METHODS AND DEVICES FOR CALCULATING BLOOD PRESSURE BASED ON MEASUREMENTS OF ARTERIAL BLOOD FLOW AND ARTERIAL LUMEN

• US 20170231578A1
• Filed: 06/17/2016
• Published: 08/17/2017
• Est. Priority Date: 02/12/2016
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Lading, Lars, Baek, David Boettcher
• Granted Patent: US 11,020,058 B2
• Time in Patent Office: Days
• CPC Class Codes: A61B 2560/0261 using hydrostatic pressure
• CPC Class Codes: A61B 2560/0475 Special features of memory means, e.g. removable memory cards
• CPC Class Codes: A61B 5/0004 characterised by the type of physiological signal transmitted
• CPC Class Codes: A61B 5/002 Monitoring the patient using a local or closed circuit, e.g. in a room or building A61B5/0017 takes precedence
• CPC Class Codes: A61B 5/0022 Monitoring a patient using a global network, e.g. telephone networks, internet
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/026 Measuring blood flow A61B3/1233, A61B3/1241 take precedence
• CPC Class Codes: A61B 5/0261 using optical means, e.g. infrared light
• CPC Class Codes: A61B 5/681 Wristwatch-type devices
• CPC Class Codes: A61B 5/7282 Event detection, e.g. detecting unique waveforms indicative of a medical condition A61B5/4094, A61B5/4818, A61B5/349, A61B5/0823 take precedence
• CPC Class Codes: A61B 8/02 Measuring pulse or heart rate
• CPC Class Codes: A61B 8/04 Measuring blood pressure
• CPC Class Codes: A61B 8/06 Measuring blood flow measuring volume flow in general G01F, e.g. G01F1/66, G01F1/72; measuring speed of fluids in general G01P5/00
• CPC Class Codes: A61B 8/0883 for diagnosis of the heart
• CPC Class Codes: A61B 8/0891 for diagnosis of blood vessels
• CPC Class Codes: A61B 8/4227 characterised by straps, belts, cuffs or braces
• CPC Class Codes: A61B 8/4281 characterised by sound-transmitting media or devices for coupling the transducer to the tissue
• CPC Class Codes: A61B 8/4411 Device being modular
• CPC Class Codes: A61B 8/4427 Device being portable or laptop-like
• CPC Class Codes: A61B 8/4483 characterised by features of the ultrasound transducer
• CPC Class Codes: A61B 8/461 : Displaying means of special interest
• CPC Class Codes: A61B 8/488 : involving Doppler signals
• CPC Class Codes: A61B 8/5223 : for extracting a diagnostic or physiological parameter from medical diagnostic data for algorithms to analyse biomedical images G06T7/0012
• CPC Class Codes: A61B 8/54 : Control of the diagnostic device
• CPC Class Codes: A61B 8/56 : Details of data transmission or power supply
• CPC Class Codes: G16H 50/30 : for calculating health indices; for individual health risk assessment

Abstract

An system for calculating blood pressure may include a sensor system and a control system. The control system may be capable of controlling one or more sensors of the sensor system to take at least two measurements, the at least two measurements including at least one measurement taken at each of two or more different measurement elevations of a subject'"'"'s limb. In some examples, the control system may be capable of determining a blood flow difference based on the at least two measurements, of determining a hydrostatic pressure difference based on the two or more different elevations of the at least two measurements and of estimating a blood pressure based on one or more values of blood flow, the hydrostatic pressure difference and the blood flow difference.

Claims

1. A method of calculating blood pressure, comprising:

performing, by one or more sensors, two or more measurements, wherein at least two measurements from the two or more measurements correspond to different measurement elevations of a subject'"'"'s limb;

determining, by a processor, a blood flow difference based on the two or more measurements;

determining, by the processor, a hydrostatic pressure difference based on the two or more different measurement elevations of the two or more measurements; and

estimating, by the processor, a blood pressure based on one or more values of blood flow, the hydrostatic pressure difference and the blood flow difference.

2. The method of claim 1, wherein the performing, by the one or more sensors, the two or more measurements comprises:

directing, by the one or more sensors, waves into the limb towards an artery;

receiving, by the one or more sensors, one or more reflected waves, wherein the one or more reflected waves are based at least in part on the directed waves;

obtaining, by the one or more sensors, the two or more measurements, including the at least two measurements taken at each of two or more different measurement elevations, based on the one or more reflected waves; and

transmitting, by the one or more sensors, the two or more measurements to the processor.

3. The method of claim 2, wherein the reflected waves include scattered waves, specularly reflected waves, or both scattered waves and specularly reflected waves.

4. The method of claim 2, wherein:

the one or more sensors include one or more optical sensors of an optical sensor system;

directing waves into the limb involves directing, by the optical sensor system, light waves towards the artery to form a measuring volume having an interference pattern that illuminates at least an interior portion of the artery;

a cross-sectional diameter of the measuring volume is greater than a diameter of the artery and the interference pattern of the measuring volume has a fringe spacing greater than a diameter of blood cells; and

the one or more reflected waves include backscattered light waves.

5. The method of claim 4, wherein the light includes one or more of infrared light and visible light.

6. The method of claim 1, wherein the determining of the blood flow difference based on the two or more measurements comprises:

determining, by the processor, values of arterial lumen for each of the measurement elevations;

determining, by the processor, a value of blood velocity associated with each of the measurement elevations based, at least in part, on a Doppler shift or a Doppler shift related signal; and

determining, by the processor, a first blood flow associated with a first measurement elevation and a second blood flow associated with a second measurement elevation based on the determined values of blood velocity and the determined values of arterial lumen.

7. The method of claim 6, wherein the determined values of arterial lumen comprise values of arterial cross-section or arterial volume.

8. The method of claim 1, wherein the one or more sensors include one or more ultrasonic sensors, one or more optical sensors or any combination thereof.

9. The method of claim 8, wherein the sensor system includes an ultrasonic sensor system and wherein the performing, by the one or more sensors, the two or more measurements comprises directing ultrasonic waves into the limb towards an artery.

10. The method of claim 1, further comprising at least one of storing or transmitting, by the processor, an indication or estimation of the blood pressure.

11. A system for calculating blood pressure, comprising:

a sensor system; and

a control system configured for communication with the sensor system, the controls system being capable of;

controlling one or more sensors of the sensor system to take two or more measurements, wherein at least two of the two or more measurements correspond to different measurement elevations of a subject'"'"'s limb;

determining a blood flow difference based on the or more two or more measurements;

determining a hydrostatic pressure difference based on the two or more different measurement elevations of the two or more measurements; and

estimating a blood pressure based on one or more values of blood flow, the hydrostatic pressure difference and the blood flow difference.

12. The system of claim 11, wherein the performing, by the one or more sensors, the two or more measurements comprises:

directing, by the one or more sensors, waves into the limb towards an artery;

receiving, by the one or more sensors, one or more reflected waves, wherein the one or more reflected waves are based at least in part on the directed waves;

obtaining, by the one or more sensors, the two or more measurements, including the at least two measurements taken at each of two or more different measurement elevations, based on the one or more reflected waves; and

transmitting, by the one or more sensors, the two or more measurements to the control system.

13. The system of claim 12, wherein the reflected waves include scattered waves, specularly reflected waves, or both scattered waves and specularly reflected waves.

14. The system of claim 12, wherein:

the one or more sensors include one or more optical sensors of an optical sensor system;

directing waves into the limb involves directing, by the optical sensor system, light waves towards the artery to form a measuring volume having an interference pattern that illuminates at least an interior portion of the artery;

a cross-sectional diameter of the measuring volume is greater than a diameter of the artery and the interference pattern of the measuring volume has a fringe spacing greater than a diameter of blood cells; and

the one or more reflected waves include backscattered light waves.

15. The system of claim 14, wherein the light includes one or more of infrared light and visible light.

16. The system of claim 11, wherein the determining of the blood flow difference based on the two or more measurements comprises:

determining values of arterial lumen for each of the measurement elevations;

determining a value of blood velocity associated with each of the measurement elevations based, at least in part, on a Doppler shift or Doppler shift related signal; and

determining a first blood flow associated with a first measurement elevation and a second blood flow associated with a second measurement elevation based on the determined values of blood velocity and the determined values of arterial lumen.

17. The system of claim 16, wherein the determined values of arterial lumen comprise values of arterial cross-section or arterial volume.

18. The system of claim 11, wherein the one or more sensors include one or more ultrasonic sensors, one or more optical sensors or any combination thereof.

19. The system of claim 18, wherein the sensor system includes an ultrasonic sensor system and wherein the performing, by the one or more sensors, the two or more measurements comprises directing ultrasonic waves into the limb towards an artery.

20. A system for calculating blood pressure, comprising:

a sensor system; and

control means configured for communication with the sensor system, the control means including means for;

controlling one or more sensors of the sensor system to take two or more measurements, wherein at least two measurements of the two or more measurements correspond to different measurement elevations of a subject'"'"'s limb;

determining a blood flow difference based on the two or more measurements;

determining a hydrostatic pressure difference based on the two or more different measurement elevations of the two or more measurements; and

estimating a blood pressure based on one or more values of blood flow, the hydrostatic pressure difference and the blood flow difference.

21. The system of claim 20, wherein the performing, by the one or more sensors, the two or more measurements comprises:

directing, by the one or more sensors, waves into the limb towards an artery;

receiving, by the one or more sensors, one or more reflected waves, wherein the one or more reflected waves are based at least in part on the directed waves;

obtaining, by the one or more sensors, the two or more measurements, including the at least two measurements taken at each of two or more different measurement elevations, based on the one or more reflected waves; and

transmitting, by the one or more sensors, the two or more measurements to the control means.

22. The system of claim 21, wherein:

the one or more sensors include one or more optical sensors of an optical sensor system;

directing waves into the limb involves directing, by the optical sensor system, light waves towards the artery to form a measuring volume having an interference pattern that illuminates at least an interior portion of the artery;

a cross-sectional diameter of the measuring volume is greater than a diameter of the artery and the interference pattern of the measuring volume has a fringe spacing greater than a diameter of blood cells; and

the one or more reflected waves include backscattered light waves.

23. The system of claim 20, wherein the determining of the blood flow difference based on the two or more measurements comprises:

determining values of arterial lumen for each of the measurement elevations;

determining a value of blood velocity associated with each of the measurement elevations based, at least in part, on a Doppler shift or Doppler shift related signal; and

determining a first blood flow associated with a first measurement elevation and a second blood flow associated with a second measurement elevation based on the determined values of blood velocity and the determined values of arterial lumen.

24. The system of claim 20, wherein the sensor system includes an ultrasonic sensor system and wherein the performing, by the one or more sensors, the two or more measurements comprises directing ultrasonic waves into the limb towards an artery.

28. The non-transitory medium of claim 20, wherein the determining of the blood flow difference based on the two or more measurements comprises:

determining values of arterial lumen for each of the measurement elevations;

determining a value of blood velocity associated with each of the measurement elevations based, at least in part, on a Doppler shift or Doppler shift related signal; and

determining a first blood flow associated with a first measurement elevation and a second blood flow associated with a second measurement elevation based on the determined values of blood velocity and the determined values of arterial lumen.

29. The non-transitory medium of claim 20, wherein the sensor system includes an ultrasonic sensor system and wherein the performing, by the one or more sensors, the two or more measurements comprises directing ultrasonic waves into the limb towards an artery.

25. A non-transitory medium having software stored thereon, the software including instructions for:

controlling one or more sensors of a sensor system to take two or more measurements, wherein at least two measurements of the two or more measurements correspond to different measurement elevations of a subject'"'"'s limb;

determining a blood flow difference based on the at least two measurements;

determining a hydrostatic pressure difference based on the two or more different elevations of the at least two measurements; and

estimating a blood pressure based on one or more values of blood flow, the hydrostatic pressure difference and the blood flow difference.

26. The non-transitory medium of claim 25, wherein the performing, by the one or more sensors, the two or more measurements comprises:

directing, by the one or more sensors, waves into the limb towards an artery;

receiving, by the one or more sensors, one or more reflected waves, wherein the one or more reflected waves are based at least in part on the directed waves;

obtaining, by the one or more sensors, the two or more measurements, including the at least two measurements taken at each of two or more different measurement elevations, based on the one or more reflected waves; and

transmitting, by the one or more sensors, the two or more measurements to a control system.

27. The non-transitory medium of claim 26, wherein:

the one or more sensors include one or more optical sensors of an optical sensor system;

directing waves into the limb involves directing, by the optical sensor system, light waves towards the artery to form a measuring volume having an interference pattern that illuminates at least an interior portion of the artery;

a cross-sectional diameter of the measuring volume is greater than a diameter of the artery and the interference pattern of the measuring volume has a fringe spacing greater than a diameter of blood cells; and

the one or more reflected waves include backscattered light waves.