Evaluation of Diaphragmatic Ultrasound in Respiratory Functional Assessment in Patients with ALS

Background: Diaphragmatic ultrasound could be useful for the non-invasive evaluation of diaphragm functionality in Amyotrophic Lateral Sclerosis (ALS). Our study objective is to evaluate the diaphragmatic ultrasound characteristics of ALS patients and compare them with respiratory function test measurements and if there is any relationship with need for non-invasive ventilation (NIV). Methods: A prospective, descriptive, multicenter study including patients with recent diagnosis of ALS in 5 centers. Underwent diaphragmatic ultrasound and lung function at each visit every 3 months. Variables: age, sex, withdrawal from the study due to NIV or death, excursion, velocity, thickness, thickening fraction and spirometry and respiratory muscles function values. Results: 39 patients were included. 24 (61.5%) patients left the study before the year: 17 due to the onset of NIV, 4 due to clinical worsening without NIV, and 3 due to death. Statistically significant correlation was obtained between excursion and velocity and FVC and supine FVC (p<0.001) and with MIP and the snip test (p<0.05). Correlation between worse values in excursion and lung function (FVC, supine FVC and MEP) at the baseline visit and withdrawal from the study was observed (p<0.001). Conclusions: Assessing diaphragmatic excursion by ultrasonography can be a useful for monitoring ALS patients.