Multi-sensor patient monitor to detect impending cardiac decompensation

• US 9,125,566 B2
• Filed: 07/08/2014
• Issued: 09/08/2015
• Est. Priority Date: 09/14/2007
• Status: Active Grant

• Current Assignee: Medtronic Monitoring, Inc. (Medtronic Plc)
• Original Assignee: Medtronic Monitoring, Inc. (Medtronic Plc)
• Inventors: Libbus, Imad, Bly, Mark J., James, Kristofer J., Mazar, Scott T., Wang, Jerry S.
• Primary Examiner(s): Jackson, Gary
• Assistant Examiner(s): SANDS, DAVIN K
• Application Number:
  US14/325,968
• Publication Number:
  US 20150005590A1
• Time in Patent Office: 427 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: A61B 2560/0412 Low-profile patch shaped housings
• CPC Class Codes: A61B 2562/0215 Silver or silver chloride containing
• CPC Class Codes: A61B 2562/043 in a linear array
• 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 5/0245 by using sensing means generating electric signals, i.e. ECG signals
• CPC Class Codes: A61B 5/0537 Measuring body composition by impedance, e.g. tissue hydration or fat content
• CPC Class Codes: A61B 5/259 using conductive adhesive means, e.g. gels
• CPC Class Codes: A61B 5/28 for electrocardiography [ECG]
• CPC Class Codes: A61B 5/282 Holders for multiple electrodes for introduction into the body A61B5/287
• CPC Class Codes: A61B 5/443 Evaluating skin constituents, e.g. elastin, melanin, water
• CPC Class Codes: A61B 5/6833 Adhesive patches
• CPC Class Codes: A61B 5/6843 Monitoring or controlling sensor contact pressure
• CPC Class Codes: G16H 40/67 for remote operation
• CPC Class Codes: G16H 50/30 for calculating health indices; for individual health risk assessment

Abstract

Systems and methods of detecting an impending cardiac decompensation of a patient measure at least two of an electrocardiogram signal of the patient, a hydration signal of the patient, a respiration signal of the patient or an activity signal of the patient. The at least two of the electrocardiogram signal, the hydration signal, the respiration signal or the activity signal are combined with an algorithm to detect the impending cardiac decompensation.

Claims

1. A system to predict impending acute cardiac decompensation of a patient, the system comprising:

an adherent patch including at least four electrodes connected to the patch and capable of electrically coupling to the patient;

impedance circuitry coupled to two or more of the at least four electrodes to measure an impedance associated with the patient;

a temperature sensor configured to measure a temperature of a skin of the patient; and

a processor system in communication with the impedance circuitry and the temperature sensor, wherein the processor system calculates a hydration measurement based on the measured impedance and corrects the calculated hydration measurement based on the measured skin temperature of the patient, wherein the processor system utilizes the calculated hydration measurement to predict an impending acute cardiac decompensation of the patient.

2. The system of claim 1, wherein the impedance circuitry places a voltage and/or current at one or more of the electrodes having a frequency between 0.5 kHz and about 20 kHz such that the hydration measurement corresponds to the extracellular fluid of the patient.

3. The system of claim 1, wherein the processor system corrects the calculated hydration measurement by lowering the hydration measurement in response to an increase in measured skin temperature.

4. The system of claim 3, wherein the processor system corrects the calculated hydration measurement by increasing the hydration measurement in response to a decrease in the measured skin temperature.

5. The system of claim 1, wherein the processor system corrects the calculated hydration measurement such that the hydration measurement remains substantially unchanged when the measured impedance decreases and the skin temperature increases.

6. The system of claim 1, wherein the processor system comprises at least one processor at a location remote from the patient and configured to predict the impending acute cardiac decompensation.

7. The system of claim 1, further including:

electrocardiogram circuitry coupled to at least two of the four electrodes and configured to measure an electrocardiogram signal of the patient, wherein the processor system utilizes the electrocardiogram signal in combination with the calculated hydration measurement to predict an impending acute cardiac decompensation of the patient.

8. The system of claim 7, wherein the processor system utilizes a previously existing array of electrocardiogram signals and hydration values to predict an impending acute cardiac decompensation of the patient.

9. The system of claim 7, further including:

an activity sensor that measures an activity level of the patient, including at least one of inclination, position, orientation, and acceleration of the patient;

wherein the processor system utilizes the calculated hydration measurement and at least one of the electrocardiogram signal and the activity level to predict an impending acute cardiac decompensation of the patient.

10. The system of claim 9, wherein the processor system utilizes the electrocardiogram signal to determine a heart rate of the patient, and wherein the processor system correlates the heart rate of the patient with the activity level, wherein an increase in heart rate combined with a decrease in the activity level is indicative of an impending acute cardiac decompensation of the patient.

11. The system of claim 9, wherein the processor system combines the calculated hydration measurement with at least one of the electrocardiogram signal and the activity level with at least one of a weighted combination, a tiered combination or a logic gated combination, a time-weighted combination or a rate of change to detect an impending acute cardiac decompensation of the patient.

12. A system to predict an impending acute cardiac decompensation of a patient having heart failure, the system comprising:

an adherent device including at least four electrodes capable of electrically coupling to the patient;

impedance circuitry coupled to two or more of the at least four electrodes to measure an impedance value related to a hydration value of the patient, and a respiration signal;

electrocardiogram circuitry coupled to two or more of the at least four electrodes to measure an electrocardiogram signal associated with the patient; and

a processor system in communication with the impedance circuitry and the electrocardiogram circuitry, wherein the processor system receives the measured hydration value, the respiration signal and the electrocardiogram signal and compares the received signals with baseline values established for each, wherein the processor sets a flag indicating an impending acute cardiac decompensation based on a combination of the compared values.

13. The system of claim 12, wherein the baseline values are generated by measuring a hydration value, a respiration signal, and an electrocardiogram signal associated with the patient at a first time, wherein the processor system stores the baseline values for comparison to subsequently measured hydration values, respiration signals, and electrocardiogram signals.

14. The system of claim 12, wherein the baseline values are generated based on measurements taken from a population of patients.

15. The system of claim 12, wherein the processor system sets the flag indicating an impending acute cardiac decompensation based on a logic gated combination of the outputs of the comparison between two or more baseline values and measured values.

16. The system of claim 15, wherein the logic gated combination is a logical AND combination of the outputs of the comparison between two or more baseline values and measured values.

17. The system of claim 12, wherein the processor system affects one or more of the impedance circuitry and electrocardiogram signal to make additional signal measurements of the patient in response to the flag status.

18. The system of claim 12, further including a temperature sensor configured to measure a temperature of a skin of the patient, wherein the processor system corrects the measured hydration value based on the measured skin temperature of the patient.

19. The system of claim 18, wherein the processor system corrects the measured hydration value by lowering the hydration value in response to an increase in measured skin temperature and by increasing the hydration value in response to a decrease in the measured skin temperature.

20. The system of claim 18, wherein the processor system corrects the measured hydration value such that the hydration value remains substantially unchanged when a measured impedance decreases and the skin temperature increases.