Non-interfering blood pressure measuring

Patent metadata

Field	Value
Publication number	US-10052036-B2
Application number	US-201514714776-A
Country	US
Kind code	B2
Filing date	May 18, 2015
Priority date	May 19, 2014
Publication date	Aug 21, 2018
Grant date	Aug 21, 2018

Abstract

Systems, methods, and devices of various embodiments enable measurement of blood pressure from an artery. The various embodiments may measure, using a non-interfering arterial measurement sensor, a first change in distension of the artery at a measurement location without interference to an arterial pressure at the measurement location during a series of pulses. A first pulse rate and estimated pulse pressures may be determined from the first change in distension. A coefficient may be determined fitting an exponentially decaying function representing an exponential decay of a portion of a diastolic phase to select ones of the estimated pulse pressures corresponding to the diastolic phase. An absolute blood pressure may be determined by applying the coefficient to a select mathematical model expressing a first relationship between the first change in distension of the artery and the pulse pressure in the artery at the measurement location.

First claim

What is claimed is:

1. A method of measuring blood pressure from an artery in a limb of a subject, comprising:
measuring, by a non-interfering arterial measurement sensor, a first change in distension of the artery at a measurement location on the limb without interference to an arterial pressure at the measurement location during a series of pulses;
determining, by a processor, a first pulse rate and estimated pulse pressures in response to measuring the first change in distension, the estimated pulse pressures comprising pressure values during at least a portion of a pulse including a diastolic phase;
determining, by the processor, a coefficient fitting an exponentially decaying function representing an exponential decay of a portion of the diastolic phase to select ones of the estimated pulse pressures corresponding to the diastolic phase, the coefficient indicative of a nonzero asymptotic value of the exponentially decaying function; and
determining, by the processor, an absolute blood pressure by applying the coefficient to a select mathematical model expressing a first relationship between the first change in distension of the artery and a transmural pressure in the artery at the measurement location.

2. The method of claim 1 , further comprising:
measuring, by an elevation sensor, a change in elevation of the measurement location in response to moving the limb;
determining, by the processor, an incremental sensitivity between a second change in distension of the artery from the measurement location on the limb and a predicted change in the estimated pulse pressures after the change in elevation; and
determining, by the processor, the estimated pulse pressures using another mathematical model describing a second relationship between changes in distension and transmural pressure with the incremental sensitivity applied to the another mathematical model.

3. The method of claim 2 , wherein the predicted change in distension is based on a last measured physiological parameter at a first elevation and a hydrostatic pressure change corresponding to the change in elevation.

4. The method of claim 1 , further comprising:
determining a second pulse rate; and
determining the estimated pulse pressures further in response to determining that there is no change between the second pulse rate and the first pulse rate.

5. The method of claim 1 , further comprising:
determining a second pulse rate; and
discarding measured changes of distension in response to determining that there is a change between the second pulse rate the first pulse rate.

6. The method of claim 1 , wherein measuring the first change in distension of the artery without interfering with a pressure in the artery at the measurement location during the series of pulses includes applying a counter pressure that is below a diastolic pressure of the subject on or near the measurement location.

7. The method of claim 1 , wherein measuring the first change in distension of the artery without interference to the arterial pressure in the artery at the measurement location during the series of pulses includes applying no man-made pressure to a portion of skin on the limb that is closest to the measurement location.

8. The method of claim 1 , wherein the coefficient fitting the exponentially decaying function representing the exponential decay of the diastolic phase is an additive value applied.

9. The method of claim 1 , further comprising:
measuring, by the non-interfering arterial measurement sensor, a second change in distension of the artery from the measurement location on the limb without interference to the arterial pressure at the measurement location during an earlier series of pulses; and
determining, by the processor, a second pulse rate and a preliminary blood pressure using the second change in distension, wherein determining the absolute blood pressure is in response to determining the first pulse rate is equal to the second pulse rate.

10. A device, comprising:
a non-interfering arterial measurement sensor configured to measure a first change in distension of an artery at a measurement location on a limb of a subject without interference to an arterial pressure at the measurement location during a series of pulses; and
a processor in communication with the non-interfering arterial measurement sensor, wherein the processor is configured with processor executable instructions to perform operations to:
receive the first change in distension of the artery measured by the non-interfering arterial measurement sensor;
determine a first pulse rate and estimated pulse pressures in response to receiving the first change in distension, the estimated pulse pressures comprising pressure values during at least a portion of a pulse including a diastolic phase;
determine a coefficient by curve fitting sensor measurements to an exponentially decaying function representing an exponential decay of a portion of the diastolic phase to select ones of the estimated pulse pressures corresponding to the diastolic phase, the coefficient indicative of a nonzero asymptotic value of the exponentially decaying function; and
determine an absolute blood pressure by applying the coefficient to a select mathematical model expressing a first relationship between the first change in distension of the artery and a transmural pressure in the artery at the measurement location.

11. The device of claim 10 , further comprising:
an elevation sensor in communication with the processor and configured to measure a change in elevation of the measurement location in response to moving the limb, wherein the processor is further configured with the processor executable instructions to perform operations to:
determine an incremental sensitivity between a second change in distension of the artery from the measurement location on the limb and a predicted change in the estimated pulse pressures after the change in elevation; and
determine the estimated pulse pressures using another mathematical model describing a second relationship between changes in distension and the transmural pressure with the incremental sensitivity applied to the another mathematical model.

12. The device of claim 11 , wherein the predicted change in distension is based on a last measured physiological parameter at a first elevation and a hydrostatic pressure change corresponding to the change in elevation.

13. The device of claim 10 , wherein the processor is configured with the processor executable instructions to perform operations to:
determine a second pulse rate; and
determine the estimated pulse pressures further in response to determining that there is no change between the second pulse rate and the first pulse rate.

14. The device of claim 10 , wherein the processor is configured with the processor executable instructions to perform operations to:
determine a second pulse rate; and
discard measured changes of distension in response to determining that there is a change between the second pulse rate the first pulse rate.

15. The device of claim 10 , wherein measuring the first change in distension of the artery without interfering with a pressure in the artery at the measurement location during the series of pulses includes applying a counter pressure that is below a diastolic pressure of the subject on or near the measurement location.

16. The device of claim 10 , wherein measuring the first change in distension of the artery without interference to the arterial pressure in the artery at the measurement location during the series of pulses includes applying no man-made pres

Assignees

• Qualcomm Inc

Inventors

• Lading Lars
• Baek David Boettcher

Classifications

• A61B5/7282

  Event detection, e.g. detecting unique waveforms indicative of a medical condition (cough events A61B5/0823; seizures A61B5/4094; sleep apnoea A61B5/4818) · CPC title

• A61B5/021

  Measuring pressure in heart or blood vessels · CPC title

• A61B5/726

  using Wavelet transforms · CPC title

• A61B5/053

  Measuring electrical impedance or conductance of a portion of the body · CPC title

• A61B8/04

  Measuring blood pressure · CPC title