Controlling flow of exhaled breath during analysis

• US 20060195040A1
• Filed: 02/06/2006
• Published: 08/31/2006
• Est. Priority Date: 02/07/2005
• Status: Active Grant

• Current Assignee: Circassia AB
• Original Assignee: Aperon Biosystems Corp. (Circassia Group Plc)
• Inventors: Fay, Jonathan, Nason, Kevin, Flaherty, Bryan P., Parikh, Bhairavi R.
• Granted Patent: US 8,932,230 B2
• Time in Patent Office: Days
• US Class Current: 600/532
• CPC Class Codes: A61B 5/0803 Recording apparatus specially adapted therefor
• 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
• CPC Class Codes: A61B 5/097 Devices for facilitating collection of breath or for directing breath into or through measuring devices
• CPC Class Codes: A61M 16/0003 Accessories therefor, e.g. sensors, vibrators, negative pressure
• CPC Class Codes: A61M 16/0057 Pumps therefor
• CPC Class Codes: A61M 16/06 Respiratory or anaesthetic masks
• CPC Class Codes: A61M 16/085 Gas sampling
• CPC Class Codes: A61M 16/208 Non-controlled one-way valves, e.g. exhalation, check, pop-off non-rebreathing valves
• CPC Class Codes: A61M 2016/0027 pressure meter
• CPC Class Codes: A61M 2205/3331 Pressure; Flow
• CPC Class Codes: G01N 33/497 of gaseous biological material, e.g. breath

Abstract

The flow rate of a gaseous sample of exhaled breath through an analytical device is controlled by a pump, and in certain embodiments two pumps. Placement of the analyte sensor in a secondary stream branching off of the primary stream through the device offers further control over the manner, duration, and quantity of the breath that is placed in contact with the sensor.

Claims

1. Apparatus for detecting an analyte in exhaled breath, said apparatus comprising a housing having a flow-through passage and adapted to receive exhaled breath from a subject, an analyte sensing element responsive to said analyte retained in said flow-through passage, and pump means for drawing said exhaled breath from a subject and through said flow-through passage at a controlled rate.

2. The apparatus of claim 1 wherein said pump means is downstream of said analyte sensing element in said flow-through passage.

3. The apparatus of claim 1 further comprising a pressure sensor arranged to detect the pressure of exhaled breath entering said flow-through passage.

4. The apparatus of claim 1 further comprising flow resistance means in said conduit.

5. The apparatus of claim 1 wherein said flow-through passage comprises a primary passage and a secondary passage branched off from said primary passage.

6. The apparatus of claim 5 wherein said analyte sensing element is in said secondary passage.

7. The apparatus of claim 5 wherein said flow-through passage divides into said primary passage and said secondary passage at an upstream junction in said flow-through passage and said secondary passage recombines with said primary passage at a downstream junction in said flow-through passage.

8. The apparatus of claim 5 wherein said flow-through passage divides into said primary passage and said secondary passage at an upstream junction in said flow-through passage and said primary and secondary passages are vented separately.

9. The apparatus of claim 7 wherein said pump means comprises a single pump downstream of said downstream junction.

10. The apparatus of claim 5 wherein said pump means comprises a first pump in said primary passage and a second pump in said secondary passage.

11. The apparatus of claim 7 wherein said pump means comprises a first pump in said primary passage and a second pump in said secondary passage.

12. The apparatus of claim 5 further comprising a shut-off valve arranged to allow or prevent flow through said secondary passage.

13. The apparatus of claim 5 further comprising a check valve in said side passage.

14. The apparatus of claim 4 wherein said flow resistance means is an orifice.

15. The apparatus of claim 4 wherein said flow resistance means is a variable flow resistor.

16. The apparatus of claim 5 further comprising a first flow resistor in said primary passage and a second flow-resistor in said secondary passage.

17. The apparatus of claim 16 wherein said first flow resistor is a variable flow resistor.

18. The apparatus of claim 1 wherein said analyte sensing element is cytochrome c in a sol-gel matrix.

19. A method for determining the amount of an analyte in exhaled breath from a subject, said method comprising drawing exhaled breath from said subject through a flow-through device at a constant flow rate by use of a pump integrated with said flow-through device, said flow-through device comprising a sensing element responsive to said analyte.

20. The method of claim 19 further comprising detecting the pressure of exhaled breath thus drawn into said flow-through device.

21. The method of claim 19 wherein said flow-through device comprises a primary passage and a secondary passage with said sensing element in said secondary passage, and said method further comprises dividing exhaled breath thus drawn into said flow-through device into a primary stream through said primary passage and a secondary stream through said secondary passage.

22. The method of claim 21 comprising drawing said exhaled breath through said primary passage and said secondary passage by a single pump.

23. The method of claim 21 comprising drawing said exhaled breath through said primary passage and said secondary passage by a separate pump in each of said passages.

24. The method of claim 21 wherein said flow-through device comprises a shut-off valve in said secondary stream, and said method further comprises retaining a sample of said exhaled breath in contact with said sensing element in said secondary stream for a selected period of time.

25. The method of claim 21 comprising drawing said exhaled breath through said secondary stream at a flow rate of 5 cm³/s to 11 cm³/s.

26. The method of claim 21 comprising drawing said exhaled breath through said secondary stream at a flow rate of 6 cm³/s to 10 cm³/s.

27. The method of claim 21 comprising drawing said exhaled breath through said secondary stream at a flow rate of 7 cm³/s to 9 cm³/s.

28. The method of claim 21 comprising drawing said exhaled breath through said primary stream at a flow rate of 40 cm³/s to 45 cm³/s.

29. The method of claim 24 further comprising opening said shut-off valve to allow flow through said secondary passage at an interval of between 5 seconds and 9 seconds after the start of flow of exhaled breath through said device.

30. The method of claim 29 wherein said interval is between 6 seconds and 8 seconds.

31. The method of claim 29 further comprising maintaining said flow through said secondary passage for a duration of between 1 second and 10 seconds.

32. The method of claim 31 wherein said duration is between 1 and 7 seconds.

33. The method of claim 31 wherein said duration is between 1 and 5 seconds.