Diaphragm ultrasound in the diagnosis of respiratory dysfunction in patients with amyotrophic lateral sclerosis

In this study, we aimed to select the best diaphragm ultrasonography (DUS) parameter as an alternative index for the diagnosis of lung function impairment in amyotrophic lateral sclerosis (ALS).

Twenty-nine patients with ALS and 15 healthy subjects were enrolled in the study. DUS, lung function tests, phrenic nerve conduction study and arterial blood gas analysis were performed.

Patients with respiratory dysfunction had a significantly lower level of ΔTmax than those without (P=0.039). Significant correlations (P<0.05) were found between forced vital capacity (FVC) and Tdi-ins (r=0.665, P<0.0001) and ΔTmax (r=-0.748, P<0.0001) and Δins-exp (r=0.627, P<0.0001) and ΔTdi (r=0.485, P<0.0001). Receiver Operating Curves analysis demonstrated that ΔTmax (AUC=0.76, P=0.044) had a better overall accuracy for detection of respiratory dysfunction compared with Tdi-ins (AUC=0.27, P=0.067), Δins-exp (AUC=0.312, P=0.139), and ΔTdi (AUC=0.38, P=0.359).

ΔTmax is the most valuable DUS index in the diagnosis of diaphragmatic dysfunction.

DUS can provide functional and structural information of diaphragm and help to diagnose diaphragmatic dysfunction in ALS.