Method and System for Heart Failure Status Evaluation Based on a Disordered Breathing Index

• US 20100298733A1
• Filed: 07/30/2010
• Published: 11/25/2010
• Est. Priority Date: 12/01/2005
• Status: Active Grant

• Current Assignee: Jeffrey Stahmann, Jesse Hartley, Jonathan Kwok, Kent Lee, Marina Brockway, Quan Ni, Yachuan Pu, Yi Zhang
• Original Assignee: Jeffrey Stahmann, Jesse Hartley, Jonathan Kwok, Kent Lee, Marina Brockway, Quan Ni, Yachuan Pu, Yi Zhang
• Inventors: Kwok, Jonathan, Zhang, Yi, Lee, Kent, Ni, Quan, Brockway, Marina, Hartley, Jesse, Pu, Yachuan, Stahmann, Jeffrey
• Granted Patent: US 8,696,589 B2
• Time in Patent Office: Days
• US Class Current: 600/529
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/0809 by impedance pneumography
• 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 5/113 occurring during breathing
• CPC Class Codes: A61B 5/4818 Sleep apnoea
• 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
• CPC Class Codes: A61N 1/36535 controlled by body position or posture

Abstract

An evaluation of heart failure status is provided based on a disordered breathing index. Patient respiration is sensed and a respiration signal is generated. Disordered breathing episodes are detected based on the respiration signal. A disordered breathing index is determined based on the disordered breathing episodes. The disordered breathing index is trended and used to evaluate heart failure status. The disordered breathing index may be combined with additional information and/or may take into account patient activity, posture, sleep stage, or other patient information.

Claims

1. A system for providing a patient assessment, the system comprising:

a respiration sensor configured to generate a signal responsive to patient respiration; and

a disordered breathing detector coupled to the respiration sensor and configured to

detect disordered breathing episodes based on the respiration signal,

identify hyperventilation portions of the respiration signal during the disordered breathing episodes,

determine a respiratory rate during the hyperventilation portions, and

discriminate obstructive disordered breathing episodes from central disordered breathing episodes based on the respiratory rate during the hyperventilation portions of the respiration signal during the disordered breathing episodes.

2. The system of claim 1, further comprising an index processor configured to determine a disordered breathing index based on one or both of the obstructive disordered breathing episodes and the central disordered breathing episodes.

3. The system of claim 2, wherein the index processor is configured to determine a disordered breathing index based on a ratio of the obstructive disordered breathing episodes and the central disordered breathing episodes.

4. The system of claim 2, further comprising:

a trend processor configured to trend the disordered breathing index; and

a diagnostics unit configured to evaluate heart failure status based on the trend.

5. The system of claim 1, further comprising a rapid eye movement (REM) detector, wherein the index processor is configured to correlate the disordered breathing episodes with REM and non-REM sleep stages.

6. The system of claim 1, further comprising a posture sensor configure to provide an output indicative of tilt angle during the disordered breathing episodes, wherein the index processor is configured to determine the disordered breathing index including weighing the disordered breathing episodes based on tilt angle.

7. A system for providing a patient assessment, the system comprising:

a respiration sensor configured to generate a signal responsive to patient respiration; and

a disordered breathing detector coupled to the respiration sensor and configured to detect disordered breathing episodes based on the respiration signal and discriminate between central disordered breathing episodes and obstructive disordered breathing episodes; and

an index processor configured to determining a ratio of the central disordered breathing episodes and the obstructive disordered breathing episodes and to determine a disordered breathing index using the ratio.

8. The system of claim 7, further comprising an activity sensor configured to generate a patient activity signal, wherein the index processor is configured to determine the disordered breathing index using the activity signal including applying different weights to disordered breathing episodes that occur during periods of low activity and disordered breathing episodes that occur during periods of high activity.

9. The system of claim 7, wherein the disordered breathing detector is configured to discriminate between the central disordered breathing episodes and the obstructive disordered breathing episodes based on hyperventilation portions of the respiration signal during the disordered breathing episodes.

10. The system of claim 7, wherein the disordered breathing detector is configured to discriminate between the central disordered breathing episodes and the obstructive disordered breathing episodes based on speed of transition to hyperventilation during the disordered breathing episodes

11. The system of claim 7, further comprising a pressure sensor configured to generate a pressure signal, wherein the disordered breathing detector is configured to discriminate between the central disordered breathing episodes and the obstructive disordered breathing episodes based on the pressure signal.

12. The system of claim 11, wherein the pressure sensor is configured to sense intrathoracic pressure, intracardiac pressure or intravascular pressure.

13. A system for providing a patient assessment, the system comprising:

a respiration sensor configured to generate a signal responsive to patient respiration; and

a disordered breathing detector coupled to the respiration sensor and configured to detect disordered breathing episodes based on the respiration signal; and

an index processor configured to determine modulation of the respiration signal during the disordered breathing episodes and to determine a disordered breathing index using the respiration signal modulation during the disordered breathing episodes.

14. The system of claim 13, wherein the index processor is configured to discriminate periodic portions from non-periodic portions of the disordered breathing episodes and the modulation of the respiration signal comprises the modulation of the respiration signal during the periodic portions.

15. The system of claim 13, wherein the index processor is configured to determine to determine a frequency of the modulation and the system further comprises a diagnostics unit configured to detect progression of heart failure based on changes in the frequency of modulation.

16. The system of claim 15, wherein the diagnostics unit is configured to detect worsening heart failure if the frequency of modulation decreases.

17. The system of claim 13, wherein the index processor is configured to determine a depth of modulation and the system further comprises a diagnostics unit configured to detect progression of heart failure based on changes in the depth of modulation.

18. A system for providing a patient assessment, the system comprising:

a respiration sensor configured to generate a signal responsive to patient respiration; and

a disordered breathing detector coupled to the respiration sensor and configured to detect disordered breathing episodes based on the respiration signal; and

an index processor configured to analyze the respiration signal to determine transition times to a tidal volume value for cycles of the disordered breathing episodes, the index processor further configured to determine a disordered breathing index using the transition times.

19. The system of claim 18, wherein the tidal volume value comprises a maximum tidal volume.

20. The system of claim 18, wherein the index processor is configured to determine one or more of a maximum transition time, a minimum transition time and an average transition time and to determine the disordered breathing index based on one or more of the maximum transition time, the minimum transition time and the average transition time.