Diaphragmatic thickness in chronic obstructive lung disease and relationship with clinical severity parameters

Sonographic assessment of diaphragm structure and function would be a useful clinical tool in patients with chronic obstructive pulmonary disease (COPD). Our aim was to determine the muscle thickness of the diaphragm and the usefulness of clinical practice in patients with COPD. The diaphragmatic thickness of 34 COPD patients and 34 healthy subjects was measured during tidal volume (Tmin) and deep inspiration (Tmax) on both sides using a B-mode ultrasound. The body mass index and the modified Medical Research Council (mMRC) index values were reported. There was no correlation among TminR (P = 0.134), TminL (P = 0.647), TmaxR (P = 0.721), and TmaxL (P = 0.905) between the patients with COPD and the control group. There was also no significant difference between diaphragmatic thickness and COPD severity, respiratory function (P = 0.410), and frequency of exacerbations (P = 0.881) and mMRC (P = 0.667). Diaphragmatic dysfunction in COPD is related to mobility restriction rather than muscle thickness.