Method and apparatus for sensing respiratory pressure in an implantable stimulation system

Abstract

A method and system for sensing respiration in the treatment of sleep apnea is disclosed.

1 . A method of treating a respiratory dysfunction, the method comprising:
 positioning a sensor portion of a lead, via an intercostal access point, into an implanted location in which the sensor portion is coupled relative to respiratory pressures of a pleural space;   sensing, via the sensor portion at the implanted location, at least one of a temperature and the respiratory pressure; and   identifying a respiratory event based on a substantial change in the amplitude of at least one of the sensed temperature and the sensed respiratory pressure.   
     
     
         2 . The method of  claim 1 , wherein the respiratory event includes an obstructive sleep apnea event. 
     
     
         3 . The method of  claim 1 , comprising:
 triggering the application of an electrical stimulation signal, from an implantable pulse generator coupled to the sensor portion, based on the substantial change in the amplitude of at least one of the sensed temperature and the sensed respiratory pressure.   
     
     
         4 . The method of  claim 3 , comprising:
 synchronizing the application of the electrical stimulation signal according to cyclical respiration waveform parameters, including at least one of:   a portion of inspiratory phase;   a portion of an expiratory phase; or   a transition region between the respective inspiratory and expiratory phases.   
     
     
         5 . The method of  claim 1 , wherein identifying the respiratory event comprises:
 using the sensed temperature to indicate a polarity of the sensed respiratory pressure to differentiate inspiratory phases from expiratory phases of sensed respiratory pressure.   
     
     
         6 . The method of  claim 1 , wherein sensing at least one of the pressure and the temperature includes:
 providing a first piezo-electric transducer within the sensor portion to sense the pressure and a second piezo-electric transducer within the sensor portion to sense the temperature, independently from sensing the pressure; and   maintaining electrical independence between the first and second piezo-electric transducers.   
     
     
         7 . The method of  claim 6 , wherein identifying the respiratory event includes:
 identifying a substantial increase in the cyclical amplitudes of the sensed pressure relative to a pressure threshold and identifying, at generally the same time, a substantial decrease in the cyclical amplitudes of the sensed temperature.   
     
     
         8 . The method of  claim 6 , comprising:
 summing a signal of the sensed pressure and a signal of the sensed temperature to produce a measured respiratory signal;   wherein identifying the respiratory event includes:   identifying a substantial change in the amplitude of the measured respiratory signal.   
     
     
         9 . The method of  claim 1 , wherein positioning the sensor portion comprises:
 providing the sensor portion as a directional sensing element including a single side of the sensor portion configured to sense the respiratory pressure;   facing the directional sensing element directly toward the lungs from the extrapleural position or the intrapleural position.   
     
     
         10 . The method of  claim 1 , wherein positioning the sensor portion comprises:
 arranging the implanted location to correspond to a subcutaneous, extrapleural position in which the sensor portion is indirectly coupled relative to the respiratory pressures of the pleural space.   
     
     
         11 . The method of  claim 1 , wherein positioning the sensor portion further comprises:
 locating and forming the intercostal access point between a pair of immediately adjacent ribs on one side of a patient's body; and   inserting and advancing a distal portion of the sensor lead, including the sensor portion, through the intercostal access point to orient the distal portion to be generally parallel to the adjacent ribs and pointing toward a centerline of the body.   
     
     
         12 . The method of  claim 11 , wherein positioning the sensor portion comprises:
 arranging the implanted location of the sensor portion to be lateral to a costochondral joint of the adjacent ribs.   
     
     
         13 . The method of  claim 12 , wherein positioning the sensor portion includes causing the implanted location to be inferior to, and aligned with, a nipple on the one side of patient's body such that the alignment of the sensor portion and the nipple is generally parallel to a longitudinal axis of the patient's body. 
     
     
         14 . The method of  claim 12 , wherein locating and forming the intercostal access point comprises locating the intercostal access point between the adjacent pair of ribs within a group of ribs extending from a second uppermost rib through a seventh uppermost rib. 
     
     
         15 . The method of  claim 14 , wherein the adjacent pair of ribs comprises the fifth uppermost rib and the sixth uppermost rib. 
     
     
         16 . The method of  claim 11 , wherein locating and forming the intercostal access point comprises at least one of:
 locating the intercostal access point inferior to a pectoral muscle of the patient's body; or   locating the intercostal access point between a second uppermost rib and a sixth uppermost rib, of the patient's body.   
     
     
         17 . The method of  claim 11 , wherein positioning the sensor portion comprises:
 securing, via a fixed first anchor on the sensor lead that is proximal to the sensor portion, the sensor lead relative to a subcutaneous connective tissue that is external to the intercostal access point.   
     
     
         18 . The method of  claim 17 , wherein securing the sensor lead comprises:
 providing the first anchor as a pair of arms that extend generally perpendicular to, and outwardly from, opposite sides of a body of the sensor lead;   providing the sensor portion as a directional sensing element including a single side of the sensor portion configured to sense the respiratory pressure; and   orienting the arms, in their secured position relative to the subcutaneous connective tissue, in a direction generally perpendicular to the ribs to maintain the sensor portion to be generally parallel to the ribs and to maintain the single side of the sensor portion to face toward the lungs of the patient's body.   
     
     
         19 . The method of  claim 17 , comprising:
 securing, via a selectively movable second anchor on the sensor lead that is proximal to the fixed first anchor, the sensor lead relative to a tissue at a lateral side portion of the patient's body; and   arranging a proximal portion of the sensor lead, proximal to the fixed first anchor, to extend along the lateral side of the patient's body for connection to an implantable pulse generator.   
     
     
         20 . The method of  claim 17 , wherein the fixed first anchor is spaced apart from the sensor portion about 3 to 9 centimeters along a length of the sensor lead. 
     
     
         21 . The method of  claim 1 , wherein positioning the sensor portion comprises:
 arranging the implanted location to correspond to an intrapleural position in which the sensor portion is directly coupled relative to the respiratory pressures of the pleural space.   
     
     
         22 . The method of  claim 21 , wherein positioning the sensor portion comprises:
 locating and forming the intercostal access point between a pair of immediately adjacent ribs on a patient's body; and   inserting and advancing a distal portion of the sensor lead, including the sensor portion, through the intercostal access point to insert the sensor portion into the intrapleural position in which the sensor portion is positioned and maintained between the parietal pleura and the pulmonary pleura.   
     
     
         23 . The method of  claim 22 , wherein positioning the sensor portion comprises:
 securing, via a fixed first anchor on the sensor lead that is proximal to the sensor portion, the sensor lead relative to a subcutaneous connective tissue that is external to the intercostal access point.   
     
     
         24 . The method of  claim 23 , wherein positioning the sensor portion comprises:
 maintaining in the implanted location, via the first anchor, an active side of the sensor portion in an orientation that faces toward the lungs.   
     
     
         25 . The method of  claim 24 , wherein inserting and advancing the distal portion of the sensor lead comprises:
 arranging portions of the sensor lead proximal to the sensor portion to extend generally perpendicular to a longitudinal axis of the ribs.   
     
     
         26 . An implantable respiratory sensor system comprising:
 a sensor lead including a lead body and a sensor portion, the sensor portion extending from the lead body and including at least a pressure transducer;   a first anchor located at a fixed position on the lead body.   
     
     
         27 . The sensor system of  claim 26 , comprising:
 a second anchor located on the lead body proximal to the first anchor and being selectively movable along a length of the lead body.   
     
     
         28 . The sensor system of  claim 26 , wherein the sensor portion defines a directional sensing element configured to sense respiratory pressures on a single side of a sensor portion, and wherein the first anchor is configured to maintain the single side in an orientation facing toward the lungs. 
     
     
         29 . The sensor system of  claim 28 , wherein the first anchor includes a pair of resilient wings that extend outwardly from opposite sides of, and generally perpendicular to, the sensor lead, each wing having an outer tip and a base wider than the outer tip, and each wing omitting a suture hole. 
     
     
         30 . The sensor system of  claim 29 , wherein the first anchor is located at the sensor portion adjacent a distal end of the sensor lead. 
     
     
         31 . The sensor system of  claim 26 , wherein the first anchor is proximal to and spaced apart from the sensor, the first anchor including a pair of arms that extend outwardly from opposite sides of the lead body and generally parallel to the lead body, wherein each arm includes a suture hole. 
     
     
         32 . The sensor system of  claim 26 , wherein the fixed first anchor is spaced apart from the sensor about 3 to 9 centimeters along a length of the sensor lead. 
     
     
         33 . The sensor system of  claim 26 , wherein the sensor system includes:
 an implantable pulse generator electrically coupled to the sensor portion and configured to monitor the sensed pressure and to identify a substantial change in a cyclical amplitude of the sensed pressure.   
     
     
         34 . The sensor system of  claim 33 , wherein the implantable pulse generator is configured to perform, based on the identified substantial change in the cyclical amplitude of the sensed pressure, at least one of:
 detection of a respiratory dysfunction; and   synchronizing delivery of an electrical stimulation therapy, applied via the implantable pulse generator and a stimulation lead, to treat the detected respiratory dysfunction.   
     
     
         35 . The sensor system of  claim 34 , wherein the respiratory dysfunction comprises an obstructive sleep apnea event. 
     
     
         36 . The sensor system of  claim 34 , wherein the sensor portion comprises a temperature transducer in addition to the pressure transducer, wherein signals of each of the respective pressure and temperature transducers are electrically independent from one another. 
     
     
         37 . The sensor system of  claim 36 , wherein at least one of the pressure transducer and the temperature transducer comprise a piezo-electric transducer. 
     
     
         38 . The sensor system of  claim 36 , wherein the implantable pulse generator is configured to perform the synchronized delivery of the stimulation therapy based on a substantial decrease in a cyclical amplitude of the sensed temperature that occurs generally at the same time as the substantial change in the cyclical amplitude of the sensed pressure when the substantial change comprises a substantial increase. 
     
     
         39 . The sensor system of  claim 38 , wherein the implantable pulse generator is configured to withhold delivery of the stimulation therapy upon a combination of an absence of the substantial decrease of a cyclical amplitude of the sensed temperature and the substantial increase in the cyclical amplitude of the sensed pressure. 
     
     
         40 . An implantable respiratory sensor system comprising:
 a sensor lead including a lead body and a directional sensor portion, the directional sensor portion extending from the lead body and including a housing that contains at least:   a pressure transducer located on a single side of the housing to define a directionality of the sensor portion; and   a temperature transducer that is electrically independent of the pressure transducer;   a first anchor located at a fixed position on the lead body that is spaced proximally from the sensor portion by a distance of about 3 to 9 centimeters, the first anchor configured with a pair of elements extending generally outward from opposite sides of the lead body to maintain the single side in an orientation facing toward the lungs;   a second anchor located on the lead body proximal to the first anchor and being selectively movable along a length of the lead body.   
     
     
         41 . The sensor system of  claim 40 , wherein the elements of the first anchor include a pair of resilient wings that extend outwardly from opposite sides of, and generally perpendicular to, the sensor lead, each wing having an outer tip and a base wider than the outer tip, and each wing omitting a suture hole. 
     
     
         42 . The sensor system of  claim 41 , wherein the first anchor is located at the sensor portion adjacent a distal end of the sensor lead. 
     
     
         43 . The sensor system of  claim 26 , wherein the elements of the first anchor include a pair of arms that extend outwardly from opposite sides of the lead body and generally parallel to the lead body, wherein each arm includes a suture hole.