Diaphragm thickening assessed by ultrasonography is lower than healthy adults in patients with chronic obstructive pulmonary disease.

Our results indicate significant differences in TdiTLC and ΔTdi% between patients with COPD and healthy adults. Therefore, diaphragm ultrasonography can assess diaphragm dysfunction associated with COPD. We suggest that it is better to use TdiTLC and ΔTdi% (not only Tdi at rest) to assess diaphragm function.