Systems and methods to assess one or more body fluid metrics

• US 8,135,448 B2
• Filed: 11/18/2005
• Issued: 03/13/2012
• Est. Priority Date: 03/16/2001
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Nellcor Puritan Bennett LLC (Medtronic Plc)
• Inventors: Baker, Clark R. Jr., Schmitt, Joseph M.
• Primary Examiner(s): WINAKUR, ERIC FRANK
• Application Number:
  US11/282,947
• Publication Number:
  US 20060253016A1
• Time in Patent Office: 2,307 Days
• Field of Search: 600/309, 600/310, 600/407, 600/473, 600/476
• US Class Current: 600/310
• 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 5/02438 with portable devices, e.g. worn by the patient
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/4869 Determining body composition
• CPC Class Codes: A61B 5/4878 Evaluating oedema
• CPC Class Codes: G01N 2021/3181 using LEDs
• CPC Class Codes: G01N 21/3554 for determining moisture content
• CPC Class Codes: G01N 21/359 using near infrared light
• CPC Class Codes: G01N 21/474 Details of optical heads therefor, e.g. using optical fibres

Abstract

The present disclosure provides systems, devices, and/or methods for assessing body fluid-related metrics and/or changes therein. The disclosure further provides systems, devices, and/or methods for correlating body fluid-related metrics in a particular tissue with the corresponding whole-body metric. The disclosure also provides, systems, devices, and/or methods for assessment of such metrics to facilitate diagnosis and/or therapeutic interventions related to maintaining and/or restoring body fluid balance.

Claims

1. A method for assessing a whole-body water metric in a subject, said method comprising:

assessing a localized water metric at a tissue site in the subject using a probe;

acquiring tissue site location information; and

processing the localized water metric and the tissue site location information to produce a whole-body water metric of the subject.

2. A method according to claim 1, wherein the whole-body water metric is selected from the group of whole-body water metrics consisting of total tissue water fraction, f_w^T, fat-free water fraction, f_w^l, intravascular water fraction, f_w^IV, extravascular water fraction, f_w^EV, interstitial water fraction f_w^IS, extracellular water fraction, f_w^EC, water balance index, Q, and combinations thereof.

3. A method according to claim 1, wherein the whole-body water metric is selected from the group of whole-body water metrics consisting of changes in the total tissue water fraction, Δ

f_w^T, changes in the fat-free water fraction, Δ

f_w^l, changes in the intravascular water fraction, Δ

f_w^IV, changes in the extravascular water fraction, Δ

f_w^EV, changes in the interstitial water fraction, Δ

f_w^IS, changes in the extracellular water fraction, Δ

f_w^EC, changes in the water balance index, Δ

Q, and combinations thereof.

4. A method according to claim 1, wherein the tissue site comprises skin.

5. A method according to claim 1, wherein assessing the localized water metric comprises measuring bioimpedance, transepidermal water loss, viscoelasticity, infrared light, magnetic resonance, ultrasound, or combinations thereof.

6. A method according to claim 1, further comprising exhibiting the localized water metric, the tissue site location information, or the localized water metric and the tissue site location information on a display.

7. A method according to claim 1, wherein acquiring tissue site location information comprises assessing the location of the probe.

8. A method according to claim 7, wherein assessing the location of the probe comprises detecting probe location information with a probe location information sensor.

9. A method according to claim 8, wherein the probe and the probe location information sensor are contained within a single unit.

10. A method according to claim 8, wherein the probe and the probe location information sensor are physically connected by a linker.

11. A method according to claim 8, wherein the probe location information sensor comprises a camera, an optical emitter, an optical detector, an ultrasound emitter, an ultrasound detector, a piezoelectric vibratory gyroscope, or combinations thereof.

12. A method according to claim 1, wherein the subject is a mammal.

13. A method according to claim 12, wherein the mammal is a human.

14. A method according to claim 1, wherein processing the localized water metric and the tissue site location to produce a whole-body water metric in the subject comprises comparing the localized water metric and the tissue site location information with corresponding values in a database of body water metric data.

15. A method according to claim 14, wherein the database of body water metric data comprises data for one subject.

16. A method according to claim 14, wherein the database of body water metric data comprises data for two or more subjects.

17. A method for assessing a whole-body water metric in a subject, said method comprising:

emitting light of at least one wavelength from a light source toward a tissue site, wherein a portion of the emitted light is reflected by the tissue site;

detecting at least one wavelength of the light reflected by the tissue site with a detector positioned from about one millimeter to about five millimeters from the tissue site;

assessing the tissue site location;

processing the detected reflected light from the tissue site to determine a tissue site water metric; and

processing the tissue site water metric and the tissue site location to produce the whole-body water metric.

18. A method according to claim 17, wherein the whole-body water metric is selected from the group of whole-body water metrics consisting of total tissue water fraction, f_w^T, fat-free water fraction, f_w^l, intravascular water fraction, f_w^IV, extravascular water fraction, f_w^EV, interstitial water fraction f_w^IS, extracellular water fraction, f_w^EC, water balance index, Q, and combinations thereof.

19. A method according to claim 17, wherein the whole-body water metric is selected from the group of whole-body water metrics consisting of changes in the total tissue water fraction, Δ

f_w^T, changes in the fat-free water fraction, Δ

f_w^l, changes in the intravascular water fraction, Δ

f_w^IV, changes in the extravascular water fraction, Δ

f_w^EV, changes in the interstitial water fraction, Δ

f_w^IS, changes in the extracellular water fraction, Δ

f_w^EC, changes in the water balance index, Δ

Q, and combinations thereof.

20. A method according to claim 17, further comprising comparing the whole-body water metric with a control and determining from that comparison whether the subject'"'"'s tissue, organ, or body is dehydrated or over-hydrated.

21. A method according to claim 20, further comprising administering a hydration therapy to a dehydrated subject.

22. A method according to claim 20, further comprising administering a dehydration therapy to an over-hydrated subject.

23. A method according to claim 17, further comprising exhibiting the tissue site water metric, the whole-body water metric, or the tissue site water metric and the whole-body water metric on a display.

24. A method according to claim 17, wherein the light detected by the detector comprises a wavelength selected from the group of wavelength bands consisting of 950-1400 nm, 1500-1800 nm, and 2000-2300 nm.

25. A method according to claim 24, wherein the wavelength of light detected by the detector comprises a wavelength selected from the group of wavelengths consisting of 1180 nm, 1125 nm, 1168 nm, 1170 nm, 1185 nm, 1190 nm, 1230 nm, 1245 nm, 1250 nm, 1274 nm, 1275 nm, 1300 nm, 1330 nm, 1710 nm, 1730 nm, 1740 nm, and combinations thereof.

26. A method according to claim 24, wherein at least two wavelengths of light are detected by the first detector.

27. A method according to claim 26, wherein the wavelengths differ by at least 10 nm.

28. A method according to claim 17, wherein determining the tissue site water metric is substantially independent of light scattering variations and temperature variations.

29. A method according to claim 17, wherein the light source is from about one millimeter to about five millimeters from the tissue site.

30. A method according to claim 17, wherein the tissue site comprises skin.

31. A method according to claim 17, wherein acquiring tissue site location information comprises assessing the location of the probe.

32. A method according to claim 31, wherein assessing the location of the probe comprises detecting probe location information with a probe location information sensor.

33. A method according to claim 32, wherein the probe and the probe location information sensor are contained within a single unit.

34. A method according to claim 32, wherein the probe and the probe location information sensor are physically connected by a linker.

35. A method according to claim 32, wherein the probe location information sensor comprises a camera, an optical emitter, an optical detector, an ultrasound emitter, an ultrasound detector, a piezoelectric vibratory gyroscope, or combinations thereof.

36. A method according to claim 17, wherein the subject is a mammal.

37. A method according to claim 36, wherein the mammal is a human.

38. A method according to claim 17, wherein processing the localized water metric and the tissue site location to produce a whole-body water metric in the subject comprises comparing the localized water metric and the tissue site location information with corresponding values in a database of body water metric data.

39. A method according to claim 38, wherein the database of body water metric data comprises data for one subject.

40. A method according to claim 38, wherein the database of body water metric data comprises data for two or more subjects.

41. A method for diagnosing a water imbalance in a subject, said method comprising:

assessing a localized water metric at a tissue site in the subject using a probe;

acquiring tissue site location information;

processing the localized water metric and the tissue site location information to produce a whole-body water metric of the subject; and

comparing the whole-body water metric with a control and determining from that comparison whether the subject is appropriately hydrated, dehydrated or over-hydrated.

42. A method according to claim 41, wherein the whole-body water metric is selected from the group of whole-body water metrics consisting of total tissue water fraction, f_w^T, fat-free water fraction, f_w^l, intravascular water fraction, f_w^IV, extravascular water fraction, f_w^EV, interstitial water fraction f_w^IS, extracellular water fraction, f_w^EC, water balance index, Q, and combinations thereof.

43. A method according to claim 41, wherein the whole-body water metric is selected from the group of whole-body water metrics consisting of changes in the total tissue water fraction, Δ

f_w^T, changes in the fat-free water fraction, Δ

f_w^l, changes in the intravascular water fraction, Δ

f_w^IV, changes in the extravascular water fraction, Δ

f_w^EV, changes in the interstitial water fraction, Δ

f_w^IS, changes in the extracellular water fraction, Δ

f_w^EC, changes in the water balance index, Δ

Q, and combinations thereof.

44. A method according to claim 41, wherein the tissue site comprises skin.

45. A method according to claim 41, further comprising administering a hydration therapy to the subject if determined to be dehydrated.

46. A method according to claim 41, further comprising administering a dehydration therapy to the subject if determined to be over-hydrated.

47. A system for assessing a whole body fluid metric in a subject, said system comprising:

a local fluid content probe configured to assess a local fluid metric at a tissue site;

a location information sensor configured to assess location information of the probe, the tissue site, or the probe and the tissue site; and

a processor, wherein the processor is operably coupled to the local fluid content probe, operably coupled to the location information sensor, and configured to process the local fluid content metric at the tissue site and location information to produce a whole-body fluid content metric.

48. A system according to claim 47, wherein the local fluid content probe comprises a bioimpedance probe.

49. A system according to claim 47, wherein the local fluid content probe comprises an optical spectrophotometry probe.

50. A system according to claim 47, wherein at least a portion of the system is configured to be sterile, sanitizable, disposable, replaceable, or repairable.

51. A system according to claim 47, wherein the whole body fluid metric comprises extracellular water content.

52. A system according to claim 47, wherein the local fluid metric comprises extracellular water content.

53. A system for assessing a body fluid metric, said system comprising:

a probe housing configured to be placed proximal to a tissue site;

a probe manipulator detachably connected to the probe housing and configured to place the probe housing proximal to the tissue site;

light emission optics connected to the probe housing and configured to deliver radiation of at least one wavelength to the tissue site;

light detection optics connected to the probe housing and configured to receive at least one wavelength of radiation from the tissue site;

a location information sensor configured to detect location information for the probe housing, location information for the tissue site, or combinations thereof; and

a processing device configured to process radiation from the light emission optics, radiation from the light detection optics, and location information from the location information sensor to produce a whole-body fluid metric.

54. A system according to claim 53, wherein the probe housing has at least one sterile or sanitized surface.

55. A system according to claim 53, wherein the probe housing is configured to be disposable.

56. A system according to claim 53, wherein the probe housing is configured to be replaceable.

57. A system according to claim 53 further comprising a replacement probe housing.

58. A system according to claim 53, wherein the location information sensor is connected to the probe housing.

59. A probe for assessing a body fluid metric, said probe comprising:

a probe housing configured to be placed proximal to a tissue site;

a near infrared light emission fiber optic cable connected to the probe housing and configured to conduct radiation of at least one wavelength to the tissue site;

a near infrared light detection fiber optic cable connected to the probe housing and configured to receive at least one wavelength of radiation from the tissue site;

a location information sensor connected to the probe housing and configured to detect location information for at least a portion of the probe housing, location information for at least a portion of the tissue site, or combinations thereof; and

at least one sterile surface.

60. A probe according to claim 59, wherein the probe is configured to be disposable.

61. A probe according to claim 59 further comprising a processing device configured to process radiation from the light emission fiber optic cable, radiation from the light detection fiber optic cable, and location information from the location information sensor to produce a body fluid-related metric.