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

• US 9,585,577 B2
• Filed: 12/28/2011
• Issued: 03/07/2017
• 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): Koharski, Christopher D
• Assistant Examiner(s): KIMBALL, JEREMIAH T
• Application Number:
  US13/338,248
• Publication Number:
  US 20140249442A1
• Time in Patent Office: 1,896 Days
• Field of Search: 600/526, 352/6
• US Class Current: 1/1
• 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 methods for measuring stroke volume from a patient using a transbrachial electro-velocimetry waveform measured using an impedance sensor together with a motion waveform measured using a motion sensor.

Claims

1. A method for determining stroke volume from a patient, comprising:

(a) measuring a motion waveform with a first motion sensor;

(b) processing the motion waveform with a motion algorithm to determine a motion-related parameter;

(c) comparing the motion-related parameter to a pre-determined threshold parameter to determine if the patient'"'"'s motion exceeds an acceptable level;

(d) measuring a transbrachial electro-velocimetry (TBEV) impedance waveform from the patient with an impedance sensor if the patient'"'"'s motion does not exceed an acceptable level; and

(e) calculating a stroke volume value from the impedance waveform if the patient'"'"'s motion does not exceed an acceptable level.

6. The method of claim 1, wherein the first motion sensor is an accelerometer.

7. The method of claim 6, wherein the first motion sensor is a three-axis accelerometer.

8. The method of claim 1, where the first motion sensor and the impedance sensor are disposed on a common substrate.

9. The method of claim 8, wherein the common substrate is attached to the patient'"'"'s clavicle/brachial (CB) region.

10. The method of claim 1, wherein the first motion sensor is disposed on a first sensor module, and the impedance sensor is disposed on a second sensor module.

11. The method of claim 10, wherein the first sensor module is configured to attach to the patient'"'"'s chest, and the second sensor module is configured to attach to the patient'"'"'s CB region.

12. The method of claim 10, wherein the first sensor module is configured to attach to the patient'"'"'s wrist, and the second sensor module is configured to attach to the patient'"'"'s CB region.

13. The method of claim 1, wherein the motion-related parameter is a magnitude of motion.

14. The method of claim 1, wherein the motion-related parameter is a frequency of motion.

15. The method of claim 1, wherein the motion-related parameter is a specific type of motion.

16. The method of claim 15, wherein the specific type of motion is one of walking, running, lying down, and being motionless.

17. The method of claim 1, wherein the motion-related parameter is a posture.

18. The method of claim 17, wherein the posture is one of standing up, sitting down, lying down, lying down on the right side, and lying down on the left side.

19. The method of claim 1, wherein the impedance sensor is not powered on until after the comparing step.

20. The method of claim 1, wherein the impedance sensor is only partially powered on until after the comparing step.

21. The method of claim 1, wherein the impedance sensor is powered on after the comparing step indicates that the patient'"'"'s motion does not exceed an acceptable level.

2. A method for determining stroke volume from a patient, comprising:

(a) measuring a motion waveform with a first motion sensor;

(b) processing the motion waveform with a motion algorithm to determine a motion-related parameter;

(c) comparing the motion-related parameter to a pre-determined threshold parameter to determine if the patient'"'"'s motion exceeds an acceptable level;

(d) measuring a transbrachial electro-velocimetry (TBEV) impedance waveform from the patient with an impedance sensor;

(e) calculating a stroke volume value from the impedance waveform; and

(f) reporting the stroke volume value if the patient'"'"'s motion does not exceed an acceptable level.

3. A method for generating an alarm from a stroke volume value calculated from a patient, comprising:

(a) measuring a motion waveform with a first motion sensor;

(b) processing the motion waveform with a motion algorithm to determine a motion-related parameter;

(c) comparing the motion-related parameter to a pre-determined threshold parameter to determine if the patient'"'"'s motion exceeds an acceptable level;

(d) measuring a transbrachial electro-velocimetry (TBEV) impedance waveform from the patient with an impedance sensor;

(e) calculating a stroke volume value from the impedance waveform; and

(f) generating the alarm based on the stroke volume value if the patient'"'"'s motion does not exceed an acceptable level.

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

(a) measuring a motion waveform with a first motion sensor;

(b) processing the motion waveform with a motion algorithm to determine a motion-related parameter;

(c) processing the motion-related parameter to determine the patient'"'"'s posture;

(d) measuring a transbrachial electro-velocimetry (TBEV) impedance waveform from the patient with an impedance sensor;

(e) calculating a stroke volume value from the impedance waveform and the patient'"'"'s posture.

5. A method for generating an alarm from a stroke volume value calculated from a patient, comprising:

(a) measuring a motion waveform with a first motion sensor;

(b) processing the motion waveform with a motion algorithm to determine a motion-related parameter;

(c) processing the motion-related parameter with an algorithm to determine the patient'"'"'s posture;

(d) measuring a transbrachial electro-velocimetry (TBEV) impedance waveform from the patient with an impedance sensor;

(e) calculating a stroke volume value from the impedance waveform; and

(f) generating the alarm based on the stroke volume value and the patient'"'"'s posture.