Human Cavity Gas Measurement Device And Method

• US 20090118646A1
• Filed: 04/18/2006
• Published: 05/07/2009
• Est. Priority Date: 04/18/2005
• Status: Active Grant

• Current Assignee: GPX Medical AB (Gasporox AB)
• Original Assignee: Gasporox AB
• Inventors: Person, Linda, Svanberg, Sune, Svanberg, Katarina
• Granted Patent: US 8,190,240 B2
• Time in Patent Office: Days
• US Class Current: 600/587
• CPC Class Codes: A61B 5/08 Detecting, measuring or recording devices for evaluating the respiratory organs A61B5/0205 takes precedence
• 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 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/1459 invasive, e.g. introduced into the body by a catheter A61B5/1464 takes precedence
• CPC Class Codes: A61B 5/411 Detecting or monitoring allergy or intolerance reactions to an allergenic agent or substance
• CPC Class Codes: A61B 5/6814 Head
• CPC Class Codes: A61B 5/6817 Ear canal
• CPC Class Codes: G01N 21/3504 for analysing gases, e.g. multi-gas analysis
• CPC Class Codes: G01N 21/359 using near infrared light
• CPC Class Codes: G01N 21/49 within a body or fluid

Abstract

A device and method for gas measurements in body cavities are provided. These may be any body cavity containing a free gas, where there is an interest in detecting and/or measuring the concentration of said free gas by means of a non-invasive or minimally invasive method. According to an exemplary embodiment measurement of free oxygen in cranium cavities is performed by scattering media absorption spectroscopy, and in particular variations of such oxygen. This is particularly useful for diagnostic purposes based on the measurements, for instance for detecting sinusitis or the like.

Claims

1. A device configured to measure free gas in a body cavity, comprising a light emitter (1, 2) configured to emit light towards said body cavity from outside said body cavity,

characterized by

a light receiver (4) configured to collect scattered light from tissue surrounding said body cavity, configured to observe at least one wavelength window specific for a free gas in the body cavity;

and

a calculating means for assessing a concentration of said free gas in said body cavity from said collected scattered light, based on optical absorption spectroscopy.

2. The device according to claim 1, wherein said receiver (4) is arranged outside the body.

3. The device according to claim 1, wherein said wavelength window specific for a free gas is approximately 1/10000 of that of bound molecules.

4. The device according to claim 1, wherein said calculating means is configured to calculate a concentration ratio between a reference gas and said free gas, to thereby determine the concentration of said free gas.

5. The device according to claim 4, wherein said reference gas concentration is a known concentration of free water vapour, such as the water vapour concentration in the lungs other body cavities, and said ratio of water vapour to the unknown gas is determinable by said calculation means, as proportional to the concentration of free oxygen or free carbon dioxide.

6. The device according to claim 1, wherein said light emitter is comprised in an endoscope or a fiberoptic catheter.

7. The device according to claim 1, in a compact, handheld configuration, adapted to be applied to the outside of said body for measuring said free gas in said body cavity.

8. The device according to claim 1, wherein the light emitter is a near-IR single mode diode laser (1).

9. The device according to claim 1, wherein the light receiver is a photomultiplier tube (6).

10. The device according to claim 1, wherein said gas is selected from the group comprising oxygen, methane, carbon dioxide, water vapour, or nitric oxide.

11. The device according to claim 1, wherein said device is configured to perform said optical absorption spectroscopy in scattering media in transmission or backscattering.

12. The device according to claim 1, wherein said light emitter (1,2) and said light receiver (4) are arranged in a transmission geometry.

13. The device according to claim 1, wherein said light emitter (1,2) and said light receiver (4) are arranged in a backscattering geometry.

14. The device according to claim 1, wherein said light receiver (4) is configured to transform said collected scattered light to a signal.

15. The device according to claim 14, comprising means for splitting said signal into a first signal and a second signal.

16. The device according to claim 15, wherein said device is configured to send said first signal to a computer controlled digital oscilloscope (8), and said second signal is sent to a lock-in amplifier (9).

17. The device according to claim 16, wherein said device is configured to send said second signal thereafter to said oscilloscope (8).

18. The device according to claim 1, comprising said light emitter (1,2) and said light receiver (4) in a measurement head directly positionable onto the skin of a subject.

19. The device according to claim 1, wherein said device is configured to provide dynamic measurements of said free gas.

20. The device according to claim 1, wherein said device is configured for diagnostic purposes, such as for detecting physiological processes or physiological anomalies or diseases or in subjects.

21. The device according to claim 20, wherein said physiological processes is respiration of a subject.

22. The device according to claim 21, wherein said physiological anomalies or diseases comprise inflammations or infections.

23. The device according to claim 22, wherein said free gas is nitric oxide (NO) and said device is configured to determine a level of infection from said detected free NO.

24. The device according to claim 1, wherein said device is configured for diagnosing sinusitis, pleural infections, gastrointestinal diseases, or ear-infections in subjects.

25. The device according to claim 1, wherein said device is configured for neonatal subjects, having said body cavity.

26. A method of non-invasively measuring free gas in a body cavity, comprising emitting light towards said body cavity from outside said body cavity,

characterized by

collecting scattered light from tissue surrounding said body cavity, to thereby observe at least one wavelength window specific for a free gas in the body cavity;

and

assessing a concentration of said free gas in said body cavity from said collected scattered light, based on optical absorption spectroscopy.

27. The method of any of claim 26, wherein said gas is selected from the group comprising oxygen, methane, carbon dioxide, water vapour, or nitric oxide.

28. The method according to claim 26, wherein the method of measuring of said gas in said body cavity is a method comprising absorption spectroscopy measurement of said gas in scattering media.

29. The method according to claim 26, wherein said measurement is performed in transmission or backscattering.

30. The method according to claim 26, wherein said wavelength window specific for a free gas is approximately 1/10000 of that of bound molecules.

31. The method according to claim 26, wherein said assessing comprises calculating a concentration ratio between a reference gas and said free gas, to thereby determine the concentration of said free gas.

32. The method according to claim 31, wherein said concentration of said reference gas is a known concentration of free water vapour, such as the water vapour concentration in the lungs other body cavities, and said ratio of water vapour to the unknown gas is used to determine, the concentration of free oxygen or free carbon dioxide.

33. The method according to claim 32, wherein said concentration of free water vapour is 100% and said ratio is directly proportional to said concentration of said free gas.

34. The method according to claim 26, wherein said emitting and collecting is achieved through transmission geometry.

35. The method according to claim 26, wherein said emitting and collecting is achieved through backscattering geometry.

36. The method according to claim 26, comprising transforming said collected scattered light to a signal.

37. The method according to claim 36, comprising splitting said signal into a first signal and a second signal.

38. The method according to claim 37, wherein said first signal is sent to a computer controlled digital oscilloscope (8), and said second signal is sent to a lock-in amplifier (9).

39. The method according to claim 38, comprising sending said second signal thereafter to said oscilloscope (8).

40. The method according to claim 26, comprising introducing light for scattering media absorption spectroscopy into the body by means of a light guide, such as a fiberoptic catheter or endoscope for analysing deeper lying body regions for free gas containing cavities.

41. The method according to claim 26, comprising introducing light for scattering media absorption spectroscopy into the body cavities inside the body from the outside of the body.

42. The method according to claim 41, comprising placing a measurement head directly onto the skin of a subject.

43. The method according to claim 26, wherein method is providing dynamic measurements of said free gas.

44. Use of said free gas measurement method in body cavities according to claim 26 for diagnostic purposes, such as for detecting physiological processes or physiological anomalies or diseases or in subjects.

45. Use according to claim 44, wherein said physiological processes is respiration of a subject.

46. Use according to claim 44, wherein said physiological anomalies or diseases comprise inflammations or infections.

47. Use according to claim 46, wherein said free gas is nitric oxide (NO) and a level of detected free NO is used to determine a level of infection.

48. Use according to claim 44, for diagnosing sinusitis, pleural infections, gastrointestinal diseases, or ear-infections in subjects.

49. Use according to claim 44, wherein said subjects are neonatal subjects, having said body cavities.