Systems and methods for determining respiration metrics

• US 8,496,596 B2
• Filed: 02/05/2010
• Issued: 07/30/2013
• Est. Priority Date: 12/14/2005
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Hatlestad, John D.
• Primary Examiner(s): Natnithithadha, Navin
• Assistant Examiner(s): BERHANU, ETSUB D
• Application Number:
  US12/700,881
• Publication Number:
  US 20100137730A1
• Time in Patent Office: 1,271 Days
• Field of Search: 600/529, 600/484
• US Class Current: 600/529
• CPC Class Codes: A61B 5/08 Detecting, measuring or recording devices for evaluating the respiratory organs A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/0809 by impedance pneumography
• 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, devices and methods provide for acquiring respiration information. A respiration information device includes timer circuitry to time a plurality of shorter time apertures and a plurality of longer time apertures. A respiration sensor, which may be implemented as a transthoracic impedance sensor, is configured to generate a signal indicative of patient respiration. For each aperture of the plurality of shorter time apertures and for each aperture of the plurality of longer time apertures, an estimated characteristic of the respiration is determined. Respiration metrics are developed using one or both of the estimated respiration characteristics of the shorter time apertures and the estimated respiration characteristics of the longer time apertures.

Claims

1. A method of determining one or more respiration metrics, comprising:

generating a signal indicative of respiration of a patient using one or more sensors;

receiving the signal indicative of respiration in an implantable device and determining, for each aperture of a plurality of shorter time apertures and for each aperture of a plurality of longer time apertures, an estimated characteristic of the respiration of the patient based on the respiration signal; and

the implantable device determining one or more respiration metrics using one or both of the estimated respiration characteristics of the plurality of shorter time apertures and the estimated respiration characteristics of the plurality of longer time apertures, wherein determining the one or more respiration metrics includes determining a maximum respiration metric based on the estimated characteristics for each of the plurality of shorter time apertures and determining a minimum respiration metric based on the estimated characteristics of each of the plurality of longer time apertures.

2. The method of claim 1, wherein determining the estimated respiration characteristic for each aperture comprises:

measuring a respiration characteristic for each breath cycle of the aperture; and

determining the estimated respiration characteristic for the aperture based on the measured respiration characteristics.

3. The method of claim 2, wherein determining the estimated respiration characteristic for the aperture comprises determining the estimated respiration characteristic based on a median value of the measured respiration characteristics.

4. The method of claim 1, wherein determining the estimated respiration characteristic for each aperture comprises determining an estimated respiration rate for each aperture.

5. The method of claim 1, wherein at least one of generating the signal, determining the estimated characteristic, and determining the one or more respiration metrics is performed at least in part by the implantable device.

6. The method of claim 1, wherein:

determining the estimated respiration characteristic for each of the plurality of shorter time apertures comprises determining a maximum respiration rate for each of the plurality of shorter time apertures;

determining the estimated respiration characteristic for each of the plurality of longer time apertures comprises determining a minimum respiration rate for each of the plurality of longer time apertures; and

determining the respiration metrics comprises determining a daily maximum respiration rate using the maximum respiration rates of the plurality of shorter time apertures and determining a daily minimum respiration rate using the minimum respiration rates of the plurality of longer time apertures.

7. The method of claim 1, further comprising developing a trend using at least one of the estimated respiration characteristics determined for the plurality of shorter time apertures, the estimated respiration characteristics determined for the plurality of longer time apertures, and the one or more respiration metrics.

8. The method of claim 1, further comprising detecting a presence of a disease or disorder using at least one of the estimated respiration characteristics determined for the plurality of shorter time apertures, the estimated respiration characteristics determined for the plurality of longer time apertures, and the one or more respiration metrics.

9. The method of claim 1, further comprising tracking progression of heart failure using at least one of the estimated respiration characteristics determined for the plurality of shorter time apertures, the estimated respiration characteristics determined for the plurality of longer time apertures, and the one or more respiration metrics.

10. The method of claim 9, further comprising initiating, modifying or terminating therapy based on the heart failure progression.

11. The method of claim 10, wherein the therapy includes a cardiac pacing therapy.

12. The method of claim 1, wherein at least some of the plurality of shorter time apertures overlap each other.

13. The method of claim 1, wherein at least some of the plurality of longer time apertures overlap each other.

14. A method, comprising:

generating a signal indicative of respiration of a patient using one or more sensors;

receiving the signal indicative of respiration in an implantable device;

the implantable device determining, for each aperture of a plurality of shorter time apertures and for each aperture of a plurality of longer time apertures, an estimated characteristic of the respiration based on the respiration signal;

the implantable device determining one or more respiration metrics using one or both of the estimated respiration characteristics of the plurality of shorter time apertures and the estimated respiration characteristics of the plurality of longer time apertures, wherein determining the one or more respiration metrics includes determining a maximum respiration metric based on the estimated characteristics for each of the plurality of shorter time apertures and determining a minimum respiration metric based on the estimated characteristics of each of the plurality of longer time apertures;

the implantable device identifying spurious respiration cycles associated with cardiac activity; and

the implantable device excluding the spurious respiration cycles when determining the estimated respiration characteristic.

15. The method of claim 14, wherein determining the estimated respiration characteristic for each aperture comprises determining an estimated respiration rate for each aperture.

16. The method of claim 14, wherein:

determining the estimated respiration characteristic for each of the plurality of shorter time apertures comprises determining a maximum respiration rate for each of the plurality of shorter time apertures;

determining the estimated respiration characteristic for each of the plurality of longer time apertures comprises determining a minimum respiration rate for each of the plurality of longer time apertures; and

determining the respiration metrics comprises determining a daily maximum respiration rate using the maximum respiration rates of the plurality of shorter time apertures and determining a daily minimum respiration rate using the minimum respiration rates of the plurality of longer time apertures.

17. A method, comprising:

generating a signal indicative of respiration of a patient using one or more sensors;

receiving the signal indicative of respiration in an implantable device and determining, for each aperture of a plurality of shorter time apertures and for each aperture of a plurality of longer time apertures, an estimated characteristic of the respiration based on the respiration signal; and

the implantable device determining one or more respiration metrics using one or both of the estimated respiration characteristics of the plurality of shorter time apertures and the estimated respiration characteristics of the plurality of longer time apertures, wherein determining the one or more respiration metrics includes determining a maximum respiration metric based on the estimated characteristics for each of the plurality of shorter time apertures and determining a minimum respiration metric based on the estimated characteristics of each of the plurality of longer time apertures and wherein at least some of the plurality of shorter time apertures overlap each other and at least some of the plurality of longer time apertures overlap each other.

18. The method of claim 17, wherein:

determining the estimated respiration characteristic for each of the plurality of shorter time apertures comprises determining a maximum respiration rate for each of the plurality of shorter time apertures;

determining the estimated respiration characteristic for each of the plurality of longer time apertures comprises determining a minimum respiration rate for each of the plurality of longer time apertures; and

determining the respiration metrics comprises determining a daily maximum respiration rate using the maximum respiration rates of the plurality of shorter time apertures and determining a daily minimum respiration rate using the minimum respiration rates of the plurality of longer time apertures.

19. A method of determining one or more respiration metrics, comprising:

generating a signal indicative of respiration of a patient using one or more sensors;

receiving the signal indicative of respiration in an implantable device and determining, for each aperture of a plurality of shorter time apertures and for each aperture of a plurality of longer time apertures, an estimated characteristic of the respiration based on the respiration signal;

the implantable device determining one or more respiration metrics using one or both of the estimated respiration characteristics of the plurality of shorter time apertures and the estimated respiration characteristics of the plurality of longer time apertures,

wherein the estimated respiration characteristic of each shorter time aperture includes a median value of respiration rates measured during the shorter time aperture and the estimated respiration characteristic of each longer time aperture includes a median value of respiration rates measured during the longer time aperture and wherein determining the respiration metrics includes determining a maximum of the median values of the respiration rates measured for each of the plurality of shorter time apertures and determining a minimum of the median values of the respiration rates measured for each of the plurality of longer time apertures.

20. The method of claim 19, further comprising:

determining a daily maximum respiration rate using the maximum of the median values of the respiration rates for each of the plurality of shorter time apertures and determining a daily minimum respiration rate using the minimum of the median values of the respiration rates for each of the plurality of longer time apertures.