Human body oxygen metabolism analyzer and method based on condensation combined with water vapor calculation compensation

Abstract

The invention provides a human body oxygen metabolism analyzer and method based on condensation and water vapor calculation compensation, and relates to the technical field of medical detection equipment. Comprising a gas sampling unit, a condensation unit, a parameter acquisition unit, a gas analysis unit and a calculation processing unit, the gas sampling unit is used for collecting mixed gas of a target user in the breathing process in real time; the condensing unit is used for physically cooling the mixed gas; the parameter acquisition unit is used for acquiring the temperature of the cooled mixed gas; and the gas analysis unit is used for detecting the oxygen concentration in the cooled mixed gas. And the calculation processing unit is used for determining the oxygen concentration of the exhaled gas of the target user in the STPD state according to the breathing ratio of the target user, the temperature of the cooled mixed gas and the oxygen concentration. Accurate measurement of the oxygen metabolism parameters of the human body can be achieved, the equipment cost can be effectively reduced, and the use requirements in different use scenes can be met.

Description

Technical Field

[0001] This invention relates to the field of medical testing equipment technology, and in particular to a human oxygen metabolism analyzer and method based on condensation combined with water vapor calculation compensation. Background Technology

[0002] In the fields of sports medicine, clinical rehabilitation, basic physiological research and precision health management, the accurate measurement of human oxygen metabolism parameters (such as VO2, VCO2 and RER) is the core basis for assessing human physiological state, disease recovery process and exercise effect, and the key equipment for measuring such parameters is human oxygen metabolism analyzer.

[0003] Oxygen metabolism analysis techniques in related fields are mostly based on the principle of successive respiration. They calculate metabolic parameters by collecting the mixture of inhaled and exhaled gases and analyzing changes in oxygen and carbon dioxide concentrations. However, water vapor inevitably carried in exhaled air significantly interferes with the measurement of gas partial pressures. The presence of water vapor alters the calculation benchmark for the effective oxygen partial pressure in the gas mixture. If the influence of water vapor cannot be accurately addressed, it will directly lead to deviations in the calculation of oxygen metabolism parameters, thereby affecting the reliability of clinical diagnosis, rehabilitation assessment, and research conclusions. Therefore, how to effectively eliminate the interference of water vapor on oxygen metabolism measurements and achieve accurate measurement of human oxygen metabolism parameters has become an urgent problem to be solved. Summary of the Invention

[0004] This invention provides a human oxygen metabolism analyzer and method based on condensation combined with water vapor calculation compensation, which can accurately measure human oxygen metabolism parameters, effectively reduce equipment costs, and meet the needs of different usage scenarios.

[0005] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions: In a first aspect, a human oxygen metabolism analyzer based on condensation combined with water vapor calculation compensation is provided, comprising: a gas sampling unit, a condensation unit, a parameter acquisition unit, a gas analysis unit, and a calculation processing unit, wherein the condensation unit, the parameter acquisition unit, and the gas analysis unit are disposed in the gas sampling pipe of the gas sampling unit, and the parameter acquisition unit is disposed between the condensation unit and the gas analysis unit; the gas sampling unit is used to collect mixed gas from a target user during breathing in real time, the mixed gas including inhaled gas and exhaled gas; the condensation unit is used to physically cool the mixed gas to obtain cooled mixed gas; the parameter acquisition unit is used to acquire the temperature of the cooled mixed gas; the gas analysis unit is used to detect the oxygen concentration in the cooled mixed gas; the calculation processing unit is used to determine the respiratory rate of the target user, and to determine the oxygen concentration of the target user's exhaled gas in STPD state based on the respiratory rate of the target user, the temperature of the cooled mixed gas, and the oxygen concentration, wherein the respiratory rate is the ratio of the inhalation duration to the exhalation duration of the target user within a preset time period.

[0006] The human oxygen metabolism analyzer provided by this invention first physically cools the mixed gas through a condensation unit, which initially reduces the water vapor content by lowering the gas temperature, thus mitigating the direct interference of water vapor on subsequent detection. The parameter acquisition unit specifically acquires the temperature of the cooled gas, providing key basic data for subsequent water vapor compensation calculations. The calculation and processing unit, by introducing the respiratory ratio and multi-parameter collaborative calculation, can more comprehensively correct the influence of water vapor on oxygen concentration measurement, quickly and accurately determine the exhaled oxygen concentration under STPD conditions, and eliminate measurement errors caused by differences in environmental temperature and humidity and respiratory timing. Ultimately, it improves the accuracy of core oxygen metabolism parameters such as VO2 and VCO2, meeting the needs of sports medicine, clinical rehabilitation, and other scenarios for precise data.

[0007] In one possible implementation of the first aspect, the parameter acquisition unit includes a temperature sensor that communicates with the computing unit; the temperature sensor is disposed on the inner wall of the gas sampling pipe and is used to acquire the temperature of the cooled mixed gas.

[0008] This invention utilizes a temperature sensor positioned against the inner wall of a pipe, allowing direct contact with the cooled mixed gas. This avoids interference from ambient temperature, ensuring that the acquired gas temperature data accurately reflects the target gas state. Simultaneously, the communication connection between the sensor and the computing unit enables real-time transmission of key parameters, preventing computational delays caused by data latency. This provides reliable data input for subsequent STPD oxygen concentration calculations, further reducing measurement errors caused by inaccurate parameters.

[0009] In one possible implementation of the first aspect, the gas sampling unit is further configured to acquire gas flow rate change data of the gas sampling pipeline, and to send the gas flow rate change data to the calculation and processing unit; the calculation and processing unit is specifically configured to: determine the respiratory cycle boundary of the target user within a preset time period based on the gas flow rate change data, determine the inhalation duration and exhalation duration based on the respiratory cycle boundary, and determine the respiratory ratio of the target user based on the inhalation duration and exhalation duration of the target user within the preset time period.

[0010] This invention determines the respiratory cycle boundary based on the positive and negative switching of flow rate changes and peak nodes, accurately dividing the time range of inhalation and exhalation. The respiratory ratio is then calculated using the duration ratio. The entire process is based on objective physical signals, avoiding subjective judgment errors. An accurate respiratory ratio ensures that subsequent processing units fully consider the difference in gas mixing ratios between the inhalation and exhalation phases when correcting for water vapor effects, thereby improving the accuracy of exhaled oxygen concentration calculations under STPD conditions and laying the foundation for the precise derivation of oxygen metabolism parameters.

[0011] In one possible implementation of the first aspect, the computational processing unit is specifically configured to: determine the sum of the partial pressure of water vapor in the mixed gas under BTPS and ATPD conditions, wherein the partial pressure of water vapor in the BTPS condition is a preset value, and the partial pressure of water vapor in the ATPD condition is determined based on the actual vapor pressure of the inhaled gas; determine whether the sum is greater than the saturated vapor pressure of the mixed gas in the gas sampling pipeline, wherein the saturated vapor pressure of the mixed gas in the gas sampling pipeline is determined based on the temperature of the cooled mixed gas; if the sum is greater than the saturated vapor pressure of the mixed gas in the gas sampling pipeline, determine the oxygen concentration of the target user's exhaled gas under STPD conditions according to the oxygen concentration in the mixed gas using a first formula; if the sum is less than or equal to the saturated vapor pressure of the mixed gas in the gas sampling pipeline, determine the oxygen concentration of the target user's exhaled gas under STPD conditions according to the oxygen concentration in the mixed gas using a second formula.

[0012] This invention comprehensively reflects the total potential influence of water vapor in a gas by calculating the sum of the partial pressures of BTPS and ATPD. The saturated vapor pressure in the pipeline is determined by the cooled gas temperature and is directly related to the maximum amount of water vapor the gas can hold under its current state. If the sum is greater than the saturated vapor pressure, the gas is supersaturated, and a first formula adapted to the supersaturated state should be used. If the sum is less than or equal to the saturated vapor pressure, the gas is unsaturated, and a second formula adapted to the unsaturated state should be used. Therefore, the method provided by this invention can dynamically adjust the compensation strategy according to the actual water vapor state of the gas, avoiding the limitations of a single formula, completely eliminating the interference of different water vapor saturation states on oxygen concentration measurement, ensuring that the STPD oxygen concentration calculation results match the actual gas state, and improving measurement accuracy.

[0013] In one possible implementation of the first aspect, the first formula is: ; The second formula is: ; Wherein, FeO2 is the oxygen concentration of the target user's exhaled gas under STPD conditions, and FO 2测 Ptube represents the oxygen concentration in the cooled mixed gas, Pwater represents the pressure inside the gas sampling pipe, and Pwater represents the pressure inside the gas sampling pipe. 饱和 Here, E is the saturated vapor pressure inside the gas sampling pipe, and F is the respiration ratio. i O2 represents the oxygen concentration of the gas inhaled by the target user in the ATPD state, and PB represents the standard atmospheric pressure (Pwater). ATPD Pwater is the partial pressure of water vapor in exhaled gas under the ATPD state. BTPS This is the partial pressure of water vapor in the inhaled gas under BTPS conditions.

[0014] This invention clarifies the quantitative relationship between exhaled oxygen concentration and key parameters such as cooled gas oxygen concentration, pipeline pressure, saturated vapor pressure, breathing ratio, and inhaled oxygen concentration under STPD conditions. Each parameter has a clear physical definition, ensuring that the calculation and processing unit strictly follows a unified mathematical logic during execution, avoiding calculation errors caused by misunderstanding of formulas or confusion of parameters, and further ensuring the accuracy and consistency of oxygen metabolism parameter measurements.

[0015] In one possible implementation of the first aspect, the formulas for determining the partial pressure of water vapor P1 of the mixed gas in the BTPS state and the partial pressure of water vapor P2 of the mixed gas in the ATPD state are as follows: ; .

[0016] This invention can accurately calculate the actual water vapor partial pressure of two gas states under the current breathing mode, avoiding the error of empirical estimation; accurate water vapor partial pressure can ensure the authenticity of the partial pressure summation calculation, thereby making the subsequent saturation state judgment and STPD oxygen concentration calculation more reliable, and effectively reducing the measurement deviation caused by inaccurate water vapor partial pressure estimation.

[0017] Secondly, the present invention provides a method for analyzing human oxygen metabolism based on condensation combined with water vapor calculation compensation, applied to the human oxygen metabolism analyzer based on condensation combined with water vapor calculation compensation described in the first aspect above, comprising: a gas sampling unit to collect mixed gas from a target user during breathing in real time, the mixed gas including inhaled gas and exhaled gas; a condensation unit to physically cool the mixed gas to obtain cooled mixed gas; a parameter acquisition unit to acquire the temperature of the cooled mixed gas; a gas analysis unit to detect the oxygen concentration in the cooled mixed gas; and a calculation processing unit to determine the respiratory ratio of the target user, the calculation processing unit determining the oxygen concentration of the target user's exhaled gas in STPD state based on the respiratory ratio of the target user, the temperature of the cooled mixed gas, and the oxygen concentration, wherein the respiratory ratio is the ratio of the inhalation duration to the exhalation duration of the target user within a preset time period.

[0018] In one possible implementation of the second aspect, the parameter acquisition unit includes a temperature sensor disposed on the inner wall of the gas sampling pipe, and the method further includes: the temperature sensor acquiring the temperature of the cooled mixed gas.

[0019] In one possible implementation of the second aspect, the method further includes: the gas sampling unit acquiring gas flow rate change data of the gas sampling pipeline and sending the gas flow rate change data to the calculation and processing unit; the calculation and processing unit determining the respiratory cycle boundary of the target user within a preset time period based on the gas flow rate change data, determining the inhalation duration and exhalation duration based on the respiratory cycle boundary, and determining the respiratory ratio of the target user based on the inhalation duration and exhalation duration of the target user within the preset time period.

[0020] In one possible implementation of the second aspect, the computational processing unit determines the oxygen concentration of the target user's exhaled gas in the STPD state based on the target user's breathing ratio, the temperature of the cooled mixed gas, and the oxygen concentration. This includes: the computational processing unit determining the sum of the water vapor partial pressure of the mixed gas in the BTPS state and the water vapor partial pressure in the ATPD state, wherein the water vapor partial pressure in the BTPS state is a preset value, and the water vapor partial pressure in the ATPD state is determined based on the actual vapor pressure of the inhaled gas; the computational processing unit determines whether the sum is greater than the saturated vapor pressure of the mixed gas in the gas sampling pipeline, wherein the saturated vapor pressure of the mixed gas in the gas sampling pipeline... The vapor pressure is determined based on the temperature of the cooled mixed gas; when the sum is greater than the saturated vapor pressure of the mixed gas in the gas sampling pipeline, the calculation processing unit determines the oxygen concentration of the target user's exhaled gas in the STPD state according to the oxygen concentration in the mixed gas using a first formula; when the sum is less than or equal to the saturated vapor pressure of the mixed gas in the gas sampling pipeline, the calculation processing unit determines the oxygen concentration of the target user's exhaled gas in the STPD state according to the oxygen concentration in the mixed gas using a second formula; the formulas for determining the water vapor partial pressure P1 of the mixed gas in the BTPS state and the water vapor partial pressure P2 of the mixed gas in the ATPD state are as follows: ; ; The first formula is: ; The second formula is: ; Wherein, FeO2 is the oxygen concentration of the target user's exhaled gas under STPD conditions, and FO 2测 Ptube represents the oxygen concentration in the cooled mixed gas, Pwater represents the pressure inside the gas sampling pipe, and Pwater represents the pressure inside the gas sampling pipe. 饱和 Here, E is the saturated vapor pressure inside the gas sampling pipe, and F is the respiration ratio. i O2 is the oxygen concentration of the gas inhaled by the target user in the ATPD state, PB is the standard atmospheric pressure, and Pwater is the oxygen concentration of the gas inhaled by the target user in the ATPD state. ATPD Pwater is the partial pressure of water vapor in exhaled gas under the ATPD state. BTPS This is the partial pressure of water vapor in the inhaled gas under BTPS conditions.

[0021] Understandably, the beneficial effects that the second aspect of the method described above can achieve can be referenced from the beneficial effects of the first aspect and any of its possible design methods, and will not be repeated here. Attached Figure Description

[0022] Figure 1 A schematic diagram of the hardware structure of a human oxygen metabolism analyzer based on condensation combined with water vapor calculation compensation provided in an embodiment of the present invention; Figure 2 This is a schematic flowchart of a human oxygen metabolism analysis method based on condensation combined with water vapor calculation compensation, provided as an embodiment of the present invention. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be described below with reference to the accompanying drawings. In the description of the present invention, unless otherwise stated, " / " indicates that the objects before and after are in an "or" relationship. For example, A / B can represent A or B. The "or" in the present invention is merely a description of the relationship between the related objects, indicating that three relationships can exist. For example, A or B can represent: A alone, A and B simultaneously, and B alone. A and B can be singular or plural. Furthermore, in the description of the present invention, unless otherwise stated, "multiple" refers to two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items.

[0024] Furthermore, to facilitate a clear description of the technical solutions of the embodiments of the present invention, the terms "first" and "second" are used in the embodiments of the present invention to distinguish identical or similar items with essentially the same function and effect. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and that the terms "first" and "second" are not necessarily different.

[0025] In this embodiment of the invention, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" or "for example" in this embodiment of the invention should not be construed as superior or more advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner for ease of understanding.

[0026] In the fields of sports medicine, clinical rehabilitation, basic physiological research and precision health management, the accurate measurement of human oxygen metabolism parameters (such as VO2, VCO2 and RER) is the core basis for assessing human physiological state, disease recovery process and exercise effect, and the key equipment for measuring such parameters is human oxygen metabolism analyzer.

[0027] Oxygen metabolism analysis techniques in related fields are mostly based on the principle of successive respiration. They calculate metabolic parameters by collecting the mixture of inhaled and exhaled gases and analyzing changes in oxygen and carbon dioxide concentrations. However, water vapor inevitably carried in exhaled air significantly interferes with the measurement of gas partial pressures. The presence of water vapor alters the calculation benchmark for the effective oxygen partial pressure in the gas mixture. If the influence of water vapor cannot be accurately addressed, it will directly lead to deviations in the calculation of oxygen metabolism parameters, thereby affecting the reliability of clinical diagnosis, rehabilitation assessment, and research conclusions. Therefore, how to effectively eliminate the interference of water vapor on oxygen metabolism measurements and achieve accurate measurement of human oxygen metabolism parameters has become an urgent problem to be solved.

[0028] In view of this, embodiments of the present invention provide a human oxygen metabolism analyzer and method based on condensation combined with water vapor calculation compensation. The human oxygen metabolism analyzer includes: a gas sampling unit, a condensation unit, a parameter acquisition unit, a gas analysis unit, and a calculation processing unit. The condensation unit, the parameter acquisition unit, and the gas analysis unit are disposed in the gas sampling pipe of the gas sampling unit, and the parameter acquisition unit is disposed between the condensation unit and the gas analysis unit. The gas sampling unit is used to collect mixed gas from a target user during breathing in real time, the mixed gas including inhaled gas and exhaled gas. The condensation unit is used to physically cool the mixed gas to obtain a cooled mixed gas. The parameter acquisition unit is used to acquire the temperature of the cooled mixed gas. The gas analysis unit is used to detect the oxygen concentration in the cooled mixed gas. The calculation processing unit is used to determine the respiratory rate of the target user, and based on the respiratory rate of the target user, the temperature of the cooled mixed gas, and the oxygen concentration, to determine the oxygen concentration of the target user's exhaled gas in the STPD state. The respiratory rate is the ratio of the inhalation duration to the exhalation duration of the target user within a preset time period.

[0029] The human oxygen metabolism analyzer provided by this invention first physically cools the mixed gas through a condensation unit, which initially reduces the water vapor content by lowering the gas temperature, thus mitigating the direct interference of water vapor on subsequent detection. The parameter acquisition unit specifically acquires the temperature of the cooled gas, providing key basic data for subsequent water vapor compensation calculations. The calculation and processing unit, by introducing the respiratory ratio and multi-parameter collaborative calculation, can more comprehensively correct the influence of water vapor on oxygen concentration measurement, quickly and accurately determine the exhaled oxygen concentration under STPD conditions, and eliminate measurement errors caused by differences in environmental temperature and humidity and respiratory timing. Ultimately, it improves the accuracy of core oxygen metabolism parameters such as VO2 and VCO2, meeting the needs of sports medicine, clinical rehabilitation, and other scenarios for precise data.

[0030] The following description, in conjunction with the accompanying drawings, illustrates an embodiment of the present invention of a human oxygen metabolism analyzer based on condensation combined with water vapor calculation compensation.

[0031] Figure 1 This is a schematic diagram of the hardware structure of a human oxygen metabolism analyzer based on condensation combined with water vapor calculation compensation, provided by an embodiment of the present invention. The human oxygen metabolism analyzer 100 includes: a gas sampling unit 110, a condensation unit 120, a parameter acquisition unit 130, a gas analysis unit 140, and a calculation and processing unit 150. The condensation unit 120, the parameter acquisition unit 130, and the gas analysis unit 140 are disposed in the gas sampling pipe of the gas sampling unit 110, and the parameter acquisition unit 130 is disposed between the condensation unit 120 and the gas analysis unit 140. The gas sampling unit 110 is used to collect the mixed gas of the target user during breathing in real time, the mixed gas including inhaled gas and exhaled gas. The condensation unit 120 is used to physically cool the mixed gas to obtain a cooled mixed gas; the parameter acquisition unit 130 is used to acquire the temperature of the cooled mixed gas; the gas analysis unit 140 is used to detect the oxygen concentration in the cooled mixed gas; the calculation and processing unit 150 is used to determine the breathing ratio of the target user, and to determine the oxygen concentration of the target user's exhaled gas in STPD state based on the breathing ratio of the target user, the temperature of the cooled mixed gas, and the oxygen concentration, wherein the breathing ratio is the ratio of the inhalation duration to the exhalation duration of the target user within a preset time period.

[0032] In one example, the condensation unit 120 is integrated in the middle section of the gas sampling pipeline. It connects to the gas sampling unit upstream and the parameter acquisition unit downstream, employing a sleeve-type structure. The inner tube supplies the flow of the mixed gas, while the outer tube jacket carries the cooling medium. Combined with a cooling medium circulation module and a temperature monitoring submodule, the mixed gas is physically cooled by the heat absorption of the circulating medium. Simultaneously, the processing unit dynamically adjusts the circulation pump speed or activates the heating element to control the temperature based on the outlet temperature. The inner tube also features baffles to ensure uniform cooling, and the outer tube is wrapped with insulation cotton to reduce external thermal interference, ultimately resulting in a cooled mixed gas with a stable temperature.

[0033] In some embodiments, the parameter acquisition unit 130 includes a temperature sensor that communicates with the computing unit; the temperature sensor is disposed on the inner wall of the gas sampling pipe and is used to acquire the temperature of the cooled mixed gas.

[0034] As described above, the embodiments of the present invention, by arranging the temperature sensor in close contact with the inner wall of the pipe, can directly contact the cooled mixed gas, avoiding interference from the ambient temperature on the acquisition results and ensuring that the acquired gas temperature data truly reflects the state of the target gas. At the same time, the communication connection between the sensor and the computing unit enables real-time transmission of key parameters, avoiding calculation lag caused by data delays, and providing reliable data input for subsequent STPD oxygen concentration calculations, further reducing measurement errors caused by inaccurate parameters.

[0035] In one possible implementation, the gas sampling unit 110 is further configured to acquire gas flow rate change data of the gas sampling pipeline and to send the gas flow rate change data to the calculation and processing unit 150; the calculation and processing unit 150 is specifically configured to: determine the respiratory cycle boundary of the target user within a preset time period based on the gas flow rate change data, determine the inhalation duration and exhalation duration based on the respiratory cycle boundary, and determine the respiratory ratio of the target user based on the inhalation duration and exhalation duration of the target user within the preset time period.

[0036] Specifically, the calculation and processing unit 150 identifies the zero points in the flow data that transition from negative to positive and from positive to negative to define boundaries. For example, a negative flow indicates gas flowing out of the pipe, corresponding to exhalation, while a positive flow indicates gas flowing into the pipe, corresponding to the zero point of inhalation, which can be used as the boundary for the start of inhalation, i.e., the end of the previous expiratory cycle; conversely, a zero point where the flow rate transitions from positive to negative serves as the boundary for the start of exhalation, i.e., the end of the previous inhalation cycle. After determining the respiratory cycle boundaries, the calculation and processing unit calculates the duration of the inhalation phase and the duration of the exhalation phase within a preset time period. Finally, the ratio of the inhalation duration to the exhalation duration is determined as the respiratory ratio of the target user. This respiratory ratio is subsequently used for weighted calculation of water vapor partial pressure, providing a key parameter for the accurate derivation of exhaled gas oxygen concentration under STPD conditions.

[0037] As described above, this invention determines the respiratory cycle boundary based on the positive and negative switching of flow rate changes and peak nodes, accurately dividing the time range of inhalation and exhalation. The respiratory ratio is then calculated using the duration ratio. The entire process is based on objective physical signals, avoiding subjective judgment errors. An accurate respiratory ratio ensures that subsequent calculation and processing units fully consider the difference in gas mixing ratios between the inhalation and exhalation phases when correcting for water vapor effects, thereby improving the accuracy of exhaled oxygen concentration calculation under STPD conditions and laying the foundation for the precise derivation of oxygen metabolism parameters.

[0038] In some embodiments, the calculation processing unit 150 is specifically configured to: determine the sum of the partial pressure of water vapor in the mixed gas under BTPS and ATPD conditions, wherein the partial pressure of water vapor in the BTPS condition is a preset value, and the partial pressure of water vapor in the ATPD condition is determined based on the actual vapor pressure of the inhaled gas; determine whether the sum is greater than the saturated vapor pressure of the mixed gas in the gas sampling pipeline, wherein the saturated vapor pressure of the mixed gas in the gas sampling pipeline is determined based on the temperature of the cooled mixed gas; if the sum is greater than the saturated vapor pressure of the mixed gas in the gas sampling pipeline, determine the oxygen concentration of the target user's exhaled gas under STPD conditions according to the oxygen concentration in the mixed gas using a first formula; if the sum is less than or equal to the saturated vapor pressure of the mixed gas in the gas sampling pipeline, determine the oxygen concentration of the target user's exhaled gas under STPD conditions according to the oxygen concentration in the mixed gas using a second formula.

[0039] It should be understood that BTPS (Body Temperature, Pressure, Saturated) is a standard state defined for exhaled human gas. Specifically, it refers to a state where the gas is at or near the core body temperature (usually preset to 37°C, as human body temperature is relatively stable), the local atmospheric pressure, and water vapor is saturated (i.e., the water vapor content in the gas reaches its maximum value at the current temperature). ATPD (Ambient Temperature, Pressure, Dry) is a standard state defined for inhaled human gas. Specifically, it refers to a state where the gas is at the actual ambient temperature and local atmospheric pressure at the time of collection, and the water vapor content is extremely low (approximately dry).

[0040] It should be noted that the partial pressure of water vapor in the ATPD state is determined based on the actual vapor pressure of the inhaled gas. The embodiments of the present invention do not impose any particular restrictions on the specific method of obtaining the actual vapor pressure of the inhaled gas.

[0041] It should be noted that the preset values ​​are calculated based on the user's real-time body temperature.

[0042] Furthermore, the first formula is: ; The second formula is: ; Wherein, FeO2 is the oxygen concentration of the target user's exhaled gas under STPD conditions, and FO 2测Ptube represents the oxygen concentration in the cooled mixed gas, Pwater represents the pressure inside the gas sampling pipe, and Pwater represents the pressure inside the gas sampling pipe. 饱和 Here, E is the saturated vapor pressure inside the gas sampling pipe, and F is the respiration ratio. i O2 is the oxygen concentration of the gas inhaled by the target user in the ATPD state, PB is the standard atmospheric pressure, and Pwater is the oxygen concentration of the gas inhaled by the target user in the ATPD state. ATPD Pwater is the partial pressure of water vapor in exhaled gas under the ATPD state. BTPS This is the partial pressure of water vapor in the inhaled gas under BTPS conditions.

[0043] It should be noted that the formulas for determining the partial pressure of water vapor P1 of the mixed gas in the BTPS state and the partial pressure of water vapor P2 of the mixed gas in the ATPD state are as follows: ; .

[0044] In one example, when user A is breathing calmly, the gas sampling unit collects their mixed gas, and the condensation unit cools the gas to 25°C (the target cooling temperature). The parameter acquisition unit measures the cooled gas temperature as 25°C (corresponding to the saturated vapor pressure Pwater). 饱和 =3.17 kPa), the ATPD state water vapor partial pressure Pwater derived from the actual vapor pressure. ATPD =1.2kPa, the gas analysis unit detects the oxygen concentration FO after cooling. 2测 =16.8%; Simultaneously, the flow rate change data acquired by the sampling unit showed that the inspiratory duration was 1.8 seconds and the expiratory duration was 2.2 seconds within one respiratory cycle. The processing unit calculated the respiratory ratio E = 1.8 / 2.2 ≈ 0.82, and then calculated the BTPS weighted partial pressure P1 = 6.28 kPa / (0.82 + 1) ≈ 3.45 kPa (Pwater). BTPS (Preset to 6.28 kPa at 37℃), ATPD weighted partial pressure P2 = (0.82 × 1.2 kPa) / (0.82 + 1) ≈ 0.54 kPa, total partial pressure potential = 3.45 + 0.54 = 3.99 kPa > 3.17 kPa (oversaturation), substituting into the first formula, combined with standard atmospheric pressure PB = 101.325 kPa, tubing pressure P_tube ≈ 101.325 kPa, and inhaled oxygen concentration FiO2 = 20.9%, the final calculated oxygen concentration of exhaled gas for user A in STPD state is FeO2 ≈ 15.9%.

[0045] In another example, when user B is exercising lightly, the condensing unit cools the gas mixture to 25°C, and the parameter acquisition unit measures the temperature after cooling to 25°C (Pwater). 饱和 =3.17kPa), P water ATPD =1.5kPa, gas analysis unit detects FO2 测=15.6%; the flow data shows that the inspiratory duration is 1.5 seconds and the expiratory duration is 1.8 seconds in one respiratory cycle. The calculation unit gives the respiratory ratio E=1.5 / 1.8≈0.83, and calculates P1=6.28kPa / (0.83+1)≈3.43kPa, P2=(0.83×1.5kPa) / (0.83+1)≈0.68kPa. The total partial pressure potential =3.43+0.68=4.11kPa>3.17kPa (supersaturation). Substituting into the first formula, combined with PB=101.325kPa, P tube≈101.325kPa, FiO2=20.9%, the final calculated oxygen concentration of user B's exhaled gas in STPD state is FeO2≈14.8%.

[0046] To facilitate understanding of this solution, the following example illustrates the human oxygen metabolism analyzer provided by this invention. To achieve the above objectives, this invention employs the following technical solution: The human oxygen metabolism analyzer includes a gas sampling unit, a condensation unit, a parameter acquisition unit, a gas analysis unit, and a calculation and processing unit. The gas sampling unit is used to collect the mixed gas inhaled and exhaled by the user in real time; the condensation unit is located in the gas sampling path and is used to cool the sampled gas to room temperature, thereby condensing and releasing water vapor exceeding the saturated vapor pressure in the mixed gas; the parameter acquisition unit is used to measure the temperature of the gas in the pipeline after cooling; the gas analysis unit is used to measure the oxygen concentration and carbon dioxide concentration in the gas sample; the calculation and processing unit is used to correct the partial pressure of water vapor in the mixed gas based on the gas temperature, breathing ratio, the mixing ratio of ambient air and exhaled gas, and the room temperature saturated vapor pressure, thereby accurately calculating the oxygen partial pressure and metabolic parameters under STPD conditions.

[0047] Furthermore, the specific workflow of the computing processing unit is as follows: The calculation and processing unit determines whether the sum of P1 + P2 is greater than P_water. 饱和 ; The sum is greater than P_water 饱和 In the case of [the specific situation], the first formula mentioned above shall be used for calculation; When the sum is less than P water 饱和 If they are equal, the second formula mentioned above shall be used for calculation.

[0048] In this way, the present invention can accurately compensate for the influence of water vapor on gas measurement without relying on expensive exchange tubes, thereby improving the accuracy of oxygen metabolism measurement.

[0049] As described above, the human oxygen metabolism analyzer provided by this invention first physically cools the mixed gas through a condensation unit, which can initially reduce the water vapor content by lowering the gas temperature, thus mitigating the direct interference of water vapor on subsequent detection. The parameter acquisition unit specifically acquires the temperature of the cooled gas, providing key basic data for subsequent water vapor compensation calculations. The calculation and processing unit, by introducing the respiratory ratio and multi-parameter collaborative calculation, can more comprehensively correct the influence of water vapor on oxygen concentration measurement, quickly and accurately determine the exhaled oxygen concentration under STPD conditions, eliminate measurement errors caused by differences in environmental temperature and humidity and respiratory timing, and ultimately improve the accuracy of core oxygen metabolism parameters such as VO2 and VCO2, meeting the needs of sports medicine, clinical rehabilitation, and other scenarios for precise data.

[0050] It should be understood that this invention proposes a human oxygen metabolism analyzer and method based on condensation combined with water vapor calculation compensation, which differs from existing mainstream technologies that use exchange tubes or sensors for compensation. Its novelty lies mainly in the following aspects: First, a new mechanism for condensation combined with water vapor calculation compensation: This invention, for the first time, combines the principle of gas condensation with a mathematical compensation model based on saturated vapor pressure, accurately estimating the partial pressure of water vapor in respirable gases, thereby improving the accuracy of oxygen partial pressure calculation. Second, a consumable-free, passive condensation structure: Unlike existing solutions that rely on "exchange tubes," "membrane systems," or "dehumidification modules," this invention completes dehumidification through a simple physical cooling device, achieving not only functional substitution but also a different structural path, representing a completely new technical solution. Furthermore, a partial pressure judgment logic based on thermodynamic limits: By setting judgment rules after condensation (i.e., comparing water vapor partial pressure with saturated vapor pressure) to control the correction value, it does not rely on real-time humidity sensors or empirical formulas for estimation, exhibiting significant differences in technical principles and algorithm structure.

[0051] On the other hand, based on an in-depth analysis of the water vapor interference problem in existing respiratory metabolism measurement systems, this invention proposes a unique, low-cost, and high-precision compensation mechanism, specifically manifested as follows: Shifting from high-cost dehumidification to low-cost condensation modeling: Currently, high-cost exchange tubes or electronic dehumidification modules are commonly used to reduce water vapor interference. This invention creatively adopts a condensation method combined with a thermodynamic model for water vapor partial pressure compensation, achieving the same or higher accuracy while being simpler in structure and lower in cost. Innovative design of a two-level logic judgment mechanism: By setting two judgment conditions (i.e., the relationship between mixed water vapor partial pressure and room temperature saturated vapor pressure), a more reliable correction value is automatically selected, improving the system's adaptability to environmental fluctuations and demonstrating innovation in measurement logic. A simplified path replacing complex humidity measurement systems: In traditional methods, humidity must be measured in real time and participate in metabolic parameter reduction. This invention, however, directly provides a water vapor partial pressure correction path by designing a physical condensation interface and thermodynamic formulas, skipping complex humidity detection and signal processing steps, demonstrating high practicality and engineering creativity.

[0052] Finally, with the development of sports medicine, clinical rehabilitation, basic physiological research, and precision health management, higher demands are being placed on the accuracy and accessibility of measuring human oxygen metabolism parameters (such as VO2, VCO2, and RER). Most existing mainstream human oxygen metabolism analyzers employ "breath-by-breath" technology and use expensive exchange tubes to treat water vapor in the gas mixture to reduce its interference with the gas partial pressure reduction process. However, these devices generally suffer from high prices, large size, and frequent consumable replacements, limiting their widespread application in primary healthcare institutions, community health centers, research and teaching institutions, and home health monitoring. This invention proposes a novel, low-cost alternative that uses the condensation principle combined with a thermodynamic model to accurately reduce water vapor partial pressure, significantly reducing system complexity and manufacturing costs while ensuring the accuracy of oxygen partial pressure measurement. This solution has the following application prospects and advantages: Strong scalability: Eliminating the need for expensive exchange tube components significantly reduces the overall cost, making it possible for oxygen metabolism detection equipment to move from high-end research to mass application, especially suitable for large-scale deployment in resource-limited areas or promotional projects. Wide Applicability: It can be widely used in various scenarios such as athlete training monitoring, lung function screening for the elderly, rehabilitation tracking of COPD and cardiopulmonary diseases, metabolic status assessment of ICU patients, and respiratory assessment of children during their developmental period. Portability and Intelligent Integration: The condensation device has a simple principle and is easy to miniaturize, providing a technical path for future integration with portable wearable devices and mobile terminals, facilitating remote monitoring and connection with smart medical systems. Enhanced Data Reliability: By compensating for the influence of water vapor through objective derivation based on physical state changes (condensation), it avoids the error accumulation caused by excessive dependence on the respiratory ratio, improving the repeatability and reliability of measurement results in research and clinical environments. Significant Market Substitution Potential: Currently, high-end oxygen metabolism instruments on the market (such as Cortex and Cosmed) are expensive and complex to maintain. The low-cost, high-precision solution of this invention has strong market substitution and innovation upgrade potential, especially suitable for domestic substitution and international export.

[0053] In some embodiments, see Figure 2 The present invention also provides a method for analyzing human oxygen metabolism based on condensation and water vapor calculation compensation, comprising the following steps: S1. The gas sampling unit collects the mixed gas of the target user during breathing in real time, the mixed gas including inhaled gas and exhaled gas; In one possible implementation, the method further includes: the gas sampling unit acquiring gas flow rate change data of the gas sampling pipeline and sending the gas flow rate change data to the calculation and processing unit; so that the calculation and processing unit determines the respiratory cycle boundary of the target user within a preset time period based on the gas flow rate change data, determines the inhalation duration and exhalation duration based on the respiratory cycle boundary, and determines the respiratory ratio of the target user based on the inhalation duration and exhalation duration of the target user within the preset time period.

[0054] S2. The condensation unit performs physical cooling on the mixed gas to obtain a cooled mixed gas. S3. The parameter acquisition unit acquires the temperature of the cooled mixed gas; In one possible implementation, the parameter acquisition unit includes a temperature sensor disposed on the inner wall of the gas sampling pipe, and the method further includes: the temperature sensor acquiring the temperature of the cooled mixed gas.

[0055] S4. The gas analysis unit detects the oxygen concentration in the cooled mixed gas; S5. The calculation and processing unit determines the breathing ratio of the target user, and determines the oxygen concentration of the target user's exhaled gas in STPD state based on the breathing ratio of the target user, the temperature of the cooled mixed gas, and the oxygen concentration.

[0056] The breathing ratio is the ratio of the inhalation duration to the exhalation duration of the target user within a preset time period.

[0057] In one possible implementation, the calculation processing unit determines the oxygen concentration of the target user's exhaled gas in STPD state based on the target user's breathing ratio, the temperature of the cooled mixed gas, and the oxygen concentration. This includes: the calculation processing unit determining the sum of the water vapor partial pressure of the mixed gas in BTPS state and in ATPD state, wherein the water vapor partial pressure in BTPS state is a preset value, and the water vapor partial pressure in ATPD state is determined based on the actual vapor pressure of the inhaled gas; the calculation processing unit determining whether the sum is greater than the saturated vapor pressure of the mixed gas in the gas sampling pipeline, the saturated vapor pressure of the mixed gas in the gas sampling pipeline being determined based on the temperature of the cooled mixed gas; if the sum is greater than the saturated vapor pressure of the mixed gas in the gas sampling pipeline, the calculation processing unit determines the oxygen concentration of the target user's exhaled gas in STPD state based on the oxygen concentration in the mixed gas using a first formula; if the sum is less than or equal to the saturated vapor pressure of the mixed gas in the gas sampling pipeline, the calculation processing unit determines the oxygen concentration of the target user's exhaled gas in STPD state based on the oxygen concentration in the mixed gas using a second formula. The formulas for determining the partial pressure of water vapor P1 of the mixed gas in the BTPS state and the partial pressure of water vapor P2 of the mixed gas in the ATPD state are as follows: ; ; The first formula is: ; The second formula is: ; Wherein, FeO2 is the oxygen concentration of the target user's exhaled gas under STPD conditions, and FO 2测 Ptube represents the oxygen concentration in the cooled mixed gas, Pwater represents the pressure inside the gas sampling pipe, and Pwater represents the pressure inside the gas sampling pipe. 饱和 Here, E is the saturated vapor pressure inside the gas sampling pipe, and F is the respiration ratio. i O2 is the oxygen concentration of the gas inhaled by the target user in the ATPD state, PB is the standard atmospheric pressure, and Pwater is the oxygen concentration of the gas inhaled by the target user in the ATPD state. ATPD Pwater is the partial pressure of water vapor in exhaled gas under the ATPD state. BTPS This is the partial pressure of water vapor in the inhaled gas under BTPS conditions.

[0058] In one possible implementation, the gas analysis unit detects the carbon dioxide concentration in the cooled mixed gas, and the calculation processing unit determines the carbon dioxide concentration of the target user's exhaled gas in the STPD state based on the carbon dioxide concentration. The specific calculation method is the same as the oxygen concentration calculation method described above, except that the contents of the first and second formulas are replaced with carbon dioxide-related parameters, which will not be elaborated here.

[0059] Compared with existing technologies, this invention has the following advantages: Reduced manufacturing and maintenance costs: This invention eliminates the need for traditional high-cost exchange tubes, enabling low-cost manufacturing and long-term consumable-free operation, demonstrating excellent economic applicability. Simple system structure and easy miniaturization: The condensation component has a compact structure and low energy consumption, adaptable to a wider range of testing scenarios. Wide applicability: Applicable to multiple application areas such as exercise physiological assessment, chronic disease rehabilitation monitoring, metabolic management of critically ill patients, and scientific research data collection, possessing good prospects for promotion and market substitution value. High data reliability: Through physical condensation and temperature control mechanisms, the reliance on empirical formulas or subjective parameter estimations is reduced, resulting in more stable and repeatable measurement results, meeting both scientific research and clinical needs.

[0060] It should be understood that specific descriptions of the above-mentioned optional methods can be found in the aforementioned embodiments of the human oxygen metabolism analyzer, and will not be repeated here. Furthermore, explanations and descriptions of the beneficial effects of any of the above-mentioned human oxygen metabolism analysis methods based on condensation combined with water vapor calculation compensation can be found in the corresponding embodiments of the aforementioned human oxygen metabolism analyzer, and will not be repeated here.

[0061] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A condensation-based combined water vapor calculation compensation-based human oxygen metabolism analyzer, characterized in that, The device comprises a gas sampling unit, a condensing unit, a parameter acquisition unit, a gas analysis unit and a calculation processing unit, wherein the condensing unit, the parameter acquisition unit and the gas analysis unit are arranged in a gas sampling pipeline of the gas sampling unit, and the parameter acquisition unit is arranged between the condensing unit and the gas analysis unit. The gas sampling unit is configured to collect mixed gas of a target user in a breathing process in real time, wherein the mixed gas comprises inhaled gas and exhaled gas. The condensing unit is configured to perform physical cooling processing on the mixed gas to obtain cooled mixed gas. The parameter acquisition unit is configured to acquire the temperature of the cooled mixed gas. The gas analysis unit is configured to detect the oxygen concentration in the cooled mixed gas. The calculation processing unit is configured to determine the breathing ratio of the target user, and determine the oxygen concentration of the exhaled gas of the target user in the STPD state according to the breathing ratio of the target user, the temperature and the oxygen concentration of the cooled mixed gas, wherein the breathing ratio is the ratio of the inhalation time to the exhalation time of the target user within a preset time period. The parameter acquisition unit comprises a temperature sensor in communication with the calculation processing unit, wherein the temperature sensor is arranged on the inner wall of the gas sampling pipeline and configured to acquire the temperature of the cooled mixed gas.

2. The condensation-bound water vapor-based compensation human oxygen metabolism analyzer according to claim 1, characterized by, The gas sampling unit is further configured to acquire gas flow change data of the gas sampling pipeline, and send the gas flow change data to the calculation processing unit.

3. The condensation-bound water vapor-based compensation human oxygen metabolism analyzer according to claim 2, characterized by, The calculation processing unit is specifically configured to determine the breathing cycle boundary of the target user within a preset time period according to the gas flow change data, determine the inhalation time and the exhalation time according to the breathing cycle boundary, and determine the breathing ratio of the target user according to the inhalation time and the exhalation time of the target user within a preset time period. The calculation processing unit is specifically configured to:

4. The condensation-bound water vapor-based compensation human oxygen metabolism analyzer according to claim 3, characterized by, determine the sum of the water vapor partial pressure of the mixed gas in the BTPS state and the water vapor partial pressure of the mixed gas in the ATPD state, wherein the water vapor partial pressure in the BTPS state is a preset value, and the water vapor partial pressure in the ATPD state is determined based on the actual vapor pressure of the inhaled gas; determine whether the sum is greater than the saturated vapor pressure of the mixed gas in the gas sampling pipeline, wherein the saturated vapor pressure of the mixed gas in the gas sampling pipeline is determined based on the temperature of the cooled mixed gas; in the case that the sum is greater than the saturated vapor pressure of the mixed gas in the gas sampling pipeline, determine the oxygen concentration of the exhaled gas of the target user in the STPD state according to the oxygen concentration in the mixed gas through a first formula; in the case that the sum is less than or equal to the saturated vapor pressure of the mixed gas in the gas sampling pipeline, determine the oxygen concentration of the exhaled gas of the target user in the STPD state according to the oxygen concentration in the mixed gas through a second formula. The first formula is:

5. The condensation-bound water vapor-based compensation human oxygen metabolism analyzer according to claim 4, characterized by, The second formula is: ； ​ ； Wherein, FeO2 is the oxygen concentration of the target user's exhaled gas under STPD conditions, and FO 2测 Ptube represents the oxygen concentration in the cooled mixed gas, Pwater represents the pressure inside the gas sampling pipe, and Pwater represents the pressure inside the gas sampling pipe. 饱和 Here, E is the saturated vapor pressure inside the gas sampling pipe, and F is the respiration ratio. i O2 is the oxygen concentration of the gas inhaled by the target user in the ATPD state, PB is the standard atmospheric pressure, and Pwater is the oxygen concentration of the gas inhaled by the target user in the ATPD state. ATPD Pwater is the partial pressure of water vapor in exhaled gas under the ATPD state. BTPS This is the partial pressure of water vapor in the inhaled gas under BTPS conditions.

6. The condensation-bound water vapor-based compensation human oxygen metabolism analyzer according to claim 5, characterized by, A determination formula of a water vapor partial pressure P1 of the mixed gas in a BTPS state and a water vapor partial pressure P2 of the mixed gas in an ATPD state is: ； 。 7. A method for calculating compensation of human oxygen metabolism based on condensation combined with water vapor, applied to the human oxygen metabolism analyzer for calculating compensation based on condensation combined with water vapor according to any one of claims 1-6, characterized in that, Comprising: The gas sampling unit collects the mixed gas of the target user in real time during the breathing process, and the mixed gas includes inhaled gas and exhaled gas; The condensing unit performs physical cooling processing on the mixed gas to obtain cooled mixed gas; The parameter acquisition unit acquires the temperature of the cooled mixed gas; The gas analysis unit detects the oxygen concentration in the cooled mixed gas; The calculation processing unit determines the breathing ratio of the target user, and determines the oxygen concentration of the exhaled gas of the target user in the STPD state according to the breathing ratio of the target user, the temperature and the oxygen concentration of the cooled mixed gas, wherein the breathing ratio is a ratio of the inhalation time to the exhalation time of the target user within a preset time period.

8. The method for analyzing human oxygen metabolism calculated compensation based on condensed combined water vapor according to claim 7, characterized in that, The parameter acquisition unit includes a temperature sensor arranged on the inner wall of the gas sampling pipeline, and the method further comprises: The temperature sensor acquires the temperature of the cooled mixed gas.

9. The method for analyzing human oxygen metabolism calculated compensation based on condensed combined water vapor according to claim 8, characterized in that, The method further comprises: The gas sampling unit acquires the gas flow change data of the gas sampling pipeline and sends the gas flow change data to the calculation processing unit; The calculation processing unit determines the breathing cycle boundary of the target user within a preset time period according to the gas flow change data, determines the inhalation time and the exhalation time according to the breathing cycle boundary, and determines the breathing ratio of the target user according to the inhalation time and the exhalation time of the target user within a preset time period.

10. The method for analyzing human oxygen metabolism calculated compensation based on condensed combined water vapor according to claim 9, characterized in that, The calculation processing unit determines the oxygen concentration of the exhaled gas of the target user in the STPD state according to the breathing ratio of the target user, the temperature and the oxygen concentration of the cooled mixed gas, comprising: The calculation processing unit determines the sum of the water vapor partial pressure of the mixed gas in the BTPS state and the water vapor partial pressure of the mixed gas in the ATPD state, wherein the water vapor partial pressure in the BTPS state is a preset value, and the water vapor partial pressure in the ATPD state is determined based on the actual vapor pressure of the inhaled gas; The calculation processing unit determines whether the sum is greater than the saturated vapor pressure of the mixed gas in the gas sampling pipeline, and the saturated vapor pressure of the mixed gas in the gas sampling pipeline is determined based on the temperature of the cooled mixed gas; The calculation processing unit determines the oxygen concentration of the exhaled gas of the target user in the STPD state according to the oxygen concentration in the mixed gas through a first formula when the sum is greater than the saturated vapor pressure of the mixed gas in the gas sampling pipeline; The calculation processing unit determines the oxygen concentration of the exhaled gas of the target user in the STPD state according to the oxygen concentration in the mixed gas through a second formula when the sum is less than or equal to the saturated vapor pressure of the mixed gas in the gas sampling pipeline; A determination formula of a water vapor partial pressure P1 of the mixed gas in a BTPS state and a water vapor partial pressure P2 of the mixed gas in an ATPD state is: ； ； The first formula is: ； The second formula is: ； Wherein, FeO2 is the oxygen concentration of the target user's exhaled gas under STPD conditions, and FO 2测 Ptube represents the oxygen concentration in the cooled mixed gas, Pwater represents the pressure inside the gas sampling pipe, and Pwater represents the pressure inside the gas sampling pipe. 饱和 Here, E is the saturated vapor pressure inside the gas sampling pipe, and F is the respiration ratio. i O2 is the oxygen concentration of the gas inhaled by the target user in the ATPD state, PB is the standard atmospheric pressure, and Pwater is the oxygen concentration of the gas inhaled by the target user in the ATPD state. ATPD Pwater is the partial pressure of water vapor in exhaled gas under the ATPD state. BTPS This is the partial pressure of water vapor in the inhaled gas under BTPS conditions.

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