Ventilatory muscle strength and ultrasound evaluation of diaphragm in healthy subjects

Background: Ultrasound (US) is a simple and reproducible method of assessing diaphragmatic mobility and thickness. However, the correlation between US measurements, muscle strength, FVC and FEV1 are not fully established even in healthies. Aims: To describe the right diaphragmatic mobility, thickness and thickness fraction evaluated by US; To investigate the correlation of these US parameters with ventilatory muscle strength and spirometry. Methods: In a cross-sectional study, 28 healthy volunteers performed spirometry and right hemidiaphragmatic measurements by US during quiet breathing (QB) and deep breathing (DB). Esophageal (Pes), gastric (Pga) and transdiaphragmatic pressure (Pdi) were measured with a balloon catheter. MIP, MEP and SNIP were measured. Results: QB, DB mobility and FRC thickness had no correlation with spirometric parameters and poor correlation with ventilatory muscle strength. TLC thickness and Thickness fraction (%) were correlated with spirometry and strength - Table 1: Conclusions: In healthy subjects, TLC thickness and thickness fraction of diaphragm are better correlated with spirometric parameters and ventilatory muscle strength than diaphragmatic mobility.