EP4281755A1

EP4281755A1 - Measuring device for analyzing a respiratory gas flow

Info

Publication number: EP4281755A1
Application number: EP22701149.1A
Authority: EP
Inventors: Fritz MEHR; Otto STRÖBEL
Original assignee: Loewenstein Medical Technology SA
Current assignee: Loewenstein Medical Technology SA
Priority date: 2021-01-22
Filing date: 2022-01-20
Publication date: 2023-11-29
Also published as: US20240081676A1; DE112022000947A5; WO2022157004A1

Abstract

A measuring device (1) for analyzing a respiratory gas flow, comprising at least one measuring unit (4) and a cuvette (5), the cuvette (5) being releasably connected to the measuring unit (4) and being designed and configured so that a respiratory gas flows through said cuvette, the measuring unit (4) having at least two sensor units (41, 42), at least one sensor unit (41) being configured to determine a respiratory gas flow rate and at least one sensor unit (42) being configured to determine a CO2 concentration in a respiratory gas, and the cuvette (5) comprising at least two sensor connections (51, 52) for connecting the sensor units (41, 42) for determining at least one respiratory gas flow rate and at least one CO2 concentration of a respiratory gas.

Description

Measuring device for analyzing a respiratory gas flow

description

The invention relates to a measuring device for analyzing a respiratory gas flow, which can be analyzed by a measuring device for at least two parameters at the same time.

A low dead space volume of the measuring devices used to monitor breathing is particularly important when ventilating premature babies. State-of-the-art measuring devices for analyzing a flow of respiratory gas show attempts to reduce the actual measuring cuvette and thus also the dead space volume. However, the measuring devices usually only include individual sensor units in order to monitor the respiratory gas flow of the living being or patient. It is therefore necessary to connect several sensor units with the appropriate connections and cuvettes or connections in series, which significantly increases the dead space volume. Especially when ventilating premature babies in hospitals, too much dead space can mean that the patient cannot be supplied with sufficient fresh breathing air and a significant amount of CO2 rebreathing can be observed. Some sensors are therefore not used, which in turn can result in life-threatening changes not being recorded and being overlooked.

The object of the present invention is therefore to provide a measuring device for the effective and reliable analysis of the respiratory gas flow of a living being. The object is achieved by the inventive measuring device according to claim 1.

The object is achieved by a measuring device for analyzing a flow of respiratory gas, comprising at least one measuring unit and a cuvette, the cuvette being detachably connected to the measuring unit and being set up and designed to have a respiratory gas flowing through it, and the measuring unit having at least two sensor units, wherein at least one sensor unit is designed to determine a respiratory gas flow and at least one sensor unit is designed to determine a CO2 concentration in a respiratory gas and the cuvette comprises at least two sensor connections for connecting the sensor units to determine at least one respiratory gas flow and at least one CO2 concentration of a respiratory gas .

In some embodiments, the measuring device is characterized in that the cuvette comprises at least three sensor connections, the at least third sensor connection being a sensor connection for a sensor unit for determining a respiratory gas pressure. In this embodiment, the cuvette thus includes a connection for a sensor unit for determining (or measuring) the CO2 concentration of the respiratory gas, the respiratory gas flow and the respiratory gas pressure. In some embodiments, the measuring device is characterized in that the measuring unit comprises at least three sensor units, the at least third sensor unit being a sensor unit for determining the respiratory gas pressure. In this embodiment, the measuring unit thus includes a sensor unit for determining (or measuring) the CO2 concentration of the breathing gas, the breathing gas flow and the breathing gas pressure.

In some embodiments, the measuring device is characterized in that the sensor unit for determining the CO2 concentration in the breathing gas comprises at least one radiation source, at least one detector unit, at least one mirror, at least two lenses and at least one prism.

In some embodiments, the measuring device is characterized in that at least two of the lenses are designed as Fresnel lenses and at least one of the two lenses is arranged on the at least one prism.

In some embodiments, the measuring device is characterized in that the sensor unit comprises at least two prisms, with at least one of the at least two lenses being arranged on each prism.

In some embodiments, the measuring device is characterized in that the mirror is a concave mirror.

In some embodiments, the measuring device is characterized in that the mirror is preferably coated with gold for high reflection of rays in a wavelength range from 3500 nm to 4600 nm, in particular in the wavelength range from 3910 +/- 100 nm and 4260 +/- 100 nm is.

In some embodiments, the measuring device is characterized in that the mirror is aspherical.

In some embodiments, the measuring device is characterized in that the mirror is anamorphic.

In some embodiments, the measuring device is characterized in that the detector unit includes at least two detector surfaces.

In some embodiments, the measuring device is characterized in that at least one of the at least two detector surfaces is designed to detect one of wavelengths in a range from 3950 nm to 4550 nm, preferably in the wavelength range from 4260 +/- 100 nm, and at least one of the at least two Detector surfaces for the detection of wavelengths in a range from 3600 nm to 4200 nm, preferably in the wavelength range of 3910 +/- 100 nm, is formed.

In some embodiments, the measuring device is characterized in that at least one of the at least two detector surfaces is designed as a measuring detector and at least one of the at least two detector surfaces is designed as a comparison detector, wherein the at least two detector surfaces have the same size and wherein the detector surface for detecting wavelengths in a range of 3950 nm to 4550 nm, preferably in the wavelength range of 4260 +/- 100 nm, is designed as a measuring detector.

In some embodiments, the measuring device is characterized in that the radiation source is an infrared radiation source, preferably an incandescent lamp. Both a conventional incandescent lamp and an incandescent lamp specially designed as an infrared radiation source can be considered.

In some embodiments, the measuring device is characterized in that at least one prism is designed as an inverted prism, preferably as a roof prism.

In some embodiments, the measuring device is characterized in that at least one prism is materially connected to at least one of the at least two lenses.

In some embodiments, the measuring device is characterized in that at least one prism is manufactured in one piece with at least one of the at least two lenses. In some embodiments, the measuring device comprises at least two prisms, with both prisms being produced in one piece with one of the at least two lenses.

In some embodiments, the measuring device is characterized in that the cuvette is arranged between one of the at least two lenses and the at least one prism.

In some embodiments, the measuring device is characterized in that the cuvette is arranged between two prisms, with the two prisms being arranged between two lenses, resulting in a sequence of lens, prism, cuvette, prism, lens.

In some embodiments, the measuring device is characterized in that the mirror, the radiation source, the lenses, the prisms of the sensor unit and the sensor connection of the cuvette for connecting the sensor unit for determining the CO2 concentration are not coated with an anti-reflection coating.

In some embodiments, the measuring device is characterized in that the total transmission of the optics consisting of the mirror, radiation source, lenses and prisms of the sensor unit and the cuvette is over 50%, preferably over 60%.

In some embodiments, the measuring device is characterized in that the prisms, the lenses and the cuvette are made of a plastic, with the plastic having a material thickness of 2 mm allowing transmission of infrared rays, preferably in the wavelength range between 3910 +/- - 100 nm to 4260 +/- 100 nm, greater than 85%, preferably greater than 90%, more preferably greater than 92%.

In some embodiments, the measuring device is characterized in that the

Prisms, the lenses and the cuvette with a material thickness of 2 mm have a transmission of Infrared rays, preferably in the wavelength range of 3910 +/- 100 nm and 4260 +/- 100 nm, of over 85%, preferably over 90%, more preferably over 92%.

In some embodiments, the measuring device is characterized in that more than 90% by weight of the plastic is a polysulfone, a polyethersulfone, a polymethylene methacrylate, a polycarbonate, a polytetrafluoroethylene (Teflon), polyethersulfone, poly(arylenesulfone), a polyimide, a polyamide and/or or a mixture of at least one of the listed polymers and optionally another polymer.

In some embodiments, the measuring device is characterized in that the at least one prism of the sensor unit is made from a polysulfone and/or a polyethersulfone and/or a polycarbonate.

In some embodiments, the measuring device is characterized in that the lenses are made from a polysulfone and/or a polyethersulfone and/or a polycarbonate.

In some embodiments, the measuring device is characterized in that at least the lenses and the at least one prism of the sensor unit for determining the CO2 concentration and the cuvette are made of a polysulfone and/or a polyethersulfone and/or a polycarbonate.

In some embodiments, the measuring device is characterized in that a surface of one of the prisms forms a tapering column together with a surface of a second prism, the cuvette in the area of the sensor connection for connecting the sensor unit for determining the CO2 concentration to the tapering column has a suitable outer cross-section.

In some embodiments, the measuring device is characterized in that the cuvette has an interior, the interior having at least two side surfaces which run parallel to one another, the two side surfaces each defining a plane (C), and the cuvette having at least two outer surfaces, wherein the outer surfaces each define a plane (B, E) and the two planes (B, E) are at an angle (A) to one another, and the planes (C) are at an angle (D) to the planes (B, E) with the angle (D) being half the size of the angle (A).

In some embodiments, the measuring device is characterized in that the cuvette comprises a coupling, the coupling being designed and set up to connect a Y-piece and/or an exhalation device to the cuvette in a gas-conducting manner.

In some embodiments, the measuring device is characterized in that the cuvette and the Y-piece and/or the exhalation device are rotatably connected to one another. In some embodiments, the measuring device is characterized in that the cuvette and the Y-piece and/or the exhalation device are connected in such a way that they are secured against accidental detachment.

In some embodiments, the measuring device is characterized in that the coupling for connecting the cuvette and Y-piece and/or the exhalation device has at least one seal, at least one locking ring and at least one axial bearing, the locking ring protecting against accidental loosening.

In some embodiments, the measuring device is characterized in that at least one axial bearing and one retaining ring are designed together as a functional component.

In some embodiments, the measuring device is characterized in that the cuvette has a connection for a gas-conducting connection to a patient interface, this connection being produced in one piece with the cuvette.

In some embodiments, the measuring device is characterized in that the cuvette and the measuring unit are detachably connected to one another via at least one connecting element of the measuring unit and at least one connecting element of the cuvette.

In some embodiments, the measuring device is characterized in that the connecting elements form a click system.

In some embodiments, the measuring device is characterized in that the sensor connection for connecting a sensor unit for determining the respiratory gas flow has at least one passage for at least one sensor pin.

In some embodiments, the measuring device is characterized in that the sensor connection has at least one receptacle for accommodating the sensor unit for determining the respiratory gas flow, the at least one passage for the at least one sensor pin being arranged in the receptacle.

In some embodiments, the measuring device is characterized in that the sensor connection is designed to connect a sensor unit for determining the CO2 concentration and is set up to accommodate the cuvette so that the outer surfaces of the cuvette are in positive contact with the prisms and/or the lens.

In some embodiments, the measuring device is characterized in that the sensor connection for connecting a sensor unit for determining the CO2 concentration is essentially designed as two opposite, flat, smooth outer surfaces of the side walls of the cuvette.

In some embodiments, the measuring device is characterized in that the sensor connection for connecting a sensor unit for determining the respiratory gas pressure has at least one recess for receiving the sensor head of the sensor unit and a bore from the recess into the interior of the cuvette. In some embodiments, the measuring device is characterized in that the cuvette has an overall length of less than 120 mm, preferably less than 80 mm. If an external pressure measurement is provided, then in some embodiments it is provided that the length including the Y-piece is less than 75 mm, in some embodiments less than 65 mm. In the case of an internal pressure measurement, it can be provided that the length including the Y-piece is less than 70 mm, in some embodiments less than 55 mm.

In some embodiments, the measuring device is characterized in that the wall thickness of the cuvette in the area of the sensor connection for connecting a sensor unit for determining the CO2 concentration is between 0.5 mm and 3 mm, preferably between 0.8 mm and 2 mm.

In some embodiments, the measuring device is characterized in that the wall thickness of the cuvette in the area of the sensor connection for connecting a sensor unit for determining the CO2 concentration has a tapering cross-sectional profile.

In some embodiments, the measuring device is characterized in that the cuvette can be integrated into a patient interface.

In some embodiments, the measuring device is characterized in that the at least two sensor units of the measuring unit are arranged together in one housing.

In some embodiments, the measuring device is characterized in that at least three sensor units (41, 42, 43) of the measuring unit are arranged in one housing.

In some embodiments, the measuring device is characterized in that the sensor unit for determining the respiratory gas flow works according to the principle of a thermal gas flow determination.

In some embodiments, the measuring device is characterized in that the sensor unit for determining the respiratory gas flow works according to the principle of thermal anemometry, preferably hot-draft anemometry.

In some embodiments, the measuring device is characterized in that the sensor unit for determining the respiratory gas flow comprises at least one sensor pin, the at least one sensor pin being guided at least partially through the passage into the interior of the cuvette.

In some embodiments, the measuring device is characterized in that the sensor unit for determining the respiratory gas pressure determines the respiratory gas pressure using a difference from the atmospheric pressure.

In some embodiments, the measuring device is characterized in that the sensor unit includes at least one sensor head. In some embodiments, the measuring device is characterized in that the cuvette weighs less than 80 g, preferably less than 30 g.

In some embodiments, the measuring device is characterized in that the measuring device, consisting of the measuring unit and cuvette, has a total weight of less than 120 g, preferably less than 60 g.

In some embodiments, the measuring device is characterized in that the measuring unit is designed as a reusable and reusable item and/or the cuvette 5 is designed as a disposable item.

The object is also achieved by a system for analyzing a respiratory gas flow at least comprising a ventilator and a patient interface, the system also comprising a measuring device as described above, the measuring device being connected to the patient interface and the ventilator in a gas-conducting manner.

In some embodiments, the system is characterized in that the cuvette is connected to the patient interface via the connector and the cuvette is connected to the ventilator via the Y-piece.

In some embodiments, the system is characterized in that at least the measuring unit of the measuring device is arranged in and/or on the ventilator.

The object is also achieved by a cuvette for use in a measuring device for analyzing a respiratory gas flow, the cuvette comprising at least two sensor connections for connecting sensor units for determining at least one respiratory gas flow and at least one CO2 concentration of a respiratory gas.

The object is also achieved by a measuring unit for use in a measuring device for analyzing a respiratory gas flow, the measuring unit having at least two sensor units, wherein at least one sensor unit is designed to determine a respiratory gas flow and at least one sensor unit is designed to determine a CO2 concentration in a respiratory gas determine.

The object is also achieved by a sensor unit for determining the CO2 concentration of a respiratory gas, the sensor unit comprising at least one radiation source, at least one detector unit, at least one mirror, at least two lenses and at least one prism.

In some embodiments, the sensor unit is characterized in that at least two of the lenses are designed as Fresnel lenses and at least one of the two lenses is arranged on the at least one prism. In some embodiments, the sensor unit is characterized in that the at least one prism is materially connected to at least one of the at least two lenses.

In some embodiments, the sensor unit is characterized in that the at least one prism is made in one piece with at least one of the at least two lenses.

In some embodiments, the sensor unit is characterized in that the at least one prism and the lenses are made of a plastic, with the plastic having a material thickness of 2 mm allowing transmission of infrared rays, in particular in the wavelength range of 3910 +/- 100 nm and 4260 +/- 100 nm, of over 85%, preferably over 90%, more preferably over 92%.

In some embodiments, the sensor unit is characterized in that the plastic is more than 90% by weight of a polysulfone, a polyethersulfone, a polymethylene methacrylate, a polycarbonate, a polytetrafluoroethylene (Teflon), polyethersulfone, poly(arylenesulfone), a polyimide, a polyamide and/or is a mixture of at least one of the listed polymers and one or more other polymers of your choice.

The object is further achieved by a prism for use in a sensor unit as described above, the prism being made in one piece with a lens, the lens being a Fresnel lens

The object is also achieved by a method for producing optical components from polysulfone and/or polyethersulfone and/or polycarbonate by injection molding, the optical components being prisms and lenses.

In some embodiments of the method, the prism is manufactured in one piece with a lens.

It should be pointed out that the features listed individually in the claims can be combined with one another in any technically meaningful way and show further refinements of the invention. The description additionally characterizes and specifies the invention, in particular in connection with the figures.

It should also be pointed out that a conjunction "and/or" used herein, standing between two features and linking them to one another, must always be interpreted in such a way that in a first embodiment of the subject matter according to the invention only the first feature can be present, in a second embodiment only the second feature may be present and in a third embodiment both the first and the second feature may be present.

A ventilator is to be understood as any device which supports a user or patient in breathing naturally, takes over the ventilation of the user or living being (eg patient and/or newborn and/or premature baby) and/or is used for respiratory therapy and/or otherwise affects the breathing of the user or patient. This includes, for example but not limited to, CPAP and BiPAP machines, anesthetic machines, breathing therapy machines, (hospital, non-hospital or emergency) ventilators, high-flow therapy machines and cough machines. Ventilators can also be understood as diagnostic devices for ventilation. Diagnostic devices can generally be used to record medical and/or respiration-related parameters of a living being. This also includes devices that can record and optionally process medical parameters of patients in combination with breathing or exclusively relating to breathing.

Unless expressly described otherwise, a patient interface can be understood as any peripheral device which is intended for interaction, in particular for therapy or diagnostic purposes, of the measuring device with a living being. In particular, a patient interface can be understood as a mask of a ventilator or a mask connected to the ventilator. In the light of the invention, it is possible to arrange the cuvette or the measuring device according to the invention between the mask and the ventilator, so that the mask is connected to the ventilator via the cuvette. This mask can be a full-face mask, i.e. one that encloses the nose and mouth, or a nose mask, i.e. a mask that only encloses the nose. Tracheal tubes or cannulas and so-called nasal cannulas can also be used as masks or patient interfaces. In some cases, the patient interface can also be a simple mouthpiece, for example a tube, through which the living being at least breathes out and/or breathes in. A connection to a respirator is not necessary for the inventive measuring device in all embodiments.

The inventive measuring device is particularly suitable not only for use in the field of therapy and ventilation of patients, but can also be used in other areas where an analysis of natural breathing may be desired, such as for divers, mountaineers, in the Find protective equipment for firefighters, etc. The measuring device according to the invention can also be used in the area of determining various physiological parameters of a living being—not only with regard to diagnostics.

The measuring device according to the invention combines at least one sensor unit for determining a respiratory flow or a sensor unit for determining the respiratory gas pressure together with at least one sensor unit for determining the CO2 concentration in a common housing. Correspondingly, the cuvette of the measuring device is also designed in such a way that it has at least two corresponding sensor connections. Also integrated into the cuvette is a connection for a patient interface, for example, it being possible in principle for the cuvette to also be integrated into a patient interface. In some versions of the measuring device, three sensor units are installed in the measuring unit to determine the breathing gas flow, breathing gas pressure and CO2 concentration. The measuring device is preferably designed in such a way that no bypass line is required for the measurement of respiratory gas pressure and/or respiratory gas flow, but rather the measurements can be carried out directly in the cuvette. The sensor unit for determining the CO2 concentration includes optical components, in particular prisms and lenses, which are made of a polymer that is permeable to IR radiation. Ideally, the cuvette is also made from such a material. The production from a polymer also allows a simple production of the prisms in one piece with the lenses.

The measuring device can be used both with a ventilator and without a ventilator. In order to use the measuring device with a ventilator, the cuvette also has a coupling via which, for example, an exhalation device (e.g. an exhalation valve controlled by the ventilator or a leakage system) for a 1-tube configuration or a Y-piece for a 2-tube configuration Hose configuration can be connected. The coupling is preferably designed in such a way that no unwanted leakage occurs, and the cuvette and the connected Y-piece or the exhalation device can be easily rotated in relation to one another.

Depending on the living being on/with/by which the measuring device is to be used, certain changes or adaptations, in particular in the cross sections of the gas-conducting components such as the cuvette, must be taken into account. While, for example, premature babies have a low respiratory and lung volume and rather low respiratory pressures and flows, the smallest possible design (small cross-sections) with low dead space volumes is desirable here. In the case of larger living beings, such as adult humans, the small cross-section can result in too high a breathing resistance, so that the cuvette has to be made correspondingly larger than for premature babies.

The invention is described in more detail by way of example with reference to FIGS.

Figure 1: Schematic representation of the measuring device 1

Figure 2: Cross section through cuvette 5 and optical components of sensor unit 42

Figure 3: Cross section of cuvette 5

Figure 4: Cross section of prisms 424a, 424b and cuvette 5

Figure 5: Perspective view of measuring unit 4 with housing 453

Figure 6: Connection elements measuring unit 4 and cuvette 5

Figure 7: Perspective section through cuvette 5 with optical components of sensor unit 42

FIG. 8: Cross section along measuring device 1 in top view

Figure 9: Cross section through sensor unit 42 and cuvette 5

Figure 10: Cross section along measuring device 1 through sensor units 41, 43

Figure 11: Dimensioning of cuvette 5 with Y-piece 54 Figure 12 a): diameter of cuvette 5

Figure 12b): Dimensions of cuvette 5 without Y-piece 54

Figure 13: Schematic representation of measuring device 1 with patient interface 3

Figure 14: Schematic representation of measuring device 1 with patient interface 3

Figure 15: Schematic representation of measuring device 1 with patient interface 3 and

Ventilator 2 in 2-hose configuration

Figure 16: Schematic representation of measuring device 1 with patient interface 3 and

Ventilator 2 in 1 hose configuration

FIG. 1 shows an exemplary embodiment of the measuring device 1 according to the invention for the analysis of a respiratory gas flow. The embodiment shown comprises a measuring unit 4 and a matching cuvette 5. The measuring unit 4 comprises, for example, the three sensor units 41, 42, 43. In addition, the cuvette 5 has three sensor connections 51, 52, 53 for connecting the sensor units 41, 42, 43 on. The unit of measurement

4 additionally has at least one interface 44 via which the measurement data and/or electrical signals generated by the sensor units 41, 42, 43 can be forwarded and/or transmitted to a corresponding signal processing unit (not shown). The cuvette 5 also has a connection 59 which can be connected to a patient interface 3 in a gas-conducting manner, for example. In some embodiments, the cuvette 5 can also be integrated into the patient interface 3 . The cuvette

5, for example, is connected to the mask body of a patient interface 3 instead of a hose connection. The connection 59 then forms the transition from the patient interface 3 to the cuvette 5, for example.

For example, the interface 44 is designed as a combined interface which forwards the signals of the sensor units 41, 42, 43 bundled, but it is also possible for each sensor unit to have its own interface for transmitting the signals to a signal processing unit. The signal processing unit is used, for example, to convert the electrical signals generated by sensor units 41, 42, 43 into measured values and/or data, which are then interpreted, displayed and/or displayed by appropriate processing, output, evaluation and/or calculation units and possibly display elements can be further processed. In some embodiments of the measuring unit 4 the signal processing unit is integrated into the measuring unit 4 . Alternatively or additionally, the signal processing unit can be provided as an external device, for example together with further processing, evaluation and/or calculation units and possibly also display and control elements. In addition to a signal processing unit, the measuring unit 4 can also be set up and configured to display, interpret and/or further process the values and/or data output by the signal processing unit, for example by means of processing, evaluation and/or processing functions integrated in the measuring unit calculation units. For example, a display, optionally together with controls and / or as a touch screen on the Measuring unit 4 can be arranged, which can display and/or output the measured values of the sensor units 41, 42, 43.

The sensor unit 41 is designed, for example, as a sensor unit for determining the respiratory gas flow (“flow”), ie the value of the flow (volume per time) of the respiratory gas flow. In addition to this, the sensor connection 51 is designed for the connection of such a sensor unit 41 . The sensor unit 41 is a flow sensor, for example, which is based on a thermal measurement principle. Such a measuring principle is, for example, thermal anemometry. An exemplary embodiment of the sensor unit 41 is a hot-wire anemometer. For this purpose, at least one sensor pin 411 is placed in the respiratory gas flow, this sensor pin 411 having a thin wire which is clamped between two metal tips or welded or soldered to them. At this point it should be pointed out that other, alternative methods and sensor units for measuring the respiratory gas flow can also be installed in the measuring unit 4 . For example, no bypass line is necessary for these alternative methods of measuring the respiratory gas flow, but can be measured directly in the cuvette 5 .

The sensor unit 42 is designed and set up, for example, as a sensor unit for determining the CO2 concentration of the breathing gas. In some exemplary embodiments, the sensor unit 42 is an infrared sensor unit which measures the CO2 concentration based on the absorbed infrared radiation of the breathing gas flowing through the cuvette 5 . The matching sensor connection 52 of the cuvette 5 is accordingly designed in such a way that the cuvette 5 is transparent to the infrared radiation at least in the area of the sensor connection 52 .

The sensor unit 43 is designed, for example, as a sensor unit for determining the breathing gas pressure in the cuvette 5 . The sensor connection 53 of the cuvette 5 is designed in such a way that it can accommodate the sensor unit 43 and is connected to the interior 57 of the cuvette 5 . For example, this connection between the sensor unit 43 and the interior 57 of the cuvette 5 is realized through a bore 531 in the area of the sensor connection 53 . For example, the breathing gas pressure is measured by the sensor unit 43 using a difference from the atmospheric pressure or the ambient air pressure. For this purpose, sensor unit 43 has at least one sensor head 431, for example.

Figure 2 shows an example of the essential elements of the sensor unit 42 for determining the CO2 concentration of the breathing gas in connection with the cuvette 5. The determination of the CO2 concentration is based, for example, on the absorption of infrared radiation by the CO2 molecules in the breathing gas, which passes through the interior 57 of cuvette 5 flows.

To generate the infrared radiation, the sensor unit 42 comprises at least one radiation source 422, for example an infrared radiator and/or an incandescent lamp. As a rule, radiation sources essentially do not emit the radiation in a directed and omnidirectional manner. In order to be able to use as much of the radiation generated by the radiation source 422 to analyze the respiratory gas flow in the cuvette 5 as possible, the sensor unit 42 a mirror 421, which is set up to reflect the radiation generated by the radiation source 422 essentially in the direction of the cuvette 5. For this purpose, the mirror 421 is designed as a concave mirror, for example. In some embodiments, the mirror 421 is also aspheric and/or anamorphic, which allows the shape of the optical path 429 to be better adapted. Further, the mirror 421 is coated with gold, for example, for high reflection. In addition to gold, other coatings are also conceivable for the mirror 421 insofar as these ensure reflection of the radiation generated by the radiation source 422 . In some specific embodiments, the radiation source 422 itself can also have a reflective coating, so that the radiation generated by the radiation source 422 is already reflected by the radiation source 422 in the direction of the cuvette 5 . Alternatively, the use of a directed radiation source 422, for example an (infrared) laser, is conceivable.

A lens 423 is arranged in the beam path 429 after the mirror 421 and the radiation source 422 . The lens 423 is designed, for example, as a plano-concave lens, which is used for beam development in front of the cuvette 5, among other things. The lens 423 is also designed and set up to act as a beam splitter. For example, the lens 423 is designed as a Fresnel lens, which enables the sensor unit 42 to be constructed in a space-saving manner. A prism 424b is arranged directly on the lens 423 . In some embodiments of the cuvette 5, the outer surfaces 521a of the cuvette 5 are bevelled, as can be seen particularly in FIGS. 3 and 4, which leads to a prismatic effect of the cuvette 5. The prism 424b is beveled to the same extent, so that overall there are no refractive surfaces or refractive edges between the lens 423 and the outer surface 521a of the cuvette 5. In some embodiments of the sensor unit 42, the lens 423 and the prism 424b are made in one piece and from one material. For example, the lens 423 and the prism 424b can be produced in one piece from a plastic, for example a polysulfone, a polyethersulfone and/or a polycarbonate, in an injection molding process. In some embodiments it can also be provided that the material is Teflon. A high transmission of the infrared radiation is decisive for the choice of the plastic. For example, with a material thickness of 2 mm, the plastic should have a transmission of more than 85% of individual wavelengths in the range between 3600 nm and 4550 nm, preferably in the wavelength range of 3910 +/- 100 nm and 4260 +/- 100 nm. In some embodiments, a transmission of over 90% or over 92% is preferable. The high transmission is required in particular for the wavelengths in the range from 4200 nm to 4400 nm and 3800 nm to 4000 nm, preferably in the wavelength range from 3910 +/- 100 nm and 4260 +/- 100 nm.

The use of a plastic/polymer for the cuvette 5 and essential parts (eg prisms 424a, 424b, lenses, etc.) of the measuring unit 4 makes it possible for the entire measuring unit to have a very low weight. For example, cuvette 5 and measuring unit 4 together weigh less than 120 g, preferably less than 60 g, more preferably less than 30 g. Both the cuvette 5 and the measuring unit 4 each weigh less than 80 g, for example, preferably less than 30 g, more preferably less than 15 g. In the interior 57 of the cuvette 5, the infrared radiation impinges on the respiratory gas flow, with parts of the infrared radiation being absorbed by CO2 molecules contained in the respiratory gas. In particular, the wavelength range around 4260 (+/- 10) nm is absorbed, while the wavelength range around 3910 (+/- 10) nm is essentially not absorbed by the CO2 molecules or other (regular) components of the breathing gas of a living being. The part of the infrared radiation not absorbed by the respiratory gas passes through the side surface 571b through the side wall 522b of the cuvette 5 and emerges from the outer surface 521b. The prism 424a is arranged in a form-fitting manner on the outer surface 521b. The infrared radiation enters the prism 424a through the surface 428a of the prism 424a. The prism 424a is designed, for example, as an inverted prism, preferably as a roof prism. In addition, the prism 424a is oriented and configured such that the infrared rays strike the surface 428b of the prism 424a at an angle of at least 45° or more, for example. The infrared rays are totally reflected at the surface 428b toward the lens 425 arranged on the prism 424a. The lens 425 is designed as a Fresnel lens, for example, and in some embodiments is produced in one piece with the prism 424a, for example, so that the material of the prism 424a transitions to the lens 425. Prism 424a and lens 425 can be manufactured, for example, by injection molding and can be manufactured simultaneously in the same tool.

The lens 425 is also set up and designed in such a way that a uniform image is projected onto the detector unit 426 . The detector unit 426, which has two detector surfaces 426a, 426b, for example, converts the incoming infrared radiation into electrical signals. The detector surface 426a is designed, for example, to detect infrared radiation in the wavelength range around 4260 (+/- 100) nm and the detector surface 426b is designed, for example, to detect infrared radiation in the range around 3910 (+/- 100) nm. By comparing the two radiation intensities detected by the detector unit 426, it is possible to determine how much of the infrared radiation in the wavelength range around 4260 (+/- 100) nm is absorbed by the CO2 in the breathing gas. It is therefore important that both detector surfaces 426a, 426b are irradiated in the same way. The detector surface 426b for detecting infrared radiation in the wavelength range around 3910 (+/- 100) nm is therefore used as a reference detector, while the detector surface 426a for detecting infrared radiation in the wavelength range around 4260 (+/- 100) nm can be regarded as a measuring detector. The arrangement of the prisms 424a, 424b and the lenses 423, 425 is used for beam guidance and beam development, so that the same image can be projected onto both detector surfaces 426a, 426b, ie the beams are divided equally. In some embodiments, the detector unit 426 includes more than two detector surfaces, for example to measure other gas components of the respiratory gas flow. For example, further detector surfaces for determining the O2 concentration (e.g. range around 1580 nm and/or 1270 nm) and/or the CO concentration (e.g. range around 4670 nm and/or 2340 nm) of the respiratory gas could be part of the detector unit 426 be installed.

The individual components of the sensor unit 42 and the sensor connection 52 or the cuvette 5, in particular lenses, prisms and the cuvette 5 itself, are made, for example, from a plastic that is transparent to infrared rays. Examples of such plastics are polysulfone, polyethersulfone, polymethylene methacrylate, polycarbonate, polytetrafluoroethylene, Polyethersulfone, Poly(arylenesulfone), Polyimide, Polyamide. In some embodiments, a mixture of the plastics mentioned is also conceivable, or a mixture of one and/or more of the plastics with other plastics. In the case of a mixture of plastics, the plastic(s) mentioned should make up more than 90% by weight of the plastics mixture. For example, a plastic mixture could consist of 46% polysulfone, 46% polyethersulfone and 8% polystyrene. Preference is given to plastics and plastic mixtures which, with a material thickness of 2 mm, transmit infrared radiation, in particular in the wavelength range from 3600 nm to 4550 nm, preferably in the wavelength range from 3910 +/- 100 nm and 4260 +/- 100 nm, particularly in the range from 3850 nm to 3960 nm and 4200 nm to 4300 nm, of over 85%, preferably over 90%. In some embodiments, a transmission greater than 92% is desirable. Polysulphones, polyethersulphones and/or polycarbonates are particularly suitable as material for the lenses 423, 425, prisms 424a, 424b and the cuvette 5.

While in some exemplary embodiments the lenses, prisms and the cuvette 5 are made of the same material, it is also conceivable that the materials of the individual components vary. In some embodiments, for example, the lenses and/or prisms can be made of a mineral or an inorganic material instead of a plastic.

A further aspect which characterizes the choice of material for the cuvette 5, the prisms and the lenses, for example, can be seen in the fact that the entire optical arrangement (mirror, radiation source, lenses, prisms, cuvette) does not require the use of an anti-reflection coating.

FIG. 3 shows an exemplary embodiment of the cuvette 5 as a cross section in the area of the sensor connection 52 for connecting the sensor unit 42 for determining the CO2 concentration in the breathing gas flow. The outer surfaces 521a, 521b of the cuvette 5 are slanted, for example, so that they converge in a wedge shape. The outer surfaces 521a, 521b are planar, for example, so that the outer surfaces 521a, 521b define planes B and E, respectively, which intersect at an angle A. At least in the area of the sensor connection 52, the interior 57 of the cuvette 5 has two plane-parallel inner surfaces 571a, 571b, which define the planes C, for guiding the beam. The planes C intersect the planes B and E at an angle D, which is half the angle A, for example. In some embodiments, the outer surfaces 521a, 521b are not beveled, so that the planes B, E and C never intersect, the outer surfaces 521a, 521b therefore run plane-parallel to the inner surfaces 571a, 571b, which also run plane-parallel to one another. Insofar as the prisms 423, 425 are matched in their arrangement and the profile of the surfaces 427, 428a to the profile of the outer surfaces 521a, 521b, the infrared radiation enters the interior 57 of the cuvette 5 at an angle of approximately 90° from the inner surface 521a and then hits the inner surface 521b at an angle of about 90°. In some embodiments, the radiation does not run exactly axially parallel, for example the radiation is already bundled here in the direction of the detectors. As a result, it can happen that the radiation only runs at an angle of approximately 90° or hits the surfaces mentioned, resulting in deviations from the 90° angle. Of the A corresponding beam path is developed, for example, by the lens 423, so that the beams are perpendicular to the inner surfaces 571a, 572b.

The prisms 424b, 424a and the cuvette 5 are shown schematically in FIG. For example, surfaces 427 and 428a are tapered, as are outer surfaces 521a, 521b. Different planes B, E, F, G are defined by surfaces 427, 428a, 521a and 521b: surface 427 defines plane F, surface 428a defines plane G, outer surface 521a defines plane B and outer surface 521b defines the plane E. The surfaces 427, 428a, 521a, 521b are formed such that the planes F and B are parallel to each other and the planes G and E are parallel to each other. The planes F and B are at an angle A to the planes G and E. As already described, the surfaces 427, 428a, 521a, 521b are not beveled in some embodiments, but are all plane-parallel to one another, which is also the case for the planes B, E, F, G applies. For example, it can be advantageous if the surfaces 427, 428a, 521a, 521b are at least slightly beveled and taper in the shape of a wedge, so that the cuvette 5 can be positioned more easily in the sensor unit 42 and also that the outer surfaces 521a, 521b fit in a form-fitting manner the respective surfaces 427 and 428a can be ensured.

The three sensor units 41, 42, 43 are advantageously arranged together in a housing 45, as shown by way of example in a perspective view in FIG. The housing is roughly U-shaped, for example, so that the cuvette 5 can be inserted into the resulting space. The sensor units 41, 43 for determining the respiratory gas flow and respiratory gas pressure are arranged next to one another in the housing base 453 of the housing 45, for example. In order to ensure a beam path 429 through the cuvette 5 and thus also through the respiratory gas, the optical components of the sensor unit 42 for determining the CO2 concentration of the respiratory gas are arranged in the housing sides 452, 454. For example, the radiation source 422 is arranged together with the mirror 421, the lens 423 and the prism 424b in one side 452 of the housing and the prism 424a with the lens 425 is arranged in the other side 454 of the housing. The detector 426 or the detector surfaces 426a, 426b are also arranged, for example, in the housing side 454 or below the housing side 454 in the housing base 453 or at the transition from the housing side 454 to the housing base 453. If the measuring unit 4 has an interface 44 for connecting external devices, this interface 44 is also arranged, for example, in the housing base 453; alternatively, an arrangement of the interface 44 in one of the housing sides 452, 454 is also conceivable.

The power supply for the measuring unit 4 or the sensor units 41, 42, 43 is produced, for example, via an optionally replaceable battery or rechargeable battery integrated in the housing 45. In some embodiments, the measuring unit 4 is supplied with power via an interface. For example, a connected ventilator can also supply the measuring unit 4 with energy. For this purpose, the interface between the ventilator and the measuring unit 4 can be set up, for example, in such a way that, in addition to the signal and/or data transmission, the power supply also takes place. As an alternative or in addition, the measuring unit 4 receives an internal or external power pack, which enables a direct power supply.

For a secure and detachable connection between the measuring unit 4 and the cuvette 5, both the measuring unit 4 and the cuvette 5 can have connecting elements 451, 61, for example, as illustrated in a highly simplified manner in FIG. 6 using an exemplary embodiment. For example, the connectors 451, 61 can interlock and block each other. For example, the connecting elements 451, 61 can together form a click mechanism, so that the measuring unit 4 can be clicked onto the cuvette 5. It is also conceivable that a clicking noise gives audible feedback that the measuring unit 4 is connected to the cuvette 5 .

In some embodiments, it is also conceivable, for example, additionally or alternatively, for the measuring unit 4 to have a type of cover or bolt which is closed after the measuring unit 4 is connected to the cuvette 5 and fixes the cuvette 5 in the measuring unit 4 .

Figure 7 shows the essential optical components (mirror 421, radiation source 422, lens 423 with prism 424b, prism 424a with lens 425, detector surfaces 426a and 426b) of sensor unit 42 and a cross section through the cuvette in the area of sensor connection 52 for sensor unit 42 Determination of the CO2 concentration. Other electronic components and the housing 45 are not shown for purposes of illustration. The feed-through openings 511 of the sensor connection 51 for the sensor unit 41 for measuring the respiratory gas flow and the bore 531 of the sensor connection 53 for the sensor unit 43 for measuring the respiratory gas pressure are arranged in the bottom 523 of the cuvette 5 . The lead-through openings 511 are arranged, for example, in a receptacle 512 which is designed to receive the sensor unit 41 for determining the respiratory gas flow. The receptacle 512 is manufactured as a separate part, for example, and is placed in a corresponding recess which is designed to hold the receptacle 512 . For example, the receptacle 512 is clipped into the corresponding recess in the cuvette, for example using a click mechanism. In addition, it is also conceivable and possible for the receptacle 512 to be produced in one piece with the cuvette 5 and possibly only to be characterized by the passages 511 . In the embodiment shown, the cuvette 5 or the receptacle 512 has four passages 511 . In a further exemplary embodiment, the receptacle 512 or the cuvette 5 can have five passages 511, with a total of one to ten passages 511 generally being possible. The passages 511 can, for example, also be distributed over a number of receptacles 512 and/or can be arranged at a number of different points on the cuvette 5 .

In particular when the measuring unit 4 is designed as a reusable unit and the cuvette 5 is designed as a disposable item, the possibility described above of detachably connecting the cuvette 5 to the measuring unit 4 is decisive. If the measuring unit 4 is designed as a reusable unit, it can be considered here that the entire measuring unit can be cleaned and, for example, compared to a cleaning sterilization and/or disinfection and is not damaged. In some embodiments, for example, individual parts of the measuring unit 4 can also be exchangeable - e.g. the sensor pins 411 and/or the sensor head 431. The interior of the measuring unit 4 can also be sealed, for example, so that no substances can penetrate into the housing 45 from the outside. It would therefore be sufficient if the surfaces of the measuring unit 4 can be sterilized and/or disinfected. In particular, care must be taken to ensure that the materials used are stable during cleaning and do not dissolve or become damaged in any other way.

In some embodiments, both the cuvette 5 and the measuring unit 4 are designed as disposable items. The measuring unit 4 can, for example, be permanently connected to the cuvette 5 so that the measuring device is designed as a workpiece without the measuring unit 4 and cuvette 5 being able to be separated. In addition to the measuring unit 4, the cuvette 5 can also be designed as a reusable item, ie reusable. For this purpose, it is assumed that the cuvette 5 can be sterilized and also disinfected.

In the state shown in FIG. 7, the sensor unit 42 is connected to the cuvette 5, the prisms 424a and 424b being in positive contact with the side walls 522a and 522b on the outside. In addition, it can be seen in the exemplary representation of the cuvette in Figure 7 that the pressure measurement via the sensor connection 53 or the bore 531 can be carried out in the same area of the cuvette 5 as the CO2 measurement via the sensor unit 42. For this purpose, the bore 531 is in The bottom 523 of the cuvette 5 is formed while the side walls 522a and 522b are formed in the same portion of the cuvette 5 to function as the sensor terminal 52 for the sensor unit 42 for measuring the CO2 concentration.

In principle, an arrangement of the sensor connection 51 for the sensor unit 51 for determining the respiratory gas flow in the area of the sensor connection 52 for determining the CO2 concentration would also be possible, but it would have to be ensured that no sensor pins 411 have to be arranged in the interior 57 of the cuvette 5 or they are at least placed outside of the beam path 429 of the sensor unit 42 .

FIG. 8 shows a section along an exemplary embodiment of the cuvette 5 with the measuring unit 4 in a top view. For example, a coupling is formed on the cuvette 5, via which, for example, a Y-piece 54, an exhalation device 11 and/or in general an adapter for establishing a gas-conducting connection, for example with a ventilator, can be connected. In the embodiment shown as an example in FIG. 8, the coupling 60 is designed so that the cuvette 5 can be connected to the Y-piece 54 in a gas-conducting manner. A locking ring 58 , which also serves as an axial bearing 56 , is attached to the coupling 60 for connection to the Y-piece 54 . The securing ring 58 is designed, for example, in such a way that the Y-piece 54 can be slipped over the coupling 60 but then gets caught on the securing ring 58 so that it is no longer possible to simply pull off the Y-piece 54 . Because the locking ring 58 is also designed as an axial bearing 56, the Y-piece 54 can be freely rotatably connected to the cuvette 5 or the coupling 60. In some embodiments of the Measuring device 1 or the cuvette 5, the cuvette 5 does not include a coupling 60, in particular if no other devices (such as a ventilator 2) are to be connected to the cuvette in a gas-conducting manner. In some embodiments, the coupling 60 can also be in the form of a simple piece of pipe, over which, for example, an elastic hose or an adapter can be attached.

In order to prevent a leak, that is to say an escape of the breathing gas, in the connection between the Y-piece 54 and the cuvette 5, a seal 55 is also arranged on or around the coupling 60. The seal 55 leads around the coupling 60, for example. For example, the seal 55 is made of a silicone, for example with a low preload. While the combined circlip 58 with axial bearing 56 ensures the basic rotation of the Y-piece 54, the rotation is resistance, so the difficulty or ease of rotation primarily determined by the resulting between seal 55 and Y-piece 54 friction / friction. This resistance to rotation is particularly low, so the Y-piece 54 and cuvette 5 can easily be rotated in opposite directions. The rotational resistance between the Y-piece 54 and the cuvette 5 is preferably in a range from 10 to 80 N*cm.

The bore 531 of the sensor connection 53 and the receptacle 512 of the sensor connection 51 with the four passages 511 , for example, are arranged in the base 523 of the cuvette 5 . The prisms 424a, 424b of the sensor unit 42 for determining the CO 2 concentration of the breathing gas lie on the side walls 522a, 522b of the cuvette 5 from the outside. The beam path 429 (not shown in Figure 8), starting from the radiation source 422, guides the cuvette 5 through the interior space 57 in the area above the bore 531 of the sensor connection 53. The three sensor units 41, 42, 43 are, for example, together in one housing 45 of the measuring unit 4 are arranged, only the essential optical elements of the sensor unit 42 for determining the CO2 concentration being shown in FIG. Based on the view of FIG. 8, the sensor units 41 and 43 are arranged under the respective sensor connections 51 and 53 in the housing 45 (as shown in FIG. 5 by way of example).

The cuvette 5 is divided, for example, in such a way that the sensor connections 51 , 52 , 53 are arranged between the coupling 60 and the connection 59 . Accordingly, the measuring unit 4 is likewise connected between the coupling 60 and the connection 59 .

Another cross-sectional view through the cuvette 5 and the measuring unit 4 is shown as an example in FIG. The cross section of Figure 9 is perpendicular to the cross section of Figure 8.

The beam path 429 of the sensor unit 42 for determining the CO2 concentration of the breathing gas emanates from the radiation source 422, with the radiation source 422 emitting rays at least both in the direction of the mirror 421 and in the direction of the lens 423. In order to achieve the highest possible radiation yield, the mirror 421 is designed, for example, as a gold-coated, aspheric, anamorphic concave mirror, with the mirror 421 reflecting the rays coming from the radiation source 422 in the direction of the lens 423 reflected. The lens 423, for example designed as a Fresnel lens, is made in one piece with the prism 424b and serves to shape the beam and thus align the beams onto the cuvette 5. The beams are aligned, for example, so that they are perpendicular to the direction of the respiratory gas flow through the cuvette 5 run. The prism 424b is formed, for example, in such a way that it has a beveled side which can bear against the side wall 522a of the cuvette 5 in a form-fitting manner. The bevel is formed at an angle which also corresponds to the bevel of the side end wall 522a. On the side of the cuvette 5 opposite the prism 424b, the prism 424a, which is designed, for example, as a roof prism, rests in a form-fitting manner on the side wall 522b of the cuvette 5. The prism 424a is formed in one piece with a lens 425, for example, this lens being designed as a Fresnel lens, for example. The rays are totally reflected at the surface 428b of the prism 424a and guided in the direction of the detector 426 . The lens 425 is used, for example, to shape the beam so that the same beam image is imaged on the two detector surfaces 426a, 426b. The detector surfaces 426a, 426b are designed in such a way that the detector surfaces 426a, 426b detect two different wavelengths, one detector surface being designed as a reference detector and one detector surface as a measuring detector.

In the embodiment shown as an example, the sensor unit 43 is arranged in the same area along the cuvette 5 as the sensor unit 42. The bore 531 (not shown in Figure 9) of the sensor connection 53 is therefore below the beam path 429 of the sensor unit 42. The sensor unit 43 or for this purpose, the sensor head 431 of the sensor unit 43 is arranged in the cutout 532 of the bottom 523 of the cuvette 5 or is inserted into the cutout 532 by connecting the measuring unit 4 to the cuvette 5 .

The sensor pins 411 of the sensor unit 41 protrude through the passages 511 of the receptacle 512 or the cuvette 5 into the interior 57 of the cuvette. The sensor pins arranged in this way are used, for example, to determine the respiratory gas flow.

FIG. 10 shows a cross section along the cuvette 5, the section going through the bottom 523 and top 524 in the middle. The Y-piece 54 is connected to the cuvette 5 via the coupling 60 of the cuvette 5 . A seal 55 is arranged in the coupling 60 in order to enable a leak-free connection between the Y-piece 54 and the cuvette 5 . A locking ring 58 is arranged in the coupling 60 to prevent the Y-piece 54 from being accidentally released from the coupling 60 , which ring also serves as an axial bearing 56 , for example. For example, the locking ring 58 and the Y-piece 54 are designed in such a way that the Y-piece 54 hooks behind the locking ring 58 when it is connected to the cuvette 5 and is thus secured against accidental loosening.

Advantageously, the cuvette 5 in particular has a compact design, as a result of which the dead space volume in the cuvette 5 can be reduced, even with a Y-piece 54 connected. The maximum length 70 of the cuvette 5 including the Y-piece 54 and connection 59 is 150 mm, preferably a maximum of 80 mm, measured from the outermost edge of the cuvette 54 to the outermost edge of the connection 59, as shown in FIG. In particular, the length 70 is in a range of 30 to 80 mm, but can also be in some embodiments be less than 30 mm. In some embodiments, the length 70 is 46 (+/- 15) mm. In some embodiments, for example, the Y-piece 54 has smaller dimensions, which means that the length 70 can be reduced. The connection 59 is designed, for example, as a standard connection for a patient interface 3 or a connection (eg piece of tubing) to the patient interface 3 . Depending on the design of the patient interface 3, there is also the possibility of making the connection 59 correspondingly more compact or larger. The dimensions of the connection 59 are therefore closely related to the patient interface 3 to be connected.

The outer diameter 73 of the connection 59 also depends on the selection of the patient interface 3 . For example, the embodiment shown in FIG. 12 a) is a standard connection for a tracheostomy tube as patient interface 3. Accordingly, the outer diameter 73 of the connection 59 is 18.1 mm, which is suitable for a 15 mm inner cone, for example. Depending on the patient interface 3, the outer diameter 73 can also be smaller or larger. If, for example, a simple tube is used as the patient interface 3, through which the living being exhales into the cuvette 5, the outer diameter 73 can be made correspondingly smaller for the tube. In some specific embodiments, the inside diameter of the connection 59 in particular is at least similar in size to the inside diameter of the cuvette 5 in the area of the sensor connections. If the inner cross-section of the cuvette 5 and/or the connection 59 is not circular, the cross-sectional areas should be in a similar range, for example deviating from one another by no more than 200 mm ² and/or 50%.

The same requirements apply to the dimensions of the coupling 60, which should in particular be designed such that a Y-piece 54 can be connected, for example. In order to ensure that the cuvette 5 is as compact as possible, the outer diameter 72 of the coupling is between 5 and 20 mm, for example. These dimensions are primarily designed for use in living beings with small lung volumes (for example premature babies). Larger diameters 72 (>20 mm) may also be necessary for use on living beings with larger lung volumes (and therefore also larger respiratory flows).

The inner surfaces 571a and 571b of the side walls 522a and 522b are parallel to each other at an exemplary distance 71 of 4.2 mm. In general, the distance 71 can be from 2 mm to 100 mm, preferably between 2 mm and 10 mm. Here, too, the distance 71 can be larger, depending on the living being. In some embodiments of the cuvette 5, the side walls 522a, 522b or the inner surfaces 571a, 571b are not flat, but round, so that the cuvette 5 has a circular cross-section at least in the area of the sensor connections 51, 52, 53; this would then be the diameter, for example to be dimensioned with the distance 71.

Another view of the cuvette 5, including the lengths 74, 75, can be seen in FIG. 12b). The entire length 75 of the cuvette 5, including the coupling 60 and the connection 59, is a maximum of 120 mm, for example, preferably less than 80 mm. In some embodiments the entire length 75 of the cuvette 5 is in a range from 15 mm to 50 mm. In some exemplary embodiments, the length 75 of the cuvette 5 is preferably 36.5 (+/−15) mm.

The length 74 of the area of the sensor connections 51, 52, 53 of the cuvette 5 is 5 (+/−0.4) mm, for example, but can also vary in a range from 2 mm to 25 mm. In some embodiments of the measuring device 1, the length 74 also corresponds to the width 76 of the measuring unit 4, at least in the area of the housing sides 452, 454. In some embodiments, the width 76 of the housing sides 452, 454 can also be +/- 10 mm in length 74 and is, for example, 12 (+/- 5) mm. In particular, the sensor connections 51 and 53 are arranged next to one another in the base 523 of the cuvette 5 along the length 74 . The length 74 is thus also decisively determined by the dimensions of the sensor connections 51, 53, but is not limited. The length 74 can thus also be selected to be greater than would be necessary for the sensor connections 51, 53. Overall, the length 74 should at least be chosen such that it is sufficient to connect the measuring unit 42 .

Since the Y-pieces usually include an extra connection for the pressure measurement, but this measurement is ideally also integrated into the measuring device 1, it is possible in some embodiments to use a Y-piece, which does not include this extra connection, whereby a further shortening of the structure is made possible.

It is to be understood that the dimensions given for FIGS. 11 and 12a, b primarily serve for exemplary embodiments for living beings with small lung and/or tidal volumes (small animals, premature babies, newborns, babies). In embodiments designed for living beings with larger lung and/or respiratory volumes (e.g. adult humans), it may sometimes be necessary to adjust the dimensions accordingly.

In the figures 13 to 16 further embodiments of the measuring device 1, partly in combination with a patient interface 3 and / or a ventilator 2 can be seen. If the measuring device 1 is only connected to the ventilator 2 in a gas-conducting manner, i.e. the ventilator 2 is not also used for processing, calculating, evaluating, etc. the measurement signals of the measuring unit 4, any ventilator can be used in connection with the measuring device 1, provided that ventilator has a breathing gas source. In some embodiments, the system is designed in such a way that the measuring device 1 generates the measuring signals and, if necessary, processes them via an internal processing unit and these (processed and/or processed) measuring signals or measured values are forwarded to the ventilator 2 . The ventilator 2 is then designed and set up, for example, to evaluate and/or output the measurement signals. For this purpose, the ventilator 2 has, for example, an interface for connecting to the measuring device 1 or the measuring unit 4 as well as the necessary evaluation and calculation units and optionally output units and/or display elements. In addition, it is also conceivable that the system is designed in such a way that the ventilator 2 automatically controls the breathing gas source using the values and data from the measuring device 1 via a control unit and adjusts ventilation settings.

In some embodiment devices, the measuring device 1 is designed such that it can either be connected directly to a patient interface 3 via the connection 59 and/or is connected to the patient interface 3 via a connection 6, as shown schematically in FIG. The connection 59 can, for example, also be set up in such a way that the measuring device 1 or the cuvette 5 is integrated directly as a part in the patient interface 3 . In some embodiments, the patient interface 3 is also part of the cuvette 5, for example if the patient interface 3 consists only of a mouthpiece through which the living being at least exhales. In order to evaluate and/or process the measurement signals from measurement unit 4 or from the individual sensor units 41, 42, 43, measurement unit 4 is equipped, for example, with at least one interface 44, via which a signal processing device 10 is connected, for example, which is designed, for example, to process the measurement signals of the Sensor units 41, 42, 43 to convert at least into measured values. In some embodiments, such a signal processing device 10 is also already integrated into the measuring unit 4, as shown in FIG. 14 by way of example. For example, the interface 44 is then used to forward the measured values, for example to a display and/or to a ventilator 2, which is designed, for example, to evaluate and interpret the measured values. As already described above, the measuring device 1, specifically the measuring unit 4, can itself also have processing, calculation and evaluation units and optionally also include operating and display elements.

FIG. 15 shows an exemplary embodiment of the measuring device 1 in combination with a ventilator 2 and a patient interface 3. The cuvette 5 is connected to a Y-piece 54 via the coupling 60, for example. The Y-piece 54 is in turn connected to the ventilator 2 via the gas-conducting connections 7 and 9 . For example, connection 7 serves as an inspiration line, so while the living being is inhaling, breathing gas is routed through connection 7 from the ventilator 2 through the Y-piece 54 and the cuvette 5 via the connection 59 and the connection 6 to the patient interface 3, to which, for example a living being is connected. The connection 9 represents, for example, the expiration hose, via which the respiratory gas is conducted away while the living being exhales. When exhaling, the exhaled breathing gas of the living being is thus routed from the patient interface 3 via the connection 6 to the connection 59 through the cuvette 5 and the Y-piece 54 and the connection 9 to the ventilator 2 . For example, at least the respiratory gas flow, respiratory gas pressure and CO2 concentration of the respiratory gas are measured both during inhalation and during exhalation by the sensor units 41, 42, 43. The measuring unit 4 is connected, for example, via an electrical connection 8 to the ventilator 2, which can at least evaluate and optionally interpret and output the measuring signals of the sensor units.

In some embodiments, the measuring device 1 is designed to be connected to a ventilator 2 via an exhalation device 11, for example, as shown in FIG Figure 16 shown as an example. For this purpose, the exhalation device 11 is connected to the cuvette 5 in a gas-conducting manner, for example via the coupling 60 . In contrast to the embodiment described in FIG. 15, the measuring device 1 is only connected to the ventilator 2 via a gas-conducting connection 7 . For example, respiratory gas is supplied to the living being during inspiration via this gas-conducting connection 7 . During expiration, the breathing gas exhaled by the living being is released into the ambient air, for example via the exhalation device 11, for example via a valve.

In further supplementary or alternative embodiments, both the measuring unit 4 and the cuvette 5 can be arranged in and/or on the ventilator 2 . For example, the measuring unit 4 is integrated into the ventilator 2 and the cuvette 5 can be connected to the measuring unit 4 from the outside. Thus, the cuvette 5 would be arranged on the ventilator 2 , for example, while the measuring unit 4 is arranged in the ventilator 2 . In some embodiments, the measuring unit 4 is located in the ventilator 2 in such a way that the cuvette 5 is also integrated into the ventilator 2 so that it can be connected to the measuring unit 4 . The entire measuring device is then located in the ventilator 2. It is also possible for the measuring device 1, consisting of the measuring unit 4 and cuvette 5, to be attached to the outside of the ventilator. For example, the measuring device 1 is connected directly to a gas-conducting connection of the ventilator 2 and optionally fixed to the ventilator 2 via a holding mechanism.

It is also possible, for example, for essential electronic components for the measuring unit 4 to be integrated into the ventilator 2 and for the measuring unit 4 to consist exclusively of the sensor units 41, 42, 43 (and any cabling and housing). Further components such as the power supply are then in the ventilator 2 . The measuring unit 4 can then be connected in the ventilator 2 . Here, for example, a click solution can be installed, through which the measuring unit 4 is detachably fixed in the ventilator 2 .

It is therefore possible, for example, that the measuring unit 4 is integrated in the ventilator 2 (either permanently installed or easily removable/replaceable) and/or the measuring unit 4 is attached to the ventilator 2 and (removably) fixed and/or the measuring unit 4 is not is attached directly in or on the ventilator 2, but is arranged in the vicinity of the living being (for example a premature baby/a patient). The same applies to the cuvette 5 - this can, for example, be integrated together with the measuring unit 4 in the ventilator 2 and/or be connected to the measuring unit 4 in the ventilator 2 and/or (outside) on the ventilator 2 to the measuring unit 4, which can optionally be in the or can be arranged on the ventilator 2, can be connected and/or—if necessary together with the measuring unit 4—are arranged in the vicinity of the living being.

Reference List

1 measuring device

2 ventilator 3 patient interface

4 measurement unit

5 cuvette

6 connection

7 connection

8 cables

9 connection

10 signal processing device

11 exhalation device

41 sensor unit

42 sensor unit

43 sensor unit

44 interface

45 housing

51 sensor connector

52 sensor connector

53 sensor connector

54 Y piece

55 seal

56 thrust bearing

57 interior

58 locking ring

59 connection

60 pairing

61 fastener

70 length (cuvette + Y piece)

71 Distance

72 outer diameter (coupling)

73 outer diameter (connection)

74 length (sensor connections)

75 length (cuvette) 76 width (unit of measure)

411 sensor pin

421 mirrors

422 radiation source

423 lens

424a prism

424b prism

425 lens

426 detector

426a detector surface

426b detector surface

427 surface

428a surface

428b surface

429 beam path

431 sensor head

451 fastener

452 case side

453 caseback

454 case side

511 execution

512 recording

521a outer surface

521b outer surface

522a side wall

522b side wall

523 floor

524 ceiling

531 bore

532 recess

571a side surface 571b side surface

A angle

B extension

C extension D angle

Claims

28

Expectations

1. Measuring device (1) for analyzing a respiratory gas flow, comprising at least one measuring unit (4) and a cuvette (5), the cuvette (5) being detachably connected to the measuring unit (4) and being set up and designed for a respiratory gas to flow through to be characterized in that the measuring unit (4) has at least two sensor units (41, 42), at least one sensor unit (41) being designed to determine a breathing gas flow and at least one sensor unit (42) being designed to determine a CO2 concentration in a breathing gas to determine, the cuvette (5) comprises at least two sensor connections (51, 52) for connecting the sensor units (41, 42) for determining at least one respiratory gas flow and at least one CO2 concentration of a respiratory gas.

2. Measuring device (1) according to at least one of the preceding claims, characterized in that the cuvette comprises at least three sensor connections (51, 52, 53), the at least third sensor connection (53) being a sensor connection for a sensor unit for determining a respiratory gas pressure.

3. Measuring device (1) according to at least one of the preceding claims, characterized in that the measuring unit comprises at least three sensor units (41, 42, 43), the at least third sensor unit (43) being a sensor unit for determining the respiratory gas pressure.

4. Measuring device (1) according to at least one of the preceding claims, characterized in that the sensor unit (42) for determining the CO2 concentration in the breathing gas has at least one radiation source (422), at least one detector unit (426), at least one mirror (421) , at least two lenses (423, 425) and at least one prism (424a, 424b).

5. Measuring device (1) according to at least one of the preceding claims, characterized in that at least two of the lenses (423, 425) are designed as Fresnel lenses and at least one of the two lenses (423, 425) on the at least one prism (424a , 424b).

6. Measuring device (1) according to at least one of the preceding claims, characterized in that the sensor unit (42) comprises at least two prisms (424a, 424b), with at least one of the at least two lenses (423, 425) are arranged.

7. Measuring device (1) according to at least one of the preceding claims, characterized in that the mirror (421) is a concave mirror.

8. Measuring device (1) according to at least one of the preceding claims, characterized in that the mirror (421) for the high reflection of rays in a wavelength range from 3500 nm to 4600 nm, in particular in the wavelength range from 3910 +/- 100 nm and 4260 + /- 100 nm, preferably coated with gold.

9. Measuring device (1) according to at least one of the preceding claims, characterized in that the mirror (421) is aspherical.

10. Measuring device (1) according to at least one of the preceding claims, characterized in that the mirror (421) is anamorphic.

11. Measuring device (1) according to at least one of the preceding claims, characterized in that the detector unit (426) comprises at least two detector surfaces (426a, 426b).

12. Measuring device (1) according to at least one of the preceding claims, characterized in that at least one of the at least two detector surfaces (426a, 426b) for detecting one of wavelengths in a range of 3950 nm to 4550 nm, preferably in the wavelength range of 4260 +/- - 100 nm, and at least one of the at least two detector surfaces (426a, 426b) is designed to detect wavelengths in a range from 3600 nm to 4200 nm, preferably in the wavelength range of 3910 +/- 100 nm.

13. Measuring device (1) according to at least one of the preceding claims, characterized in that at least one of the at least two detector surfaces (426a, 426b) is designed as a measuring detector and at least one of the at least two detector surfaces (426a, 426b) is designed as a comparison detector, wherein the at least two detector surfaces (426a, 426b) have the same size and wherein the detector surface (426a) is designed as a measuring detector for detecting wavelengths in a range from 3950 nm to 4550 nm, preferably in the wavelength range from 4260 +/- 100 nm.

14. Measuring device (1) according to at least one of the preceding claims, characterized in that the radiation source (422) is an infrared radiation source, preferably an incandescent lamp.

15. Measuring device (1) according to at least one of the preceding claims, characterized in that at least one prism (424a, 424b) is designed as an inverted prism, preferably as a roof prism.

16. Measuring device (1) according to at least one of the preceding claims, characterized in that at least one prism (424a, 424b) is materially connected to at least one of the at least two lenses (423, 425).

17. Measuring device (1) according to at least one of the preceding claims, characterized in that at least one prism (424a, 424b) is produced in one piece with at least one of the at least two lenses (423, 425).

18. Measuring device (1) according to at least one of the preceding claims, characterized in that the cuvette (5) is arranged between one of the at least two lenses (423, 425) and the at least one prism (424a, 424b).

19. Measuring device according to at least one of the preceding claims, characterized in that the cuvette (5) is arranged between two prisms (424a, 424b), the two prisms (424a, 424b) being arranged between two lenses (423, 425), resulting in a sequence of lens (423), prism (424b), cuvette (5), prism (424a), lens (425). 0. Measuring device (1) according to at least one of the preceding claims, characterized in that the mirror (421), the radiation source (422), the lenses (423, 425), the prisms (424a, 424b) of the sensor unit (42) and the sensor connection (52) of the cuvette (5) for connecting the sensor unit (42) for determining the CO2 concentration are not coated with an anti-reflection coating.

21. Measuring device (1) according to at least one of the preceding claims, characterized in that the total transmission of the optics consisting of mirror (421), radiation source (422), lenses (423, 425) and prisms (424a, 424b) of the sensor unit (42 ) and the cuvette (5), is over 50%, preferably over 60%.

22. Measuring device (1) according to at least one of the preceding claims, characterized in that the prisms (424a, 424b), the lenses (423, 425) and the cuvette (5) are made of a plastic, the plastic being a material al thickness of 2 mm has a transmission of infrared rays, preferably in the wavelength range between 3910 +/- 100 nm to 4260 +/- 100 nm, of over 85%, preferably over 90%, more preferably over 92%.

23. Measuring device (1) according to at least one of the preceding claims, characterized in that the prisms (424a, 424b), the lenses (423, 425) and the cuvette (5) with a material thickness of 2 mm transmit infrared - Rays, preferably in the wavelength range of 3910 +/- 100 nm and 4260 +/- 100 nm, of more than 85%, preferably more than 90%, more preferably more than 92%.

24. Measuring device (1) according to at least one of the preceding claims, characterized in that the plastic is more than 90% by weight a polysulfone, a polyether sulfone, a polymethylene methacrylate, a polycarbonate, a polytetrafluoroethylene, polyether sulfone, poly(arylene sulfone), a polyimide, is a polyamide and/or a mixture of at least one of the listed polymers and optionally another polymer.

25. Measuring device (1) according to at least one of the preceding claims, characterized in that the at least one prism (424a, 424b) of the sensor unit (42) is made from a polysulfone and/or a polyethersulfone and/or a polycarbonate.

26. Measuring device (1) according to at least one of the preceding claims, characterized in that the lenses (423, 425) are made from a polysulfone and/or a polyethersulfone and/or a polycarbonate.

27. Measuring device (1) according to at least one of the preceding claims, characterized in that at least the lenses (423, 425) and the at least one prism (424a, 424b) of the sensor unit (42) for determining the CO2 concentration, and the cuvette (5) made of a polysulfone and/or a polyethersulfone and/or a polycarbonate.

28. Measuring device (1) according to at least one of the preceding claims, characterized in that a surface (427, 428) of one of the prisms (424a, 424b) together with a surface (427, 428) of a second prism (424a, 424b) a form tapering gaps, the cuvette (5) having an outer cross section matching the tapering gap in the area of the sensor connection (52) for connecting the sensor unit (42) for determining the CO2 concentration.

29. Measuring device (1) according to at least one of the preceding claims, characterized in that the cuvette (5) has an interior (57), the interior (57) having at least two side surfaces (571a, 571b) which run parallel to one another, wherein the two side surfaces (571a, 571b) each define a plane (C), and wherein the cuvette (5) has at least two outer surfaces (521a, 521b) wherein the outer surfaces (521a, 521b) each define a plane (B) and the two planes (B) are at an angle (A) to one another, and the planes (C) are at an angle (D) to the planes (B ) where the angle (D) is half the angle (A).

30. Measuring device (1) according to at least one of the preceding claims, characterized in that the cuvette (5) comprises a coupling (60), wherein the coupling

(60) is designed and set up to connect a Y-piece (54) and/or an exhalation device (11) to the cuvette (5) in a gas-conducting manner.

31. Measuring device (1) according to at least one of the preceding claims, characterized in that the cuvette (5) and the Y-piece (54) and/or the exhalation device (11) are rotatably connected to one another.

32. Measuring device (1) according to at least one of the preceding claims, characterized in that the cuvette (5) and the Y-piece (54) and/or the exhalation device (11) are connected in such a way that they are secured against accidental release .

33. Measuring device (1) according to at least one of the preceding claims, characterized in that the coupling (60) for connecting the cuvette (5) and Y-piece (54) and/or the exhalation device (11) has at least one seal (55) Has at least one locking ring (58) and at least one axial bearing (56), wherein the locking ring (58) secures against accidental loosening.

34. Measuring device (1) according to at least one of the preceding claims, characterized in that at least one axial bearing (56) and one retaining ring (58) are designed together as a functional component.

35. Measuring device (1) according to at least one of the preceding claims, characterized in that the cuvette (5) has a connection (59) for a gas-conducting connection (6) to a patient interface (3), this connection being in one piece with the cuvette ( 5) is made.

36. Measuring device (1) according to at least one of the preceding claims, characterized in that the cuvette (5) and the measuring unit (4) have at least one connecting element (451) of the measuring unit (4) and at least one connecting element

(61) of the cuvette (5) are detachably connected to one another.

37. Measuring device (1) according to at least one of the preceding claims, characterized in that the connecting elements (61, 451) form a click system.

38. Measuring device (1) according to at least one of the preceding claims, characterized in that the sensor connection (51) for connecting a sensor unit (41) for determining the respiratory gas flow has at least one passage (511) for at least one sensor pin (411).

39. Measuring device (1) according to at least one of the preceding claims, characterized in that the sensor connection (51) has at least one receptacle (512) for accommodating the sensor unit (41) for determining the respiratory gas flow, the at least one passage (511) for the at least one sensor pin (411) is arranged in the receptacle (512). 32

40. Measuring device (1) according to at least one of the preceding claims, characterized in that the sensor connection (52) is designed for connecting a sensor unit (42) for determining the CO2 concentration and is set up to accommodate the cuvette (5) so that the outer surfaces (521a, 521b) of the cuvette (5) are in positive contact with the prisms (424a, 424b) and/or the lens (423).

41. Measuring device (1) according to at least one of the preceding claims, characterized in that the sensor connection (52) for connecting a sensor unit (42) for determining the CO2 concentration is essentially designed as two opposite, flat, smooth outer surfaces (521a, 521b ) of the side walls (522a, 522b) of the cuvette.

42. Measuring device (1) according to at least one of the preceding claims, characterized in that the sensor connection (53) for connecting a sensor unit (43) for determining the respiratory gas pressure has at least one recess (532) for receiving the sensor head (431) of the sensor unit (43 ) and a bore (531) from the recess (532) into the interior (57) of the cuvette (5).

43. Measuring device (1) according to at least one of the preceding claims, characterized in that the cuvette (5) has an overall length (75) of less than 120 mm, preferably less than 80 mm.

44. Measuring device (1) according to at least one of the preceding claims, characterized in that the wall thickness of the cuvette (5) in the area of the sensor connection (52) for connecting a sensor unit (42) for determining the CO2 concentration is between 0.5 mm and 3 mm, preferably between 0.8 mm and 2 mm.

45. Measuring device (1) according to at least one of the preceding claims, characterized in that the wall thickness of the cuvette (5) in the area of the sensor connection (52) for connecting a sensor unit (42) for determining the CO2 concentration has a tapering cross-sectional profile.

46. Measuring device (1) according to at least one of the preceding claims, characterized in that the cuvette (5) can be integrated into a patient interface (3).

47. Measuring device (1) according to at least one of the preceding claims, characterized in that the at least two sensor units (41, 42) of the measuring unit (4) are arranged together in a housing (45).

48. Measuring device (1) according to at least one of the preceding claims, characterized in that at least three sensor units (41, 42, 43) of the measuring unit (4) are arranged in one housing (45).

49. Measuring device (1) according to at least one of the preceding claims, characterized in that the sensor unit (41) for determining the respiratory gas flow works according to the principle of a thermal gas flow determination.

50. Measuring device (1) according to at least one of the preceding claims, characterized in that the sensor unit (41) for determining the respiratory gas flow works according to the principle of thermal anemometry, preferably hot-draft anemometry.

51. Measuring device (1) according to at least one of the preceding claims, characterized in that the sensor unit (41) for determining the respiratory gas flow 33 comprises at least one sensor pin (11), the at least one sensor pin (411) being guided at least partially into the interior (57) of the cuvette (5) through the passage (511).

52. Measuring device (1) according to at least one of the preceding claims, characterized in that the sensor unit (43) for determining the respiratory gas pressure determines the respiratory gas pressure via a difference to the atmospheric pressure.

53. Measuring device (1) according to at least one of the preceding claims, characterized in that the sensor unit (43) comprises at least one sensor head (431).

54. Measuring device (1) according to at least one of the preceding claims, characterized in that the cuvette (5) has a weight of less than 80 g, preferably less than 30 g.

55. Measuring device (1) according to at least one of the preceding claims, characterized in that the measuring device (1), consisting of measuring unit (4) and cuvette (5), has a total weight of less than 120 g, preferably less than 60 g.

56. Measuring device (1) according to at least one of the preceding claims, characterized in that the measuring unit (4) is designed as a reusable and reusable item and/or the cuvette 5 is designed as a disposable item.

57. System for analyzing a respiratory gas flow at least comprising a. a ventilator (2), b. a patient interface (3), characterized in that the system further comprises a measuring device (1) according to at least one of the preceding claims, wherein the measuring device (1) is gas-conductively connected to the patient interface (3) and the ventilator (2).

58. System according to at least one of the preceding claims, characterized in that the cuvette (5) is connected to the patient interface (3) via the connection (59) and the cuvette (5) is connected to the ventilator via the Y-piece (54). (2) is connected.

59. System according to claim 52, characterized in that at least the measuring unit (4) of the measuring device (1) is arranged in and/or on the ventilator (2).

60. Cuvette (5) for use in a measuring device (1) for analyzing a respiratory gas flow, characterized in that the cuvette (5) has at least two sensor connections (51, 52) for connecting sensor units (41, 42) for determining at least one Breathing gas flow and at least one CO2 concentration of a breathing gas.

61. Measuring unit (4) for use in measuring device (1) for analyzing a respiratory gas flow, characterized in that the measuring unit (4) has at least two sensor units (41, 42), at least one sensor unit (41) being designed to determine a respiratory gas flow and at least one sensor unit (42) is designed to determine a CO2 concentration in a breathing gas.

62. Sensor unit (42) for determining the CO2 concentration of a breathing gas, characterized in that the sensor unit (42) has at least one radiation source (422), 34 comprises at least one detector unit (426), at least one mirror (421), at least two lenses (423, 425) and at least one prism (424a, 424b).

63. Sensor unit (42) according to at least one of the preceding claims, characterized in that at least two of the lenses (423, 425) are designed as Fresnel lenses and at least one of the two lenses (423, 425) on the at least one prism (424a , 424b).

64. Sensor unit (42) according to at least one of the preceding claims, characterized in that the at least one prism (424a, 424b) is materially connected to at least one of the at least two lenses (423, 425).

65. Sensor unit (42) according to at least one of the preceding claims, characterized in that the at least one prism (424a, 424b) is produced in one piece with at least one of the at least two lenses (423, 425).

66. Sensor unit (42) according to at least one of the preceding claims, characterized in that the at least one prism (424a, 424b) and the lenses (423, 425) are made of a plastic, the plastic having a material thickness of 2 mm a transmission of infrared rays, in particular in the wavelength range of 3910 +/- 100 nm and 4260 +/- 100 nm, of more than 85%, preferably more than 90%, more preferably more than 92%.

67. Sensor unit (42) according to at least one of the preceding claims, characterized in that the plastic is more than 90 wt% a polysulfone, a

polyethersulfone, a polymethylene methacrylate, a polycarbonate, a

Polytetrafluoroethylene, polyether sulfone, poly(arylene sulfone), a polyimide, a polyamide and/or a mixture of at least one of the polymers listed and one or more other polymers of your choice.

68. Prism (424a, 424b) for use in a sensor unit (42) according to at least one of the preceding claims, characterized in that the prism (424a, 424b) is produced in one piece with a lens (423, 425), the lens ( 423, 425) is a Fresnel lens

69. Method for producing optical components from polysulfone and/or polyethersulfone and/or polycarbonate by injection molding, characterized in that the optical components are prisms (424a, 424b) and lenses (423, 425).

70. Method according to the preceding claim, characterized in that the prism (424a, 424b) is produced in one piece with a lens (423, 425).