory bronchus (14) detected by the built-in expiratory flow sensor (61) or the built-in inspiratory flow sensor (62) obtained by the microprocessor (5) is less than the preset flow rate value, the microprocessor (5) uses the gas flow rate in the first pipe (212) obtained according to the electrical signal output by the second differential amplifier (4b) as the output value of the gas flow rate.

9. The tidal volume measurement system for anesthesia machine tubing according to claim 7, characterized in that: The external flow sensor (21) also includes a partition (216), which is fixed inside the housing (211). A third through hole (2161) is provided on the partition (216). The other end of the first pipe (212) is connected to one side of the third through hole (2161), and the other end of the second pipe (213) is connected to the other side of the third through hole (2161).

10. The tidal volume measurement system for anesthesia machine tubing according to claim 7, characterized in that: The inner diameter of the second pipe (213) is twice the inner diameter of the first pipe (212).

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