Serial ultrasound assessment of diaphragmatic function and clinical outcome in patients with amyotrophic lateral sclerosis

Abstract

Background Diaphragmatic assessment by ultrasound (US) is a non-invasive and useful method in the clinical management of patients with Amyotrophic Lateral Sclerosis (ALS). The aim of our observational study was to evaluate the impact of serial assessment of the diaphragmatic function by US on long-term outcomes in a series of patients suffering from ALS and to correlate US indices of diaphragmatic function and respiratory function tests with these outcomes. Methods A cohort of 39 consecutive patients has been followed up to 24 months. Both lung volume (forced vital capacity, FVC) and diaphragmatic pressure generating capacity (by sniff inspiratory nasal pressure (SNIP) and by both US thickening fraction, ΔTdi, and the ratio of the thickening fraction between tidal volume and maximal lung capacity, ΔTmax) were recorded at baseline and every 3 months. Parameters were then correlated with outcomes (nocturnal hypoventilation, daily hypercapnia, start of ventilatory support (NIV), and death at 1 year) over time. Results The occurrence of ΔTmax > 0.75 increased the risk to start NIV (HR = 5.6, p = 0.001) and to die (HR = 3.7, p = 0.0001) compared with patients maintaining lower values. Moreover, compared with the occurrence of FVC < 50% of predicted, ΔTmax > 0.75 appeared slightly better correlated with NIV commencement within 6 months. Conclusions Serial diaphragmatic assessment by ultrasound is a useful and accurate method to predict the initiation of NIV earlier in patients with ALS. Electronic supplementary material The online version of this article (10.1186/s12890-019-0924-5) contains supplementary material, which is available to authorized users.

Ultrasound Assessment of Diaphragm Thickness and Thickening: Reference Values and Limits of Normality When in a Seated Position

“…Lastly, the ratio between diaphragm thickness at the end of tidal volume and the diaphragm thickness at maximal inspiration (ΔTmax) has been proposed by Fantini et al ( 16 ) to detect impairment in pulmonary function tests and as an indication for mechanical ventilation support in patients suffering from ALS. Indeed, the ΔTmax has been related to respiratory function tests ( 17 ).…”

Determinants and functional impacts of diaphragmatic involvement in patients with inclusion body myositis

“…Following this, diaphragmatic dysfunction was documented by histopathology or ultrasonography in case reports of single patients with sporadic IBM 6,7 . The usefulness of ultrasonography to help quantify diaphragm function has already been described in other neuromuscular diseases such as amyotrophic lateral sclerosis (ALS), Duchenne muscular dystrophy, and Pompe disease, 8‐11 and has been validated in the evaluation of isolated unilateral diaphragm paralysis and in the intensive care unit setting 12‐20 …”

Diaphragmatic ultrasound: a review of its methodological aspects and clinical uses

“…The authors suggested that the measurement of diaphragmatic mobility could be a reliable tool to identify impaired respiratory function (FVC < 50% of predicted) in patients with ALS or myotonic dystrophy. In a more recent study, Fantini et al 88 found that, in patients with ALS, a Tdi at V T /Tdi at TLC ratio > 0.75 (suggesting diaphragmatic weakness) increased the risk of requiring NIV (hazard ratio = 5.6; p = 0.001) and the risk of death (hazard ratio = 3.7; p = 0.0001), inferring that diaphragmatic ultrasound is an accurate method of predicting the need for NIV in ALS.…”

“…Maximal excursion correlated with FVC 87 4. The Tdi at V T /Tdi at TLC ratio is indicative of weakness and may predict NIV initiation in ALS 88 5. Duchenne muscular dystrophy and myotonic dystrophy type 1: Reduced mobility during DB and VS 89 DB excursion correlated with FVC values 89 Diaphragm thickness and excursion are reduced and correlate with lung function in ALS.…”