Prediction of cough effectiveness in amyotrophic lateral sclerosis (ALS) patients assessed by ultrasonography of the diaphragm during the cough expiration phase

Background: We hypothesized that the assessment of diaphragmatic excursion during the expiratory phase of cough is able to predict Cough Peak Flow (CPF) in Amyotrophic Lateral Sclerosis (ALS) patients. Cough effectiveness, assessed by measuring Cough Peak Flow (CPF), is clinically important, especially for patients with Neuromuscular Diseases (NMDs) and before extubation of mechanically ventilated patients. Methods: 25 healthy subjects and 22 patients with ALS were enrolled. The upward displacement of the diaphragm was measured with ultrasonography during voluntary cough expiration and CPF was simultaneously measured. The correlation between CPF and diaphragmatic expiratory excursion was assessed using Pearson9s correlation coefficient. Results: The expiratory excursion was smaller among ALS patients than healthy subjects (3.8 cm ±1.4 cm vs. 5.5 cm ±1.2 cm; p<0.001). Significant correlations between CPF and expiratory excursion were found both in healthy subjects (r=0.76; p<0.001) and in ALS patients (r=0.86; p<0.001). Figure 1 Conclusions: Ultrasonographic evaluation of the diaphragm excursion during the expiratory phase of cough seems to be a valid alternative to CPF in evaluating the efficacy of cough. Clinical Implications: Ultrasound is widely available, non-invasive and is especially useful for patients who are unable to perform conventional tests.