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.
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
Study Type
OBSERVATIONAL
Enrollment
36
Parameters measured during ultrasound: Thickening fraction; End-expiratory thickness, and; Diaphragm excursion.
Isala Klinieken
Zwolle, Overijssel, Netherlands
UCMG
Groningen, Netherlands
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.
Time frame: From referall till completion of diagnostic tests.
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