UNIVERSAL PORTABLE BREATH CONTENT ALAYZER

Abstract

A universal portable breath content analyzer is proposed for analyzing the exhale breath components under constant pressure maintained in the sealed housing of the analyzer via the use of a pressure sensor connected to central processing unit that controls operation of the air evacuation valve and a probe admission air valve to maintain a constant pressure regime.

Claims

1. A universal portable breath content analyzer comprising: a sealed housing having an outer wall, a first end face wall and a second end face wall located opposite to the first end face, the sealed housing having an interior defined by the outer wall, the first end face, and the second end face; a first electrode that that has a predetermined polarity and passes into the interior of the sealed housing through the first end face wall or the second end face wall; a voltage supply source connected to the first electrode for applying a voltage to the first electrode; a counter electrode that has a polarity opposite to the polarity of the first electrode for interaction with the first electrode and for generating a discharge in the interior of the sealed housing when a voltage sufficient for generating a discharge between the first electrode and the second electrode is applied to the first electrode; a mouthpiece for taking a sample of a gas exhaled by a patient and for supplying the exhaled air into the interior of the sealed housing; a flow control valve installed in the mouthpiece for keeping the mouthpiece open or closed; an air evacuation tube inserted into the interior of the sealed housing; a vacuum pump with a driver connected to the air evacuation tube; a shut-off valve installed in the air evacuation tube between the interior of the sealed housing and the vacuum pump; a pressure sensor located inside the interior of the sealed housing for measuring pressure in said interior; an opening in the outer wall; a transparent plate installed in the opening; a set of replaceable optical filter/waveband sensor assemblies removably installable onto the transparent plate, each of the replaceable optical filter/waveband filter assemblies comprising at least one waveband filter for passing light of the discharge having a predetermined waveband and at least one sensor capable of converting optical signals of the discharge into electrical signals; and central processing unit, which is connected to the flow control valve, the shut-off valve, the voltage supply source, the driver of the vacuum pump, and the pressure sensor of each replaceable optical filter/waveband filter assembly for controlling operations of aforementioned devices depending on the pressure measured by the pressure sensor.

2. The universal portable breath content analyzer according to claim 1, wherein the housing is a cylindrical body, at least a part of the outer wall is transparent, and the counter electrode is a semi-cylindrical mirror that is located outside the outer housing and encompasses said at least a part of the outer wall, which is transparent.

3. The universal portable breath content analyzer according to claim 1, wherein the counter electrode is a metal rod.

4. The universal portable breath content analyzer according to claim 1, wherein the CPU is selected from the group consisting of a personal computer, a tablet, and a smart phone.

5. The universal portable breath content analyzer according to claim 2, wherein CPU is selected from the group consisting of a personal computer, a tablet, a smart phone.

6. The universal portable breath content analyzer according to claim 1, wherein each of the replaceable optical filter assemblies comprises: a plurality of flat optical bandpass filters, each intended for filtering out light of a predetermined bandwidth; and a plurality of sensor capable of converting optical signals of the discharge into electrical signals, each sensor of said plurality being aligned with one of the flat optical bandpass filter for receiving optical signals from the filters and for converting these optical signals Into electrical signals that correspond to the sample of the gas exhaled by the patient.

7. The universal portable breath content analyzer according to claim 2, wherein each of the replaceable optical filter assemblies comprises: a plurality of flat optical bandpass filters, each intended for filtering out light of a predetermined bandwidth; and a plurality of sensor capable of converting optical signals of the discharge into electrical signals, each sensor of said plurality being aligned with one of the flat optical bandpass filter for receiving optical signals from the filters and for converting these optical signals into electrical signals that correspond to the sample of the gas exhaled by the patient.

8. The universal portable breath content analyzer according to claim 3, wherein the metal rod passes into the interior of the sealed housing through the first end face wall or the second end face, which is located opposite to the first electrode.

9. The universal portable breath content analyzer according to claim 8, wherein each of the replaceable optical filter assemblies comprises: a plurality of flat optical bandpass filters, each intended for filtering out light of a predetermined bandwidth; and a plurality of sensor capable of converting optical signals of the discharge into electrical signals, each sensor of said plurality being aligned with one of the flat optical bandpass filter for receiving optical signals from the filters and for converting these optical signals into electrical signals that correspond to the sample of the gas exhaled by the patient.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0021] FIG. 1 is a longitudinal sectional view that shows main parts of the device of the invention.

[0022] FIG. 2 is a cross-section along line II-II of FIG. 1.

[0023] FIG. 3 a schematic sectional view of the entire system according to one aspect of the device of the invention that illustrates interconnection of the device with components of the control system.

[0024] FIG. 4 is an exploded three-dimensional view of the replaceable optical waveband filter assembly.

[0025] FIG. 5 is a block diagram of the entire breath content analyzer in accordance with another aspect of the invention.

[0026] FIGS. 6A and 6B are examples of spectra obtained with the use of a spectrometer in a sample of an exhaled gas associated with a glow discharge, wherein FIG. 6A is for 20 ppm concentration of acetone in the exhaled test probe and FIG. 6B for 100 ppm concentration of acetone in the exhaled test probe.

DETAILED DESCRIPTION OF THE INVENTION

[0027] The invention relates to a spectral analysis of gases exhaled by a patient and, more particularly, to a universal portable breath content analyzer for analyzing gases exhaled by a patient.

[0028] A universal portable breath content analyzer (herein after referred to as a “device” or “analyzer”) according to one aspect of the invention is shown in FIGS. 1 and 2, wherein FIG. 1 is a longitudinal sectional view of the device, and FIG. 2 is a cross-section along line II-II of FIG. 1.

[0029] As shown in FIGS. 1 and 2, the device, which in an assembled state is designated by reference numeral 20, has a sealed tubular housing 22, which consists of a cylindrical body 24 and end-face wall 24a and 24b. Let us conventionally call the face-end wall 24a a front wall and the face-end wall 24b a rear wall.

[0030] Through the rear wall 24b, an interior 24c of the sealed housing 22, which is defined by the outer wall, in this case the cylindrical body 24, the front end wall 24a, and the rear end face wall 24b, is connected to an air evacuation tube 26, which, in turn, is connected to a vacuum pump (not shown in FIGS. 1 and 2) and through an electrode 28 that passes through the front wall 24a to a high-voltage source (not shown in FIGS. 1 and 2).

[0031] A respiratory sampling mouthpiece 30 through which a sample of an air exhaled from a patient is taken also passes into the interior 24c of the sealed tubular housing 22 through the front wall 24a.

[0032] In accordance with one aspect of the invention, at least a part of the outer wall is transparent, and the counter electrode is a mirror that is located outside the outer housing and encompasses said at least a part of the outer wall, which is transparent. In the modification shown in FIGS. 1 and 2, the entire sealed tubular housing 22 is made, e.g., from a purified fused silica or suprasil glass. From the outer side, the sealed tubular housing 22 is encompassed by a semi-cylindrical mirror 32 (FIG. 2). The mirror is intended for amplifying an output signal, which is generated by molecules of gases that are present in the interior 24c of the sealed tubular housing 22 and activated by a discharge, e.g., a glow discharge 34 induced in the tubular housing 22. FIG. 3 is a schematic sectional view of the entire system of the device 20 of the invention that illustrates interconnection of the device 20 with components of the control system. In the modification of FIG. 3, the mirror 32 is used as a counter electrode relative to the electrode 28 located on the high-voltage source side.

[0033] On the side opposite to the mirror 32, the tubular housing 22 has an opening 36. Inserted into the opening 36 is a flat transparent glass plate 37 made from the same material as the tubular housing 22. The glass plate 36 supports a set of replaceable optical filter/waveband sensor assemblies, hereinafter referred to as replaceable optical filter assemblies 38, which contains a number of flat optical bandpass filters 40a, 40b, 40c, and 40d that are shown in FIG. 4, which is an exploded three-dimensional view of the replaceable optical waveband filter assembly 38. Four optical waveband filters are shown only as an example and the number of the optical filters may be different. Herein, each bandwidth filter is intended for filtering out lights of a predetermined bandwidth. It is well known that molecules of different excited gases emit lights of different wavelengths, which are used for identification of the presence of respective gaseous components, in this case, in the respiratory gases exhaled by a patient into the interior 24 of the sealed tubular housing 22 through the respiratory sampling mouthpiece 30.

[0034] The optical filter assembly 38 supports sensors 42a, 42b, 42c, and 42d, which are aligned with the respective optical bandwidth filters 40a, 40b, 40c, and 40d and intended for receiving optical signals from the respective filters and for converting these optical signals into electrical signals that correspond to the gas components contained in the respiratory gas sampled and analyzed by the device 20. The following sensors/photodiodes can be used for UV wavelengths GaP photodiodes (e.g. FGAP71 from Thorlabs), for visual and in the beginning of infrared range wavelengths Si photodiodes (e.g. FDS010 from Thorlabs), and for near-infrared wavelengths InGaAs photodiodes (e.g. FD10D from Thorlabs). However, particular sensors are determined by the particular task with regard to measured gas components.

[0035] The optical sensors 42a, 42b, 42c, and 42d are parts of the optical filter assembly 38 and are replaceable together with the filters as an integral unit. In other words, the breath content analyzer 20 of the invention may contain a set of such replaceable filter assemblies 38 for covering different bandwidth ranges. Since in visible and near-infrared light spectra the light-emitting molecules present in a gas discharge show more than one line of illumination, the use of the aforementioned set of replaceable optical filter assemblies 38 makes it possible to expand an assortment of gas components to be identified and thus increase versatility of the breath content analyzer 20 of the invention.

[0036] In the modification of FIG. 3, the mirror 32, as an electrode, is grounded at GR. The mirror 32 is also connected to the high-voltage power source 44 via a link 48. The high-voltage power source 44 is connected to the CPU via a link 50. An example of a high-voltage power source is E15 by EMCO which can deliver up to 1500V with power of 3 W.

[0037] In FIG. 4, reference numerals 42a-1, 42a-2, 42b-1, 42b-2 . . . 42d-1, 42d-2 designate electrical terminals, from which the component-identifying electric signals of the sensors are sent to a central processing unit, hereinafter CPU 40, shown in FIG. 3. The CPU 40 may be comprised of a personal computer, a tablet, or even a smart phone with a special software or App.

[0038] In addition to the parts and assemblies mentioned above, the analyzer 20 contains some other important parts and components, which are shown in the modification of FIG. 5. This modification differs from one shown in FIGS. 1 to 4 in that a rod-like counter electrode 32′ that passes into the interior 24 of the housing 22 through the rear wall 24b is used instead of the mirror 32. In FIG. 5, those parts and assemblies that were described earlier will be designated by the same numeral references as in FIGS. 1 to 4 but with addition of a prime (′). Thus, in FIG. 5 the housing is designated by reference numeral 22′, the electrode 28 is designated by reference numeral 28′, etc.

[0039] As can be seen from FIG. 5, in addition to the sealed tubular housing 22′, air evacuation tube 26′, electrode 28′, CPU 40′, respiratory sampling mouthpiece 30′, flat transparent glass plate 36′, and the replaceable optical waveband filter assembly 38′, the analyzer 20′ is also equipped with other important elements, which have not been described above. Among them is a high voltage power source 44′, which is connected to the electrode 28′ via a link 46′. It is understood that both electrodes have opposite polarities. Reference numeral 52′ designates a vacuum pump, which evacuates air from the interior 24′ of the sealed tubular housing 22′ via a cut-off valve 54′ of the air evacuation system. The cut-off valve 54′ is connected to the CPU 40′ via a link 55′. The vacuum pump 52′ is controlled by a driver 56′, which is connected to the CPU via a link 58′.

[0040] A flow control valve 60′ that ensures a metered gas flow into the vacuum system is installed on the inlet end of the respiratory sampling mouthpiece 30′. The valve 60′ is also linked to the CPU 40′ via a link 62′.

[0041] As has been mentioned above with reference to FIG. 3, the electrical terminals 42a-1, 42a-2, 42b-1, 42b-2 . . . 42d-1, 42d-2 of the respective sensors 42a, 42b, 42c, and 42c are linked to the CPU 40. In FIG. 5, these links are designated by reference numerals 64a′, 64b,′ 64c′, and 64d′.

[0042] Installed in the interior 24 of the sealed tubular housing 22 is a pressure sensor 66, which is linked to the CPU via a link 68. As will be shown below, a provision of the pressure sensor 66 for measuring the pressure of gas in the interior 24′ of the housing 22′ is a factor very important for realization of the method of the invention according to which at all measurements of the breath components the pressure is maintained at a constant level regardless of the expiratory volume produced by the patient. Accomplishment of this condition is absolutely necessary for obtaining quantitative data on the content of the sought components, which are necessary for the subsequent data analysis and diagnostics.

[0043] Let us consider the operation of the device 20 of the invention in accordance with the first modification shown in FIG. 3.

[0044] First a pressure that has to be maintained in the interior 24 is pre-assigned in the CPU 40. The valve 60 is shut off, and the air contained in the interior of the housing 22 is evacuated via the valve 54 by the vacuum pump 52. After evacuation, the valve 54 is shut off, the valve 60 is open, and the patient exhales a portion of air into the interior 24′ of the housing 22 via the valve 60. The gas evacuation valve 54 remains closed, the pressure inside the housing is controlled by the pressure sensor 66, and when a given pressure at which all measurements are conducted the valve 60 is closed.

[0045] A voltage of about 300V-5000V is then applied to the electrode 28, and a glow discharge 34 (FIG. 2) is generated in the interior 24 of the tubular housing between the electrodes, i.e., the mirror 32 and the electrode 28. Conditions for generation of the glow discharge in the analyzer of a specific geometry are provided by precondition data inputted to the CPU with reference to the specific dimensions, inter-electrode distance, level of vacuum in the interior 24 of the housing 22, type of the gas, etc.

[0046] Since the tubular housing 22 is transparent, the portion of light incident onto the mirror 32 is reflected back to the glow discharge whereby the signal of the luminescent light of glow discharge is intensified.

[0047] Through the glass plate 37 and the respective optical bandwidth filters 40a, 40b, 40c, and 40d, the light passes to sensors 42a, 42b, 42c, and 42d that convert the optical signals into electric signals, which are then sent to the CPU from their terminals 42a-1, 42a-2, 42b-1, 42b-2, 42c-1, 42c-2, 42d-1, and 42d-2 via respective lines 64a, 64b, 64c, and 64d.

[0048] Upon completion of the measurement, both valves 60 and 54 are opened, and the interior 24 of the cylindrical housing 22 is scavenged by evacuating the exhaled air probe from the housing for the preparation of the device to the next breath analysis cycle.

[0049] The analyzer 20′ of the second modification shown in FIG. 5 works in the same manner as the analyzer 20 except that a metal counter electrode 32′ is used instead of a mirror-type electrode 32 of the previous modification. For the modification of FIG. 5, the mirror is not needed.

[0050] FIGS. 6A and 6B are examples of spectra obtained with the use of a spectrometer in samples of an exhaled gas associated with a glow discharge, wherein FIG. 6A is for 20 ppm concentration of acetone in the exhaled test probe, and FIG. 6B for 100 ppm concentration of acetone in the exhaled test probe.

[0051] These spectrograms also show that intensity of the lines of the spectra depends on a partial concentration of the acetone in the exhaled gas. This fact is used in calibration of the breath content analyzer 20 (20′) of the invention.

[0052] In two considered examples the following intensity values in arbitrary units have been obtained for four considered characteristic lines: 20 ppm case: Line 1—3650.9, Line 2—4230.9, Line 3—3231.9, Line 4—1079.0; 100 ppm case: Line 1—7376.4, Line 2—8147.4, Line 3—4853.4, Line 4—1250.4. These data can be used further in order to correlate concentration of acetone with the measured intensity on characteristic lines, for instance regression analysis can be considered as the prediction model. If only Line 1 data are used the prediction model can be defined as follows: concentration level=−59.5+0.02.Math.Line 1.

[0053] This spectrogram also shows that intensity of the lines of the spectra depends on a partial concentration of the acetone in the exhaled gas. This fact is used in calibration of the breath content analyzer 20 (20′) of the invention.

[0054] It is understood that main parameters of the optical bandpass filters 40a, 40b, 40c, and 40d are bands of transparency for respective lines of luminescence. Each filter passes only one line of predetermined wavelength. Such an approach makes it possible to reveal and identify specific gas components present in the gas mixture, in this case, an exhaled gas sample. The search for components other than those associated with an appropriate group of filters will require replacement of the present kit of filter-sensor assemblies 38 (FIG. 1 and FIG. 3). As mentioned above, the analyzer 20 (20′) of the invention contains a set of such replaceable filter assemblies for covering different bandwidth ranges. On the other hand, dependence of the intensity of luminescence from concentration of the sought gas component makes it possible to evaluate the presence of this component quantitatively.

[0055] The analyzer 20 (20′) of the invention may operate in different modes. Let us consider as an example the operation of the analyzer system in accordance with the second modification shown in FIG. 5. First, with the flow control valve 60′ being shut off, the valve 54′ is open, and air is evacuated from the interior of the housing 22′ by activating the pump 52′. The pressure inside the housing 22′ is controlled by the CPU 40′ via the pressure sensor 66′. When a predetermined pressure optimal from the viewpoint of obtaining the most reliable measurement results is achieved, the valve 54′ is shut off, the mouthpiece 30′ is inserted into the patient's mouth (not shown), the flow control valve 60′ is opened, a sample of an exhaled air is admitted into the housing 22′, and when the pressure in the housing reaches a predetermined value, the valve 60′ is shut off.

[0056] Simultaneously with shutting off the valve 60′, a high voltage is applied to the electrode 28′ from the high-voltage power source 44′. As a result, a glow discharge 34 of the type shown in FIG. 2 is generated inside the housing 22′ between the electrode 28′ and the counter electrode 24′. The light of the discharge is transmitted through the glass plate 37′ and the filters 40a, 40b, 40c, and 40d to the respective sensors 42a′, 42b′, 42c′, and 42d′. The sensors 42a′, 42b′, 42c′, and 42d′, which receive the discharge emission light that passed through the corresponding filters generate electrical signals the amplitudes of which are proportional to the concentration of the sought components. These signals are transmitted via the respective links 64a′, 64b′, 64c′, and 64d′ to the CPU′ 40, where the obtained data are analyzed.

[0057] The analyzer of the present invention has the following essential distinctions from conventional devices of this class:

1) It is intended for operation, i.e., for taking the breath sample, i.e., in a mode of constant pressure. This makes it possible to obtain quantitative data and conduct quantitative analysis of components present in an exhaled gas for use in disease diagnostics. This is achieved by maintaining a pressure in the device housing 22 (22′) at a desired level due to a provision of a pressure sensor 66 (66′) inside the housing 22 (22′) and the CPU-controlled inlet and outlet valves 60 (60′) and 54 (54′) of the housing. In this manner it is possible to select a pressure for the light emission optimal from the viewpoint of obtaining meaningful results.

[0058] Conventional breath analyzers with permanent evacuation of gas from the analyzer housing are subject to considerable variations in the volume of the test gas since the volumes of exhale from different patients may vary almost in the range of 100%. Thus, quantitative evaluation of the exhale gas content becomes practically impossible.

2) The material and construction of the analyzer housing are selected to improve sensitivity of the analysis.
3) Provision of replaceable sets of filter-sensor assemblies 38 (38′) for different wavelength bands makes it possible to match the sensor assemblies with specific emission lines that correspond to specific component contents.
4) The analyzer features mentioned above make it possible to diagnose various diseases and determine a degree of their severity.
5) The design and parts from which the analyzer is built make it possible to embody it in a form of a small portable device having dimensions in the range of 25 and 50 mm for length, 40 and 70 mm for width, and 100 and 250 mm for height.

[0059] Although the invention was described and illustrated in detail using the preferred example embodiments, the invention is not restricted to the examples disclosed and other variations can be derived by a person skilled in the art without departing from the scope of protection of the invention. For example, the housing may be made from materials different from those indicated in the description and the housing itself is not necessarily cylindrical and may have a different geometry, e.g., parallelepipedal. The mirror reflector may have shapes and geometry different from those shown in the drawings. Not only a glow discharge can be used for activation of the emission from the sought components. Sensors may be comprised of a system of bandwidth filters applied one onto the other.