GB2363196A

GB2363196A - Sampling breath

Info

Publication number: GB2363196A
Application number: GB0013967A
Authority: GB
Inventors: Elizabeth Angela Woolfenden; Alun Cole
Original assignee: Markes International Ltd
Current assignee: Markes International Ltd
Priority date: 2000-06-09
Filing date: 2000-06-09
Publication date: 2001-12-12
Anticipated expiration: 2020-06-09
Also published as: GB0013967D0; GB2363196B

Abstract

A device for taking a sample of breath has a tubular body 10 with a piston 12 inserted into a first end thereof, a first port 18 formed through a side wall and a second port 16 formed at or adjacent a second end. The first port 18 or the second port 16 provides an inlet for receiving a breath sample and the second port 16 provides an outlet through which the breath sample may subsequently be discharged from the tubular body. The second part is typically coupled to a sample tube 20 housing an adsorbent 22 for any volatile compounds present in the breath sample when it is expelled from the sampling device by depression of the piston 12 into the tubular body 10. The sample tube 20 may then be subjected to analysis.

Description

2363196 Breath SWmplinq Device The present invention relates to a device

for taking a sample of a subject's breath.

There are a number of situations in which it is desirable to take a sample of a subject's breath for analysis:

5 for example, it may be desirable to analyse the subject's breath as part of an evaluation of the subject's clinical condition; as another example, it may be desirable to analyse the subject's breath in order to evaluate the hygiene of the ambient atmosphere at the subject's occupational environment.

10 Hitherto, devices for taking a breath sample have been of relatively complex construction, or complicated to use. We have now devised a breath sampling device which is of simple construction and easy to use.

In accordance with the Fesent invention, there is 15 provided a device for taking a sample of a subject's breath, the device comprising a tubular body having a piston inserted into a first end thereof, a first port formed through the side wall thereof and a second port formed at or adjacent a second end thereof opposite said first end, the first or the second 20 port providing an inlet for receiving a breath sample and the second port providing an outlet through which the breath sample may subsequently be discharged.

In use, the subject breathes into the tubular body of the device, either via the first port or via the second port 25 to provide a breath sample. A f ixed volume of the breath sample may then be discharged via the second port, either by depressing the piston completely into the tubular body or by drawing the sample out of the device through the second port until the piston is completely inserted into the tubular body.

30 A sample tube may be coupled to the second port of the sampling device, the sample tube containing a quantity of adsorbent material which accordingly absorbs any volatile substances in the breath sample which is expelled through it.

The sample tube can then be taken to a laboratory for analysis by coupling the sample tube to an analytical apparatus.

Alternatively an analytical apparatus may be coupled directly to the second port of the device for analysing the breath sample.

Where the first port provides the inlet for receiving a breath sample, the first port preferably comprises a 10 passageway provided by the though-bore of a tube projecting from the side of the tubular body of the device.

Preferably the second port comprises a passageway provided by the throughbore of a tube projecting from the end of the tubular body or from the side of the body adjacent its 15 end.

Preferably the length of the second passageway is substantially greater than its internal width: accordingly, negligible air will diffuse into or out of the device though the second passageway during the time between taking the breath 20 sample and transferring it to the sample tube. Preferably the length of the second passageway is at least 5 times its respective width.

Where the first port is provided by the through-bore of a tube projecting from the side of the tubular body of the 25 device, the length of the first passageway is preferably greater than its internal width. Preferably the length of the first passageway is at least 5 times its respective width.

An embodiment of the present invention will now be described by way of example only and with reference to the 30 accompanying drawing, the single figure of which is. a diagrammatic longitudinal section through a breath sampling device in accordance with the invention.

Referring to Figure 1, there is shown a breath sampling device which comprises a tubular body 10 having an open end which receives a piston or plunger 12. The opposite end of the tubular body 10 is closed except for a relatively narrow passage formed by the through- bore of an extension tube 16.

5 A second tube 18 projects from the side of the tubular body 10 at a point spaced from both ends of the body.

In use, the piston 12 is inserted a short distance into the open end of the tubular body 10, thus closing this end of the body 10 but not occluding the tube 18. The subject then 10 applies his or her mouth, either to the tube 18 or to the tube 16, either directly or via an adaptor or coupling (not shown), and breathes out. Expired air thus passes into the interior of the tubular body 10, with the air previously within the tubular body 10 being expelled, together with any excess expired 15 breath, through the unobstructed tube 16 or 18 of the device. Accordingly, the device is now filled with a sample of the subject's breath.

If now the piston 12 is pushed into the tubular body 10, firstly a small volume of the air within the tubular body 20 will be expelled through the tube 18 until the piston 12 reaches a position fully closing the tube. Thereafter, as the piston 12 is pushed fully into the tubular body 10, a predetermined volume of air (being that contained within the body 10 between the tube 18 and the closed end of the body 10) 25 will be expelled through the tube 16.

In the example shown, a sample tube 20 is coupled to the tube 16 of the breath sampling device before the piston 12 is depressed into the tubular body 10: the sample tube 20 contains a quantity of granular absorbent material 22 held 30 between two pervious screens 24,26 e.g. of stainless steel gauze. As the breath sample is expelled from the breath sampling device to pass through the sample tube 20, any volatile substances in the breath sample are absorbed by the absorbent material 22. It will be appreciated that a predetermined volume of the subject's breath will have been expelled from the tubular body 10, so that the quantity of substances absorbed by the material 22 is accurately related, in a predetermined way, to the concentration of those 5 substances in the subject's breath.

The sample tube 20 is then uncoupled from the breath sampling device and closure caps (not shown) fitted to its opposite ends. The sample tube 20 is then taken to a laboratory for analysis. Typically, the analysis process involves desorption, in which the sample tube 20 is heated to liberate the absorbed substances and a flow of inert gas is passed through the tube to carry the liberated substances out of the sample tube and to the analysing elements of an analytical apparatus.

15 Alternatively, it would remain in accordance with the present invention for the tube 16 of the sampling device to be coupled directly to, or form part of, an analytical apparatus, which may comprise a pump for drawing the breath sample from within the tubular body 10.

20 It would also remain in accordance with the present invention to reduce the manufacturing costs of the device by omitting the tubular projecting portion 18 of the port formed through the side-wall of the tubular body 10, with the tube 16 then providing both the inlet and the outlet for the device.

25 However, in this case, it will be appreciated that with the diffusion limiting projection removed, the piston 12 must be inserted sufficiently into the tubular body 10 to close the aperture in the side of the body between the taking of a breath sample and its subsequent analysis.

30 It will be appreciated that the breath sampling device is of simple construction and easy to use. In particular,--it does not involve the use of valves or complex seals, yet delivers a constant volume of the subject's breath to enable reliably repeatable results. The device comprises two parts /. 5 only, which may be vacuum-formed of plastics material: the two parts, when formed in this way, provide a sufficient seal at least for a single use; because of the inexpensive construction, the device may be disposed of after a single use.

Claims

Claims

1) A device for taking a sample of a subject's breath, the device comprising a tubular body having a piston inserted into a first end thereof, a first port formed through the side wall 5 thereof and a second port formed at or adjacent a second end thereof opposite said first end, the first or the second port providing an inlet for receiving a breath sample and the second port providing an outlet through which the breath sample may subsequently be discharged.

2) A device as claimed in Claim 1, comprising a sample tube coupled to, or for coupling to, the second port of the device, the sample tube containing a quantity of adsorbent material for absorbing any volatile substances in a breath sample which may is be expelled through it via the second port.

3) A device as claimed in Claim 1, wherein the second port is arranged to be coupled to an analytical device for analysing the breath sample.

4) A device as claimed in any preceding Claim, wherein the 20 first port comprises a passageway provided by the though-bore of a tube projecting from the side of the tubular body of the device.

5) A device as claimed in Claim 4, wherein the length of the passageway of the first port is substantially greater than its internal width.

6) A device as claimed in Claim 5, wherein the length of the first passageway is at least 5 times greater than is internal width.

7) A device as claimed in any preceding claim, wherein the second port comprises a passageway provided by the through-bore c i of a tube projecting from the end of the tubular body or from the side of the body adjacent its end.

8) A device as claimed in Claim 4, wherein the length of the passageway of the first port is substantially greater than its internal width.

9) A device as claimed in Claim 5, wherein the length of the f irst passageway is at least 5 times greater than its internal width.

10) A method for taking a sample of a subject's breath, the method comprising: providing a device comprising a tubular body having a piston inserted into a first end thereof, a first port formed through the side wall thereof and a second port formed at or adjacent a second end thereof opposite said first end; and is receiving a breath sample into the tubular body via the first or the second port.

11) A method as claimed in Claim 10, wherein the breath sample is discharged from the tubular body via the second port.

12) A method as claimed in Claim 11, wherein the breath 20 sample is discharged by depressing the piston completely into the tubular body.

13) A method as claimed in Claim 11, wherein the breath sample is discharged by drawing the sample out of the device through the second port until the piston is completely inserted 25 into the tubular body.

15) A method as claimed in any of Claims 11 to 13, wherein the breath sample is discharged through a sample tube containing a quantity of adsorbent material which accordingly absorbs any volatile substances in the breath sample discharged through it, the sample tube being subsequently coupled to an analytical apparatus for analysing of its contents.

16) A method as claimed in any of Claims 11 to 13, wherein the breath sample is discharged into an analytical apparatus 5 coupled directly to the second port of the device for analysing the breath sample.

17) A device f or taking a sample of a subj ect 1 s breath, the device being substantially as herein described with reference to the accompanying drawings.

10 18) A method f or taking a sample of a subj ect 1 s breath, the method being substantially as herein described with reference to the accompanying drawings.

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