Implantable cardiac device with dyspnea measurement

• US 7,680,534 B2
• Filed: 02/28/2005
• Issued: 03/16/2010
• Est. Priority Date: 02/28/2005
• Status: Expired due to Fees

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Hartley, Jesse W., Scheiner, Avram, Hopper, Donald L., Voegele, John M.
• Primary Examiner(s): Layno; Carl H
• Assistant Examiner(s): Dinga; Roland
• Application Number:
  US11/067,964
• Publication Number:
  US 20060195149A1
• Time in Patent Office: 1,842 Days
• Field of Search: 607/17, 607/18, 607/19, 607/20, 600/484, 600/547
• US Class Current: 607/9
• CPC Class Codes: A61B 5/0022 Monitoring a patient using a global network, e.g. telephone networks, internet
• CPC Class Codes: A61B 5/0024 for multiple sensor units attached to the patient, e.g. using a body or personal area network
• CPC Class Codes: A61B 5/02028 Determining haemodynamic parameters not otherwise provided for, e.g. cardiac contractility or left ventricular ejection fraction
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/076 Permanent implantations telemetry using implanted circuitry A61B5/0031; implanted stimulators for therapy A61N1/3605, A61N1/362, A61N1/372
• 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 5/0826 Detecting or evaluating apnoea events A61B5/4818 takes precedence
• CPC Class Codes: A61B 5/085 Measuring impedance of respiratory organs or lung elasticity
• CPC Class Codes: A61B 5/091 Measuring volume of inspired or expired gases, e.g. to determine lung capacity
• CPC Class Codes: A61B 5/1118 Determining activity level
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/346 Analysis of electrocardiograms
• CPC Class Codes: A61B 5/4836 Diagnosis combined with treatment in closed-loop systems or methods A61B5/0036 takes precedence
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• 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: A61B 5/7282 Event detection, e.g. detecting unique waveforms indicative of a medical condition A61B5/4094, A61B5/4818, A61B5/349, A61B5/0823 take precedence
• CPC Class Codes: A61B 5/746 Alarms related to a physiological condition, e.g. details of setting alarm thresholds or avoiding false alarms alarms per se G08B
• CPC Class Codes: A61B 5/747 in case of emergency, i.e. alerting emergency services
• 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 1/36585 : controlled by two or more physical parameters
• CPC Class Codes: A61N 1/3702 : Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371
• CPC Class Codes: A61N 1/3987 : characterised by the timing or triggering of the shock
• CPC Class Codes: G16H 50/20 : for computer-aided diagnosis, e.g. based on medical expert systems
• CPC Class Codes: G16H 50/30 : for calculating health indices; for individual health risk assessment

Abstract

Cardiac monitoring and/or stimulation methods and systems employing dyspnea measurement. An implantable cardiac device may sense transthoracic impedance and determine a patient activity level. An index indicative of pulmonary function is implantably computed to detect an episode of dyspnea based on a change, trend, and/or value exceeding a threshold at a determined patient activity level. Trending one or more pulmonary function index values may be done to determine a patient'"'"'s pulmonary function index profile, which may be used to adapt a cardiac therapy. A physician may be automatically alerted in response to a pulmonary function index value and/or a trend of the patient'"'"'s pulmonary index being beyond a threshold. Computed pulmonary function index values and their associated patient'"'"'s activity levels may be stored periodically in a memory and/or transmitted to a patient-external device.

Claims

1. A method, comprising:

providing an implantable cardiac device configured to sense transthoracic impedance and make an activity measurement;

implantably computing an index indicative of pulmonary function using the sensed transthoracic impedance by computing a ratio of multiple respiration parameters;

implantably computing a patient activity level using the activity measurement; and

detecting an episode of dyspnea based on a parameter of the computed pulmonary function index exceeding an index value of a pulmonary function index versus activity level profile, the index value associated with an activity range of the pulmonary function index versus activity level profile which the patient activity level is calculated to be within, wherein the pulmonary function index versus activity level profile comprises a plurality of index values associated with different ranges of patient activity levels.

2. The method of claim 1, wherein the index value for detecting the dyspnea episode is based on the pulmonary function index versus activity level profile.

3. The method of claim 1, wherein the pulmonary function index versus activity level profile is formed by trending a plurality of pulmonary function index values and associating the trended pulmonary function index values with patient activity levels at which the plurality of pulmonary function index values were collected.

4. The method of claim 1, wherein the pulmonary function index versus activity level profile is formed by trending a plurality of pulmonary function index values and their associated patient activity levels, wherein the threshold for detecting the dyspnea episode is based on the pulmonary function index versus activity level profile.

5. The method of claim 1, wherein computing the pulmonary function index comprises computing a ratio of a respiratory rate value and a tidal volume value for the patient.

6. The method of claim 1, comprising:

adapting a cardiac therapy for the patient based on the computed index indicative of pulmonary function of the patient; and

delivering the adapted cardiac therapy to the patient.

7. The method of claim 1, comprising determining a patient'"'"'s sleep-state at least in part using the pulmonary function index.

8. The method of claim 1, comprising alerting a physician in response to a pulmonary function index value being beyond the index value.

9. The method of claim 1, comprising alerting a physician in response to a trend of the patient'"'"'s calculated index indicative of pulmonary function.