Relationship Between PFTs and Pdi in DMD

Study Overview
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Brief Summary
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A cross-sectional study to explore the relationship between clinically assessed pulmonary function test (PFT) measures and transdiaphragmatic (Pdi) measures in Duchenne muscular dystrophy (DMD) as well as to explore the relationship between sniff nasal inspiratory pressure (SNIP) and transdiaphragmatic (Pdi) measures in Duchenne muscular dystrophy.

Detailed Description
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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.

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

Conditions
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Duchenne Muscular Dystrophy

Intervention / Treatment
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* Diagnostic Test: Esophageal Balloon
* Diagnostic Test: Gastric Balloon
* Diagnostic Test: Nasal Pressure Transducer


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Clinical diagnosis of Duchenne muscular dystrophy Exclusion Criteria: Inability to follow verbal instructions

Ages Eligible for Study
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Minimum Age: 6 Years
Maximum Age: 25 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Health Services Research
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Cross-sectional
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Measurement of Pdi<br>Two small balloons, which are attached to small, flexible tubes, will be put into the esophagus (food tube) and stomach through the nose. Each balloon is about 2 inches long (deflated) and about the width of a pencil tip. A gastric balloon will be inserted into subject's stomach while an esophageal balloon will be inserted into the subject's esophagus. 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. | Diagnostic Test: Esophageal Balloon<br>* Small flexible catheter with deflated balloon at distal end to be inserted into the esophagus through the nose<br>Diagnostic Test: Gastric Balloon<br>* Small flexible catheter with deflated balloon at distal end to be inserted into the stomach through the nose<br>|
| Experimental: Measurement of SNIPs<br>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 nasal pressure transducer to measure airway pressure during maximal inspiration. 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. | Diagnostic Test: Nasal Pressure Transducer<br>* Pressure transducer inserted into nasal plug<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Evaluation of Pdi | For all subjects Pdi (transdiaphragmatic pressure measures) will be assessed with gastric and esophageal balloons | 1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Evaluation of SNIP | For all subjects, SNIP (sniff nasal inspiratory pressures) will be assessed with a nasal pressure transducer | 1 year | 
| Evaluation of FVC | For all subjects, FVC (forced vital capacity) will be assessed with spirometry | 1 year | 
| Evaluation of FEV1 | For all subjects, FEV1 (forced expiratory volume in 1 second) will be assessed with spirometry | 1 year | 
| Evaluation of FEFmax | For all subjects, FEFmax (maximal forced expiratory flow) will be assessed with spirometry | 1 year | 
| Evaluation of FEF25-75 | For all subjects, FEF25-75 (the average forced expiratory flow during the mid (25 - 75%) portion of the FVC) will be assessed with spirometry | 1 year | 
| Evaluation of FEF50 | For all subjects, FEF50 (forced expiratory flow at 50% of FVC) will be assessed with spirometry | 1 year | 
| Evaluation of MIP | For all subjects, MIP (maximal inspiratory pressure) will be assessed with spirometry | 1 year | 
| Evaluation of MEP | For all subjects, MEP (maximal expiratory pressure) will be assessed with spirometry | 1 year |