Body-worn sensor for characterizing patients with heart failure

Patent metadata

Field	Value
Publication number	US-11712170-B2
Application number	US-201916436631-A
Country	US
Kind code	B2
Filing date	Jun 10, 2019
Priority date	Dec 31, 2012
Publication date	Aug 1, 2023
Grant date	Aug 1, 2023

Abstract

The invention provides a sensor for measuring both impedance and ECG waveforms that is configured to be worn around a patient's neck. The sensor features 1) an ECG system that includes an analog ECG circuit, in electrical contact with at least two ECG electrodes, that generates an analog ECG waveform; and 2) an impedance system that includes an analog impedance circuit, in electrical contact with at least two (and typically four) impedance electrodes, that generates an analog impedance waveform. Also included in the neck-worn system are a digital processing system featuring a microprocessor, and an analog-to-digital converter. During a measurement, the digital processing system receives and processes the analog ECG and impedance waveforms to measure physiological information from the patient. Finally, a cable that drapes around the patient's neck connects the ECG system, impedance system, and digital processing system.

First claim

What is claimed is:

1. A sensor worn on a patient for measuring fluid and blood pressure in the patient, comprising:
a flexible member comprising a first electrode and a second electrode integrated within a flat, flexible cable, the flexible member comprising sufficient length and width so that when draped across the patient, the first and second electrodes adhere to the patient, wherein each of the first and second electrodes is disposed within a respective electrode holder, and wherein each of the first and second electrodes is removable from its respective electrode holder,
an impedance-measuring system, comprised by a first circuit board integrated within the flexible member and in electrical contact with the first electrode and the second electrode and worn on the patient, the impedance-measuring system configured to receive the electrical signals from the first and second electrodes and process them to determine a first impedance signal comprising a baseline that varies with fluid in the patient, and a second impedance signal comprising heartbeat-induced pulses measured directly from the patient; and,
a data-processing system, comprised by a second circuit board integrated within the flexible member and in electrical contact with the impedance-measuring system and worn on the patient, the data-processing system operating a computer algorithm configured to process the first impedance signal to determine fluid in the patient, the second impedance signal to determine a transit time, and the transit time to determine blood pressure.

2. The sensor of claim 1 , comprising at least four electrodes.

3. The sensor of claim 2 , comprising a first current-injecting electrode, a second current-injecting electrode, and wherein the first electrode is a first voltage-measuring electrode, and the second electrode is a second voltage-measuring electrode.

4. The sensor of claim 3 , wherein the flexible member comprises a first segment comprising the first current-injecting electrode and the first electrode, the first segment configured to contact a first portion of the patient, and a second segment comprising the second current-injecting electrode and the second electrode, the second segment configured to contact a second portion of the patient.

5. The sensor of claim 4 , wherein the first segment comprises a first rigid member, and the second segment comprises a second rigid member, and both the first and second rigid members comprise connectors configured to connect to the first electrode, the second electrode, the first current-injecting electrode, and the second current-injecting electrode.

6. The sensor of claim 5 , wherein the flexible member comprises a flexible, current-conducting member that connects the first electrode, the second electrode, the first current-injecting electrode, and the second current-injecting electrode to the impedance-measuring system.

7. The sensor of claim 6 , wherein the impedance-measuring system is configured to receive electrical signals that are measured by the first and second electrodes and pass through the flexible, current-conducting member.

8. The sensor of claim 7 , wherein the impedance-measuring system comprises a differential amplifier.

9. The sensor of claim 8 , wherein the differential amplifier is configured to measure a time-dependent voltage indicating the product of electrical impedance in the patient and current injected by the first and second current-injecting electrodes.

10. The sensor of claim 9 , wherein the differential amplifier is configured to measure a first time-dependent voltage indicating the first impedance signal.

11. The sensor of claim 10 , wherein the data-processing system is configured to operate a first computer algorithm configured to process the first impedance signal to estimate the fluid levels in the patient.

12. The sensor of claim 10 , wherein the data-processing system is further configured to operate a second computer algorithm configured to process the first impedance signal to estimate the patient's respiration rate.

13. The sensor of claim 9 , wherein the differential amplifier is configured to measure a second time-dependent voltage indicating the second impedance signal.

14. The sensor of claim 13 , wherein the data-processing system is further configured to operate a second computer algorithm configured to process the second impedance signal to estimate the patient's blood pressure.

15. The sensor of claim 13 , wherein the data-processing system is further configured to operate a third computer algorithm configured to process the second impedance signal to estimate the patient's cardiac output.

16. The sensor of claim 13 , wherein the data-processing system is further configured to operate a fourth computer algorithm configured to process the second impedance signal to estimate the patient's stroke volume.

Assignees

• Tosense Inc
• Baxter Int
• Baxter Healthcare Sa

Inventors

• Banet Matthew
• Pede Susan Meeks
• Dhillon Marshal Singh
• Hunt Kenneth Robert

Classifications

• A61B5/053 Primary

  Measuring electrical impedance or conductance of a portion of the body · CPC title

• A61B5/0531

  Measuring skin impedance · CPC title

• A61B5/282

  Holders for multiple electrodes (for introduction into the body A61B5/287) · CPC title

• A61B5/6822

  Neck · CPC title