Detecting and treating disordered breathing
Detection and treatment of disordered breathing, with treatment being primarily delivered using electrical stimulation of the diaphragm, either directly or by stimulating appropriate nerves. In some embodiments, the stimulus is applied to still at least one lung upon detection of an apnea-hypopnea of some length or upon the detection of hyperpnea. The stimulation may be initiated during the apnea-hypopnea period or upon detection of a breath of a predetermined intensity near the end of apnea-hypopnea. The stimulation may be initiated in phase with respiration or irrespective of the phase of respiration.
1. A system for treating disordered breathing comprising:
a. a stimulation lead having a stimulation electrode;
b. a respiration sensor;
c. an energy source, a pulse generator, and circuitry, the circuitry operative to:
i. determine the onset of a hyperpnea episode based on a signal from the respiration sensor; and
ii. deliver a stimulation signal to the stimulation electrode during the hyperpnea episode, the stimulation signal having a duration of at least one second and operative to extend a duration of time of a breath of a subject, the duration of time of a breath being defined as the time from an onset of inhalation to the onset of inhalation of a successive breath wherein the stimulation is initiated proximate a peak of inhalation, wherein the stimulation signal acts to reduce the minute ventilation during the hyperpnea episode.
2. The system of claim 1 , wherein the circuitry receives respiration signals from the respiration sensor to calculate a baseline breath duration.
3. The system of claim 2 , wherein the stimulation signal duration is at least 25% of the baseline breath duration.
4. The system of claim 1 , wherein the circuitry is operative to determine the peak of inspiration.
5. The system of claim 1 , wherein the stimulation signal is configured to retain a lung in a patient to a fully inflated position.
6. The system of claim 1 , wherein the respiration sensor is selected from a group consisting of an impedance sensor, a pressure sensor, and an accelerometer.
7. The system of claim 1 , wherein the circuitry is operative to store data relating to respiratory rate, tidal volume, cyclic changes of tidal volume, and periodicity of respiration.
8. The system of claim 1 , wherein the circuitry is operative to determine the duration of a hyperpnea episode and deliver a stimulation signal proximate the peak of inhalation for several breaths extending beyond the normal duration of a hyperpnea episode.
9. The system of claim 1 , wherein circuitry is operative to determine the duration of a hyperpnea episode and the stimulation signal is initiated after the midpoint of the hyperpnea episode and is configured to initiate the stimulation signal proximate the peak of inhalation of each breath after the midpoint of the hyperpnea episode.
10. The system of claim 9 , wherein the circuitry is operative to deliver a stimulation signal proximate the peak of inspiration for several breaths beginning after the midpoint of the hyperpnea episode.
11. The system of claim 9 , wherein the stimulation signal has a duration of at least 2 seconds.
12. The system of claim 1 , wherein the stimulation signal has a duration of at least 2 seconds.
13. The system of claim 1 , wherein the circuitry is operative to provide at least three segmented stimulation signals during the hyperpnea episode.
14. The system of claim 1 , wherein the circuitry is operative to:
a. determine the average duration of a hyperpnea episode;
b. determine the average duration of an apnea-hypopnea episode;
c. deliver a stimulation signal during a hyperpnea episode based on the average duration of a hyperpnea episode; and
d. establish a blanking period based on the average duration of an apnea-hypopnea episode.
15. The system of claim 1 , wherein the stimulation signal is in the form of a gradually rising and descending pulse train envelope.
16. The system of claim 15 , wherein the rising and descending portion of the pulse train envelope are of a shape selected from the group comprising linear, parabolic, and elliptical.
17. The system of claim 1 , wherein the circuitry is configured to determine a blanking period that prevents the stimulation signal from being sent for a selected amount of time.