The Relationship Between Pulmonary Function Measures and Transdiaphragmatic Measures in Duchenne Muscular Dystrophy Subjects

Two small balloons, which are attached to small, flexible tubes, will be put into the esophagus and stomach through your nose. Each balloon is about 2 inches long (deflated) and about the width of a pencil tip. To reduce any discomfort with this procedure, lidocaine gel or spray will be put into the subject's nose and administered to the back of the throat before the balloon. In addition, swallowing water during the procedure will help to reduce any gagging sensation and will assure that the balloon goes into the esophagus. Proper placement of the catheters will be determined using normal tidal breathing against an occluded mouthpiece with a nose clip. Once proper placement is ensured, the catheters will remain in place during your normal PFT maneuvers. Additionally, while the gastric and esophageal balloon catheters are in place, the subject will be asked to perform a maximal sniff maneuver (SNIP) while one nostril is occluded with a plug containing a distal pressure measurement catheter to measure airway pressure. The distal end of the pressure catheter will be connected to a hand held pressure meter to display peak pressure and to provide you visual feedback. This maneuver will be performed 10 times.