Monitor for blood pressure and other arterial properties

Patent metadata

Field	Value
Publication number	US-2018289288-A1
Application number	US-201815946889-A
Country	US
Kind code	A1
Filing date	Apr 6, 2018
Priority date	Apr 7, 2017
Publication date	Oct 11, 2018
Grant date	—

Abstract

A method and apparatus for monitoring arterial properties, including systolic and diastolic pressure levels, of a subject is provided, in which a hardware processor receives and analyzes ballistocardiogram (BCG) data of the subject. A non-transient computer readable medium, accessible by the hardware processor, contains instructions that, when executed by the hardware processor, identify features of the BCG waveform and determine the arterial properties therefrom. For example, a diastolic pressure level may be determined from a time interval between the ‘I’ and ‘J’ peaks of the waveform and a systolic pressure level determined from the amplitude difference between the ‘J’ and ‘K’ peaks of the waveform in combination with the ‘I-J’ time interval or amplitude difference. A physical mechanism for the BCG data is disclosed that enables other arterial properties of the subject to be determined from the BCG data alone or from the BCG data in combination with other measurements.

First claim

What is claimed is:

1 . A blood pressure monitor for sensing systolic and diastolic pressure levels of a subject, the blood pressure monitor comprising:
a sensor configured to provide ballistocardiogram data in response to cardiac forces acting on the subject, where the ballistocardiogram data comprises a waveform having ‘I’, ‘J’ and ‘K’ peaks; a hardware processor configured to receive the ballistocardiogram data; and a non-transient computer readable medium accessible by the hardware processor and containing instructions that, when executed by the hardware processor, perform a method comprising:
determining the diastolic pressure level from a time interval between the ‘I’ and ‘J’ peaks of the waveform;
determining an amplitude difference between the ‘J’ and ‘K’ peaks of the waveform; and
determining the systolic pressure level from the time interval between the ‘I’ and ‘J’ peaks of the waveform and the amplitude difference between the ‘J’ and ‘K’ peaks of the waveform,

where the systolic and diastolic pressure levels are provided as outputs from the blood pressure monitor.

2 . The blood pressure monitor of claim 1 , where the sensor comprises a force plate.

3 . The blood pressure monitor of claim 1 , where the sensor comprises a bed.

4 . The blood pressure monitor of claim 1 , where the sensor comprises a chair.

5 . The blood pressure monitor of claim 1 , where the sensor comprises an acceleration, velocity, or displacement sensor.

6 . The blood pressure monitor of claim 1 , where sensor comprises one or more body-mountable devices configured to sense whole-body motion in response to cardiac forces.

7 . The blood pressure monitor of claim 6 , where the one or more body-mountable devices configured to sense whole-body motion in response to cardiac forces comprises an accelerometer.

8 . The blood pressure monitor of claim 1 , where the method performed by the instructions further comprises:
determining a pulse pressure level from the amplitude difference between the ‘J’ and ‘K’ peaks of the waveform,
where the systolic pressure level is determined from the pulse pressure level and the diastolic pressure level.

9 . The blood pressure monitor of claim 8 , where the non-transient computer readable medium is configured to store calibration data that is used in determining the pulse pressure level from the amplitude difference between the ‘J’ and ‘K’ peaks of the waveform.

10 . The blood pressure monitor of claim 1 , where the non-transient computer readable medium is configured to store calibration data that is used in determining the diastolic pressure level from the time interval between the ‘I’ and ‘J’ peaks of the waveform.

11 . The blood pressure monitor of claim 1 , further comprising a user interface configured to display the systolic and diastolic pressure levels.

12 . A method for sensing one or more arterial properties of a subject, the method comprising:
collecting ballistocardiogram data of the subject for one or more cardiac cycles; detecting a ‘J’ peak in the ballistocardiogram data; detecting a ‘K’ peak in the ballistocardiogram data determining an amplitude difference between the ‘J’ peak and the ‘K’ peak; and determining a pulse pressure level from the determined amplitude difference,
where the one or more arterial properties comprise the determined pulse pressure level.

13 . The method of claim 12 , further comprising determining a pressure pulse transit time by detecting a time interval between an ‘I’ peak and a ‘J’ peak in the ballistocardiogram data, where the one or more arterial properties further comprise the pulse pressure transit time.

14 . The method of claim 13 , further comprising determining a diastolic pressure level from the pressure pulse transit time.

15 . The method of claim 14 , further comprising adding the determined diastolic pressure to the pulse pressure to provide a systolic pressure, where the one or more arterial properties comprise the diastolic pressure and the systolic pressure.

16 . The method of claim 12 , further comprising applying a calibration factor to the ballistocardiogram data or the one or more arterial properties derived therefrom.

17 . The method of claim 12 , where collecting ballistocardiogram data comprises:
sensing cardiac forces acting on the subject in at least a head-to-foot direction to provide a first signal; sampling the first signal to provide the ballistocardiogram data as a sequence of sampled values; and providing the sequence of sampled values to a hardware processor.

18 . The method of claim 17 , further comprising displaying the one or more arterial properties at a user interface in communication with the hardware processor.

19 . The method of claim 17 , where sensing cardiac forces acting on the subject comprises sensing acceleration, velocity, or displacement data of the subject.

20 . A method for sensing systolic and diastolic pressure levels of a subject, the method comprising:
sensing ballistocardiogram data of the subject, where the ballistocardiogram data comprises a waveform having ‘I’, ‘J’ and ‘K’ peaks; determining, by a hardware processor, a pulse pressure level from an amplitude difference between the ‘J’ and ‘K’ peaks of the waveform; determining, by the hardware processor, the diastolic pressure level from a time interval between the ‘I’ and ‘J’ peaks of the waveform; and determining the systolic pressure level by adding the diastolic pressure to the pulse pressure.

21 . The method of claim 20 , where sensing ballistocardiogram data comprises sensing acceleration, velocity, or displacement data of the subject.

22 . An apparatus for sensing arterial properties of a subject, the apparatus comprising:
a sensor configured to provide measured ballistocardiogram data in response to at least head-to-foot cardiac forces acting on of the subject; a blood pressure sensor configured to provide blood pressure level data; and a hardware processor configured for:
receiving the ballistocardiogram data and blood pressure level data;
determining arterial parameters of a parametric model responsive to the blood pressure level data for which an output from the parametric model using the determined arterial parameters approximates the measured ballistocardiogram data; and
mapping the arterial parameters to the sensed arterial properties.

23 . The apparatus of claim 22 , where arterial parameters of the parametric model comprise one or more parameters selected from a group of parameters consisting of:
a cross-sectional area of an ascending aorta of the subject; a cross-sectional area of a descending aorta of the subject; a pulse transit time of the ascending aorta of the subject; a pulse transit time of the descending aorta of the subject; a reflection coefficient for a distal end of the ascending aorta of the subject; and a reflection coefficient for a distal end of the descending aorta of the subject.

24 . The apparatus of claim 22 , where the blood pressure level data comprises a pulse pressure level and where the arterial parameters comprise:
a cross-sectional area of a descending aorta of the subject, determined from the pulse pressure level and an amplitude difference between ‘J’ and ‘K’ peaks of the measured ballistocardiogram data.

25 . The apparatus of claim 22 , where the hardware processor is further configured for:
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Assignees

• Univ Of Maryland At College Park
• Univ Michigan State

Inventors

• Kim Chang-Sei
• Ober Stephanie
• Hahn Jin-Oh
• Mukkamala Ramakrishna
• Inan Omer T

Classifications

• A61B5/02438

  with portable devices, e.g. worn by the patient · CPC title

• A61B5/02108

  from analysis of pulse wave characteristics · CPC title

• A61B5/1102 Primary

  Ballistocardiography · CPC title

• A61B5/7253

  characterised by using transforms · CPC title