Granted Patent B2

US 11,363,994 · App. 16/533,778 · Granted Jun 21, 2022

Inventors: Alton Reich (Huntsville, AL); Rodrigo E. Teixeira (Madison, AL)

A61B5/7275A61B5/02007A61B5/029A61B5/02108A61B5/02233A61B5/02255A61B5/742G16H50/50A61B2560/0223

Abstract

Claims (64)

1. A method for estimating a state of a cardiovascular system of a person having a limb, comprising the steps of:

providing a cardiac stroke volume analyzer, comprising:

a blood pressure sensor, said blood pressure sensor generating a time-varying pressure state waveform output from the limb of the person;

a system processor connected to said blood pressure sensor; and

a dynamic state-space model of a cardiovascular system;

said system processor receiving cardiovascular input data, from said blood pressure sensor, related to a transient pressure state of the cardiovascular system;

at least one probabilistic model, of said dynamic state-space model, operating on the time-varying pressure state waveform output to generate a probability distribution function to a non-pressure state of the cardiovascular system;

iteratively updating said probability distribution function using synchronized updated time-varying pressure state waveform output from said blood pressure sensor; and

said system processor processing the probability distribution function to generate a non-pressure state output related to an arterial compliance of the person, said output displayed on a display screen to at least one of the person and a medical professional.

2. The method of claim 1 , further comprising the steps of:

providing an optical input to the limb of the person; and

said blood pressure sensor generating a response to the optical input to yield said time-varying pressure state waveform output.

3. The method of claim 2 , further comprising the step of:

relating the time-varying pressure state waveform output to a blood volume; and

relating the blood volume to the arterial compliance.

4. The method of claim 3 , said step of relating further comprising the step of:

using an equation with a first term related to a pressure to inflate an artery and a second term related to a second pressure to radially stretch the artery.

5. The method of claim 1 , further comprising the step of:

a pressure transducer output measuring pressure from an alternating partial inflation of a blood pressure cuff and a partial deflation of said blood pressure cuff to yield said time-varying pressure state waveform output.

6. The method of claim 1 , further comprising the step of:

a pressure transducer, of said blood pressure sensor, reading a passive change of the blood pressure of the person on a blood pressure cuff.

7. The method of claim 1 , said blood pressure sensor generating a time-varying pressure state waveform output further comprising the step of:

using an automated blood pressure cuff to alternatingly measure systolic pressure and diastolic pressure at at least one of: a fixed time interval and a non-fixed time interval.

8. The method of claim 1 , further comprising the step of:

measuring pressure directly as a function of time to yield said time varying pressure state waveform.

9. The method of claim 1 , further comprising the steps of:

using a pulse oximeter to generate said time varying pressure state waveform; and

using a blood pressure cuff to calibrate the time varying pressure state waveform.

10. The method of claim 1 , further comprising the step of:

measuring pressure, using a blood pressure cuff alternatingly at a first partially inflated pressure in excess of 100 mm Hg and a second partially deflated pressure of less than 100 mm Hg, directly as a function of time to yield said time varying pressure state waveform.

11. An apparatus for estimating state of a cardiovascular system of a person having a limb, comprising:

a noninvasive cardiac stroke volume analyzer, comprising:

a blood pressure sensor, said blood pressure sensor configured to generate a time-varying pressure state waveform output from the limb of the person, said cardiac stroke volume analyzer not comprising a Doppler sensor for measuring acoustic information;

a system processor connected to said blood pressure sensor; and

a dynamic state-space model of a cardiovascular system linked to said system processor;

said system processor configured to receive cardiovascular input data, from said blood pressure sensor, related to a transient pressure state of the cardiovascular system;

at least one probabilistic model, of said dynamic state-space model, configured to operate on the time-varying pressure state waveform output to generate a probability distribution function to a non-pressure state of the cardiovascular system;

said system processor configured to iteratively update said probability distribution function using synchronized updated time-varying pressure state waveform output from said blood pressure sensor; and

said system processor configured to process the probability distribution function to generate a non-pressure state output related to at least one of a stroke volume of a heart of the person and arterial compliance of the person, said output displayed to at least one of the person and a doctor.

12. The apparatus of claim 11 , said blood pressure sensor integrated into said cardiac stroke volume analyzer.

13. The apparatus of claim 12 , said blood pressure sensor comprising:

a blood pressure cuff, said system processor configured to alternatingly partially inflate said blood pressure cuff to a sub-peristaltic pressure and to partially deflate said blood pressure cuff from said sub-peristaltic pressure to generate said time-varying pressure state waveform output.

14. The apparatus of claim 13 , further comprising:

a computer display screen configured to display said output.

15. The apparatus of claim 11 , said blood pressure sensor comprising:

an optical meter configured to provide an optical input to the limb of the person and responsive thereto generate said time-varying pressure state waveform; and

a reference blood pressure cuff, said system processor configured to use output from said reference blood pressure cuff to calibrate said time-varying pressure state waveform.

16. The apparatus of claim 15 , said system processor configured to relate the time-varying pressure state waveform output to a blood volume and subsequently relate the blood volume to the arterial compliance.

17. The apparatus of claim 11 , said blood pressure sensor comprising a pressure transducer configured to output a pressure measure from an alternating partial inflation of a blood pressure cuff and a partial deflation of said blood pressure cuff to yield said time-varying pressure state waveform output.

18. The apparatus of claim 11 , said blood pressure sensor further comprising:

a blood pressure cuff; and

a pressure transducer between at least a portion of said blood pressure cuff and the limb of the person, said pressure transducer configured to generate and output a passive change of pressure of the person as the time-varying pressure state waveform output.

19. The apparatus of claim 11 , said blood pressure sensor further comprising:

an automated blood pressure cuff configured to alternatingly measure systolic pressure and diastolic pressure at at least one of: (1) a fixed time interval and (2) a non-fixed time interval, and output the results as said time-varying pressure state waveform output.

20. The apparatus of claim 19 , said automated blood pressure cuff configured to measure pressure in the limb alternatingly at a first partially inflated and sub-peristaltic pressure and a second partially deflated pressure of less than said sub-peristaltic pressure directly as a function of time to yield said time varying pressure state waveform.

21. An apparatus for estimating state of a cardiovascular system of a person having a limb, comprising:

a noninvasive cardiac stroke volume analyzer, comprising:

a blood pressure sensor, said blood pressure sensor configured to generate a time-varying pressure state waveform output from the limb of the person, said cardiac stroke volume analyzer not comprising an electrocardiogram sensor;

a system processor connected to said blood pressure sensor; and

a dynamic state-space model of a cardiovascular system linked to said system processor;

said system processor configured to receive cardiovascular input data, from said blood pressure sensor, related to a transient pressure state of the cardiovascular system;

at least one probabilistic model, of said dynamic state-space model, configured to operate on the time-varying pressure state waveform output to generate a probability distribution function to a non-pressure state of the cardiovascular system;

said system processor configured to iteratively update said probability distribution function using synchronized updated time-varying pressure state waveform output from said blood pressure sensor; and

said system processor configured to process the probability distribution function to generate a non-pressure state output related to at least one of a stroke volume of a heart of the person and arterial compliance of the person, said output displayed to at least one of the person and a doctor.

Continuity (10)