WO2025002553A1

WO2025002553A1 - Device for analysis of a gas medium

Info

Publication number: WO2025002553A1
Application number: PCT/EP2023/067685
Authority: WO
Inventors: Sergei DAVYDOV
Original assignee: Halitus Gmbh
Priority date: 2023-06-28
Filing date: 2023-06-28
Publication date: 2025-01-02

Abstract

Provided is a device for the analysis of a gas medium, comprising: an optical cell with a light-reflective innersurface, an IR emitter and an IR sensor mounted in the optical cell, the optical cell having an optical path length from the IR emitter to the IR sensor to determine a concentration of at least one chemical compound or chemical substance of the gas medium, the optical cell being configured to have an airflow of the gas medium to pass through the optical cell; and a set of airflow pressure sensors for an evaluation of a flow characteristics of the passing airflow.

Description

DEVICE FOR ANALYSIS OF A GAS MEDIUM

Technical Field

The present disclosure relates to a device for the analysis of a gas medium and a method for analyzing a gas medium. In particular, the present disclosure relates to a device for the analysis of an exhaled gas medium and a method for analyzing an exhaled gas medium.

Background

RU 2625258 C2 "Method and device for dynamic gas analysis integrated into a breath mask exhalation line" and RU 2773603 Cl "Method of deturbulation and subsequent analysis of dynamic gas mediums and device for its implementation integrated into a breath mask" describe dynamic gas medium analysis methods. Such methods allow getting continuous data directly from exhaled air without air sampling and sidestream cuvettes with a low detection limit.

GB 2576137 A "Multi-test respiratory diagnostic device" describes a respiratory testing device performing multiple diagnostic tests comprising a housing and a plurality of sensors. The device has at least two configurations: in the first configuration a first respiratory test is performed using a first set of sensors, and in the second configuration a second respiratory test is performed using a second set of sensors. The device may be modular having a primary component and secondary components to create different configurations. The secondary components may adapt the device to make it suitable for the primary component to perform different tests. For example, spirometry may be performed when a spirometry module is attached to optimize airflow, biomarkers may be measured with a nitric oxide sensor module attached, impulse oscillometry testing may occur when an oscillometry module with an occluder is attached, and capnography may be performed when a carbon dioxide sensing component is attached. Different mouthpieces may also be used in different arrangements. RU 192522 U1 "Device for measuring the chlorine content in a gas mixture" uses an infrared (IR) optical analysis of the air mixture. The device is designed to measure the concentration of chlorine vapor.

A wide range of medical devices such as stand-alone compact portable spirometers are known (e.g. US 11166634 B2 "System for monitoring patients suffering from respiratory disease comprising a portable medical device and method based on the use of such system"). Their diagnostic application is functional lung tests which can be done through the measurement of a flowrate or a pressure of exhaled air (e.g., TV, FEV1, FEV).

Summary

Technical Problem

The teachings of RU 2625258 C2 and RU 2773603 Cl result, however, in high cost of producing precision segmented elements due to the high expenses of reflective coatings and microelectronic components, in particular diode lasers operating in the near- and mid-infrared range (IR). In addition, condensation of exhaled gas or air on the internal surfaces of a gas analysis device may reduce detection accuracy.

GB 2576137 A implements a method of absorption spectroscopy. However, the main measurements may not be performed continuously, the number of simultaneous parameter measurements is limited, and a patient's exhaled airflow is only insufficiently measured.

RU 192522 U1 does not analyze the chemical composition of dynamically exhaled air and also does not assess the lungs' functional state.

Spirometers do not have the capability of obtaining continuous data on the qualitative and quantitative content of biomarkers (e.g., CO, CO2, Acetone) in exhaled air.

Solution

The subject-matter of the independent claim solves the above-identified technical problems. The dependent claims describe further preferred embodiments. In particular, a device for the analysis of a gas medium, in particular a dynamic gas medium comprises: an optical cell with a light-reflective inner surface, an IR emitter and an IR sensor mounted in the optical cell, the optical cell having an optical path length from the IR emitter to the IR sensor to determine a concentration of at least one chemical compound or chemical substance of the gas medium, and the optical cell being configured to have an airflow of the gas medium to pass through the optical cell. The airflow of the gas medium preferably passes through the optical cell directly, i.e. preferably without side-stream cuvettes; and a set of airflow pressure sensors for an evaluation of a flow characteristics of the passing airflow.

Brief of the

Embodiments of the disclosure will now be explained in detail, by way of non-limiting examples only, with reference to the accompanying figures, described below. Like reference numerals appearing in different ones of the figures can denote identical or functionally similar elements unless indicated otherwise.

Figure 1 illustrates an optical unit of a device according to an embodiment.

Figure 2 illustrates an optical unit of a device according to an embodiment with a composite flange.

Figure 3 illustrates a device according to an em bodiment.

Figures 4A, 4B, and 4C show additional configuration embodiments for placing IR emitter 2 and I R sensor 3.

Figure 5 illustrates an exterior configuration of the device in Fig. 3.

Figure 6 illustrates an example of collected and processed device data.

Detailed description of Embodiments Where technical features in the drawings, detailed description, or any claim are followed by reference signs, the reference signs have been included for the sole purpose of increasing the intelligibility of the drawings, detailed description, and claims. Accordingly, neither the reference signs nor their absence has any limiting effect on the scope of any claim elements.

It is further noted that dimensions and layout of respective elements of the device (e.g. regarding the optical unit, pressure sensors, dimensions of IR emitter and IR sensor, shape and size of holes in flanges) are given as an example and may vary depending on the technical task.

The present disclosure relates to dynamic gas environment monitoring systems and devices (gas analyzer device, gas analyzer sensor) suitable for:

(i) a non-invasive monitoring of a living organism (e.g. patient) with and without the use of various breathing mixtures under physical, physiological, psychological, and stress loads, as well as multiple types of painful conditions, environmental exposure, and nutritional, microbiological and general metabolic states based on the dynamics and composition of exhaled air;

(ii) an assessment of a biological system's functional state, including long-term, under the influence of multidirectional overloads;

(iii) expressing and screening diagnostics of various diseases and pathologies (bacterial or viral respiratory tract infections, asthma, lung cancer, COPD, and others);

(iv) a primary diagnosis in determining the severity of the condition to triage victims of emergencies;

(v) a determination of a body's health or metabolic state during and after a workout and physical activity or under the external effects of different nature (including psychological)

(vi) a monitoring of the mental or health state of crew members of autonomous, isolated systems and human-crewed vehicles. The purpose of the proposed embodiments is to determine and interpret changes in the composition of the respiratory mixture during exhalation and/or during the respiratory cycle in real time, i.e. implementation of the principle of dynamic gas medium analysis in determining the quantitative and qualitative composition of exhaled airflow by a continuous analysis of a gases absorption spectrum being determined using an optical unit based on an optical cell - for example, an optical spectrum emitter and an IR sensor, including constant and continuous monitoring of the subject (e.g., a patient). The optical spectrum emitter is preferably a broad optical spectrum emitter, for example in a broad IR range between 2 and 12 microns.

The described technical result can be achieved by the fact that the proposed method and device for analysis of a dynamic (e.g. during exhalation by a patient) gas medium may perform continuous analysis of exhaled airflow or breathing mixture directly in a main airway or air path throughout an illuminated (e.g. by an IR emitter) volume of the optical unit without sampling and side-stream cuvettes, which allows (by using the advantages of absorption spectroscopy, a set of gas-dynamic sensors and spirometer) to work with gas mixtures of any humidity, temperature, and flow pattern.

The method of dynamic gas mediums analysis may be based on absorption spectroscopy and continuous airflow monitoring directly in the air pathway by using an optical unit and a set of pressure sensors.

The optical unit may be an air line and may consist of an optical cell (e.g. a cylindrical optical cell, a spherical optical cell, or the like) with a reflective surface, a wide or broadband optical spectrum IR emitter, and an IR sensor. Within the optical cell, a gas (e.g. exhaled airorothergas mixture) flows and/or is guided through the optical cell in such a way that the emitted light interacts with the gas. The IR sensor may have two or more channels provided with respectively preset optical filters for spectral line extraction. At least one channel of the IR sensor may be tuned to the spectral absorption line of the exhaled sample. One of the channels may be a reference channel whose spectral line does not overlap with the absorption spectral lines of the exhaled test substances.

The optical unit may be equipped with a set of pressure, humidity, and/or temperature sensors to analyze a dynamic gas medium. In addition to pressure sensors, a spirometer or flow meter can be used to measure parameters of a person's lung function, for example, an exhalation rate, the volume of the passing gas mixture, and other functional indicators of the human respiratory system (such as FEV1, Vital Capacity, Tidal Volume, etc.).

To prevent water vapour condensation due to temperature differences between the exhaled air (for example, 32-33 degrees Celsius on average) and the optical unit (on the order of ambient environmental temperature), the device may further have a thermoregulation system to maintain the set temperature of the optical cell. Accordingly, the optical unit may be heated by the thermoregulation system when airflow passes through the optical cell. This can suppress a condensation on the inner surface of the optical cell which otherwise would significantly distort optical measurement results due to emission scattering and its partial absorption.

The thermoregulation system may include one or more heating elements or wires (e.g. based on resistive Joule heating, a thermoelectric element) at the optical unit (e.g. along or around the optical cell, adjacent to the IR emitter and/or I R sensor or the like). A temperature sensor may detect the tem perature of the exhaled air of the patient and the thermoregulation system of the device may thus use a setting for the heating elements to bring the inside of the optical unit (in particular, the internal reflection surface of the optical unit) to a temperature that matches the detected temperature of the exhaled air. The skilled person understands that this temperature balancing can suppress condensation on the inner surface of the optical cell.

Moreover, as the temperature of the exhaled air is user-specific and may be significantly higher for a patient with a fever, using this thermoregulation system allows to bring the inside of the optical unit to a temperature that matches the detected temperature for the specific user. In other words, if a first temperature of 32°C of the exhaled air is detected for a first user, the thermoregulation system uses a setting to bring the inside of the optical unit (in particular the internal reflection surface of the optical unit) to a temperature that matches this first temperature. On the other hand, if a second temperature of 36°C of the exhaled air is detected for a second user, the thermoregulation system uses a setting to bring the inside of the optical unit (in particular, the internal reflection surface of the optical unit) to a temperature that matches this second temperature.

The device may have optical/acoustic/haptic feedback to indicate to the user that the thermoregulation system has sufficiently heated the optical cell. For example, a patient may initially exhale into the device (e.g. into a mouthpiece of the device) and the temperature sensor may detect a temperature of the exhaled air of the patient. As soon as the thermoregulation system has sufficiently heated the optical cell to match this detected temperature, the feedback to the user may indicate that the device is ready to accurately perform an analysis of the exhaled gas medium.

The optical cell may have one or more temperature sensors to detect a temperature of the optical cell (e.g. a temperature related to the inner surface of the optical cell, a temperature related to the IR emitter, and/or IR sensor). Using more than one temperature sensor for the optical cell allows to determine whether the heating of the optical cell has achieved a thermal equilibrium, for example, when the detected temperatures of two temperature sensors indicate a substantially same temperature. In contrast, if the detected temperatures of two temperature sensors indicate different temperatures, implying that there is not a thermal equilibrium inside the optical cell, then the optical/acoustic/haptic feedback to the user may indicate that the device is not yet ready to perform an analysis of the exhaled gas medium accurately.

Further, the optical cell or the device itself may further have an additional insulating cover to stabilize the temperature regime. If the device operates in an environment with electromagnetic interference, it can be fitted with a unique casing with shielding protection.

Further, the inner surface of the optical cell preferably has reflective properties to reflect the IR light from the emitter towards the sensor. That is, IR light incidence on the inner surface of the optical cell, directly from the emitter and/or scattered due to interaction with the gas medium, is reflected at the inner surface toward the sensor. In addition, the inner surface of the optical cell may have a hydrophobic and/or oleophobic coating. This enables the removal of condensate (e.g. any residual condensate after the initial usage of the device before heating) and/or orga nic contamination, which can lead to a significant error in measuring the concentration of the biomarkers (chemical components in the gas medium) being detected. For example, when liquid microdroplets hit the light-reflective surface, the scattering and absorption coefficients increase, and the measurement accuracy decreases due to distortions in the signal. The hydrophobic and/or oleophobic coating can avoid such problems.

A forced air intake (e.g. suction based) system may be installed in the air line to regulate the airflow speed in the optical unit. Such a suction system may be located after the optical unit on the side opposite of the object (e.g., patient). Such a solution may allow an operator to refresh the gas mixture in the optical unit without additional manipulation or to distribute the passing airflow evenly, if necessary.

The airflow can thus be either inhaled or exhaled airflows of different origins and compositions. Such airflows may include the breathing mixture delivered to or exhaled by a biological object (e.g., patient).

To assess the condition of a biological object (e.g., patient) more accurately, an additional set of physical condition sensors may be used, which can be placed on or around the optical unit. These sensors may include one or more of: a single and/or multi-point ECG system, a pulse oximeter, a body temperature meter, and other sensors.

More than one IR sensor and IR emitter in one optical unit or several paired (in series or parallel) optical units (each itself including one or more than one IR sensor and IR emitter) may be used to improve the accuracy of qualitative analysis of the airflow and expand the list of detectable chemical compounds, including volatile organic compounds (VOCs), biomarkers, chemical substances or ingredients and the like in the gas medium.

Due to the handling of biological objects, it may often be necessary to provide disinfection of the outgoing air stream. One or more ultraviolet (UV) light sources may be used for this purpose. The location of the UV radiation sources in relation to the optical unit can vary, i.e. the location of the UV radiation sources can be located in front of the optical unit, directly in the optical unit, and/or after the optical unit. The direction of the radiation (from the UV radiation source) should be designed so as not to harm the object (patient) and/or the operator (medical personnel).

The (dynamic, i.e. based on exhaled, inhaled, or forced air intake) gas analyzer device or gas analyzer sensor may be based on an air line in the form of an optical unit. The optical unit may have a cylindrical or otherwise shaped optical cell with a reflective inner surface and optical elements (for example, an IR emitter and IR sensor). I n addition, flanges with through-holes to allow an airflow (exhaled, inhaled, or forcedin gas) through the optical cell may be connected to the respective ends of the optical cell. For example, the I R emitter and I R sensor may be located on opposite sides of the optical cell to ensure minimum aerodynamic resistance to the airflow and a sufficient optical path length from the IR emitter of the wide optical spectrum to the IR sensor through the gas mixture under study for the absorption spectroscopy method. The optical and electronical elements are selected according to the list of chemical compounds to be detected and chosen for a particular application. For example, the IR emitter may be selected to emit in a predetermined wavelength range that corresponds to the chemical compound(s) that should be analyzed. The optical cell may be designed so that the IR sensor is positioned at the focal point with the highest light intensity to give an emission path sufficient for a reliable concentration determination of the component of interest according to the Bouguer-Lambert-Beer equation.

The IR emitter and IR sensor can be positioned in two basic ways: (i) along the airflow and (ii) perpendicular to the airflow. In the first case along the airflow (longitudinal case), the exhaled, inhaled, or forced-in gas flows (essentially) along the same direction which is defined for the optical path between the IR emitter and IR sensor. In the second case (perpendicular case), the exhaled, inhaled, or forced-in gas may enter and leave the optical cell via through-holes of the optical cell in a direction that is perpendicular to the optical path between the IR emitter and IR sensor.

The IR emitter and the IR sensor can be mounted in the flanges of the optical cell, with the optical axis from the IR emitter of a broad optical spectrum to the IR sensor located along the airflow direction (longitudinal case). In this case, the optical axis is positioned along the airflow and can reach several tens of centimeters to even meters. This solution significantly reduces the detection limit and increases the sensitivity of the device to the detriment of compactness.

For precision optical unit adjustment, the flanges at one or both ends of the optical cell (with the IR emitter and IR sensor located in them) may have two parts: the outer part being attached to the optical cell, and the inner part with the embedded emitter or sensor, mated to the outer part. Such a setting allows the two different parts of the flange to move freely in relation to each other along the axis of the optical cell. The skilled person understands that this can increase the amount of emission reaching the IR sensor by reflecting off the inner surface, thus increasing the accuracy of measuring the concentration of exhaled gas mixtures of different origins and compositions. In addition, the flanges may have through-holes with a pre-calculated profile that ensures minimal aerodynamic resistance of the airflow passing through the flanges and/or guidance of the airflow into and out of the optical cell. The second case (perpendicular case) of mounting the IR emitter and the IR sensor fixes them on a cylindrical optical cell so that the optical path from the IR emitterto the IR sensor is (essentially) perpendicular to the direction of airflow. This solution is compact and practical for measuring the concentration of components in a gas mixture at relatively high concentrations (100 ppm and above).

The selection of optical elements depends on the list of chemical gas compounds being the target of detection. More than one IR sensor and more than one IR emitter can be used in one optical unit to increase the number of detectable components of the gas mixture.

The IR sensor may have at least two channels with pre-installed optical filters. One of the channels can be used as a reference channel to improve measurement accuracy and signal-to-noise ratio.

The basic information in the device is acquired by the optical unit/cell, which may be connected to a microcontroller of the device, for example via a shielded pair, fibreoptic cable, or a wireless communication channel. The microcontroller may process the signal from the IR sensor during the measurement of concentrations of gas components and transmit information about the signal (measurement data of one or more components of the gas mixture) to an output device (which may be a smartphone, a tablet, a wearable device, a dedicated server, or the like). The device may also additionally be equipped with a unit for processing and storing the captured data in digital form.

The device may be used in an emergency and extreme situation to ensure the vital activity of a biological object (e.g., patient), for example in conjunction with various patient monitoring systems, which are designed to monitor possible deviations of vital signs from normal ones and have feedback with the control units of breathing mixture and medication delivery. These patient monitoring systems may include wearable systems for obtaining data such as ECG, EEG, blood pressure values and others.

The use of feedback to a breathing mixture control unit may allow the output parameters to be monitored and to equalize the conditions for measuring gas component concentrations, which improves the quality of the gas analysis. In addition, feedback to a medication supply unit (drug delivery unit) allows maintaining the patient's condition at minimum vital signs in an emergency or other extreme situation. For example, a drug or medication (in the form of a gas or aerosol) delivery valve can be connected (e.g., to an air airline in a handle of the device) and can be opened automatically or due to a pressure drop at inhalation.

The device may further comprise a respiratory mixture control unit. That is a drug or medication (e.g., in the form of a gas or aerosol) delivery valve may be connected (e.g. to an air airline in a handle of the device) and can be opened in a pre-programmed way or in case of detection of dangerous breath patterns in exhaled air.

The device can also be provided with an alarm unit for measured parameters exceeding critical values, ensuring a timely response of the patient or medical staff to the threat.

The number of optical units installed in the device may depend on the task at hand for detecting different gases or gas components. The above technical result(s) can be achieved either by a single optical u nit/ce 11 or by optical u nits/ce I Is installed in parallel or "one by one". The device can also be equipped with external fixing elements for fixing the device in space. The device can be mounted on horizontal and vertical surfaces.

The optical unit may further be supplemented with an integrated set of pressure sensors, one or more temperature sensors, and/or one or more humidity sensors for gas dynamics evaluation and implementation of gas dynamics methods. In addition, a spirometer or flow meter can measure the exhalation rate, the volume of the passing gas mixture and other indicators of the respiratory system functioning of a biological object (patient).

Further, an adapter may be fitted in front of the optical unit to allow a mouthpiece to be used and changed quickly for safe and ergonomic use. The adaptor can also be connected to an air tube of a breath mask. Such an adaptor can be fitted with a petal valve to prevent the airflow from reversing.

The skilled person understands that using an exchangeable mouthpiece in combination with the interchangeable and cleanable optical unit minimizes the risk of possible transmission of infection between objects (e.g., patients) and ensures that many objects (e.g., patients) can be handled. The use of a mouthpiece also reduces measurement errors due to the distance of the object's (e.g., patient's) lips to the instrument when exhaling, the angle of inclination, or environmental conditions (presence of various gaseous contaminants in the environment, wind strength and direction, etc.). The adapter can optionally be equipped with pressure, humidity and temperature sensors.

To prevent contamination of the elements of the device by biological agents (saliva, sputum, blood, etc.), the adapter may be supplemented with a replaceable membrane filter. The membrane filter can also have a desiccant property to reduce water vapor concentration to ambient levels. This can partially reduce the formation of condensation on the internal surfaces of the optical unit. When a petal valve and a membrane filter are used together, the latter is installed upstream of the petal valve.

After the optical unit, a forced air intake (suction) system can be installed on the opposite side of the object (patient). This system allows the airflow rate in the airline to be regulated and the gas mixture to be refreshed if necessary. Furthermore, synchronization of the forced-air intake system with the pressure sensors (for example to activate or deactivate the forced-air intake system with changes in the pressure inside the optical cell or device) facilitates uniform airflow and a further reduction of aerodynamic resistance in the airline.

The concentrations of the different gas mixture components may be measured in precomputed, non-overlapping spectral ranges for different optical units/cel Is. An optical cell with pre-installed one or more IR emitters and IR sensors may be installed in a unique cassette-type device and can be replaced if required. A system that allows for the rapid replacement of the entire optical unit is also provided. That is, the optical unit including the optical cell is preferably a replaceable optical unit and can be easily connected and removed from the device. As such, a first optical unit (specific to a first set of chemical compounds) can easily be replaced with a second optical unit (specific to a second set of chemical compounds) so that the device can flexibly be used with regard to the analysis of a large variety of chemical compounds.

To ensure uninterrupted operation, the device may be equipped with a fixed power supply unit connected to the mains or a mobile battery-powered power supply unit, depending on the configuration. The rechargeable batteries can be charged using a wireless charger. When working with biological objects (e.g., patients), it is necessary to ensure safe multiple uses and compliance with sanitary requirements. It can be achieved by disinfecting the optical unit and the outgoing air stream. At least one UV radiation source can be installed to provide a high level of biosafety. UV radiation sources' location in relation to the optical unit may vary, i.e. they may be located before the optical unit, directly in the optical unit or after the optical unit, and in the adapter before the membrane filter.

The flange-mounted IR emitter and/or IR sensor may further be fitted with optical lenses to correct the optical radiation, which can also have a fixed optical transmission range. Correcting the radiation can further reduce measurement errors, while the lens's fixed optical transmission range allows filtering of the radiation spectrum. Similarly, optical windows with a fixed wavelength range installed between gas medium and IR sensor can filter out the optical radiation, also reducing measurement errors due to pressure and temperature influences on the radiation receptor. This may further eliminate noise emissions from the infrared radiation from the outside. These lenses and windows can be made, for example, of CaF2 material, which is transparent in the infrared spectrum.

Before the IR radiation enters the optical cell, the radiation can be directed or focused by a parabolic reflector and/or mirror system. Additional mirror-type focusing elements can also be positioned before the IR sensor to reduce the loss of emission outside the active area of the I R sensor.

The device may also be equipped with built-in sensors set for assessing the condition of a biological object (patient), which are located on the optical unit itself or in its immediate vicinity. Such sets can include a body temperature sensor, a pulse oximeter, and/or a body electrical resistance evaluation system.

The device may be fitted with a handle that the user can grasp while performing breathing maneuvers (inhaling, exhaling, sucked-in air). This handle may also contain the electronics necessary for the operation of the device.

In order to make the device compact and portable, flexible or semi-flexible circuit boards may be used on which all the associated electronics are mounted. These PCBs can be wrapped around the optical cells to keep the entire device round and compact without any protruding parts. The proposed embodiments of the device allow for the following advantages:

1) The measurement and processing of the obtained information can be done in realtime throughout the time of use of the breath analyzer, including variations in temperature, pressure and humidity in the exhaled air stream. Therefore, the device interacts with the exhaled air stream rather than on gas samples and does not use a sampling/side-stream cuvettes.

2) The device is based on absorption spectroscopy, which is a method of dynamic gas analysis based on continuous analysis of the flowing gas stream using a set of emittersensor pairs and gas-dynamic sensors to obtain the ratio between the total volume of exhaled air and the quantity of the test component in the gas mixture. Absorption spectroscopy provides information on both the quantitative flow of the gas mixture and the concentration of the chemical components in real time, including the viscous flow regime with variable flow characteristics.

3) The use of specially selected emitter-sensor pairs reduces the uncertainty of the concentrations of the substances of interest, the spectral ranges being chosen to prevent overlapping and being calculated for a given combination of components of interest.

4) As the optical cell has a configuration (length, usage of specific optical elements, for example, usage of specific wavelength ranges) that is specific for the chemical compound or component of interest, there is no need for an additional movable focusing element. The absence of a separate movable focusing element eliminates the effects of defocusing due to vibration, side acceleration and other mechanical influences.

5) Minimized weight and size: the system is based on the compact optical emittersensor pairs that are built-in the main air pathway.

6) The elements used in the absorption spectroscopy method do not require cryogenic cooling to maintain special operating conditions.

7) Unlike photoionization and semiconductor sensors, absorption spectroscopy avoids accumulating errors over time. Sensors of this type are not affected by external influences and have no inertia, that is they can take readings during a breathing cycle repeatedly and over a long period of time.

8) Systems of thermoregulation and thermal stabilization of optical elements guarantee the stability of work of these elements and observe the required accuracy and reliability of results.

Figure 1 illustrates an optical unit of a device according to an embodiment. In particular, Figure 1 shows an optical cell 1, an IR emitter 2 and an IR sensor 3 for the gas analyzer device or gas analyzer sensor. While the optical cell 1 in Figure 1 has a cylindrical shape, this is not a limiting geometry. Preferably the IR emitter 2 and the IR sensor 3 are placed at a common optical axis 12. The IR emitter 2 may be placed and positioned in a first flange 4 in such a way that an airflow (e.g. exhaled airflow, from side B) of a gas flows or is guided around the IR emitter 2 into the interior of the optical cell 1. On the opposite side of the optical cell 1, the IR sensor 3 may be placed and positioned at a second flange 5 in such a way that the airflow can flow or can be guided around the IR sensor 3 and leave the optical cell. The skilled person understands that the direction of the airflow is not restricted to flow in a direction from the IR emitter to the IR sensor but can also be in a reversed direction. The skilled person understands that Figure 1 is an example of a longitudinal configuration in which the IR emitter 2 and the IR sensor 3 are positioned along the airflow direction.

Figure 1 further illustrates an optical window 6 in front of the IR sensor 3. As explained, the optical window may be used to filter radiation. For example, the optical window may have a fixed wavelength range to filter out the optical radiation (pass a band of wavelengths corresponding to the IR emitter), which further reduces measurement errors due to pressure and temperature influences on the radiation receptor. This may further eliminate noise emissions from the infrared radiation from the outside of the optical cell. While Figure 1 only shows one optical window 6, another optical window may also be provided at the IR emitter 2.

Figure 1 further illustrates that the device can be provided with a plurality of pressure sensors 9. As shown, pressure sensors may be provided at both sides of the optical cell 1, that is at the side at which the airflow enters the device and at the side at which the airflow leaves the device. Such an array or set of pressure sensors may be used to assess the gas-dynamic characteristics of the airflow, in particular on both sides of the optical cell. The set of pressure sensors, alone or in combination with a spirometer or flow meter, may be used to measure specific parameters of the airflow and therefore also a lung function such as an exhalation rate, a volume of the passing gas mixture and other functional indicators of the human respiratory system (such as FEV1, Vital Capacity, Tidal Volume, etc.).

Figure 1 further illustrates that the device can be provided with an adaptor 8. The adaptor 8 may be an adaptor for a mouthpiece (not shown) into which the user (patient) exhales the airflow directly into the optical cell 1. In such a way, the adaptor provides an appropriate fitting between the optical cell and the mouthpiece, so that the mouthpiece can be changed quickly for safe and ergonomic use. As illustrated in Figure 1, a plurality of pressure sensors 9 may be placed at the adaptor 8. The skilled person understands that pressure sensors may also or additionally be placed at the flange 4 (in particular in the airflow path around the IR emitter 2, as shown for the pressure sensor at the IR sensor 3), and that the adaptor may also incorporate additional sensors such as a temperature sensor to initially detect the temperature of the exhaled gas. This initial detection of the temperature of the exhaled gas can be used in the setting and operation of the thermoregulation system, as explained above. Moreover, the adaptor may be fitted with a petal valve to prevent the airflow from reversing.

Figure 1 further illustrates a plurality of heating wires 18 at the outer circumference of optical cell 1. The heating wires 18 are part of the thermoregulation system, as explained above, to heat the optical cell 1, in particular, the inner reflective surface of the optical cell 1 and to maintain the optical cell at a temperature that matches the temperature of the airflow. In this way, the reflection of the IR emission at the inner reflective surface of the optical cell 1 is not hindered by the condensation of air droplets at the inner surface.

While Figure 1 shows the heating wires to be circularly wound around the outer circumference of the optical cell 1 from the side of the IR sensor 3 toward the side of the IR emitter 2, this is not a limiting configuration. The skilled person understands that heating wires may also be placed as individual heating wires along the optical cell 1, for example in a straight way from the side of the IR sensor 3 toward the side of the IR emitter 2.

Figure 1 further illustrates cross-sections when considering optical cell 1 from side A (toward the IR sensor 3) and from side B (toward IR emitter 2). The skilled person recognizes a plurality of through holes for the airflow to enter and leave the optical cell. The cross-sections are shown not necessarily to be identical. This enhances the flexibility to use specific optical elements targeted to the analysis of specific components (molecules, biomarkers) of the gas, and also may support guidance of the airflow throughout the optical cell.

Figure 2 illustrates an optical cell of a device according to an embodiment with a composite flange, and a corresponding cross-section from side A (toward the IR sensor 3). Figure 2 specifically shows flange 5 to have a fixed flange part 10 on the optical cell 1 and a second adjustable or movable flange part 11 with the IR sensor 3 that can be moved along the optical axis 12. In this way, the position of the IR sensor 3 with regard to the optical cell 1 can be changed to adapt and fine-tune the distance between the IR emitter 2 (not shown in Figure 2) and the IR sensor 3. As explained above, thus positioning the IR sensor 3 at a focal point with a highest emission intensity allows the emission path to have a sufficient path length for an accurate and reliable determination of a concentration of a component (e.g. specific molecule, biomarker) in the gas. The adjusted position of the flange part 11 also can define the aerodynamic resistance of the device.

Figure 3 illustrates a device according to another embodiment which is an example of a perpendicular configuration in which the IR emitter 2 and the IR sensor 3 are positioned perpendicular to the airflow direction within an optical unit 14.

Figure 3 shows that the device has a mouthpiece 15 into which the user (patient) exhales. The mouthpiece 15 can be detached and thus can be easily changed for cleaning purposes or the like. When the user (patient) exhales into the mouthpiece 15, the exhaled air flows through a flow meter (spirometer) 7 and then via through- holes from a side (perpendicular direction) of the optical cell 1 into and out of the optical cell. It is noted that the through holes for exhaled airflow on the fixed flange part 10 are outside the cross-sectional area. The flow meter (spirometer) 7 may include movable parts (e.g., in combination with optical elements) to measure properties of the airflow thus indicating parameters of the lung function, for example, an exhalation rate, a volume of the passing gas mixture and other functional indicators of the human respiratory system (such as FEV1, Vital Capacity, Tidal Volume, etc.).

Figure 3 shows that the optical unit 14 is oriented perpendicular to the mouthpiece 15 so that the airflow of the exhaled gas into the mouthpiece continues in an essentially perpendicular direction with regard to the optical axis 12 of the IR emitter 2 and the IR sensor 3. However, the IR emitter 2 and the IR sensor 3 may also be placed with an offset with regard to the common optical axis in order to increase the number of reflections at the inner surface of the optical cell 1.

In such a configuration, heating wires or other heating elements (not shown) of the thermoregulation system (as explained above) may also be placed next or adjacent to the IR emitter 2 and/or the IR sensor 3. Such a configuration may avoid placing the heating wires along or around the outer circumference of the optical cell 1 and therefore the airflow can enter the optical cell via through-holes in the optical cell 1 in an undisturbed manner, avoiding perturbances or the like.

Figure 3 further shows that the optical unit 14 of the device may have a thermal stabilization cover 13 and that the device has a handle 16. The thermal stabilization cover 13 may be of a thermally insulating material to stabilize the temperature regime, in other words, to stabilize the temperature within the optical cell 1. The device may further have a casing with a shielding protection to avoid electromagnetic interference of the optical cell 1 with the environment. The handle 16 has a suitable ergonomic shape and form so that the user can grasp the handle while performing breathing maneuvers (inhaling, exhaling, sucked-in air). This handle 16 may also contain the electronics (e.g. microcontroller, control unit, batteries, data storage unit and the like) necessary for the operation of the device.

To increase the optical path (and therefore decrease the detection limit), IR emitter and IR sensor in Figure 3 can be tilted at the same angle to the cylindrical axis of the optical cell and spaced at some predetermined distance apart along this axis (e.g., 3 to 7 cm). In this way, the emission is more repeatedly reflected from the walls of the optical cell before it reaches the IR sensor, which allows the detection of chemical compounds with lower concentrations. Figures 4A, 4B and 4C show additional configurations for placing IR emitter 2 and IR sensor 3. According to Figure 4A, the IR emitter 2 and IR sensor 3 may be placed along a common optical axis. According to Figure 4B, the IR emitter 2 and IR sensor 3 may be non-diagonally placed, for example with an angular offset to each other (e.g. not along a common optical axis), for example, having a predetermined angular offset (with regard to a central midpoint of the optical axis) or may both be placed in one half-side of the optical axis in order to increase the number of reflections within the optical cell before the IR signal from the IR emitter 2 reaches the IR sensor 3 (increasing the interactions with the chemical compounds). Figure 4C shows another configuration in which an additional focusing mirror 18 may be provided to collect and concentrate the emission onto the IR sensor 3.

The gas analyzer device may also be equipped with external fixing elements (brackets) for fixing the device in space. The device can be mounted on horizontal and vertical surfaces.

Figure 5 illustrates an exterior configuration of the device shown in Figure 3, in particular the outer casing that encloses the optical unit 14 and the spirometer 7, as well as the mouthpiece 15. As shown, reference sign 17 further indicates an optional pulse oximeter for non-invasively monitoring the user's blood oxygen saturation during the usage of the device. The optical unit 14 may be adapted to be easily combined with and removed from the device; that is, the optical unit 14 can be readily replaced with another optical unit having a different configuration to analyse a different set of chemical compounds, as described above.

Preferably, the casing includes, at least in part, a heat-insulating material such as a fiberglass insulation (e.g. glass wool), polyisocyanurate or PIR insulation, and/or a polystyrene insulation.

Figure 6 illustrates an example of collected and processed device data when using the example of the device in Figures 3 and 5. Each of the six panels indicates timedependent measurement data: (i) an example of the time-dependent concentration of CO2 detected based on the usage of IR emitter and IR sensor in the optical cell (upper left panel), (ii) an example of the overall CO2 mass flow over time determined from the time-dependent concentration of CO2 and cumulative exhaled volume (upper right panel), (iii) an example of the tidal volume as determined from the flow meter (spirometer) (middle left panel), (iv) an example of the cumulative exhaled volume over time determined from the tidal volume (middle right panel), (v) an example of the flow rate as determined from the flow meter (spirometer) (lower left panel), and (vi) an example of a time-dependent variation of temperature, pressure and humidity as determined by respective sensors inside the optical cell (lower right panel). The skilled person recognizes that the temperature inside the optical cell is regulated at a temperature of the exhaled air of the user (even during the pressure variations due to the breathing cycle) and thus avoids condensation at the inner surface of the optical cell.

For the gas analyzer devices described above, a user's (patient's) exhaled air is passed into the mouthpiece and/or adapter (which can also be referred to as exhalation tubing or line). When the air flows through the exhalation line and through the optical unit, the gas dynamic characteristics and chemical composition of exhaled air are recorded and determined by transmitting the signal from the IR emitter to the IR sensor. Then, the detection signals of the IR sensor may be transmitted on a wired information line or a wireless communication channel to the microcontroller or the control unit of the device. The microcontroller or the control unit may implement direct feedback and may be connected to an information or data processing unit, where the received signal is decoded and analyzed. Acquiring information from the optical unit begins when the patient has contact with the device (for example, after a pressure jump during the first exhalation or as detected by a contact sensor). Between acquiring information sessions, the device may determine background characteristics (e.g. ambient temperature, pressure and humidity and other related parameters).

The information acquired from the IR sensor indicates the concentrations of the specific substance(s) under examination in the gas medium. They may be compared with the values adopted for the substances under examination as a physiological norm for the measuring conditions (e.g. test with or without physical activity). In case of deviations from a baseline, a signal may be given to the external control system and/or medical professionals.

A disposable membrane filter can be fitted upstream of the exhalation line (before an entrance into the optical cell) to prevent a contamination of the reflective surface with liquids (saliva, sputum, blood). A petal valve may be installed in the main air pathway before the optical unit to avoid air backflow. The petal valve can be combined with the mouthpiece and/or the filter. To improve the ergonomics of the device, the adapter can be installed in front of the optical unit to provide a connection between (i) the spirometer or flow meter, optical unit or a cassette-type device in which the optical unit is installed and (ii) a mouthpiece, a replaceable membrane filter and a petal valve which can be installed inside the adapter.

At least two pressure and humidity sensors may be installed to estimate exhaled air volume, breath maneuvers and humidity: one in the breathing mixture supply system and one/other in the exhalation pathway behind the filter and in front of or between the optical units, providing real-time information on the volumes and humidity of the air entering optical units as well as the concentration of detectable components, regardless of pressure variations in the line.

A protective enclosure can be fitted to protect the optical unit against mechanical and other damage. As such, the device can be used in conditions of variable temperatures, as well as due to the temperature difference between exhaled air (on average 32- 33°C) and the optical unit (about ambient temperature) to avoid condensation on the inner surface of the optical cell and, consequently, distortion of measurement results. In that case, the above thermal regulation system is used to maintain the optical cell's set temperature. When the exhalation temperature and the optical cell temperature match, the heating process can be terminated. The use of an additional thermal insulating jacket contributes to the stabilization of the temperature mode. If the device is operated in an electromagnetically disturbed environment, it can be fitted with a unique casing with shielding protection.

A disinfection of the optical unit and outgoing airflow may be provided to ensure safe repeated operation and compliance with sanitary and epidemiological requirements when working with biological objects (patients). For this purpose, one or several sources of UV radiation may be installed, which can be located in front of the optical unit, directly in the optical unit or after the optical unit and in the adapter before the membrane filter.

This device can be used either on its own or in conjunction with long-wear condition monitoring and emergency systems.

When this device is used in medical facilities, as well as in training systems for professionals working in various types of stress conditions (including the training of mountaineers, scuba divers, emergency personnel, athletes and flight personnel), the feedback can be provided in the form of a warning system for the operating personnel. In such cases, the attending personnel make the decision to change the composition of the breathing mixture or to administer other preparations.

The device may also be used in an intensive care unit or an intensive care box. In that case, the feedback may be in the form of a notification system for the attending personnel, coupled with systems for monitoring the supply of breathing mix and/or supply of medication, the decision to change parameters is made by the system based on a deviation of the patient condition from the vital signs.

The embodiments of the present disclosure can be used in medicine as diagnostic equipment and in disaster medicine (including resuscitation equipment installed on vehicles); in protective equipment and outfit of emergency staff during the elimination of high-risk fires (when there is a risk of release of harmful substances) and artificial disasters; for example in an outfit of scuba divers and divers during underwater works with high physical load and diving to great depths; in the composition of mountaineering oxygen equipment or the like.

A method for analyzing an exhaled gas medium uses a device (gas analyzer device orgas analyzer sensor) as described above. In particular, a gas medium (for example, exhaled from a user or patient) flows or is guided through one or more optical units of the device, wherein the gas medium has an airflow that passes through the optical cell along the IR emitter and IR sensor. Light from the IR sensor is reflected from a light-reflective inner surface of the optical cell to reach the IR sensor. Absorption of emitted light in the gas medium allows to a concentration of at least one chemical compound or chemical substance of the gas medium. This can be combined with a detection and evaluation of a flow characteristics of the passing airflow by a set of airflow pressure sensors. The flow characteristics can, for example, refer to an exhalation rate, a volume of the passing gas mixture and other functional indicators of the human respiratory system (such as FEV1, Vital Capacity, Tidal Volume, etc.).

List of Reference Signs

1- optical cell

2 - IR emitter

3 - IR sensor 4 - flange with IR emitter

5 - flange with IR sensor

6 - optical window

7 - flow meter (spirometer) 8 - adapter

9 - pressure sensor

10 - fixed flange on optical cell

11 - flange with IR sensor moving along the optical axis

12 - optical axis 13 - thermal stabilization cover

14 - optical unit

15 - mouthpiece

16 - handle

17 - pulse oximeter 18 - mirror

Claims

1. A device for the analysis of a gas medium, comprising: an optical cell with a light-reflective inner surface, an IR emitter and an IR sensor mounted in the optical cell, the optical cell having an optical path length from the IR emitter to the IR sensor to determine a concentration of at least one chemical compound or chemical substance of the gas medium, the optical cell is configured to have an airflow of the gas medium to pass through the optical cell; and a set of airflow pressure sensors for an evaluation of a flow characteristics of the passing airflow.

2. The device of claim 1, further comprising a thermoregulation system configured to maintain a predetermined temperature inside the optical cell.

3. The device of claim 2, wherein the predetermined temperature is a user-specific temperature.

4. The device of one of claims 1 - 3, wherein the light-reflective inner surface of the optical cell is coated with a coating having hydrophobic properties and/or oleophobic properties.

5. The device of one of claims 1 - 4, wherein the IR emitter and the IR sensor are located in respective flanges of the optical cell.

6. The device of one of claims 1 - 5, wherein an IR emitter flange comprises two flange parts capable of moving relative to each other along the axis of the optical cell, wherein a first flange part is attached to the optical cell and a second flange part includes the IR emitter, and /or wherein an IR sensor flange comprises two flange parts capable of moving relative to each other along the axis of the optical cell, wherein a third flange part is attached to the optical cell and a fourth flange part includes the IR sensor.

7. The device of one of claims 1 - 6, wherein the IR emitter and the IR sensor are arranged in the optical cell such that the optical path from the IR emitter to the IR sensor is perpendicular to a direction of the airflow, or wherein the IR emitter and the IR sensor are arranged in the optical cell such that the optical path from the IR emitter to the IR sensor is along the direction of the airflow.

8. The device of one of claims 1 - 7, wherein the optical cell includes one or more additional IR sensors and/or one or more additional IR emitters.

9. The device of one of claims 1 - 8, comprising one or more additional optical cells combined in parallel or in series.

10. The device of one of claims 1 - 9, further comprising a microcontroller providing both forward and backward communication with the optical cell.

11. The device of one of claims 1 - 10, further comprising a data processing and storage unit.

12. The device of one of claims 1 - 11, further comprising a drug delivery unit.

13. The device of one of claims 1 - 12, further comprising a respiratory mixture control unit.

14. The device of one of claims 1 - 13, capable of being coupled to one or more patient monitoring systems, preferably including a long-term use and/or a wearable and/or alerting system.

15. The device of one of claims 1 - 14, further comprising a casing of a heat-insulating material.

16. The device of claim 15, wherein the casing is fitted with a shielding protection against electromagnetic radiation.

17. The device of one of claims 1 - 16, further comprising external fixing elements for fixing the device in space.

18. The device of one of claims 1 - 17, further comprising a spirometer or flow meter, preferably positioned in front of the optical cell.

19. The device of one of claims 1 - 18, further comprising an adaptor for a mouthpiece or a mouthpiece being fitted in front of the optical cell, the adaptor preferably connectable to a breathing mask.

20. The device of claim 19, wherein a petal valve is incorporated into the adapter to prevent the airflow from being reversed.

21. The device of one of claims 19 - 20, further comprising an ultraviolet emitter being installed in the adapter to disinfect the optical cell, the adapter and/or the airflow in the device.

22. The device of one of claims 19 - 21, wherein the adapter is provided with at least one pressure sensor, at least one humidity sensor, and/or at least one temperature sensor.

23. The device of one of claims 19 - 22, wherein the adapter is provided with a membrane filter.

24. The device of claim 23, wherein the membrane filter is replaceable. 1

25. The device of one of claims 1 - 24, wherein a forced air intake system is mounted after the optical unit.

26. The device of claim 25, wherein the forced air intake system at an exit of the optical cell is synchronized with the pressure sensors.

27. The device of one of claims 1 - 26, further comprising a cassette-type system for integrating the optical cell to allow replacement of the optical cell.

28. The device of one of claims 1 - 27, further comprising a set of biological subject assessment sensors.

29. The device of one of claims 1 - 28, further comprising an alarm unit for measured parameters exceeding critical values.

30. The device of one of claims 1 - 29, further comprising a wired or wireless data transmission unit.

31. The device of one of claims 1 - 30, further comprising an ultraviolet emitter being installed directly in the optical cell to disinfect the optical cell and/or an ultraviolet emitter being installed downstream of the optical cell to disinfect the airflow exiting the device.

32. The device of one of claims 1 - 31, further comprising one or more humidity sensors to evaluate the gas dynamic characteristics, and/or one or more temperature sensors to evaluate the gas dynamic characteristics.

33. The device of one of claims 1 - 32, wherein the IR emitter and/or IR sensor mounted in the optical cell is provided with a lens for correcting the radiation.

34. The device of claim 33, wherein the lens has a fixed IR transmission range for filtering the radiation.

35. The device of one of claims 1 - 34, wherein the IR emitter and/or the IR emitter mounted in the optical cell is provided with an optical window for filtering the radiation.

36. The device of one of claims 1 - 35, wherein through-holes in the optical cell have a predetermined profile to ensure a minimal aerodynamic resistance of the airflow passing through the flanges.

37. The device of one of claims 1 - 36, further comprising a handle, wherein the handle comprises microelectronics required for the operation of the device.