INDICATOR

• US 20110251513A1
• Filed: 05/13/2008
• Published: 10/13/2011
• Est. Priority Date: 05/14/2007
• Status: Abandoned Application

• Current Assignee: ImpediMed Limited
• Original Assignee: ImpediMed Limited
• Inventors: Ziegelaar, Brian William, Chetham, Scott, Essex, Tim
• Application Number:
  US12/600,224
• Publication Number:
  US 20110251513A1
• Time in Patent Office: Days
• US Class Current: 600/547
• CPC Class Codes: A61B 5/0531 Measuring skin impedance
• CPC Class Codes: A61B 5/0537 Measuring body composition by impedance, e.g. tissue hydration or fat content
• CPC Class Codes: A61B 5/418 lymph vessels, ducts or nodes
• CPC Class Codes: A61B 5/4869 Determining body composition
• CPC Class Codes: A61B 5/4872 Body fat
• CPC Class Codes: A61B 5/4875 Hydration status, fluid retention of the body
• CPC Class Codes: A61B 5/4878 Evaluating oedema
• CPC Class Codes: A61B 5/7445 Display arrangements, e.g. multiple display units

Abstract

A method for use in analysing impedance measurements performed on a subject, the method including, in a processing system determining at least one impedance value, representing the impedance of at least a segment of the subject, determining an indicator indicative of a subject parameter using the at least one impedance value and a reference and displaying a representation of the indicator.

Claims

1. ) A method for use in analysing impedance measurements performed on a subject, the method comprising, in a processing system:

a) determining at least one impedance value, representing the impedance of at least a segment of the subject;

b) determining an indicator indicative of a subject parameter using the at least one impedance value and a reference; and

,

c) displaying a representation of the indicator.

2. ) The method according to claim 1, wherein the indicator is scaled relative to at least one reference value.

3. ) The method according to claim 1, wherein the subject parameter is at least one of:

a) fluid levels within the subject; and

,

b) extracellular fluid levels in a subject limb.

4. ) The method according to claim 1, wherein the indicator is for use in assessing the presence, absence or degree of a condition.

5. ) The method according to claim 1, wherein the indicator is at least one of:

a) an oedema indicator for use in assessing a presence, absence or degree of oedema in the subject.

b) a hydration indicator for use in assessing a hydration levels in a subject.

6. ) The method according to claim 1, wherein the method comprises, in the processing system:

a) generating an impedance ratio representing the impedance of the unaffected limb against the impedance of the affected limb; and

,

b) determining the oedema indicator using the impedance ratio.

7. ) The method according to claim 6, wherein the method comprises, in the processing system:

a) determining first measured impedance values representing the impedance of the unaffected limb;

b) determining second measured impedance values representing the impedance of the affected limb;

c) determining impedance ratio using the first and second measured impedance values.

8. ) The method according to claim 7, wherein the method comprises, in the processing system, determining the impedance ratio using the equation:

9. ) The method according to claim 6, wherein the method comprises, in the processing system:

a) determining one or more impedance parameter values from measured impedance values; and

,

b) determining the impedance ratio using the impedance parameter values.

10. ) The method according to claim 9, wherein the impedance parameter values include at least one of:

a) an impedance at infinite applied frequency (R_∞

);

b) an impedance at zero applied frequency (R₀); and

,

c) an impedance at a characteristic frequency (Z_c).

11. ) The method according to claim 10, wherein the method comprises, in the processing system, determining the impedance parameter values at least in part using the equation:

12. ) The method according to claim 11, wherein the method comprises, in the processing system, determining the impedance ratio using the equation:

13. ) The method according to claim 1, wherein the method comprises, in the processing system, determining the oedema indicator by scaling an impedance ratio relative to a reference.

14. ) The method according to claim 13, wherein the method comprises, in the processing system:

a) determining a mean impedance ratio value for a normal population;

b) determining a three standard deviation value for the normal population; and

,

c) scaling the impedance ratio using the mean and three standard deviation values.

15. ) The method according to claim 14, wherein the method comprises, in the processing system, determining the oedema indicator using the equation:

16. ) The method according to claim 15, wherein the scaling factor has an integer value.

17. ) The method according to claim 16, wherein the scaling factor is a multiple of ten.

18. ) A method according to claim 1, wherein the indicator is a hydration indicator for use in determining a hydration level of a subject.

19. ) The method according to claim 18, wherein the method comprises, in the processing system:

a) determining measured resistance and reactance for the subject;

b) normalizing the measured resistance and reactance for the subject using a subject height; and

,

c) determining the hydration indicator using the normalized resistance and reactance.

20. ) The method according to claim 19, wherein the method comprises, in the processing system, determining the normalized resistance and reactance using:

R_v=[(R/h)_mean]/(R/h)_std.dev

X_cv=[(Xc/h)−

(Xc/h)_mean]/(Xc/h)_std.dev

21. ) The method according to claim 19, wherein the method comprises, in the processing system, determining the hydration indicator using a normalized vector distance of the normalized resistance and reactance values from mean and standard deviation resistance and reactance values for a reference population.

22. ) The method according to claim 21, wherein the method comprises, in the processing system, scaling the normalized vector distance using a scaling factor.

23. ) The method according to claim 22, wherein the method comprises scaling the normalized vector using the equation:

24. ) The method according to claim 23, wherein the scaling factor has an integer value.

25. ) The method according to claim 1, wherein the reference is at least one of:

a) derived from a normal population; and

,

b) determined from predetermined values.

26. ) The method according to claim 25, wherein the method comprises, in the processing system:

a) determining one or more subject details; and

,

b) selecting the reference at least partially in accordance with the subject details.

27. ) The method according to claim 26, wherein the subject details include at least one of:

a) limb dominance;

b) ethnicity;

c) age;

d) sex;

e) weight; and

,

f) height.

28. ) The method according to claim 1, wherein the method comprises, in the processing system, displaying the representation as a linear scale, the linear scale comprising:

a) a linear indicator;

b) a scale; and

,

c) a pointer, the pointer being positioned on the scale in accordance with the indicator.

29. ) The method according to claim 1, wherein the method comprises, in the processing system, displaying the representation as a linear scale, the linear scale comprising:

a) a linear indicator;

b) a scale;

c) at least one bar representing the indicator value; and

,

d) at least one bar representing at least one of a previous indicator value and a baseline indicator value.

30. ) The method according to claim 29, wherein the method comprises, in the processing system, displaying the representation comprising an indication of a change in indicator value from at least one of a previous indicator value and a baseline indicator value.

31. ) The method according to claim 1, wherein the method comprises, in the processing system, displaying the representation as a chart comprising:

a) an axis defining measurements performed;

b) an axis defining indicator values; and

,

c) one or more points representing one or more determined indicator values.

32. ) The method according to claim 1, wherein the method comprises, in the processing system:

a) determining at least one threshold using the reference; and

,

b) displaying the threshold on the representation, the position of the threshold being indicative of the presence of a condition.

33. ) The method according to claim 1, wherein the method comprises, in the processing system:

a) determining two thresholds using the reference; and

,

b) displaying the thresholds on the representation, the thresholds being indicative of a normal range.

34. ) The method according to claim 1, wherein the method comprises, in the processing system, displaying, on the representation, at least one of:

a) a normal range;

b) an intervention range;

c) a hydration range; and

,

d) an oedema range.

35. ) The method according to claim 34, wherein the method comprises, in the processing system, displaying, on the representation, at least one color coded region representing a respective range.

36. ) The method according to claim 1, wherein the method comprises, in the processing system, displaying a representation comprising at least one of:

a) textual information representing at least one of;

i) a measurement date;

ii) an indicator value; and

,

iii) whether or not the indicator value is in a normal range; and

,

b) an icon indicative of whether or not the indicator value is in a normal range.

37. ) The method according to claim 1, wherein the method comprises, in the processing system, displaying a representation comprising a Gaussian curve representing a normal population distribution.

38. ) The method according to claim 1, wherein the method comprises, in the processing system, generating a report, the report comprising:

a) a section comprising information relating to at least one of;

i) the subject;

ii) an operator; and

,

iii) a CPT code; and

,

b) a section comprising at least one representation.

39. ) The method according to claim 1, wherein method comprises in the process system, causing one or more impedance measurements to be performed.

40. ) The method according to claim 1, wherein the method comprises, in the processing system:

a) causing at least one excitation signals to be applied to the subject;

b) determining an at least one signal measured across the subject; and

,

c) determining at least one impedance value using an indication of the excitation signal and the signal measured across the subject.

41. ) Apparatus for use in analysing impedance measurements performed on a subject, the apparatus comprising a processing system for:

a) determining at least one impedance value, representing the impedance of at least a segment of the subject;

b) determining an indicator indicative of a subject parameter using the at least one impedance value and a reference; and

,

c) displaying a representation of the indicator.

42. ) The apparatus according to claim 41, wherein the apparatus comprises:

a) a signal generator for applying one or more electrical signals to the subject using a first set of electrodes;

b) a sensor for measuring electrical signals across a second set of electrodes applied to the subject; and

,

c) a controller for;

i) controlling the signal generator; and

,

ii) determining the indication of the measured electrical signals.

43. ) The apparatus according to claim 42, wherein the controller comprises the processing system.

44. ) The apparatus according to claim 42, wherein the processing system comprises the controller.

45. ) (canceled)

46. ) A method for use diagnosing the presence, absence or degree of oedema in a subject by using impedance measurements performed on the subject, the method comprising, in a processing system:

a) determining at least one impedance value, representing the impedance of at least one limb of the subject;

b) determining an oedema indicator using the at least one impedance value and a reference; and

,

c) displaying a representation of the oedema indicator, to thereby allow the presence, absence or degree of oedema in the subject to be assessed.

47. ) A method for use in determining the hydration status of a subject, the method comprising, in a processing system:

a) determining at least one impedance value, representing the impedance of at least one limb of the subject;

b) determining an indicator using the at least one impedance value and a reference; and

,

displaying a representation of the indicator to thereby allow the hydration status of the subject to be assessed.