FLOORMAT PHYSIOLOGICAL SENSOR

• US 20170188856A1
• Filed: 01/05/2016
• Published: 07/06/2017
• Est. Priority Date: 01/05/2016
• Status: Abandoned Application

• Current Assignee: Tosense Inc (Baxter International Inc.)
• Original Assignee: Tosense Inc (Baxter International Inc.)
• Inventors: HAYWARD, Lauren Nicole Miller, COCHRAN, Jonas Dean, BANET, Matthew, DHILLON, Marshal Singh, PEDE, Susan Meeks, DEPTALA, Arthur
• Application Number:
  US14/988,665
• Publication Number:
  US 20170188856A1
• Time in Patent Office: Days
• CPC Class Codes: A61B 2562/066 in a matrix array
• CPC Class Codes: A61B 5/0022 Monitoring a patient using a global network, e.g. telephone networks, internet
• 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 5/02233 Occluders specially adapted therefor tourniquets A61B17/132
• 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 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/6825 Hand
• CPC Class Codes: A61B 5/6829 Foot or ankle
• CPC Class Codes: A61B 5/6892 Mats
• CPC Class Codes: A61B 5/7225 Details of analog processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation A61B5/30, A61B5/316 take precedence; transformers for specific applications H01F38/00; amplifiers H03F
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence
• CPC Class Codes: G01G 19/50 having additional measuring devices, e.g. for height

Abstract

A stand-on physiological sensor (e.g. floormat) measures vital signs and various hemodynamic parameters, including blood pressure and ECG waveforms. The sensor is similar in configuration to a common bathroom scale and includes electrodes that take electrical measurements from a patient'"'"'s feet to generate bioimpedance waveforms, which are analyzed digitally to extract various other parameters, as well as a cuff-type blood pressure system that takes physical blood pressure measurements at one of the patient'"'"'s feet. Blood pressure can also be calculated/derived from the bioimpedance waveforms. Measured parameters are transmitted wirelessly to facilitate remote monitoring of the patient for heart failure, chronic heart failure, end-stage renal disease, cardiac arrhythmias, and other degenerative diseases.

Claims

1. A system for measuring a pulse transit time value from a patient, comprising:

a base comprising a bottom surface configured to rest on or near a substantially horizontal surface, and a top surface configured to receive at least one of the patient'"'"'s feet;

an optical system connected to the top surface and comprising at least one light source that emits optical radiation, and a photodetector, the photodetector configured to receive the optical radiation after it irradiates a portion of the patient'"'"'s feet to generate a first set of signals representative of a photoplethysmogram from the patient;

a heart rate monitoring system connected to the top surface and comprising at least two electrodes connected to a differential amplifier, the differential amplifier configured to measure a second set of signals representative of a cardiac rhythm from the patient; and

a processing system in electrical contact with the electrical impedance system and the heart rate monitoring system, and configured to;

     1) receive the first signals from the optical system and convert them into a set of photoplethysmogram values;

     2) analyze the set of photoplethysmogram values to determine a first time value indicating a first pulsatile component;

     3) receive the second set of signals from the heart rate monitoring system and convert them into a set of cardiac rhythm values;

     4) analyze the set of cardiac rhythm values to determine a second pulsatile component; and

     5) collectively process the first and second pulsatile components to determine the pulse transit time.

2. The system of claim 1, wherein the processing system comprises computer code configured to:

1) calculate a mathematical derivative of the impedance plethysmogram to determine a set of derivative values; and

     2) determine a local maximum of the set of derivative values to determine the first pulsatile component.

3. The system of claim 1, wherein the processing system comprises computer code configured to:

1) calculate a mathematical derivative of the impedance plethysmogram to determine a set of derivative values; and

     2) determine a zero-point crossing of the set of derivative values to determine the first pulsatile component.

4. The system of claim 1, wherein the processing system comprises computer code configured to:

1) calculate a mathematical derivative of the impedance plethysmogram to determine a set of derivative values;

     2) estimate the set of derivative values with a mathematical function; and

     3) analyze the mathematical function to determine the first pulsatile component.

5. The system of claim 1, wherein the processing system comprises computer code configured to determine a local maximum of the cardiac rhythm to determine the second pulsatile component.

6. The system of claim 1, wherein the cardiac rhythm is representative of an ECG waveform.

7. The system of claim 6, wherein the processing system comprises computer code configured to determine a QRS complex in the ECG waveform to determine the second pulsatile component.

8. The system of claim 7, wherein the processing system comprises computer code configured to determine an R point in the QRS complex in the ECG waveform to determine the second pulsatile component.

9. The system of claim 7, wherein the processing system comprises computer code configured to determine a Q point in the QRS complex in the ECG waveform to determine the second pulsatile component.

10. The system of claim 1, wherein the processing system comprises computer code configured to further process the cardiac rhythm to determine a heart rate value.

11. The system of claim 10, wherein the cardiac rhythm is representative of an ECG waveform.

12. The system of claim 11, wherein the processing system comprises computer code configured to determine a QRS complex in the ECG waveform.

13. The system of claim 12, wherein the processing system comprises computer code configured to determine a first R point in a first QRS complex, and a second R point in a second QRS complex, and then determine a heart rate from a time interval separating the first and second R points.

14. A system for measuring a pulse transit time value from a patient, comprising:

a base comprising a bottom surface configured to rest on or near a substantially horizontal surface, and a top surface configured to receive at least one of the patient'"'"'s feet;

an optical system connected to the top surface and comprising at least one light source that emits optical radiation, and a photodetector, the photodetector configured to receive the optical radiation after it irradiates a portion of the patient'"'"'s feet to generate a first set of signals representative of a photoplethysmogram from the patient;

a heart rate monitoring system connected to the top surface and comprising at least two electrodes connected to a differential amplifier, the differential amplifier configured to measure a second set of signals representative of a cardiac rhythm from the patient;

a weight-measuring system connected to the top surface, the weight-measuring system comprising an electrical system that measures a set of voltages that correlates with a force applied to the top surface; and

a processing system in electrical contact with the electrical impedance system and the heart rate monitoring system, and configured to;

     1) receive the first signals from the optical system and convert them into a set of photoplethysmogram values;

     2) analyze the set of photoplethysmogram values to determine a first time value indicating a first pulsatile component;

     3) receive the second set of signals from the heart rate monitoring system and convert them into a set of cardiac rhythm values;

     4) analyze the set of cardiac rhythm values to determine a second pulsatile component; and

     5) collectively process the first and second pulsatile components to determine the pulse transit time.

15. The system of claim 14, wherein the electrical system comprises a Wheatstone Bridge.

16. The system of claim 15, wherein the Wheatstone Bridge connects electrically with an amplifier system.

17. The system of claim 16, wherein the processing system is further configured to receive the set of voltages, and analyze them to determine a value of weight corresponding to the force applied on the top surface.

18. The system of claim 14, wherein the processing system comprises computer code configured to:

1) calculate a mathematical derivative of the photoplethysmogram to determine a set of derivative values; and

     2) determine a local maximum of the set of derivative values to determine the first pulsatile component.

19. The system of claim 14, wherein the processing system comprises computer code configured to:

1) calculate a mathematical derivative of the photoplethysmogram to determine a set of derivative values; and

     2) determine a zero-point crossing of the set of derivative values to determine the first pulsatile component.

20. The system of claim 14, wherein the processing system comprises computer code configured to:

1) calculate a mathematical derivative of the photoplethysmogram to determine a set of derivative values;

     2) estimate the set of derivative values with a mathematical function; and

     3) analyze the mathematical function to determine the first pulsatile component.

21. The system of claim 14, wherein the processing system comprises computer code configured to determine a local maximum of the cardiac rhythm to determine the second pulsatile component.

22. The system of claim 14, wherein the cardiac rhythm is representative of an ECG waveform.

23. The system of claim 22, wherein the processing system comprises computer code configured to determine a QRS complex in the ECG waveform to determine the second pulsatile component.

24. The system of claim 23, wherein the processing system comprises computer code configured to determine an R point in the QRS complex in the ECG waveform to determine the second pulsatile component.

25. The system of claim 23, wherein the processing system comprises computer code configured to determine a Q point in the QRS complex in the ECG waveform to determine the second pulsatile component.

26. The system of claim 14, wherein the processing system comprises computer code configured to further process the cardiac rhythm to determine a heart rate value.

27. The system of claim 26, wherein the cardiac rhythm is representative of an ECG waveform.

28. The system of claim 27, wherein the processing system comprises computer code configured to determine a QRS complex in the ECG waveform.

29. The system of claim 28, wherein the processing system comprises computer code configured to determine a first R point in a first QRS complex, and a second R point in a second QRS complex, and then determine a heart rate from a time interval separating the first and second R points.