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

• US 20140249435A1
• Filed: 12/27/2011
• Published: 09/04/2014
• Est. Priority Date: 12/28/2010
• Status: Active Grant

• Current Assignee: Sotera Wireless Incorporated (Foxconn Technology Co., Ltd.)
• Original Assignee: Donald Bernstein, Matt Banet
• Inventors: BANET, Matt, HENRY, Isaac, BERNSTEIN, Donald
• Granted Patent: US 10,722,130 B2
• Time in Patent Office: Days
• US Class Current: 600/506
• 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) an 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 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 measuring at least one of stroke volume and cardiac output 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 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) be worn on the body;

ii) operably connect to both the impedance sensor and the optical sensor;

iii) receive the impedance signal from the impedance sensor and process it to determine a first value of at least one of stroke volume and cardiac output;

iv) receive the optical signal from the optical sensor and process it to determine a second value of at least one of stroke volume and cardiac output; and

v) collectively process both the first and second values of at least one of stroke volume and cardiac output to determine a third value of at least one of stroke volume and cardiac output.

5. The system of claim 1, wherein the impedance sensor comprises a housing configured to be worn on the patient'"'"'s body.

6. The system of claim 5, wherein the impedance sensor comprises a housing configured to be worn on the patient'"'"'s clavicle/brachium region.

7. The system of claim 5, wherein the at least two electrodes are configured to be worn proximal to the patient'"'"'s brachium.

8. The system of claim 5, wherein the at least two electrodes are configured to be worn proximal to the patient'"'"'s shoulder.

9. The system of claim 1, wherein the impedance sensor comprises an analog-to-digital converter configured to convert the impedance signal into a digital impedance signal.

10. The system of claim 9, wherein the impedance sensor comprises a transceiver configured to transmit the digital impedance signal through a cable to the processing system.

11. The system of claim 9, wherein the impedance sensor comprises a transceiver configured to transmit the digital impedance signal through a wireless interface to the processing system.

12. The system of claim 11, wherein the transceiver comprises a short-range radio.

13. The system of claim 1, wherein the optical probe is configured to be worn proximal to the patient'"'"'s hand.

14. The system of claim 13, wherein the optical probe is configured to be worn on the patient'"'"'s thumb.

15. The system of claim 14, wherein the processing system comprises a wrist strap configured to wrap around the patient'"'"'s wrist so that the processing system can be worn on the wrist.

16. The system of claim 15, wherein the optical circuit and the processing system are comprised by a single housing.

17. The system of claim 16, further comprising a cable configured to connect on one end to the optical probe and on an opposing end to the optical circuit.

18. The system of claim 1, further comprising a motion sensor configured to receive and process motion signals related to the patient'"'"'s motion.

19. The system of claim 18, wherein the processing system is further configured to operably connect to the motion sensor to:

i) receive the motion signals or a signal determined from the motion signals; and

ii) process the motion signals or a signal determined from the motion signals to determine at least one of the patient'"'"'s degree of motion, posture, and activity level.

20. The system of claim 19, wherein the processing system is further configured to generate an alarm by collectively processing the patient'"'"'s posture and stroke volume.

21. The system of claim 19, wherein the processing system is further configured to suppress an alarm by collectively processing the patient'"'"'s degree of motion and stroke volume.

22. The system of claim 18, wherein the motion sensor is an accelerometer.

2. A system for measuring 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 representing time-dependent blood flow in a first region of the patient;

an 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 representing time-dependent blood flow in a second region of the patient; and

a processing system configured to;

i) be worn on the body;

ii) operably connect to both the impedance sensor and the optical sensor;

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

iv) receive the optical signal from the optical sensor and process it to determine a relative value of stroke volume; and

v) calibrate the relative value of stroke volume with the calibration value of stroke volume to determine a first value of stroke volume.

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

a first sensor, configured to worn proximal to the patient'"'"'s brachium, comprising an impedance sensor;

a second sensor, configured to be worn proximal the patient'"'"'s hand, comprising an optical sensor; and

a processing system, configured to be worn on the patient'"'"'s body and operably connect to both the first and second sensors, the processing system configured to determine the stroke volume by collectively processing time-domain properties of signals from both the first and second sensors.

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

an impedance sensor connected to at least two electrodes attached proximal to the patient'"'"'s brachium and comprising an impedance circuit, the impedance circuit configured to process signals measured by the at least two electrodes to generate an impedance signal comprising a first pulsatile component indicative of blood flow proximal to the brachium;

an optical sensor connected to an optical probe attached to the patient'"'"'s hand and comprising an optical circuit, the optical circuit configured to process signals from the optical probe to generate an optical signal comprising a second pulsatile component indicative of blood flow proximal to the hand; and

a processing system configured to;

i) be operably connected to both the impedance sensor and the optical sensor;

ii) receive the impedance signal from the impedance sensor and process it to determine a derivative indicating blood flow;

iii) receive the optical signal from the optical sensor and process it to determine an ejection time; and

iv) determine the stroke volume by collectively processing the derivative and ejection time.