APPARATUS AND METHOD FOR MEASURING BLOOD PRESSURE

• US 20110270098A1
• Filed: 11/18/2009
• Published: 11/03/2011
• Est. Priority Date: 11/18/2008
• Status: Active Grant

• Current Assignee: SunTech Medical, Inc. (Halma PLC)
• Original Assignee: King's College London
• Inventors: Guilcher, Antoine Yves Marie, Brett, Sally Emma, Chowienczyk, Philip Jan
• Granted Patent: US 9,289,138 B2
• Time in Patent Office: Days
• US Class Current: 600/500
• CPC Class Codes: A61B 5/02108 from analysis of pulse wave characteristics
• CPC Class Codes: A61B 5/02116 of pulse wave amplitude A61B5/02225 takes precedence
• CPC Class Codes: A61B 5/022 by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
• CPC Class Codes: A61B 5/02225 using the oscillometric method
• CPC Class Codes: A61B 5/7271 Specific aspects of physiological measurement analysis A61B5/316, A61B5/349 and A61B5/374 take precedence

Abstract

The application relates to an apparatus and a method for estimating a central systolic blood pressure (cSBP) of a subject, in which a peripheral blood pressure waveform of the subject'"'"'s pulse and at least two peripheral blood pressure measurements within the cardiac cycle of the subject are determined and the peripheral blood pressure waveform is manipulated with a transfer function to provide an estimate of the central blood pressure waveform of the subject'"'"'s pulse. The at least two peripheral blood pressure measurements within the cardiac cycle of the subject and the peripheral blood pressure waveform of the subject'"'"'s pulse are determined at substantially the same point on a peripheral artery of the subject. The estimate of the central blood pressure waveform of the subject'"'"'s pulse provides an estimate of the central systolic blood pressure of the subject.

Claims

1. A method of estimating a central systolic blood pressure (cSBP) of a subject, the method comprising the steps of:

determining a peripheral blood pressure waveform of the subject'"'"'s pulse and at least two peripheral blood pressure measurements within the cardiac cycle of the subject; and

manipulating the peripheral blood pressure waveform with a transfer function to provide an estimate of the central blood pressure waveform of the subject'"'"'s pulse,

wherein the at least two peripheral blood pressure measurements within the cardiac cycle of the subject and the peripheral blood pressure waveform of the subject'"'"'s pulse are determined at substantially the same point on a peripheral artery of the subject, and wherein the estimate of the central blood pressure waveform of the subject'"'"'s pulse provides an estimate of the central systolic blood pressure of the subject.

2. The method of claim 1, wherein the at least two peripheral blood pressure measurements within the cardiac cycle of the subject are selected from the group consisting of:

pSBP, pDBP and pMAP.

3. The method of claim 1, wherein the at least two peripheral blood pressure measurements are pSBP and pDBP.

4. The method of claim 1, wherein the at least two peripheral blood pressure measurements are pDBP and pMAP,

5. The method of claim 1, wherein the at least two peripheral blood pressure measurements are pSBP, pDBP and pMAP.

6. The method of claim 1, wherein the at least two peripheral blood pressure measurements within the cardiac cycle of the subject and the peripheral blood pressure waveform of the subject'"'"'s pulse are determined using a single blood pressure determining device.

7. The method of claim 6, wherein the blood pressure determining device comprises a cuff and the step of determining the peripheral blood pressure waveform comprises adjusting the pressure in the cuff to the pDBP of the subject plus between 10% and 50% of the pulse pressure of the subject.

8. The method of claim 1, wherein the transfer function is a filter or an algorithm for removing amplification associated with transmission of the subject'"'"'s pulse from the heart to the peripheral artery.

9. The method of claim 8, wherein the transfer function is a Butterworth 1^st order filter.

10. The method of claim 1, wherein the step of determining a peripheral blood pressure waveform of the subject'"'"'s pulse comprises:

recording at least 10 peripheral blood pressure waveforms corresponding to at least 10 cardiac cycles; and

averaging the waveforms to obtain a single average peripheral blood pressure waveform,

wherein the average peripheral blood pressure waveform is manipulated with a transfer function.

11. The method of claim 1, further comprising the step of calculating the augmentation index (AI) using the relationship;

AI=(cSBP−

DBP)/(pSBP−

DBP).

12. The method of claim 1, wherein the subject is human.

13. The method of claim 12, wherein the peripheral artery is selected from the group consisting of brachial artery, radial artery, digital artery, dorsalis pedis artery, posterior tibial artery, popliteal artery and femoral artery.

14. The method of claim 13, wherein the peripheral artery is the brachial artery.

26. The method of claim 1, wherein a non-invasive blood pressure determining device is used that can determine at least two peripheral blood pressure measurements within the cardiac cycle of a subject and a peripheral blood pressure waveform of a subject'"'"'s pulse.

15. An apparatus for estimating a central systolic blood pressure (cSBP) of a subject, the apparatus comprising:

a non-invasive blood pressure determining device configured to determine a peripheral blood pressure waveform of the subject'"'"'s pulse and at least two peripheral blood pressure measurements within the cardiac cycle of the subject; and

a processor to apply a transfer function to the peripheral blood pressure waveform to provide an estimate of the central blood pressure waveform of the subject'"'"'s pulse,

wherein the at least two peripheral blood pressure measurements within the cardiac cycle of the subject and the peripheral blood pressure waveform of the subject'"'"'s pulse are determined at substantially the same point on a peripheral artery of the subject, and

wherein the estimate of the central blood pressure waveform of the subject'"'"'s pulse provides an estimate of the central systolic blood pressure of the subject.

16. The apparatus of claim 15, wherein the at least two peripheral blood pressure measurements within the cardiac cycle of the subject are selected from the group consisting of:

pSBP, pDBP and pMAP.

17. The apparatus of claim 15, wherein the at least two peripheral blood pressure measurements are pSBP and pDBP.

18. The apparatus of claim 15, wherein the at least two peripheral blood pressure measurements are pDBP and pMAP.

19. The apparatus of claim 15, wherein the at least two peripheral blood pressure measurements are pSBP, pDBP and pMAP.

20. The apparatus of claim 15, wherein the non-invasive blood pressure determining device is an oscillometric non-invasive blood pressure determining device.

21. The apparatus of claim 20, wherein the oscillometry non-invasive blood pressure determining device comprises a cuff and wherein the peripheral blood pressure waveform is determined by adjusting the pressure in the cuff to the pDBP of the subject plus between 10% and 50% of the pulse pressure of the subject.

22. The apparatus of claim 15, wherein at least 10 peripheral blood pressure waveforms are determined and averaged to give an average peripheral blood pressure waveform, and wherein the processor applies the transfer function to the average peripheral blood pressure waveform.

23. The apparatus of claim 15, wherein the transfer function is a filter or an algorithm to remove amplification associated with transmission of the subject'"'"'s pulse from the heart to a peripheral artery.

24. The apparatus of claim 23, wherein the transfer function is a Butterworth 1^st order filter.

25. A device for use with a non-invasive blood pressure determining device for estimating a central systolic blood pressure of a subject, the device comprising:

a processor to apply a transfer function to a peripheral blood pressure waveform of the subject'"'"'s pulse to provide an estimate of a central waveform of the subject'"'"'s pulse which provides an estimate of the central systolic blood pressure of the subject,

wherein the processor is for attachment to a non-invasive blood pressure determining device which determines at least two peripheral blood pressure measurements within the cardiac cycle of a subject and the peripheral blood pressure waveform of a subject'"'"'s pulse at substantially the same point on a peripheral artery.

27. A non-invasive blood pressure determining device for use in the estimation of a central systolic blood pressure of a subject, wherein the blood pressure determining device is configured to determine at least two peripheral blood pressure measurements within the cardiac cycle of a subject and a peripheral blood pressure waveform of a subject'"'"'s pulse.

28. (canceled)

29. (canceled)