Rapid shallow breathing detection for use in congestive heart failure status determination

• US 20070073168A1
• Filed: 09/16/2005
• Published: 03/29/2007
• Est. Priority Date: 09/16/2005
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Zhang, Yi, Dalal, Yousufali, Hatlestad, John, Brockway, Marina
• Granted Patent: US 7,775,983 B2
• Time in Patent Office: Days
• US Class Current: 600/483
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/053 Measuring electrical impedance or conductance of a portion of the body
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/091 Measuring volume of inspired or expired gases, e.g. to determine lung capacity
• CPC Class Codes: A61B 5/411 Detecting or monitoring allergy or intolerance reactions to an allergenic agent or substance
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy
• CPC Class Codes: A61N 1/36521 the parameter being derived from measurement of an electrical impedance

Abstract

Systems and methods involve use of a medical device comprising sensing circuitry. One or more respiratory parameters are detected using the device. Patient baseline weight is provided, and an output signal indicative of a patient'"'"'s congestive heart failure status is generated based on a change in the one or more respiratory parameters and a change in the patient'"'"'s measured weight or predicted weight relative to the patient baseline weight. The respiratory parameters may include one or more of respiration rate, relative tidal volume, an index indicative of rapid shallow breathing by the patient, an index derived by computing a respiration rate and a tidal volume for each patient breath, and an index indicative of dyspnea, for example.

Claims

1. A method, comprising:

detecting one or more respiratory parameters;

providing patient baseline weight; and

generating an output signal indicative of a patient'"'"'s congestive heart failure status based on a change in the one or more respiratory parameters and a change in the patient weight relative to the patient baseline weight.

2. The method of claim 1, wherein the one or more respiratory parameters comprises respiration rate.

3. The method of claim 1, wherein the one or more respiratory parameters comprises an index indicative of rapid shallow breathing by the patient.

4. The method of claim 3, wherein the index is derived by computing a respiration rate and a tidal volume for each patient breath.

5. The method of claim 1, wherein the one or more respiratory parameters comprises an index indicative of dyspnea.

6. The method of claim 1, wherein the one or more respiratory parameters comprises an index indicative of rapid shallow breathing by the patient, the method further comprising using the index as a basis to triage or discharge the patient.

7. The method of claim 1, wherein generating the output signal comprises generating a perceivable signal indicating a need for clinician intervention or initiation, adjustment or termination of therapy delivery to the patient.

8. The method of claim 1, wherein generating the output signal comprises generating a signal for facilitating automatic initiation, adjustment or termination of therapy delivery to the patient.

9. The method of claim 1, further comprising:

detecting the change in the one or more respiratory parameters;

initiating a computation of a change in the patient weight; and

generating the output signal in response to the change in the one or more respiratory parameters exceeding a first threshold and the computed change in the patient weight exceeding a second threshold.

10. The method of claim 9, wherein the change in the one or more respiratory parameters represents a cumulative change or slope of change in the one or more respiratory parameters.

11. The method of claim 9, further comprising updating the first and second thresholds in response to the detected change in the one or more respiratory parameters exceeding the first threshold and the computed change in the patient weight exceeding the second threshold.

12. The method of claim 1, further comprising:

detecting the change in the one or more respiratory parameters relative to a first threshold; and

predicting the change in patient weight based on the change in the one or more respiratory parameters.

13. The method of claim 12, wherein predicting the change in patient weight comprises:

computing a change in respiration rate based on the change in the one or more respiratory parameters; and

deriving coefficients based on a relationship between change in patient weight relative to change in respiration rate.

14. The method of claim 13, wherein the coefficients are derived from a linear regression of change in patient weight relative to change in respiration rate.

15. The method of claim 13, further comprising:

generating a baseline relationship between change in patient weight relative to change in respiration rate for a patient; and

updating the baseline relationship in response to a change in therapy delivered to the patient or change in patient condition.

16. The method of claim 1, further comprising:

computing a change in respiration rate based on the change in the one or more respiratory parameters relative to a first threshold;

predicting a change in patient weight based on the change in respiration rate; and

generating the output signal in response to the predicted weight change exceeding a second threshold.

17. The method of claim 16, further comprising updating the first and second thresholds in response to the detected change in the one or more respiratory parameters exceeding the first threshold and the predicted weight change exceeding the second threshold.

18. The method of claim 1, wherein generating the output signal is performed at least in part by the implantable medical device.

19. The method of claim 1, wherein generating the output signal is performed at least in part by a patient-external system.

20. The method of claim 1, wherein one of the change in the one or more respiratory parameters and the change in patient weight is used to validate the other of the change in the one or more respiratory parameters and the change in patient weight

21. The method of claim 1, wherein detecting one or more respiratory parameters comprises detecting the one or more respiratory parameters from within the patient'"'"'s body.

22. A system, comprising:

a medical device comprising sensing circuitry;

detection circuitry disposed in the medical device and coupled to the sensing circuitry, the detection circuitry configured to detect one or more respiratory parameters;

a memory configured to store baseline weight of a patient; and

a processor coupled to the memory and to the detection circuitry, the processor configured to generate an output signal indicative of the patient'"'"'s congestive heart failure status based on a change in the respiration rate developed from the one or more respiratory parameters and a change in the patient'"'"'s weight relative to the patient'"'"'s baseline weight.

23. The system of claim 22, wherein the processor and memory are disposed in a patient-external system.

24. The system of claim 22, wherein the processor computes the respiration rate.

25. The system of claim 22, wherein the detection circuitry computes the respiration rate.

26. The system of claim 22, further comprising a user interface configured to receive the patient'"'"'s baseline weight for storage in the memory.

27. The system of claim 26, further comprising a weight scale coupled to the user interface and configured to provide the patient'"'"'s weight.

28. The system of claim 22, wherein:

the processor computes a prediction of the change in the patient'"'"'s weight based on the change in the respiration rate; and

the processor is configured to generate the output signal based on the change in the respiration rate and the predicted change in the patient'"'"'s weight.

29. The system of claim 22, wherein the sensing circuitry comprises a transthoracic impedance sensor.

30. The system of claim 22, wherein the sensing circuitry comprises an accelerometer.

31. The system of claim 22, wherein the medical device is configured as an implantable medical device.

32. A system, comprising:

means for detecting one or more respiratory parameters;

means for providing patient baseline weight; and

means for generating an output signal indicative of a patient'"'"'s congestive heart failure status based on a change in the one or more respiratory parameters and a change in the patient weight relative to the patient baseline weight.

33. The system of claim 32, comprising means for predicting the change in the patient weight.

34. The system of claim 32, comprising means for indicating a need for clinician intervention or initiation, adjustment or termination of therapy delivery to the patient.

35. The system of claim 32, comprising means for facilitating automatic initiation, adjustment or termination of therapy delivery to the patient.

36. A method, comprising:

detecting one or more respiratory parameters;

detecting a change in the one or more respiration parameters;

predicting a change in patient weight based on the change in the one or more respiratory parameters; and

generating an output signal indicative of the predicted change in patient weight.

37. The method of claim 36, wherein detecting one or more respiratory parameters comprises detecting one or more respiratory parameters from within the patient'"'"'s body.