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

• US 10,052,041 B2
• Filed: 07/04/2016
• Issued: 08/21/2018
• Est. Priority Date: 12/28/2010
• Status: Active Grant

• Current Assignee: Sotera Wireless Incorporated
• Original Assignee: Sotera Wireless Incorporated
• Inventors: Banet, Matthew, Henry, Isaac, Bernstein, Donald
• Primary Examiner(s): Johnson, Nicole F
• Application Number:
  US15/201,567
• Publication Number:
  US 20160310017A1
• Time in Patent Office: 778 Days
• Field of Search: 600526
• 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 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. The processing system analyzes the ECG, TBEV and optical signals to determine SV, and further analyzes SV and HR determined from an ECG sensor to determine CO.

Claims

1. A method for measuring a time-dependent stroke volume (SV) value from a patient, comprising:

measuring a time-dependent impedance waveform from the patient using a transbrachial electro-velocimetry (TBEV) sensor worn on the patient'"'"'s body;

measuring a time-dependent heart rate waveform from the patient using a heart rate sensor worn on the patient'"'"'s body;

receiving the time-dependent impedance waveform and the time-dependent heart rate waveform at a processing component, wherein the processing component recursively determines time-dependent SV values by (i) processing the time-dependent impedance waveform to determine a value of Z₀ and a value of (dZ/dt)_max, (ii) processing the time-dependent heart rate waveform to determine a value for systolic flow time (SFT); and

(iii) collectively processing the value of Z₀, the value of (dZ/dt)_max and the value of SFT to determine a SV value; and

displaying the time-dependent SV value on a display operably connected to the processing component.

2. The method of claim 1, wherein the heart rate sensor is an electrocardiogram (ECG) sensor, and the time-dependent heart rate waveform is an ECG waveform.

3. The method of claim 1, wherein the heart rate sensor is a photoplethysmogram (PPG) sensor, and the time-dependent heart rate waveform is a PPG waveform.

4. The method of claim 1, wherein the processing component further processes a heart rate value determined from the time-dependent heart rate waveform and the time-dependent SV value to determine a time-dependent cardiac output (CO) value, and wherein the time-dependent CO value is displayed on the display.

5. The method of claim 1, wherein the processing component is worn on the patient'"'"'s body.

6. The method of claim 5, wherein the display is a part of the processing component.

7. The method of claim 1, wherein the display is remote from the processing component.

8. The method of claim 1, wherein both an ECG sensor and a PPG sensor are worn on the patient'"'"'s body and are both operably connected to the processing component.

9. The method of claim 8, wherein the processing component further processes a time-dependent PPG waveform from the PPG sensor to determine a time-dependent SpO₂ value, and wherein the time-dependent SpO₂ value is displayed on the display.

10. The method of claim 9, wherein the processing component further collectively processes a time-dependent ECG waveform from the ECG sensor and the time-dependent PPG waveform to determine a time-dependent mean arterial blood pressure (MAP) value, wherein the time-dependent MAP value is displayed on the display.

11. The method of claim 1, wherein the processing component further processes the time-dependent impedance waveform to determine a time-dependent left ventricular ejection time (LVET) value.