AU693344B2 - A device for detecting components in exhaled air - Google Patents

Description

WO 96/32062 PCT/SE96/00474 1 A DEVICE FOR DETECTING COMPONENTS IN EXHALED AIR The present invention relates to a device for detecting one or more components in exhaled air, and particularly for detecting the presence of pathogenic bacteria Helicobacter pylori in stomach and intestinal tracts of human beings.

BACKGROUND OF THE INVENTION Gaseous components can be analyzed in various ways, such as by gas chromatography, flame photometry and spectrophotometry, for instance. These methods, however, require the use of expensive equipment and are much too advanced in many cases. Simpler, alternative methods are those in which the gas is absorbed by a material and the presence or absence of a gaseous component indicated with the aid of a colour indicator. Examples in this respect are the blow tubes used to indicate the presence of alcohol in exhalation air. These devices have the drawback of not being constructed for separate measurements on the absorbent material.

Certain conditions and illnesses can be indicated by analyzing exhalation air. For instance, stomach ulcers are caused mainly by the pathogenic bacteria Helicobacter pylori. A method has been described for indicating the presence of this bacteria and has been applied in clinical research for a number of years. According to this method, patients are to swallow an isotope-labelled, preferably radioactive, urea preparation. Helicobacter pylori present in the gastric and intestinal tract will break the urea down to carbon dioxide, among other materials. This carbon dioxide is then transported to the lungs through the normal physiology of the body, where it is exhaled together with the carbon dioxide that has been formed in remaining body organs. Because the carbon dioxide that is formed by the bacteria is labelled, the amount of carbon dioxide exhaled can be measured by causing the patient to blow the exhalation air through a tube WO 96/32062 PCT/SE96/00474 2 and down into a liquid which absorbs carbon dioxide. This liquid is then examined with the aid of appropriate measuring instruments, for instance a scintillator counter, to indicate isotope labelled components in the exhaled carbon dioxide as a sign of the presence of Helicobacter pylori.

The aforesaid method is relatively complicated and timeconsuming. In addition, it requires the use of expensive and bulky apparatus. Furthermore, no product for carrying out this method is actually available commercially.

OBJECTS OF THE INVENTION The object of the present invention is to provide apparatus for use in detecting one or more components in exhalation air. The apparatus shall be producible at low costs and shall also satisfy requirements of long-term storability and reproducibility of test results. Another object is also to obviate the complex handling of liquids and the use of spaceconsuming analysis instruments.

These objects are fulfilled by the present invention, which relates to a device which consists of a tubular element, which may be rigid or soft as a plastic bag and through which air is conducted. A nozzle is formed on one end of the tube.

The opposite end of the tube is fitted with a plate, which may either be an airtight plate or a porous membrane. The plate is attached to the tube in a manner which will enable it to be readily removed therefrom. The plate fitting may either have the form of a screw device or snap-coupling, or may simply comprise adhesive tape. A dry, absorbent material has been mounted on or incorporated in the plate. This absorbent material is adapted solely to absorb a specific amount of desired gaseous component. A colour indicator in the absorbent substance indicates when the maximum amount of gaseous component has been absorbed. When an airtight plate is used, the outer edge of the plate is perforated so as to c WO 96/32062 PCT/SE96/00474 3 allow air to pass out and therewith enable air to flow through the tube.

The patient blows exhalation air through the nozzle and causes said air to flow across or through the plate. The plate can be separated from the tube when the plate becomes saturated. The plate is then analyzed in an appropriate measuring instrument, to indicate the presence or absence of components in question.

In a preferred embodiment, the present invention is used to indicate the presence of isotope labelled carbon dioxide in exhalation air, and in particular to indicate the presence of radioactive carbon dioxide formed as a conversion product of the bacteria Helicobacter pylori. To this end, the plate has mounted thereon or incorporates a carbon dioxide absorbing material. A patient administered with radioactive labelled urea is asked to blow through the inventive device.

Carbon dioxide, including radioactively labelled carbon dioxide, is absorbed on the plate. The plate is then removed from the device and analyzed with regard to radioactivity in an appropriate measuring device, to indicate the presence of the bacterium Helicobacter pylori.

The present invention thus provides a simple device for use in indicating the presence or absence of components in exhalation air.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of an inventive devic.

Figure 2a is a view from above of a further embodiment of the inventive device.

Figure 2b is a side view of the embodiment shown in Figure 2a.

i I I- I WO 96/32062 PCT/SE96100474 4 DETAILED DESCRIPTION OF THE FIGURES Figure 1 illustrates primarily the embodiment in which a porous membrane is used and the air shall be caused to flow through the plate. The device is comprised of a tubular element 1 provided with a nozzle 2 at one end. An absorbent plate 3 is fitted detachably to the opposite end. When an airtight plate is used in this embodiment, the outer edge of the plate will be perforated with holes 4, so as to enable air to flow through the device. These perforations are excluded when a porous membrane is used.

Figures 2a and 2b show two views of one embodiment of the device suitable when an airtight plate is used. The reference signs used in the Figures correspond to those used in Figure 1. The broken line in Figure 2b indicates that the whole of the upper part of the device including the plate can be separated from the lower part and introduced into a measuring instrument. When a porous membrane is used, the device is not provided with perforations 4.

When using the device, a patient exhales through the nozzle 2. The exhalation air then passes through the tubular element 1, and flows through the plate 3, or across the plate 3, and out through the holes 4. The tube is constructed to ensure maximum contact between the air flow and the absorbent plate.

Subsequent to having absorbed a maximum amount of gaseous component, as indicated by the colour indicator, the plate is detached from the tubular element and introduced in a measuring instrument for indication of a desired component.

Alternatively, the whole of the upper part, including the plate, is detached from the remainder of the device and introduced into the measuring instrument.

The device may be made from any suitable material, preferably cardboard, paperboard or plastic of different kinds. Examples of plastics that can be used are polyethylene, polystyrene s~ _I I WO 96/32062 PCT/SE96/00474 or PVC. It is appropriate that the device can be sterilized by radiation or heat. The absorbent material will vary in dependence on the component to be indicated. Examples of carbon dioxide absorbent materials are sodium hydroxide and soda lime. The colour reaction on the plate that signals when the plate is saturated can be achieved with the use of commercially available soda lime as a colour indicator. Part of the device beneath or above the absorbent material will preferably be transparent, so that the colour reaction can be observed. Components that are to be detected may, for instance, be labelled or marked by means of isotopes. The measuring instrument used to detect labelled components will vary in accordance with labelling. For instance, radioactively labelled components can be indicated with a Geiger M1ller tube. From the aspect of mechanical strength, the device will preferably be packed in an airtight bag in a durable environment, for instance 4n a nitrogen gas environment when a carbon dioxide absorbent material is used.

The device may conveniently be adapted for one-time use only, for hygienic reasons.

1 I

Claims (7)

1.A device for use in detecting one or more~ components in exhalation air, comprising a tubular element through which S exhalation air is conducted and at one end of which the exhalation air is introduced, and characterized in that at the other end of the tubular element is provided a plate having mounted thereon or incorporating therein a material that will absorb said component said component being brought into contact with said plate and said material when exhaling -i-nto the device, and that said place is detachable for detenijining said component in a measuring apparatus.

2. A device according to Claim 1, characterized in that 1,5the material is mounted on the surface of an airtight plate and in that exhalation air is brought into contact with said material by causing the air to flow across said plate.

A device according to Claim 1, characterized in that the* plate has the form of a porous membrane that has absor- bent material mounted thereon or incorporated therein; and :in that exhalation air is brought into contact with said material by causing said air to flow through the membrane.

4. A device according to any one of Claims 1-3, character- ized in that said mter ial is a carbon dioxide absorbing ra~erial.

B. A device acqording to any one of Claims 1-4, character- 3D ized in that the absorbent material includes colour indicator.

6. A device according to any one of Claims 1-5 for ind~cating carbon dioxide 'formned as a conversion product from Helicobacter pylori in the gastro-intestinal tract. p DATED this 5th day of May 1998 NOSTER SYSTEM AB, By its Patent Attorneys, E. F. WELLINGTON CO., fy.

7< I (Bruce Wellington) C/BA/6949