Ultrasound as Diagnostic Tool in Diaphragm Dysfunction

Study Overview
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Brief Summary
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The diaphragm is the main muscle for inspiration and vital for ventilation. Multiple diagnostic modalities can be performed in the work-up of suspected diaphragm dysfunction. Fluoroscopy has traditionally been the method of choice in diagnosing diaphragm paralysis and is still widely used in clinical practice, while alternative non-invasive and accessible methods have been available. Superiority of ultrasound over fluoroscopy for the diagnosis of diaphragm dysfunction has been suggested. The primary objective of this study is to investigate the construct validity of ultrasound in diaphragm paralysis.

Detailed Description
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To study the sensitivity of ultrasound in diaphragm dysfunction we propose a prospective, operator-blinded, two-center, observational study. Participants will be evaluated for diaphragm dysfunction with fluoroscopy and pulmonary function testing as in standard of care. Additionally, ultrasound will be performed. Construct validity The primary objective of this study is to investigate the construct validity of ultrasound in diaphragm paralysis. Validity is defined as the degree to which an instrument truly measure the construct(s) it purports to measure. In general, three different types of validity can be distinguished: content validity, criterion validity, and construct validity. Since evaluation with gold standard testing is invasive, as explained in the introduction, criterion validity testing not a feasible option. Therefore, in this study, we use construct validity to provide evidence of validity. Construct validity is defined as the degree to which the scores of an instrument (here: ultrasound) are consistent with scores of other instruments (here: pulmonary function tests, fluoroscopy). Construct validation is often considered less powerful, however, with strong theories and specific and challenging hypothesis, it is possible to acquire substantial evidence. Therefore, specific definitions of 'diaphragm paresis' and 'diaphragm paralysis' regarding diagnostic modalities are established in this protocol before the start of the study

Official Title
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Ultrasound as Diagnostic Tool in Diaphragm Dysfunction: a Prospective Observational Study.

Conditions
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Diaphragm Disease

Intervention / Treatment
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* Diagnostic Test: ultrasound of the diaphragm


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 18 years or older Suspicion of diaphragm dysfunction based on medical history and/or physical examination; as determined by the treating physician. Exclusion Criteria: Inability for fluoroscopy (e.g. severely limited mobility, or unable to follow vocal instructions). Inability for diaphragm imaging (e.g. mechanical ventilation, or unable to follow vocal instructions). Those not able or unwilling to give written informed consent. Pregnant women

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Patients suspected of diaphragm dysfunction<br>After inclusion, participants will be evaluated for diaphragm dysfunction with fluoroscopy, as in standard of care. Additionally, during the same hospital visit ultrasound will be performed. The sonographer and the radiologist assessing the ultrasound and fluoroscopy, respectively, will be blinded to each other's' test results. Further assessment, and possible treatment, for diaphragm dysfunction is performed at the discretion of the treating physician. The primary outcome is the concordance of diaphragm paralysis as determined by ultrasound compared with the construct for diaphragm paralysis based on traditional measurements. | Diagnostic Test: ultrasound of the diaphragm<br>* Parameters measured during ultrasound: Thickening fraction; End-expiratory thickness, and; Diaphragm excursion.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Concordance of diaphragm paralysis as determined by ultrasound compared with the construct for diaphragm paralysis based on traditional measurements | Parameters: Paralysis (ultrasound): Qualitative (visual): Paradoxal movement OR Quantitative: Diaphragm Excursion(DE) < 0cm (negative). Paralysis (reference): (Physical examination suggestive of diaphragm dysfunction (i.e. paradoxal abdominal movement) OR Decrease in vital capacity of >15% when suspine) AND Paradoxal movement during fluoroscopy. | From referall till completion of diagnostic tests. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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diaphragm dysfunction, ultrasound, fluoroscopy