METHOD AND APPARATUS FOR DERIVING A HEALTH INDEX FOR DETERMINING CARDIOVASCULAR HEALTH

• US 20130289366A1
• Filed: 12/01/2011
• Published: 10/31/2013
• Est. Priority Date: 01/20/2011
• Status: Active Grant

• Current Assignee: Nitto Denko Corporation
• Original Assignee: Nitto Denko Corporation
• Inventors: Chua, Juliana, Aung, Myo Myint, Cheah, Xinying, Thaveeprungsriporn, Visit
• Granted Patent: US 9,232,915 B2
• Time in Patent Office: Days
• US Class Current: 600/301
• CPC Class Codes: A61B 5/02028 Determining haemodynamic parameters not otherwise provided for, e.g. cardiac contractility or left ventricular ejection fraction
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/7271 Specific aspects of physiological measurement analysis A61B5/316, A61B5/349 and A61B5/374 take precedence
• CPC Class Codes: A61B 5/7435 Displaying user selection data, e.g. icons in a graphical user interface
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems
• CPC Class Codes: G16H 50/30 for calculating health indices; for individual health risk assessment

Abstract

A method 1300 and apparatus for deriving a health index for determining cardiovascular health of a person is disclosed herein. In a described embodiment, the method 1300 includes (i) obtaining values of respiratory rate, SpO2 and heart rate from a PPG signal of the person at step 1304; (ii) assigning a score based on the values from a reference scoring system at step 1306; and (iii) deriving the health index based on the assigned scores at step 1308/1314. A method and device for obtaining the PPG signal at optimum pressure is also disclosed.

Claims

1. A computer implemented method of deriving a health index for determining cardiovascular health of a subject;

the method comprising

(i) obtaining values of at least two parameters from one or more PPG signals of the subject, the at least two parameters including SpO2 and at least one other parameter;

(ii) assigning a score based on the values of the at least two parameters from a reference scoring system; and

(iii) deriving the health index based on the assigned score.

2. A computer implemented method according to claim 1, wherein the at least one other parameter is selected from the group consisting of heart rate and respiratory rate.

3. A computer implemented method according to claim 1 or 2, the reference scoring system includes a plurality of groupings for each parameter, and each grouping includes a range of readings for the respective parameter and is associated with a corresponding score for assigning to, and dependence on, the obtained values.

4. A computer implemented method according to claim 3, wherein the score is assigned based on a combination of the values of the at least two parameters.

5. A computer implemented method according to claim 3 or 4, wherein the reference scoring system further includes respective band classifications associated with each corresponding score.

6. A computer implemented method according to claim any of claims 3 to 5, each corresponding score is associated with clinical interpretation of the cardiovascular health of the subject.

7. A computer implemented method according to any of claims 3 to 6, further includes deriving a preliminary health indication based on the score.

8. A computer implemented method according to any preceding claim, wherein the reference scoring system is derived from a matrix of the at least two parameters, wherein values of the at least two parameters are mapped to respective cells associated with respective preliminary scores.

9. A computer implemented method according to claim 8, wherein the preliminary scores are associated with respective preliminary bands;

and the method further include adjusting the preliminary scores and/or preliminary bands to derive the reference scoring system.

10. A computer implemented method according to claim 3, further comprising adding the assigned scores together to derive the health index to represent the cardiovascular health of the subject.

11. A computer implemented method according to claim 3 or 10, wherein (iii) deriving the health index includes deriving a preliminary health index from the groupings for each parameter based on the obtained values and verifying if combination of the groupings is medically possible.

12. A computer implemented method according to claim 11, further comprising adding up the assigned scores to derive the preliminary health index.

13. A computer implemented method according to claim 11 or 12 wherein if the combination of the groupings is medically not possible, displaying an error message as the health index.

14. A computer implemented method according to any of claims 11 to 13, wherein if the combination of the groupings is medically possible, the method further includes verifying if the preliminary health index requires adjustment.

15. A computer implemented method according to claim 12, wherein if adjustment is needed, adjusting the preliminary health index to a revised health index and using the revised health index as the health index.

16. A computer implemented method according to claim 14, wherein verifying if the preliminary health index requires adjustment includes comparing the combination of groupings with a reference list of combinations.

17. A computer implemented method according to any preceding claim, wherein the at least one other parameter is categorized based on the subject'"'"'s age group and gender.

18. A computer implemented method according to any preceding claim, wherein the health index is associated with clinical interpretation of the cardiovascular health of the subject, and the method further include displaying the clinical interpretation as part of the health index.

19. A computer implemented method according to any preceding claim, wherein the at least two parameters are obtained from more than one PPG signals.

20. A computer implemented method according to any preceding claim, wherein the score is based on relative health significance of the parameters considered collectively,

21. A computer implemented method according to any preceding claim, wherein (i) further includes:

illuminating a portion of living tissue of the subject and detecting transmitted or reflected light as a signal using an illumination and detection assembly;

detecting an amount of pressure applied by the portion of living tissue of the subject to the illumination and detection assembly;

correlating the quality of the detected signal with the amount of applied pressure; and

providing feedback related to the correlation to the subject.

22. A computer implemented method according to claim 21, further comprising providing an indication of whether the amount of pressure being applied to the illumination and detection assembly should be adjusted.

23. A computer implemented method according to claim 21 or 22, further comprising displaying a range of optimal applied pressures along with actual applies pressure being applied by the subject.

24. A computer implemented method according to any of claims 21-23, further comprising displaying a range of optimal applied pressures which corresponds to a state of zero transmural pressure.

25. A computer implemented method according to any of claims 21-23, wherein the PPG signal is obtained when the applied pressure is at its optimal.

32. An apparatus according to claim 24, wherein the apparatus is in the form of a mobile phone.

26. A reference scoring system for determining cardiovascular health of a subject, the system comprising

(i) a first array of categories with each category representing a range of typical heart rates of subjects;

(ii) a second array of categories with each category representing a range of typical respiratory rates of subjects;

(iii) a third array of categories with each category representing a range of typical SpO2 levels of subjects;

wherein each category of a said array is associated with a score; and

wherein the scores corresponding to each of the categories of heart rate, respiratory rate and SpO2 when combined together provides a health index for determining the cardiovascular health of the subject.

28. A computer implemented method of deriving a health index for determining cardiovascular health of a subject, the method comprising

(i) obtaining values of SpO2, heart rate and respiratory rate from one or more PPG signals of the subject,

(ii) assigning a scored based on the obtained values from a reference scoring system of claim 26 or claim 27;

and

(iii) deriving the health index based on the assigned score.

27. A reference scoring system for determining cardiovascular health of a subject, the system comprising

(i) a first array of categories with each category representing a range of typical heart rates of subjects;

(ii) a second array of categories with each category representing a range of typical respiratory rates of subjects;

(iii) a third array of categories with each category representing a range of typical SpO2 levels of subjects;

wherein combinations of the categories of the first, second and third arrays are associated with respective scores; and

wherein each score provides a health index for determining the cardiovascular health of the subject.

29. A method of deriving a reference scoring system for determining cardiovascular health, the method including

listing all possible permutations of at least two parameters for a PPG in a list, each permutation corresponding to a band classification and a score;

checking the list against a list of impossible and atypical combinations;

identifying which of the possible permutations in the list falls within the list of impossible and atypical combinations and marking the identified possible permutations;

manipulating the band classification of the atypical combinations;

manipulating the scores corresponding to the manipulated band classifications based on predefined scores and band classification relationships; and

deriving the reference scoring system based on the list of possible permutations and the manipulated scores and bands.

30. A method of deriving a health index for determining cardiovascular health of a subject;

the method comprising

(i) obtaining values of at least two parameters from a PPG signal of the subject, the at least two parameters including SpO2 and at least one other parameter;

(ii) assigning a score based on the values of the at least two parameters from a reference scoring system; and

(iii) deriving the health index based on the assigned scores.

31. Apparatus for deriving a health index for determining cardiovascular health of a subject, the apparatus comprising

a processor configured to obtain values of at least two parameters from a PPG signal of the subject, the at least two parameters including SpO2 and at least one other parameter;

to assign a score based on the values of the at least two parameters from a reference scoring system; and

to derive the health index based on the assigned scores.