Apparatus and method for non-invasive and minimally-invasive sensing of parameters relating to blood

• US 7,747,301 B2
• Filed: 09/22/2005
• Issued: 06/29/2010
• Est. Priority Date: 03/30/2005
• Status: Active Grant

• Current Assignee: Skyline Medical Inc.
• Original Assignee: Skyline Medical Inc.
• Inventors: Khuri-Yakub, Butrus T., Kim, Daniel Hwan, Cheng, Xuefeng
• Primary Examiner(s): Winakur; Eric F
• Assistant Examiner(s): Berhanu; Etsub D
• Application Number:
  US11/233,308
• Publication Number:
  US 20060253007A1
• Time in Patent Office: 1,741 Days
• Field of Search: 600/323, 600/324, 600/333, 600/338, 600/407, 600/437
• US Class Current: 600/322
• CPC Class Codes: A61B 5/0048 Detecting, measuring or recording by applying mechanical forces or stimuli A61B5/021, A61B5/4884 and A61B9/00 take precedence
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• CPC Class Codes: A61B 5/0261 using optical means, e.g. infrared light
• CPC Class Codes: A61B 5/029 Measuring or recording blood output from the heart, e.g. minute volume A61B8/065 takes precedence
• CPC Class Codes: A61B 5/14539 for measuring pH
• CPC Class Codes: A61B 5/14542 for measuring blood gases A61B5/14551 takes precedence
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/1464 specially adapted for foetal tissue
• CPC Class Codes: A61B 5/413 Monitoring transplanted tissue or organ, e.g. for possible rejection reactions after a transplant
• CPC Class Codes: A61B 5/489 Blood vessels
• CPC Class Codes: A61B 8/065 to determine blood output from the heart in general A61B5/029
• CPC Class Codes: A61B 8/08 Detecting organic movements or changes, e.g. tumours, cysts, swellings A61B8/02 - A61B8/06 take precedence
• CPC Class Codes: A61B 8/488 involving Doppler signals
• CPC Class Codes: G01S 15/8968 using acoustical modulation of a light beam acousto-optical light control devices G02F1/11, G02F1/33

Abstract

Medical diagnostic system, apparatus and methods are disclosed. Optical transmitters generate radiation-containing photons having a specific interaction with at least one target chromophore in a target structure, preferably a blood vessel such as the interior jugular vein. The optical transmitters transmit the radiation into at least a first area including a substantial portion of the target structure and into a second area not including a substantial portion of the target structure. Optical receivers detect a portion radiation scattered from at least the first area and the second area. A processor estimates oxygenation, pH or cardiac output based on the scattered radiation detected from the first area, and the scattered radiation from the second area.

Claims

1. A system for monitoring one or more parameters relating to blood of a patient comprising:

one or more optical transmitters configured to generate pulsed radiation containing photons having a specific interaction with at least one target chromophore in a target structure within the patient, said one or more optical transmitters configured and positioned to transmit the pulsed radiation from the optical transmitter into at least a first area including a substantial portion of the target structure and into a second area not including a substantial portion of the target structure;

one or more optical receivers configured and positioned to detect a portion of the pulsed radiation scattered from at least the first area and the second area; and

a processor configured to estimate the one or more parameters relating to the patient'"'"'s blood, the estimation based in part on the scattered pulsed radiation detected from the first area, and the scattered pulsed radiation from the second area, wherein the processor comprises a central processing unit and a memory device and said one or more optical receivers are configured and adapted to measure optical properties associated with the second area, and wherein said processor is further configured to calculate a probability for the pulsed radiation to pass through the first area and the second area.

2. A system according to claim 1 wherein the target structure is a blood vessel.

3. A system according to claim 1 wherein the second area is selected such that optical properties of tissue in close proximity to the target structure can be estimated.

4. A system according to claim 3 wherein the second area is in close proximity to the target structure.

5. A system according to claim 1 wherein said one or more optical transmitters is adapted to transmit the pulsed radiation into the first and second areas simultaneously.

6. A system according to claim 1 wherein said processor is further adapted to estimate average tissue scattering and absorption properties for the radiation associated with the second area.

7. A system according to claim 1 wherein said probabilities are calculated using a photon diffusion equation.

8. A system according to claim 1 wherein said processor estimates the one or more parameters in part by relating probabilities for the pulsed radiation to pass through the first and second areas.

9. A system according to claim 8 wherein the target structure is a blood vessel and said processor is further adapted to calculate relative blood oxygen saturation in the blood vessel.

10. A system according to claim 1 wherein the pulsed radiation comprises photons having a first wavelength and photons having a second wavelength, the first wavelength selected to have the specific interaction with a first target chromophore, and the second wavelength selected to have a specific interaction with a second target chromophore.

11. A system according to claim 10 wherein the first target chromophore is oxy-hemoglobin and the second target chromophore is deoxy-hemoglobin.

12. A system according to claim 11 wherein the target structure is a blood vessel the one or more of the parameters relating to blood includes oxygenation saturation of blood in the blood vessel.

13. A system according to claim 12 wherein the blood vessel is a major vein.

14. A system according to claim 13 wherein the major vein is the internal jugular vein.

15. A system according to claim 13 wherein the one or more optical sources are further adapted and positioned to transmit the pulsed radiation into a third area including a substantial portion of a second target structure, the one or more optical receivers are further configured and positioned to detect pulsed radiation scattered from the third area, and the third target structure is a major artery.

16. A system according to claim 15 further comprising a filter coupled to at least one of the optical receivers, the filter being configured to select pulsed radiation from the third area with a modulation component at the same frequency or at a harmonic frequency of the pulse in the major artery.

17. A system according to claim 12 wherein the blood vessel is a major artery.

18. A system according to claim 1 wherein the one or more of the parameters relating to blood includes the patient'"'"'s cardiac output.

19. A system according to claim 1 wherein said one or more optical transmitters comprise an optical source and one or more launch optics coupled to the optical source via one or more optical fibers.

20. A system according to claim 19 wherein said one or more optical receivers comprise one or more optical detectors and one or more collecting optics coupled to the one or more optical detectors via one or more optical fibers.

21. A system according to claim 20 wherein said one or more launch optics and said one or more collecting optics are mounted on a sensor patch designed to be engaged to the patient'"'"'s skin.

22. A system according to claim 20 further comprising two or more transmitter-receiver pairs each pair comprising one launch optic and one collecting optic, including a first pair having a spacing and position such that the launch optic and collecting optic associated with the first pair transmits pulsed radiation into and detects pulsed radiation scattered from the first area, and a second pair having a spacing and position such that the launch optic and collecting optic associated with the second pair transmits pulsed radiation into and detects pulsed radiation scattered from the second area.

23. A system according to claim 22 wherein the first pair has a spacing between the launch optic and collecting optic of between about 3 cm and about 7 cm, and the second pair has a spacing between the lunch optic and collecting optic of between about 0.5 cm and about 3 cm.

24. A system according to claim 20 wherein said processor comprises a general purpose computer, and said optical source, said system further comprising a system box in which said one or more optical detectors, and said processor are housed, and said box station is in communication with a display adapted to display the one or more parameters relating to blood to a human operator.

25. A system according to claim 20 wherein said processor comprises a portable general purpose computer, said system further comprising a portable box in which said optical source, said one or more optical detectors, and said processor are housed, said portable box being dimensioned and sized such the patient can carry the portable box for extended periods, and said portable box further housing a battery and a wireless transmitter for data communication to a station box located at a hospital or clinic.

26. A system according to claim 1 wherein the one or more optical transmitters are adapted and positioned to transmit the pulsed radiation into the patient at least 10 locations and the one or more optical receivers is adapted and positioned to detect scattered pulsed radiation from the patient at least 10 locations.

27. A system according to claim 26 wherein the optical transmitters and receivers are used to generate an image of tissues with the patient.

28. A system according to claim 26 wherein pairs of transmitter and receiver locations are selected dynamically in order to provide improved monitoring of the one or more parameters relating to blood.

29. A system according to claim 1 further comprising an ultrasound transducer configured to transmit ultrasound radiation into the patient at locations including the first area and the target structure.

30. A system according to claim 29 wherein the ultrasound transducer is adapted to generate an image of tissues within the first area including the target structure to enable placement of the one or more optical transmitters and the one more optical receivers on the patient so as to enhance the accuracy of the monitoring of the system.

31. A system according to claim 29 wherein the ultrasound transducer is configured to provide an ultrasound radiation pressure field to modulate the target structure at a modulation frequency, and the system further comprising a filter coupled to at least one of the optical detectors, the filter being configured to select detected photons with a modulation component at the same frequency as the modulation frequency of the radiation pressure modulation field, or at a harmonic of the modulation frequency.

32. A system according to claim 31 wherein the processor is adapted to calculate a calibration adjustment based on measurements performed by the one or more optical receivers both with and without the use of the ultrasound transducer and the filter.

33. A system according to claim 1 wherein the one or more parameters relating to blood is blood pH level, and one of the at least one target chromophores is met-hemoglobin.

34. A system according to claim 1 wherein the one or more parameters relating to blood relates to water or lipid concentrations in the blood.

35. A system according to claim 1 wherein the target structure is selected from a set consisting of exterior jugular vein, subclavian vein, superior vena cava and pulmonary artery.

36. A system according to claim 1 wherein the patient is a neonatal patient.

37. A system according to claim 1 wherein the patient is a fetus.

38. A system according to claim 1 wherein the second area has a depth of at least 1 cm from a tissue boundary.

39. A system according to claim 38 wherein the target structure is located about 2 cm from a tissue boundary of the patient.

40. A system according to claim 1 wherein the second area excludes portions of the target structure having a 20% or greater photon probability for photon generated by the one or more optical transmitters when transmitting into the second area.

41. A system according to claim 40 wherein the second area excludes portions of the target structure having a 5% or greater photon probability for photon generated by the one or more optical transmitters when transmitting into the second area.

42. A system according to claim 41 wherein the second area excludes portions of the target structure having a 1% or greater photon probability for photon generated by the one or more optical transmitters when transmitting into the second area.

43. A method for monitoring one or more parameters relating to blood of a patient comprising the steps of:

engaging one or more optical transmitters and one or more optical receivers on a tissue boundary of the patient;

generating pulsed radiation containing photons having a specific interaction with at least one target chromophore in a target structure within the patient;

transmitting said pulsed radiation through the optical transmitters into a first area including a substantial portion of a target blood vessel and into a second area not including a substantial portion of the target structure;

detecting with the one or more optical receivers a portion of the pulsed radiation scattered from at least the first area and the second area;

estimating the one or more parameters relating to a patient'"'"'s blood based in part on the detected scattered pulsed radiation from the first area, and the scattered pulsed radiation from the second area; and

calculating optical properties associated with the second area, wherein said step of estimating is based in part on the measured optical properties associated with the second area, and wherein said step of estimating the one or more parameters includes calculating a probability for the pulsed radiation to pass through the first area and the second area.

44. A method according to claim 43 wherein the target structure is a blood vessel.

45. A method according to claim 43 wherein the second area is selected such that optical properties of tissue in close proximity to the target structure can be estimated.

46. A method according to claim 43 wherein said one or more optical transmitters is adapted to transmit the pulsed radiation into the first and second areas simultaneously.

47. A method according to claim 43 wherein said optical properties associated with the second area includes average tissue scattering and absorption properties for the pulsed radiation associated with the second area.

48. A method according to claim 43 wherein said probabilities are calculated using a photon diffusion equation.

49. A method according to claim 43 wherein the target structure is a blood vessel and said step of estimating the one or more parameters comprises calculating relative blood oxygen saturation in the blood vessel.

50. A method according to claim 43 wherein the pulsed radiation comprises photons having a first wavelength and photons having a second wavelength, the first wavelength selected to have the specific interaction with the target chromophore, and the second wavelength selected to have a specific interaction with a second target chromophore.

51. A method according to claim 50 wherein the target chromophore is oxy-hemoglobin and the second target chromophore is deoxy-hemoglobin.

52. A method according to claim 50 wherein the target structure is a blood vessel the one or more of the parameters relating to blood includes oxygenation saturation of blood in the blood vessel.

53. A method according to claim 43 wherein the one or more parameters relating to blood is blood pH level, and one of the at least one target chromophores is met-hemoglobin.

54. A method according to claim 43 wherein the target structure comprises an internal jugular vein, and the tissue interface is neck skin of the patient.

55. A method according to claim 43 wherein the target structure is selected from a set consisting of exterior jugular vein, subclavian vein, superior vena cava and pulmonary artery.

56. A method according to claim 43 wherein the patient is a neonatal patient.

57. A method according to claim 43 wherein the patient is a fetus.

58. A method according to claim 43 wherein the step of transmitting said pulsed radiation includes transmitting the pulsed radiation through the optical transmitters into a third area including a substantial portion of a second target structure, and said step of detecting comprises detecting pulsed radiation scattered from the third area.

59. A method according to claim 58 wherein the second target area is an artery and the method further comprises the step of filtering radiation detected from the third area with a modulation component at the same frequency or at a harmonic frequency of the pulse in the artery.

60. A method according to claim 43 wherein the one or more of the parameters relating to blood includes the patient'"'"'s cardiac output.

61. A method according to claim 43 wherein said step of generating pulsed radiation uses at least one optical source, said step of transmitting uses one or more launch optics coupled to the at least one optical source via one or more optical fibers, said one or more optical receivers comprise one or more optical detectors and one or more collecting optics coupled to the one or more optical detectors via one or more optical fibers.

62. A method according to claim 61 wherein the tissue boundary is the patient'"'"'s skin, said one or more launch optics and said one or more collecting optics are mounted on a sensor patch designed to be engaged to the patient'"'"'s skin, and said step of engaging includes engaging the sensor patch onto the patient'"'"'s skin.

63. A method according to claim 62 wherein said steps of transmitting and detecting use a first transmitter-receiver pair have a spacing and position such that the launch optic and collecting optic associated with the first pair transmits pulsed radiation into and detects pulsed radiation scattered from the first area, and a second transmitter-receiver pair having a spacing and position such that the launch optic and collecting optic associated with the second pair transmits pulsed radiation into and detects pulsed radiation scattered from the second area.

64. A method according to claim 63 wherein the first pair has a spacing between the launch optic and collecting optic of between about 3 cm and about 7 cm, and the second pair has a spacing between the launch optic and collecting optic of between about 0.5 cm and about 3 cm.

65. A method according to claim 43 further comprising the step displaying to a human operator the estimated one or more parameters relating to blood.

66. A method according to claim 43 further comprising the steps of:

recording data, calculations and estimates on a memory housed within a portable unit, said portable unit being dimensioned and sized such that the patient can carry the portable unit for extended periods; and

wirelessly transmitting data relating to the one or more parameters to a station box located at a hospital or clinic.

67. A method according to claim 43 wherein the one or more optical transmitters are adapted and positioned to transmit the pulsed radiation into the patient at least 10 locations and the one or more optical receivers is adapted and positioned to detect scattered pulsed radiation from the patient at least 10 locations.

68. A method according to claim 67 wherein the optical transmitters and receivers are used to generate an image of tissues with the patient.

69. A method according to claim 68 further comprising the step of dynamically selecting pairs of transmitter and receiver locations in order to provide improved monitoring of the one or more parameters relating to blood.

70. A method according to claim 43 further comprising the step of transmitting ultrasound radiation into the patient at locations including the first area and the target structure using an ultrasound transducer.

71. A method according to claim 70 further comprising the step of generating an image of tissues within the first area including the target structure, wherein the step of engaging uses the generated image of tissues in order to place the one or more optical transmitters and the one more optical receivers on the tissue boundary of the patient so as to enhance the accuracy of the monitoring of the system.

72. A method according to claim 70 further comprising the steps of:

generating an ultrasound radiation pressure field to modulate the target structure at a modulation frequency; and

filtering detected photons with a modulation component at the same frequency as the modulation frequency of the radiation pressure modulation field, or at a harmonic of the modulation frequency.