Detection of Respiratory System Lesions

• US 20120165693A1
• Filed: 09/02/2010
• Published: 06/28/2012
• Est. Priority Date: 09/02/2010
• Status: Active Grant

• Current Assignee: Anaxsys Technology Limited
• Original Assignee: Anaxsys Technology Limited
• Inventors: Williams, Deryk John Peter, Williams, Jonh Jam Peter, Varney, Mark Sinclair, Garrett, Michael
• Granted Patent: US 8,403,861 B2
• Time in Patent Office: Days
• US Class Current: 600/532
• CPC Class Codes: A61B 2562/029 Humidity sensors
• CPC Class Codes: A61B 5/082 Evaluation by breath analysis, e.g. determination of the chemical composition of exhaled breath A61B5/083, A61B5/091 take precedence

Abstract

Humidity profiles of exhaled air of individuals obtained using a sensor to detect water vapour content or temperature versus time of exhalation may exhibit an irregularity indicative of a space-occupying respiratory system lesion. Detection of such irregularities provides an inexpensive and rapid means of pre-screening individuals for lung cancer diagnosis, and is applicable even to individuals with other respiratory disorders such as asthma and COPD.

Claims

1. A method of pre-selecting an individual for determination of the presence and nature of a space-occupying respiratory system lesion said method comprising determining whether one of a humidity profile and a temperature profile of exhaled air of said individual exhibits an irregularity indicative of such a lesion, said irregularity equating with one of lowered water vapour content and lowered temperature than to be expected at the same time point after the start of exhalation in the absence of a respiratory system lesion.

2. A method as claimed in claim 1, wherein said profile is of water vapour content, temperature versus time.

3. A method as claimed in claim 2, wherein the initial upward phase II portion of said profile is examined for an indent indicative of a space-occupying respiratory system lesion.

4. A method as claimed in claim 1, wherein the method is used for pre-selecting an individual for further investigation of any of lung cancer, tuberculosis and lung pathology.

5. A method as claimed in claim 1, wherein said humidity profile has been obtained using a humidity sensor for sensing water vapour in a gas stream.

6. A sensor for sensing water in an exhaled air stream, the sensor comprising:

a sensing element disposed to be exposed to the air stream, the sensing element comprising a working electrode, a counter electrode and a layer of ion exchange material extending between the working electrode and the counter electrode, wherein in use, contact of the ion exchange layer with the air stream forms an electrical circuit between the working and counter electrodes; and

a conduit through which the air stream is channelled to impinge upon a sensing element, the conduit being arranged to allow turbulent flow in the air stream.

7. The sensor as claimed in claim 6, wherein the conduit comprises a diameter having a range selected from any of between 10 and 20 mm and between 15 and 18 mm.

8. The sensor as claimed in to claim 6, wherein the ion exchange material comprises one of a sulphonated tetrafluoroethylene copolymer, and a mixture of a sulphonated tetrafluoroethylene copolymer with a fine dispersion of a particulate material.

9. The sensor as claimed in claim 8, wherein the particulate material comprises a zeolite, preferably Zeolite 13X or Zeolite 4A.

10. The sensor as claimed in claim 6 wherein the sensor comprises means for drying the sensing element.

11. The sensor as claimed in claim 10, wherein the sensor is for use in detecting water vapour in exhaled air, and the means for drying the sensing element comprises any of a side hole adjacent to the sensing element such that during inhalation, dry air is passed over the sensing element, a source of infrared radiation, a source of microwave radiation and a source of a dry reference gas.

12. A sensor for sensing a temperature of an exhaled air stream, the sensor comprising:

a conduit through which the air stream is channelled, the conduit being arranged to allow turbulent flow in the exhaled air, and

a temperature sensing element disposed to be able to measure a temperature of the exhaled air in the conduit.

13. A system for pre-selecting an individual for determination of the presence and nature of a space-occupying respiratory system lesion, the system characterized by:

a sensor for sensing one of water in a stream of exhaled air and temperature of a stream of exhaled air;

means for receiving an output from the sensor, the output relating to one of water vapour content and temperature in the stream of exhaled air;

a processor for determining one of a profile of water vapour content in the stream of exhaled air and a temperature of the stream of exhaled air, the processor being further arranged to determine whether the profile exhibits an irregularity indicative of such a lesion, said irregularity equating with one of lowered water vapour content and lowered temperature than to be expected at the same time point after the start of exhalation in the absence of a respiratory system lesion.

14. A system as claimed in claim 13 wherein said humidity profile is one of water vapour content versus time and temperature versus time.

15. A system as claimed in claim 14 wherein the processor is arranged to determine the presence of an irregularity in the humidity profile in an initial upward phase II portion of said profile.

16. A system as claimed in claim 13, wherein the sensor comprises a sensing element arranged to sense water content, the sensor disposed to be exposed to the exhaled air, the sensing element comprising a working electrode, a counter electrode and a layer of ion exchange material extending between the working electrode and the counter electrode, wherein in use, contact of the ion exchange layer with the air stream forms an electrical circuit between the working and counter electrodes;

and

a conduit through which the exhaled air is channelled to impinge upon a sensing element, the conduit being arranged to allow turbulent flow in the exhaled air.