Detection and the treatment of ventilatory disorders during sleep for an active implantable medical device, in particular a pacemaker

• US 20040006375A1
• Filed: 02/10/2003
• Published: 01/08/2004
• Est. Priority Date: 02/15/2002
• Status: Active Grant

• Current Assignee: Ela Medical S.A. (LivaNova Plc)
• Original Assignee: Ela Medical S.A. (LivaNova Plc)
• Inventors: Poezevera, Yann
• Granted Patent: US 7,395,115 B2
• Time in Patent Office: Days
• US Class Current: 607/17
• CPC Class Codes: A61B 5/053 Measuring electrical impedance or conductance of a portion of the body
• CPC Class Codes: A61B 5/4812 Detecting sleep stages or cycles
• CPC Class Codes: A61B 5/4818 Sleep apnoea
• CPC Class Codes: A61N 1/3601 of respiratory organs
• CPC Class Codes: A61N 1/36514 controlled by a physiological quantity other than heart potential, e.g. blood pressure controlled by two or more physical parameters A61N1/36585

Abstract

An active medical device that is able to detect and treat ventiliatory activity disorders during sleep. This device measures the patient'"'"'s respiratory activity, delivers a signal of the ventilatory activity of the patient, analyzes the ventilatory activity signal, and detects the occurrence of hypopneas. The analysis includes calculating at regular intervals a sliding average of the signal of ventilatory activity, comparing the values of the successive sliding averages thus calculated, and detecting an occurrence of an hypopnea when, for two successive sliding averages, the difference between the averages crosses a predetermined threshold of comparison. When the device is one that also delivers cardiac stimulation pulses, it is advantageously envisaged to modify an operating parameter, in particular the stimulation rate based on the detected hypopnea, to treat the hypopnea.

Claims

1. An active implantable medical device, comprising:

means for measuring a respiratory activity of a patient having an output signal corresponding to ventilatory activity of the patient;

means for analyzing the output signal of ventilatory activity and detecting therefrom an occurrence of a hypopnea;

means for delivering cardiac stimulation pulses at a stimulation rate,

means for modifying said stimulation rate, including means for increasing said stimulation rate in response to a first detected hypopnea.

2. The device of claim 1, further comprising means for detecting a phase of patient activity including an awakening phase and a sleep phase and a transition between said sleep and awakening phases, wherein the analyzing means further comprises means for comparing a modification of said operating parameter and a detected transition from a sleep phase to an awakening phase and means for determining a correlation between said modification and said transitions and providing a correlation indicator indicative of a correlation between a modification of the operating parameter and consecutive transitions from a sleep phase to an awakening phase, and for delivering said correlation indicator in the event of a determined correlation.

3. The device of claim 2, wherein the analyzing means further comprises means for delivering said correlation indicator in the event of an occurrence of a transition during a given time interval following a modification of the stimulation rate.

4. The device of claim 2, wherein the means for modifying the stimulation rate further comprises a means for modifying in a reverse direction said modified operating parameter in response to a provided indicator of correlation by the analyzing means.

5. The device of claim 4, wherein the means for modifying the stimulation rate in the reverse direction further comprises means for counting delivered correlation indicators and means for modifying said stimulation rate in the reverse direction when the count of delivered correlation indicators is greater than a predetermined level.

6. The device of claim 4 wherein the means for modifying the stimulation rate in the reverse direction further comprises means for decreasing said stimulation rate to a rate that is greater than or equal to a base rate.

7. The device of claim 1, wherein the analyzing means further comprises:

means for determining at regular intervals a measure of ventilatory activity;

means for calculating a first sliding average of a first number of ventilatory activity measures;

means for calculating a second sliding average of a second number of ventilatory activity measures, the second number of ventilatory activity measures being consecutive to said first number of ventilatory activity measures;

means for determining a difference between the first and second sliding averages; and

means for detecting an occurrence of a hypopnea in response to said difference being greater than a predetermined threshold of comparison.

8. The device of claim 7, wherein the means for determining a ventilatory activity measure at regular intervals further comprises means for calculating said ventilatory activity measure during a predetermined time interval.

9. The device of claim 7, wherein the means for determining a ventilatory activity measure at regular intervals further comprises means for calculating said ventilatory activity measure during a respiratory cycle and said first number is a non-zero integer number N′

, and said second number a non-zero integer number N, wherein N and N′

are a predetermined number of respiratory cycles.

10. The device of claim 1, wherein the analyzing means further comprises:

means for determining a duration of hypopnea in response to an occurrence of a first hypopnea.

11. The device of claim 10, wherein the analyzing means further comprises means able to discriminating a respiratory pause phase from a hypopnea phase, and suspend the determination of the duration of hypopnea during a respiratory pause phase.

12. The device of claim 1 wherein analyzing means further comprises:

means for determining at regular intervals a measure of ventilatory activity;

means for calculating a first sliding average of a first number of ventilatory activity measures;

means for calculating a second sliding average of a second number of ventilatory activity measures, the second number of ventilatory activity measures being consecutive to said first number of ventilatory activity measures,

means for determining a difference between the first and second sliding averages;

means for detecting an occurrence of a hypopnea in response to said difference being greater than a predetermined threshold of comparison; and

means for determining a duration of hypopnea in response to an occurrence of a first hypopnea;

wherein the means for determining the duration of hypopnea further comprises means for counting a number of consecutive respiratory cycles for which the average of the ventilatory signal of activity remains lower than the said predetermined threshold of comparison of the last non-hypopneic average.

13. The device of claim 1 wherein the analyzing means further comprises:

means for determining at regular intervals a measure of ventilatory activity;

means for calculating a first sliding average of a first number of ventilatory activity measures;

means for calculating a second sliding average of a second number of ventilatory activity measures, the second number of ventilatory activity measures being consecutive to said first number of ventilatory activity measures,

means for determining a difference between the first and second sliding averages;

means for detecting an occurrence of a hypopnea in response to said difference being greater than a predetermined threshold of comparison; and

means for determining a duration of hypopnea in response to an occurrence of a first hypopnea;

wherein the means for determining the duration of hypopnea further comprises means for counting a number of periods of calculation of the first and second sliding averages for which the calculated average of the ventilatory activity signal remains below the predetermined threshold of comparison of the last non-hypopneic average.

14. The device of claim 1 wherein the analyzing means further comprises means for determining a duration of hypopnea in response to an occurrence of a first hypopnea, wherein the control means further comprises means for modifying said operating parameter in response to an accumulated duration of hypopneas measured over a given period being greater than a predetermined threshold.

15. The device of claim 1 wherein the analyzing means further comprises:

means for determining a duration of hypopnea in response to an occurrence of a first hypopnea; and

the control means further comprises means for modifying said stimulation rate in response to the count of hypopneas measured over a given period being greater than a predetermined threshold.