Handheld physiological sensor

• US 10,105,053 B2
• Filed: 01/05/2016
• Issued: 10/23/2018
• Est. Priority Date: 01/05/2016
• Status: Active Grant

• Current Assignee: Baxter Healthcare SA (Baxter International Inc.), Baxter International Inc.
• Original Assignee: OtoSense, Inc. (Analog Devices, Inc.)
• Inventors: Banet, Matthew, Dhillon, Marshal Singh, Pede, Susan Meeks, Hayward, Lauren Nicole Miller, Deptala, Arthur, Cochran, Jonas Dean
• Primary Examiner(s): Patel, Niketa
• Assistant Examiner(s): PHAM, MINH DUC GIA
• Application Number:
  US14/988,691
• Publication Number:
  US 20170188828A1
• Time in Patent Office: 1,022 Days
• Field of Search: 600513
• CPC Class Codes: A61B 2560/0425 Ergonomically shaped housings A61B2560/0418 takes precedence
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• 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 5/02028 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 5/02055 Simultaneously evaluating both cardiovascular condition and temperature
• CPC Class Codes: A61B 5/02141 Details of apparatus construction, e.g. pump units or housings therefor, cuff pressurising systems, arrangements of fluid conduits or circuits A61B5/02233, A61B5/0235 take precedence
• CPC Class Codes: A61B 5/022 by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
• CPC Class Codes: A61B 5/02233 Occluders specially adapted therefor tourniquets A61B17/132
• CPC Class Codes: A61B 5/02405 Determining heart rate variability
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/02438 with portable devices, e.g. worn by the patient
• 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 5/053 Measuring electrical impedance or conductance of a portion of the body
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/282 : Holders for multiple electrodes for introduction into the body A61B5/287
• CPC Class Codes: A61B 5/332 : Portable devices specially adapted therefor
• CPC Class Codes: A61B 5/349 : Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/352 : Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval
• CPC Class Codes: A61B 5/366 : Detecting abnormal QRS complex, e.g. widening
• CPC Class Codes: A61B 5/4872 : Body fat
• CPC Class Codes: A61B 5/4875 : Hydration status, fluid retention of the body
• CPC Class Codes: A61B 5/6813 : Specially adapted to be attached to a specific body part A61B5/6802 takes precedence
• 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 5/6825 : Hand
• CPC Class Codes: A61B 5/7275 : Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor
• CPC Class Codes: A61B 5/7282 : Event detection, e.g. detecting unique waveforms indicative of a medical condition A61B5/4094, A61B5/4818, A61B5/349, A61B5/0823 take precedence

Abstract

A handheld device measures all vital signs and some hemodynamic parameters from the human body and transmits measured information wirelessly to a web-based system, where the information can be analyzed by a clinician to help diagnose a patient. The system utilizes our discovery that bio-impedance signals used to determine vital signs and hemodynamic parameters can be measured over a conduction pathway extending from the patient'"'"'s wrist to a location on their thoracic cavity, e.g. their chest or navel. The device'"'"'s form factor can include re-usable electrode materials to reduce costs. Measurements made by the handheld device, which use the belly button as a ‘fiducial’ marker, facilitate consistent, daily measurements, thereby reducing positioning errors that reduce accuracy of standard impedance measurements. In this and other ways, the handheld device provides an effective tool for characterizing patients with chronic diseases, such as heart failure, renal disease, and hypertension.

Claims

1. A biometric sensor configured to measure a value of stroke volume (SV) from a patient, comprising:

an arm-receiving portion comprising an opening configured to receive a distal portion of the patient'"'"'s arm and first and second electrodes configured and arranged to contact the distal portion of the patient'"'"'s arm when it is inserted in the opening; and

a body-contacting portion comprising an exterior-facing surface and third and fourth electrodes configured and arranged to contact a second body location that is one of the patient'"'"'s torso, legs, opposing arm, and neck when the body-contacting portion is pressed against the second body location while the patient'"'"'s arm is inserted in the opening;

wherein the first and third electrodes are configured to inject electrical current into the patient at their respective points of contact with the patient and the second and fourth electrodes are configured to sense first and second biometric signals, respectively, which are induced by the injected electrical current;

the biometric sensor further comprising a first analog system configured to receive the first and second biometric signals and to process them to generate first and second analog physiological waveforms; and

a first digital system configured to digitize the analog physiological waveforms and to process them with computer code to determine the value of SV, wherein the computer code is configured to determine SV from the equation;

2. The biometric sensor of claim 1, wherein the first analog system comprises a differential amplifier configured to amplify a difference between the first and second biometric signals to generate the first and second analog physiological waveforms.

3. The biometric sensor of claim 2, wherein the first and second analog physiological waveforms are impedance waveforms, and wherein the first analog waveform comprises AC information and the second physiological waveform comprises DC information.

4. The biometric sensor of claim 3, wherein the first analog waveform comprises heartbeat-induced pulsations.

5. The biometric sensor of claim 1, wherein the computer code is configured to process the first analog physiological waveform to calculate a derivative and determine a dΔ

Z(t)/dt waveform.

6. The biometric sensor of claim 5, wherein the computer code is configured to determine a maximum value of the dΔ

Z(t)/dt waveform.

7. The biometric sensor of claim 5, wherein the computer code is configured to determine an area of a pulse in the dΔ

Z(t)/dt waveform.

8. The biometric sensor of claim 5, wherein the computer code is configured to estimate an ejection time from the dΔ

Z(t)/dt waveform.

9. The biometric sensor of claim 8, wherein the computer code is configured to determine i) a maximum value of the dΔ

Z(t)/dt waveform ((dΔ

Z(t)/dt)_max), and ii) a left ventricular ejection time (LVET) from the dΔ

Z(t)/dt waveform.

10. The biometric sensor of claim 5, wherein the computer code is configured to process the second analog physiological waveform to estimate a baseline impedance (Z₀).

11. The biometric sensor of claim 1, wherein the arm-receiving portion comprises first and second spaced-apart wall portions that form the opening, which wall portions are arranged so as to be located on opposite sides of the patient'"'"'s arm when it is inserted in the opening.

12. The biometric sensor of claim 11, wherein the first and second wall portions extend from the body-contacting portion.

13. The biometric sensor of claim 12, wherein the first and second electrodes are disposed on inner surfaces of the first and second wall portions, respectively.

14. The biometric sensor of claim 1, wherein the arm-receiving portion comprises an annular ring component that forms the opening.

15. The biometric sensor of claim 14, wherein the first and second electrodes are disposed on an inner surface of the annular ring component.

16. The biometric sensor of claim 1, wherein the arm-receiving portion comprises an inflatable cuff configured to engage the distal portion of the patient'"'"'s arm.

17. The biometric sensor of claim 16, wherein the cuff comprises a pair of inflatable bladders which oppose each other across the opening.

18. The biometric sensor of claim 17, wherein the first and second electrodes are formed from conductive, elastomeric material disposed over surfaces of the inflatable bladders that face the opening.

19. The biometric sensor of claim 16, wherein the cuff is formed from elastomeric material.

20. The biometric sensor of claim 16, wherein the cuff is formed from inelastic material.

21. The biometric sensor of claim 16, wherein the cuff is configured to be wrapped around the distal portion of the patient'"'"'s arm and secured by means of a closure member.

22. The biometric sensor of claim 1, wherein the first, second, third, and fourth electrodes each comprise a conductive material.

23. The biometric sensor of claim 22, wherein the conductive material is one of a conductive fabric, a metal component, a conductive foam, a conductive polymeric material, and a hydrogel material.

24. The biometric sensor of claim 1, wherein the first and second electrodes are each disposed on top of an inflatable bladder.

25. The biometric sensor of claim 24, wherein the sensor further comprises a microprocessor-controlled pneumatic inflation system configured and arranged to control inflation and deflation of the inflatable bladders.

26. The biometric sensor of claim 25, wherein the pneumatic system comprises a pump and a valve.

27. The biometric sensor of claim 25, wherein the first and second electrodes are formed from elastomeric fabric which stretches and contracts with the inflatable bladders as the bladders are inflated and deflated.

28. The biometric sensor of claim 1, further comprising a circuit board disposed within the sensor.

29. The biometric sensor of claim 28, wherein the analog and digital systems are disposed on the circuit board and the digital system includes a microprocessor that is programmed with said computer code to process the analog physiological waveform to determine the value of stroke volume.

30. The biometric sensor of claim 29 wherein the first and second electrodes are in electrical, signal-conducting contact with the analog system.

31. A biometric sensor configured to measure a value of stroke volume (SV) from a patient, comprising:

an arm-receiving portion comprising an opening configured to receive a distal portion of the patient'"'"'s arm and first and second electrodes configured and arranged to contact the distal portion of the patient'"'"'s arm when it is inserted in the opening; and

a body-contacting portion comprising an exterior-facing surface and third and fourth electrodes configured and arranged to contact a second body location that is one of the patient'"'"'s torso, legs, opposing arm, and neck when the body-contacting portion is pressed against the second body location while the patient'"'"'s arm is inserted in the opening;

wherein the first and third electrodes are configured to inject electrical current into the patient at their respective points of contact with the patient and the second and fourth electrodes are configured to sense first and second biometric signals, respectively, which are induced by the injected electrical current;

the biometric sensor further comprising a first analog system configured to receive the first and second biometric signals and to process them to generate first and second analog physiological waveforms; and

a first digital system configured to digitize the analog physiological waveforms and to process them with computer code to determine the value of SV, wherein the computer code is configured to determine SV from the equation;