Body-worn system for continuous, noninvasive measurement of cardiac output, stroke volume, cardiac power, and blood pressure

• US 10,722,130 B2
• Filed: 12/27/2011
• Issued: 07/28/2020
• Est. Priority Date: 12/28/2010
• Status: Active Grant

• Current Assignee: Sotera Wireless Incorporated
• Original Assignee: Sotera Wireless Incorporated
• Inventors: Banet, Matt, Henry, Isaac, Bernstein, Donald
• Primary Examiner(s): Bloch, Michael R
• Application Number:
  US13/338,216
• Publication Number:
  US 20140249435A1
• Time in Patent Office: 3,136 Days
• Field of Search: None
• 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 a stroke volume of a patient, comprising:

an impedance sensor comprising at least two electrodes and an impedance circuit, the at least two electrodes configured to be positioned on the patient in the clavicle/brachial region, and the impedance circuit configured to receive and process signals from the at least two electrodes to measure a transbrachial electro-velocimetry (TBEV) signal from the patient;

an optical sensor configured to be positioned on a hand of the patient and comprising an optical probe and an optical circuit, the optical circuit configured to receive and 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 patient'"'"'s body;

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

(iii) receive the TBEV signal from the impedance sensor;

iv) receive the at least one optical signal from the optical sensor;

(v) process the TBEV signal to determine a time dependent derivative of the TBEV signal (d(TBEV)dZ/dt), a first zero value in d(TBEV)dZ/dt indicating onset of a pulse in d(TBEV)dZ/dt representing opening of the patient'"'"'s aortic valve, a second zero value in d(TBEV)dZ/dt after onset of the pulse indicating closing of the patient'"'"'s aortic valve, a d(TBEV)dZ/dt_max value;

(vi) determine a first systolic flow time (SFT) value calculated using the first zero value in d(TBEV)dZ/dt and the second zero value in d(TBEV)dZ/dt;

(vii) collectively process d(TBEV)dZ/dt_max and the first SFT value to determine a first stroke volume (SV) value;

(viii) process the optical signal to determine a second SFT value;

(ix) collectively process d(TBEV)dZ/dt_max and the second SFT value to determine a second SV value;

(x) collectively process the first and second SV values to determine a third SV value; and

(xi) display the third SV value on a display device.

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

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

4. The system of claim 3, wherein the impedance sensor comprises a transceiver configured to transmit the digital impedance signal through a cable to the processing system.

5. The system of claim 3, wherein the impedance sensor comprises a transceiver configured to transmit the digital impedance signal through a wireless interface to the processing system.

6. The system of claim 5, wherein the transceiver comprises a short-range radio.

7. The system of claim 1, wherein the optical probe is configured to be worn on the patient'"'"'s thumb.

8. The system of claim 7, 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.

9. The system of claim 8, wherein the optical circuit and the processing system are comprised by a single housing.

10. The system of claim 9, further comprising a cable configured to connect on one end to the optical probe and on an opposing end to the optical circuit.

11. The system of claim 1, further comprising a motion sensor configured to generate one or more motion signals related to the patient'"'"'s motion.

12. The system of claim 11, wherein the processing system is further configured to operably connect to the motion sensor to:

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

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

13. The system of claim 12, wherein the processing system is further configured to generate an alarm by collectively processing the patient'"'"'s posture and the third stroke volume value.

14. The system of claim 12, wherein the processing system is further configured to suppress an alarm by collectively processing the patient'"'"'s degree of motion and the third stroke volume value.

15. The system of claim 11, wherein the motion sensor is an accelerometer.