METHODS, SYSTEMS AND DEVICES FOR MONITORING RESPIRATORY DISORDERS

• US 20100152560A1
• Filed: 02/19/2010
• Published: 06/17/2010
• Est. Priority Date: 07/21/2004
• Status: Active Grant

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Inventors: Turcott, Robert G.
• Granted Patent: US 9,022,030 B2
• Time in Patent Office: Days
• US Class Current: 600/323
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/411 Detecting or monitoring allergy or intolerance reactions to an allergenic agent or substance
• CPC Class Codes: A61B 5/415 the glands, e.g. tonsils, adenoids or thymus
• CPC Class Codes: A61B 5/4818 Sleep apnoea

Abstract

Methods, systems and devices are provided for monitoring respiratory disorders based on monitored factors of a photoplethysmography (PPG) signal that is representative of peripheral blood volume. The monitored factors can be respiratory effort as well as respiratory rate and/or blood oxygen saturation level. The systems and devices may or may not be implanted in a patient.

Claims

1. A method of monitoring respiration comprising:

obtaining a photoplethysmography (PPG) signal that is representative of blood volume;

determining an average of the PPG signal;

adding an offset to the average to produce a first threshold;

subtracting an offset from the average to produce a second threshold; and

monitoring respiratory rate by determining a number of transitions from one of the first and second thresholds to the other threshold.

2. The method of claim 1 further comprising:

monitoring respiratory effort by determining amplitudes of the PPG signal; and

detecting an exacerbation of a respiratory disorder based on respiratory effort and respiratory rate.

3. The method of claim 2 wherein the respiratory disorder is asthma, and wherein detecting an exacerbation comprises detecting the asthmatic episode by comparing the respiratory effort to a threshold.

4. The method of claim 2 wherein the respiratory disorder is asthma, and wherein detecting an exacerbation comprises detecting an asthmatic episode based on the respiratory rate and respiratory effort.

5. The method of claim 4 wherein detecting an exacerbation comprises detecting an asthmatic episode by comparing the respiratory rate to a first threshold and the respiratory effort to a second threshold.

6. The method of claim 1 further comprising:

monitoring respiratory effort by determining amplitudes of the PPG signal;

monitoring blood oxygen saturation level based on the PPG signal.

detecting an exacerbation of a respiratory disorder based on respiratory effort and blood oxygen saturation level.

7. The method of claim 6 wherein detecting an exacerbation of a respiratory disorder based on respiratory effort and blood oxygen saturation level comprises detecting an exacerbation of a respiratory disorder based on the respiratory effort, respiratory rate and blood oxygen saturation level.

8. The method of claim 6 wherein the respiratory disorder is asthma.

9. The method of claim 8 wherein detecting an exacerbation comprises detecting an asthmatic episode by comparing the respiratory rate to a first threshold, the respiratory effort to a second threshold and the oxygen saturation level to a third threshold.

10. The method of claim 1 wherein obtaining a PPG signal comprises producing the PPG signal while a patient, whose respiratory disorder is being monitored, is sleeping.

11. The method of claim 10 further comprising:

monitoring respiratory effort by determining amplitudes of the PPG signal; and

detecting an episode of sleep apnea based on the respiratory effort.

12. The method of claim 11 wherein detecting an episode of sleep apnea based on the monitored respiratory effort, further comprises detecting an episode of sleep apnea based on the respiratory rate and respiratory effort.

13. The method of claim 11 further comprising:

monitoring blood oxygen saturation level based on the PPG signal; and

wherein detecting an episode of sleep apnea based on respiratory effort comprises detecting an episode of sleep apnea based on the respiratory effort and blood oxygen saturation level.

14. The method of claim 13 wherein detecting an episode of sleep apnea based on respiratory effort comprises detecting an episode of sleep apnea based on the respiratory rate, respiratory effort and blood oxygen saturation level.

15. A method of monitoring respiration, comprising

obtaining a photoplethysmography (PPG) signal that is representative of blood volume using a light source and a light detector;

monitoring respiratory rate based on the PPG signal by analyzing a frequency spectrum of the PPG signal and detecting a peak frequency.

16. A method of detecting episodes of sleep apnea, and distinguishing between hypopnea, obstructive sleep apnea (OSA) and central sleep apnea (CSA), said method comprising:

obtaining a photoplethysmography (PPG) signal that is representative of the patient'"'"'s peripheral blood volume;

monitoring respiratory effort and respiratory rate based on the PPG signal;

detecting an episode of sleep apnea based on at least one of the monitored respiratory effort and respiratory rate; and

distinguishing between hypopnea, OSA and CSA, for a detected episode of sleep apnea, based on the monitored respiratory effort and respiratory rate.

17. The method of claim 16 further comprising monitoring blood oxygen saturation level of the patient based on the PPG signal.

18. The method of claim 17 wherein detecting an episode of sleep apnea comprises detecting an episode of sleep apnea based at least two of the monitored respiratory effort, respiratory rate and blood oxygen saturation level.

19. The method of claim 17 wherein distinguishing between hypopnea, OSA and CSA, for a detected episode of sleep apnea, comprises distinguishing between hypopnea, OSA and CSA based on the monitored respiratory effort, respiratory rate and blood oxygen saturation level.