Transthoracic ultrasonography as an alternative to respiratory pressures in assessing respiratory muscles strength in patients with neuromuscular disorders

Background Respiratory complications are the chief causes of morbidity plus mortality in patients with neuromuscular diseases (NMD). The diaphragm acts as the main inspiratory muscle during regular breathing, and its weakness predisposes to respiratory failure. Aim The aim was to explore the role of transthoracic diaphragmatic ultrasonography compared with respiratory pressures measured by spirometer in assessing respiratory muscle strength in patients with NMD. Patients and methods A prospective observational cross-sectional study was conducted in Chest Department, Mansoura University Hospital. Patients with NMD (n=50) who were spontaneously breathing and could understand and cooperate with the sonographic maneuvers, maximal inspiratory pressure, and maximal expiratory pressure (Pi Max and Pe Max) were recruited. They were classified into group I (n=35), which included myopathic patients with NMD owing to muscle disease or neuromuscular junction diseases. Group II (n=15) involved nonmyopathic patients with NMD not owing to muscle or neuromuscular junction diseases. Results In forced breathing, functional assessment of sonographic diaphragmatic muscle thickness and excursion agreed with Pi Max in ascertaining weakness in 28% and 64%, respectively (kappa=0.61 and 0.913), whereas agreed with Pe Max in 34 and 74%, respectively (kappa=0.48 and 0.74). The agreement was less during quiet breathing. Conclusion Sonographic evaluation of diaphragmatic muscle could be a prospective applicable substitute for the assessment of respiratory muscle affection in neuromuscular disabled patients, taking into consideration its feasibility and cheapness, but with obtained cleverness.