Method and system for heart failure status evaluation based on a disordered breathing index

• US 7,766,840 B2
• Filed: 12/01/2005
• Issued: 08/03/2010
• Est. Priority Date: 12/01/2005
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Brockway, Marina, Stahmann, Jeffrey, Kwok, Jonathan, Zhang, Yi, Lee, Kent, Ni, Quan, Hartley, Jesse, Pu, Yachuan
• Primary Examiner(s): Mallari; Patricia C
• Application Number:
  US11/291,525
• Publication Number:
  US 20070129643A1
• Time in Patent Office: 1,706 Days
• Field of Search: 600/533
• US Class Current: 600/508
• 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 method for operating a medical device to provide a patient assessment, the method comprising:

sensing patient respiration and generating a respiration signal;

detecting disordered breathing episodes based on the respiration signal;

determining a disordered breathing index based on the detected disordered breathing episodes;

trending the disordered breathing index over a period of time; and

evaluating a status of heart failure based on the disordered breathing index trend, wherein at least one of detecting, determining, trending, and evaluating is performed at least in part implantably using the medical device;

wherein detecting the disordered breathing episodes based on the respiration signal comprises discriminating obstructive disordered breathing episodes from central disordered breathing episodes;

wherein determining the disordered breathing index comprises determining the disordered breathing index based on at least one of the obstructive disordered breathing episodes and the central disordered breathing episodes; and

wherein discriminating the obstructive disordered breathing episodes from the central disordered breathing episodes comprises discriminating based on a respiratory rate during hyperventilation portions of the respiration signal during periodic breathing episodes.

2. A method for operating a medical device to provide a patient assessment, the method comprising:

sensing patient respiration and generating a respiration signal;

detecting disordered breathing episodes based on the respiration signal;

determining a disordered breathing index based on the detected disordered breathing episodes;

trending the disordered breathing index over a period of time; and

evaluating a status of heart failure based on the disordered breathing index trend, wherein at least one of detecting, determining, trending, and evaluating is performed at least in part implantably using the medical device;

wherein detecting the disordered breathing episodes based on the respiration signal comprises discriminating obstructive disordered breathing episodes from central disordered breathing episodes;

wherein determining the disordered breathing index comprises determining the disordered breathing index based on at least one of the obstructive disordered breathing episodes and the central disordered breathing episodes; and

wherein determining the disordered breathing index comprises determining a ratio of the central disordered breathing episodes to the obstructive disordered breathing episodes.

3. A method for operating a medical device to provide a patient assessment, the method comprising:

sensing patient respiration and generating a respiration signal;

detecting disordered breathing episodes based on the respiration signal;

determining a disordered breathing index based on the detected disordered breathing episodes;

trending the disordered breathing index over a period of time; and

evaluating a status of heart failure based on the disordered breathing index trend, wherein at least one of detecting, determining, trending, and evaluating is performed at least in part implantably using the medical device;

wherein detecting the disordered breathing episodes comprises detecting periodic breathing episodes; and

wherein determining the disordered breathing index comprises;

determining a waveform modulating the respiration signal during the periodic breathing episodes; and

determining the disordered breathing index based on a degree of modulation of the waveform.

4. A method for operating a medical device to provide a patient assessment, the method comprising:

sensing patient respiration and generating a respiration signal;

detecting disordered breathing episodes based on the respiration signal;

determining a disordered breathing index based on the detected disordered breathing episodes;

trending the disordered breathing index over a period of time; and

evaluating a status of heart failure based on the disordered breathing index trend, wherein at least one of detecting, determining, trending, and evaluating is performed at least in part implantably using the medical device;

wherein detecting the disordered breathing episodes comprises detecting periodic breathing episodes; and

wherein determining the disordered breathing index comprises;

detecting the maximum tidal volume during periods of hyperventilation; and

determining a time to reach the maximum tidal volume.