BODY-WORN SYSTEM FOR CONTINUOUS, NONINVASIVE MEASUREMENT OF CARDIAC OUTPUT, STROKE VOLUME, CARDIAC POWER, AND BLOOD PRESSURE

• US 20140249432A1
• Filed: 12/27/2011
• Published: 09/04/2014
• Est. Priority Date: 12/28/2010
• Status: Abandoned Application

• Current Assignee: Sotera Wireless Incorporated
• Original Assignee: Donald Bernstein, Matt Banet
• Inventors: BANET, Matt, HENRY, Isaac, BERNSTEIN, Donald
• Application Number:
  US13/338,233
• Publication Number:
  US 20140249432A1
• Time in Patent Office: Days
• US Class Current: 600/485
• CPC Class Codes: A61B 2562/04 Arrangements of multiple sensors of the same type
• CPC Class Codes: A61B 5/0008 Temperature signals
• CPC Class Codes: A61B 5/0022 Monitoring a patient using a global network, e.g. telephone networks, internet
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• CPC Class Codes: A61B 5/02028 Determining haemodynamic parameters not otherwise provided for, e.g. cardiac contractility or left ventricular ejection fraction
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/02427 Details of sensor
• CPC Class Codes: A61B 5/0245 by using sensing means generating electric signals, i.e. ECG signals
• CPC Class Codes: A61B 5/029 Measuring or recording blood output from the heart, e.g. minute volume A61B8/065 takes precedence
• CPC Class Codes: A61B 5/0295 using plethysmography, i.e. measuring the variations in the volume of a body part as modified by the circulation of blood therethrough, e.g. impedance plethysmography
• CPC Class Codes: A61B 5/0535 Impedance plethysmography for measuring blood flow A61B5/0295
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/1116 Determining posture transitions
• CPC Class Codes: A61B 5/14542 for measuring blood gases A61B5/14551 takes precedence
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/681 Wristwatch-type devices
• CPC Class Codes: A61B 5/6823 Trunk, e.g., chest, back, abdomen, hip
• CPC Class Codes: A61B 5/6824 Arm or wrist
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6833 : Adhesive patches
• CPC Class Codes: A61B 5/7239 : using differentiation including higher order derivatives
• CPC Class Codes: A61B 5/725 : using specific filters therefor, e.g. Kalman or adaptive filters A61B5/316 take precedence
• CPC Class Codes: A61B 5/746 : Alarms related to a physiological condition, e.g. details of setting alarm thresholds or avoiding false alarms alarms per se G08B
• CPC Class Codes: G16H 40/67 : for remote operation

Abstract

The invention provides a system for measuring stroke volume (SV), cardiac output (CO), and cardiac power (CP) from a patient that features: 1) impedance sensor connected to at least two body-worn electrodes and including an impedance circuit that processes analog signals from the electrodes to measure an impedance signal (e.g. a TBEV waveform); 2) an ECG sensor connected to at least two chest-worn electrodes and including an ECG circuit that processes analog signals from the electrodes to measure and ECG signal; 3) an optical sensor connected to a body-worn optical probe and including an optical circuit that processes signals from the probe to measure at least one optical signal (e.g. a PPG waveform) from the patient; 4) a processing system, typically worn on the patient'"'"'s wrist and connected through a wired interface to the optical sensor, and through either a wired or wireless interface to the TBEV and ECG sensors.

Claims

1. A system for simultaneously measuring blood pressure and stroke volume from a patient, comprising:

an impedance sensor connected to at least two electrodes attached to the patient and comprising an impedance circuit, the impedance circuit configured to process signals from the at least two electrodes to measure an impedance signal from the patient;

a optical sensor connected to an optical probe attached to the patient and comprising an optical circuit, the optical circuit configured to process signals from the optical probe to measure at least one optical signal from the patient;

an ECG sensor connected to at least two electrodes attached to the patient and comprising an ECG circuit, the ECG circuit configured to process signals from the at least two electrodes to measure an ECG signal from the patient; and

,

a processing system configured to;

i) operably connect to the impedance sensor, optical sensor, and the ECG sensor;

ii) receive the impedance signal from the impedance sensor and process it to determine a first value of stroke volume;

iii) receive the optical signal from the optical sensor and the ECG signal from the ECG sensor and collectively process the optical and ECG signals to determine a set of blood pressure values;

iv) determine a first stroke volume estimator from a first blood pressure value in the set of blood pressure values;

v) determine a second stroke volume estimator from a second blood pressure value in the set of blood pressure values;

vi) collectively process the first and second stroke volume estimators to determine a second value of stroke volume; and

vii) collectively process the first and second values of stroke volume to determine a third value of stroke volume.

5. The system of claim 1, wherein the set of blood pressure values is determined by processing a time difference between a QRS complex in the ECG signal and a time-dependent component of the optical signal.

6. The system of claim 5, wherein the time-dependent component of the optical signal is an onset of a pulse in a PPG waveform.

7. The system of claim 5, wherein the set of blood pressure values includes SYS, DIA, MAP, and PP.

8. The system of claim 7, wherein at least one of the first and second stroke volume estimators are determined from the following equation or a mathematical derivative thereof:

[(PP/(SYS+DIA)]*HR.

9. The system of claim 7, wherein at least one of the first and second stroke volume estimators are determined from the following equation or a mathematical derivative thereof:

(163+HR−

0.48*MAP)*SYS_area*HR.

10. The system of claim 7, wherein at least one of the first and second stroke volume estimators are determined from the following equation or a mathematical derivative thereof:

SYS_area*HR.

11. The system of claim 7, wherein at least one of the first and second stroke volume estimators are determined from the following equation or a mathematical derivative thereof:

(MAP−

DIA)*HR.

12. The system of claim 7, wherein at least one of the first and second stroke volume estimators are determined from the following equation or a mathematical derivative thereof:

PP*HR.

13. The system of claim 1, wherein the processing system is configured to process the impedance signal to determine the first value of stroke volume using the following equation or a mathematical derivative thereof:

(N. B. Matt, lower case Greek letter “

delta”

should be replaced throughout your equations to Latin lower case, “

d”

. Diminutive Greek “

delta”

is reserved for partial derivatives. dZ/dt is a first-order derivative.)

14. The system of claim 1, wherein the processing system is configured to process the impedance signal to determine the first value of stroke volume using the following equation or a mathematical derivative thereof.

2. A system for simultaneously measuring blood pressure and stroke volume from a patient, comprising:

an impedance sensor connected to at least two electrodes attached to the patient and comprising an impedance circuit, the impedance circuit configured to process signals from the at least two electrodes to measure an impedance signal from the patient;

an ECG sensor connected to at least two electrodes attached to the patient and comprising an ECG circuit, the ECG circuit configured to process signals from the at least two electrodes to measure an ECG signal from the patient; and

,

a processing system configured to;

i) operably connect to the impedance sensor and the ECG sensor;

ii) receive the impedance signal from the impedance sensor and process it to determine a first value of stroke volume;

iii) receive the ECG signal from the ECG sensor and collectively process the impedance and ECG signals to determine a set of blood pressure values;

iv) determine a first stroke volume estimator from a first blood pressure value in the set of blood pressure values;

v) determine a second stroke volume estimator from a second blood pressure value in the set of blood pressure values;

vi) collectively process the first and second stroke volume estimators to determine a second value of stroke volume; and

vii) collectively process the first and second values of stroke volume to determine a third value of stroke volume.

15. The system of claim 2, wherein the set of blood pressure values is determined by processing a time difference between a QRS complex in the ECG signal and a time-dependent component of the optical signal.

16. The system of claim 15, wherein the time-dependent component of the optical signal is an onset of a pulse in a PPG waveform.

17. The system of claim 15, wherein the set of blood pressure values includes SYS, DIA, MAP, and PP.

18. The system of claim 17, wherein at least one of the first and second stroke volume estimators are determined from the following equation or a mathematical derivative thereof:

[(PP/(SYS+DIA)]*HR.

19. The system of claim 17, wherein at least one of the first and second stroke volume estimators are determined from the following equation or a mathematical derivative thereof:

(163+HR−

0.48*MAP)*SYS_area*HR.

20. The system of claim 17, wherein at least one of the first and second stroke volume estimators are determined from the following equation or a mathematical derivative thereof:

SYS_area*HR.

21. The system of claim 17, wherein at least one of the first and second stroke volume estimators are determined from the following equation or a mathematical derivative thereof:

(MAP−

DIA)*HR.

22. The system of claim 17, wherein at least one of the first and second stroke volume estimators are determined from the following equation or a mathematical derivative thereof:

PP*HR.

23. The system of claim 2, wherein the processing system is configured to process the impedance signal to determine the first value of stroke volume using the following equation or a mathematical derivative thereof:

24. The system of claim 2, wherein the processing system is configured to process the impedance signal to determine the first value of stroke volume using the following equation or a mathematical derivative thereof:

3. A system for simultaneously measuring blood pressure and stroke volume from a patient, comprising:

an impedance sensor connected to at least two electrodes attached to the patient and comprising an impedance circuit, the impedance circuit configured to process signals from the at least two electrodes to measure an impedance signal from the patient;

a optical sensor connected to an optical probe attached to the patient and comprising an optical circuit, the optical circuit configured to process signals from the optical probe to measure at least one optical signal from the patient; and

,

a processing system configured to;

i) operably connect to the impedance sensor and the optical sensor;

ii) receive the impedance signal from the impedance sensor and process it to determine a first value of stroke volume;

iii) receive the optical signal from the optical sensor and collectively process the optical and impedance signals to determine a set of blood pressure values;

iv) determine a first stroke volume estimator from a first blood pressure value in the set of blood pressure values;

v) determine a second stroke volume estimator from a second blood pressure value in the set of blood pressure values;

vi) collectively process the first and second stroke volume estimators to determine a second value of stroke volume; and

vii) collectively process the first and second values of stroke volume to determine a third value of stroke volume.

4. A system for determining a stroke volume for a patient, comprising:

a first sensor comprising an impedance sensor;

a second sensor comprising an optical sensor;

a third sensor comprising an ECG sensor; and

a processing system configured to;

i) operably connect to the first, second, and third sensors;

ii) determine a first stroke volume value by processing a signal from the first sensor;

iii) collectively process time-domain properties of signals from at least two of the first, second and third sensors to determine a set of blood pressure values;

iv) determine a first stroke volume estimator from a first blood pressure value in the set of blood pressure values;

v) determine a second stroke volume estimator from a second blood pressure value in the set of blood pressure values;

vi) collectively process the first and second stroke volume estimators to determine a second stroke volume value; and

vii) collectively process the first and second stroke volume value to determine a third stroke volume value.