METHOD AND SYSTEM FOR TEMPERATURE ANALYSIS TO PROVIDE AN EARLY MARKER OF CONGESTIVE HEART FAILURE PROGRESS THAT PRECEDES A PATIENT'S SYMPTOMS

• US 20100010552A1
• Filed: 07/10/2009
• Published: 01/14/2010
• Est. Priority Date: 07/10/2008
• Status: Active Grant

• Current Assignee: Texas Heart Institute
• Original Assignee: Texas Heart Institute
• Inventors: WILSON, James W., COX, Casey D., FERGUSON, James J.
• Granted Patent: US 8,855,761 B2
• Time in Patent Office: Days
• US Class Current: 607/6
• 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 5/7257 using Fourier transforms
• CPC Class Codes: A61B 5/726 using Wavelet transforms
• 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: A61N 1/3655 controlled by body or blood temperature
• CPC Class Codes: G16H 40/63 for local operation

Abstract

The temperature of a patient is a significant predictor of death in heart failure patients. Temperature provides a window into the physiology of the patient'"'"'s underlying condition and may be used as an early marker for CHF exacerbations. The patient'"'"'s temperature is taken to form a time series of temperature values. In accordance with some embodiments, the time series of temperature values is converted to the frequency domain by, for example, a discrete Fourier Transform. The frequency domain representation then is analyzed for a marker indicative of the worsening condition of the patient. In accordance with other embodiments, the patient'"'"'s time series of temperature values is analyzed for a marker using, for example, Cosinor analysis. In yet other embodiments, both the time and frequency domain temperature data is analyzed for markers of the patient'"'"'s worsening medical condition.

Claims

1. A method of predicting worsening of a patient'"'"'s medical condition, comprising:

obtaining time domain temperature data (TDTD) pertaining to said patient;

converting said TDTD to a frequency domain representation (FDR); and

determining a marker indicative of the worsening medical condition by analyzing the FDR or by analyzing the TDTD or by analyzing both, wherein analyzing the TDTD comprises performing at least one of Cosinor analysis, approximate entropy, tempogram, day-night mean temperature difference, body temperature daily range, interdaily stability, and time-lag embedding.

2. The method of claim 1 wherein said TDTD is selected from the group consisting of temperature taken by a Foley™

urinary catheter, temperature taken by a rectal probe, core body temperature, tympanic cavity temperature, oral cavity temperature, rectal cavity temperature, axilla temperature, bladder temperature, esophagus temperature, trachea temperature, an airway temperature, and the big toe temperature.

3. The method of claim 1 wherein obtaining the TDTD comprises acquiring temperature values from at least one temperature sensor or reading temperature values from storage.

4. The method of claim 1 wherein converting said TDTD to FDR comprises performing at least one of Fourier transform, wavelet transform, and Chirplet transform.

5. A system comprising a processor that receives time domain temperature data (TDTD) pertaining to a patient, converts said TDTD to a frequency domain representation (FDR), and determines a marker indicative of the worsening medical condition of the patient by analyzing the FDR or by analyzing TDTD or by analyzing both, wherein analyzing the TDTD comprises performing at least one of Cosinor analysis, approximate entropy, tempogram, day-night mean temperature difference, body temperature daily range, interdaily stability, and time-lag embedding.

6. The system of claim 5 wherein said processor utilizes at least one of Fourier transform, wavelet transform, and Chirplet transform to convert said TDTD to FDR.

7. The system of claim 5 wherein the marker indicative of the worsening medical condition is determined upon detecting oscillation in the amplitude of the peak at the patient'"'"'s circadian frequency in the FDR.

8. The system of claim 5 wherein the marker indicative of the worsening medical condition is determined upon detecting an increase in the harmonics of the FDR at frequencies lower than the patient'"'"'s circadian frequency.

9. The system of claim 5 wherein the marker indicative of the worsening medical condition is determined upon detecting a change in at least one of the mesor, amplitude, and acrophase of the Cosinor analysis of the TDTD.

10. The system of claim 5 wherein analyzing the FDR or the TDTD or both comprises weighing outputs of at least two analysis techniques to render a total score indicative of the current condition of the patient.

11. The system of claim 5 wherein said processor reports at least one of the TDTD, the FDR, analysis outputs, and the total score to the patient or a healthcare provider, or both.

12. The system of claim 5 further comprising an alarm unit that generates an alarm upon determining the marker indicative of the worsening medical condition of the patient.

13. The system of claim 5 further comprising a therapy delivery unit (TDU) that delivers therapy to the patient upon determining the marker indicative of the worsening medical condition of the patient.

14. The system of claim 13, wherein the TDU comprises an implantable medical device.

15. The system of claim 13, wherein the TDU comprises an implantable pacemaker or defibrillator, comprising a pulse generator which is configured to generate an electrical stimulation signal upon determining the marker.

16. The system of claim 13, wherein the TDU comprises an implantable drug reservoir and a pump which is connected to the drug reservoir and configured to be activated upon determining the marker to deliver a drug in the reservoir to the patient.

17. The system of claim 5 further comprising a temperature sensor.

18. The system of claim 5 wherein the system is implantable.

19. A computer-readable storage medium (CRSM) containing software that, when executed by a processor, causes the processor to:

receive time domain temperature data (TDTD) pertaining to a patient;

convert said TDTD to a frequency domain representation (FDR);

and determine a marker indicative of the worsening medical condition of the patient by analyzing the FDR or by analyzing TDTD or by analyzing both, wherein analyzing the TDTD comprises performing at least one of Cosinor analysis, approximate entropy, tempogram, day-night mean temperature difference, body temperature daily range, interdaily stability, and time-lag embedding.

20. The CRSM of claim 19 wherein said software further causes the processor to weigh outputs of at least two analysis techniques to render a total score indicative of the current condition of the patient.

21. The CRSM of claim 19 wherein said software further causes the processor to report at least one of the TDTD, the FDR, analysis outputs, and the total score to the patient or a healthcare provider, or both.

22. The CRSM of claim 19 wherein said software further causes the processor to activate an alarm unit connected to said processor to generate an alarm upon determining the marker indicative of the worsening medical condition of the patient.

23. An implantable medical device comprising

a pacemaker or a defibrillator including an electrical pulse generator;

and

a processor that receives time domain temperature data (TDTD) pertaining to a patient, performs Cosinor analysis on said TDTD, and determines a marker indicative of the worsening medical condition of the patient upon detecting a change in at least one of the mesor, amplitude, and acrophase of the Cosinor analysis of the TDTD;

wherein said electrical pulse generator is configured to generate an electrical stimulation signal upon determination of the marker.

24. The device of claim 23 wherein said processor reports at least one of the TDTD, the FDR, analysis outputs, and the total score to the patient or a healthcare provider, or both.

25. The device of claim 23 further comprising an alarm unit that generates an alarm upon determining the marker indicative of the worsening medical condition of the patient.