HANDHELD PHYSIOLOGICAL SENSOR

• US 20170188849A1
• Filed: 01/05/2016
• Published: 07/06/2017
• Est. Priority Date: 01/05/2016
• Status: Active Grant

• Current Assignee: Baxter Healthcare SA (Baxter International Inc.), Baxter International Inc.
• Original Assignee: Tosense Inc (Baxter International Inc.)
• Inventors: BANET, Matthew, DHILLON, Marshal Singh, PEDE, Susan Meeks, DEPTALA, Arthur, HAYWARD, Lauren Nicole Miller, COCHRAN, Jonas Dean
• Granted Patent: US 10,736,523 B2
• Time in Patent Office: Days
• 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 5/02125 of pulse wave propagation time
• 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 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/0245 by using sensing means generating electric signals, i.e. ECG signals
• CPC Class Codes: A61B 5/0809 by impedance pneumography
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• 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 5/6823 Trunk, e.g., chest, back, abdomen, hip
• 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 blood pressure value from a patient, comprising:

an arm-receiving portion comprising a first opening configured to receive a distal portion of one of the patient'"'"'s arm and a first electrode configured and arranged to contact the distal portion of the patient'"'"'s arm when it is inserted in the first opening, the first electrode comprising a conductive material disposed on an inflatable bladder;

a pressure-control system comprising a pump, a valve, and a pressure sensor connected to the inflatable bladder, the pressure-control system being configured to inflate and deflate the bladder in response to computer commands;

a finger-receiving portion comprising a second opening, configured and arranged to receive a finger of said one of the patient'"'"'s arms while the distal portion thereof is received by the arm-receiving portion, and an optical system, the optical system comprising a first light source configured to irradiate the finger and a photodetector configured to receive radiation after it irradiates the finger;

a body-contacting portion comprising an exterior-facing surface and a second electrode configured and arranged to contact a 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 inserted in the first opening;

a first analog system configured to receive biometric signals from the first electrode and the second electrode and to process them to generate an ECG waveform;

a second analog system configured to receive signals from the pressure sensor and to process them to generate a pressure signal;

a third analog system configured to receive signals from the photodetector and to process them to generate a photoplethysmogram waveform comprising pulsatile signals; and

a processing system configured to issue computer commands to the pressure-control system to inflate and deflate the bladder while the third analog system generates the photoplethysmogram waveform, and further configured to analyze modulations in a digital versions of the photoplethysmogram waveform and a digital version of the pressure signal to estimate the blood pressure value.

2. The biometric sensor of claim 1, wherein the processing system comprises computer code configured to analyze an amplitude and a pressure corresponding to at least one of the pulsatile signals.

3. The biometric sensor of claim 2, wherein the processing system comprises computer code configured to analyze sets of amplitudes and pressure values corresponding to a set of pulsatile signals.

4. The biometric sensor of claim 3, wherein the computer code is configured to determine an amplitude in the set of amplitudes having a minimum value.

5. The biometric sensor of claim 4, wherein the computer code is configured to estimate systolic blood pressure (SYS) from the amplitude having the minimum value.

6. The biometric sensor of claim 3, wherein the computer code is configured to approximate amplitude values in the set of amplitudes using a mathematical function.

7. The biometric sensor of claim 6, wherein the computer code is configured to estimate SYS from a minimum value of the mathematical function.

8. The biometric sensor of claim 3, wherein the computer code is configured to determine an amplitude in the set of amplitudes having a maximum value.

9. The system of claim 8, wherein the computer code is configured to estimate mean arterial pressure (MAP) from the amplitude having the maximum value.

10. The biometric sensor of claim 3, wherein the computer code is configured to approximate amplitude values in the set of amplitudes using a mathematical function.

11. The system of claim 10, wherein the computer code is configured to estimate MAP from a maximum value of the mathematical function.

12. 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.

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

14. The biometric sensor of claim 13, wherein the first electrode is disposed on an inner surface of one of the first and second wall portions.

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

16. The biometric sensor of claim 15, wherein the first electrode is disposed on an inner surface of the annular ring component.

17. 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.

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

19. The biometric sensor of claim 18, wherein the first electrode is formed from conductive, elastomeric material disposed over a surface of the inflatable bladder that faces the opening.

20. The biometric sensor of claim 17, wherein the cuff is formed from elastomeric material.

21. The biometric sensor of claim 17, wherein the cuff is formed from inelastic material.

22. The biometric sensor of claim 17, 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.

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

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

25. The biometric sensor of claim 1, wherein the first electrode is disposed on top of an inflatable bladder.

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

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

28. The biometric sensor of claim 26, wherein the first electrode is formed from elastomeric fabric which stretches and contracts with the inflatable bladder as the bladder is inflated and deflated.

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

30. The biometric sensor of claim 29, wherein the analog systems and the processing system are disposed on the circuit board.

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

32. The biometric sensor of claim 1, wherein the ECG waveform comprises a set of heartbeat-induced QRS complexes, and the processing system includes computer code configured to calculate a time difference between the QRS complexes to determine the patient'"'"'s heart rate.