Apparatus for tracking a specific blood pressure

Patent metadata

Field	Value
Publication number	US-2016270673-A1
Application number	US-201415034015-A
Country	US
Kind code	A1
Filing date	Mar 3, 2014
Priority date	Nov 8, 2013
Publication date	Sep 22, 2016
Grant date	—

Abstract

The invention relates to a device configured for tracking e.g. the diastolic blood pressure in a patient. The device applies a pressure to a body part, e.g. by use of an inflatable cuff. By performing repeated and alternating pressure changes in the cuff a specific feature of a signal that relates to the diastolic blood pressure can be tracked and possibly measured.

First claim

1 . A device for performing repeated measurements and tracking of a distinctive blood pressure level in a blood vessel in a body part, wherein the device comprises,
a pressure control unit for controlling a pressure providing device to apply an external pressure to the body part, a detector unit for detecting appearance of a physical characteristic indicative of the distinctive blood pressure level, wherein the device is configured to:
(i) control the pressure control unit to change the external pressure in a first direction until the physical characteristic has been detected;
(ii) in response to the detection of the physical characteristic, measure the external pressure between the body part and the pressure providing device by use of a pressure sensor connected to the pressure providing device so as to provide a measure of the distinctive blood pressure level;
(iii) in response to the detection of the physical characteristic, control the pressure control unit to change the external pressure in the direction opposite to the first direction until the physical characteristic is no longer detected; and
(iv) cyclically repeat (i), (ii) and (iii) to produce a signal that tracks the distinctive blood pressure level over time.

2 . A device according to claim 1 , wherein the the distinctive blood pressure level is the diastolic blood pressure and wherein changing the external pressure in the first direction comprises applying the external pressure at a level which is at or near atmospheric pressure and then increasing the external pressure, and changing the external pressure in the direction opposite to the first direction comprises decreasing the external pressure.

3 . A device according to claim 1 , wherein the distinctive blood pressure level is the systolic blood pressure and wherein changing the external pressure in the first direction comprises applying the external pressure at a level above systole and then decreasing the external pressure, and changing the external pressure in the direction opposite to the first direction comprises increasing the external pressure.

4 . A device according to claim 1 , wherein the physical characteristic comprises one of: the appearance of a characteristic sound from the blood vessel or the disappearance of a characteristic sound from the blood vessel, and wherein the detector unit is configured for detecting a characteristic sound.

5 . A device according to claim 1 , wherein the physical characteristic is a particular oscillation amplitude in an oscillation in the external pressure measured by the pressure sensor, wherein the detector unit is configured to detect the particular oscillation amplitude, and wherein the device is configured to control the pressure control unit to change the external pressure over a pressure range, to determine a maximum oscillation amplitude present within the pressure range, and to set the particular oscillation amplitude as the maximum oscillation amplitude or to set the particular oscillation amplitude as a fraction of the maximum oscillation amplitude.

6 . A device according to claim 1 , wherein the physical characteristic is a characteristic ultrasound reflection from the blood vessel, and wherein the detector unit is configured for detecting the characteristic ultrasound reflection.

7 . A device according to claim 1 , wherein:
the physical characteristic is a characteristic amplitude of a photoplethysmograph, PPG, waveform, and the detector unit is configured to detect the characteristic PPG waveform amplitude; or the physical characteristic is a characteristic morphology of a PPG waveform, and the detector unit is configured to detect the characteristic PPG waveform morphology.

8 . A device according to claim 1 , wherein the detector unit is configured to detect validity of the physical characteristic as a function of an amplitude, a duration or a spectral content of a signal containing the physical characteristic.

9 . A device according to claim 1 , wherein the detector unit is configured to detect the physical characteristic as a function of an input signal containing information about timing of chest compressions applied to a cardiac arrest victim and/or timing of an electrocardiogram.

10 . A CPR device configured for applying chest compressions to a cardiac arrest victim, wherein the CPR device comprises the device according to claim 1 .

11 . A CPR device according to claim 10 , wherein the CPR device is configured to determine a quality parameter of the performed chest compressions by use of the measured distinctive blood pressure level and to adapt chest compression as a function of the quality parameter.

12 . A CPR device according to claim 10 , wherein the CPR device is configured to detect return of spontaneous circulation, ROSC, based on the measured distinctive blood pressure level.

13 . An ambulatory monitoring device for monitoring the blood pressure of a subject, the ambulatory monitoring device comprising the device according to claim 1 , the ambulatory monitoring device further comprising a unit arranged to be worn by the subject, the unit comprising the pressure control unit.

14 . A method for tracking a distinctive blood pressure level in a blood vessel in a body part, wherein the method comprises,
(a) applying an external pressure to the body part, (b) changing the external pressure applied to the body part in a first direction until a physical characteristic indicative of the distinctive blood pressure level has been detected, (c) in response to the detection of the physical characteristic, measuring the external pressure between the body part and the pressure providing device so as to provide a measure of the distinctive blood pressure level, (d) in response to the detection of the physical characteristic, changing the external pressure applied to the body part in the direction opposite to the first direction until the physical characteristic is no longer detected; and (e) cyclically repeating steps (b), (c) and (d) to produce a signal that racks the distinctive blood pressure level over time.

15 . A computer program product comprising program code instructions which when executed by a processor causes the processor to:
(i) control a pressure control unit to change the external pressure applied by a pressure providing device in a first direction until the physical characteristic has been detected; (ii) in response to the detection of the physical characteristic, control a pressure sensor connected to the pressure providing device to measure the external pressure between the body part and the pressure providing device so as to provide a measure of the distinctive blood pressure level; (iii) in response to the detection of the physical characteristic, control the pressure control unit to change the external pressure in the direction opposite to the first direction until the physical characteristic is no longer detected; and (iv) cyclically repeat (i), (ii) and (iii) to produce a signal that tracks the distinctive blood pressure level over time.

Assignees

• Koninklijke Philips Nv

Inventors

• Aelen Paul
• Woerlee Pierre Hermanus
• Peeters Wouter Herman
• Ordelman Simone Cornelia Maria Anna

Classifications

• A61H31/005

  with feedback for the user · CPC title

• A61B5/02225

  using the oscillometric method · CPC title

• A61B5/0225

  the pressure being controlled by electric signals, e.g. derived from Korotkoff sounds · CPC title

• A61B2090/378

  using ultrasound · CPC title

• A61B5/02255 Primary

  the pressure being controlled by plethysmographic signals, e.g. derived from optical sensors · CPC title