Assessment Of Diaphragmatic Function By Ultrasound In Normal Subjects

Background Although the assessment of diaphragmatic function is readily studied by ultrasonography, application remains poor popularization in China.Objective The aim of this prospective study was to determine the reference values for diaphragmatic thick and motion as recorded by ultrasonography. Statistical analysis such as correlation analysis and determination of reference value were done.Methods One hundred and fifty healthy adult subjects (75 men,75 women) were investigated. To determine the mean values of normal for thick and motion of the right hemidiaphragms, B-and M-mode ultrasound was used and examinations were performed during quiet breathing and deep breathing. Furthermore, we analyze corelations between the diaphragmatic thick/motion and demographic or anthropometric parameters. In addition, we measured maximal inspiratory mouth pressure,which could assess respiratory muscle strength, and analyzed whether they were corelated with the diaphragmatic thick/motion in order to assess diaphragmatic function.Results Complete data was successfully assessed in 138/150 adult healthy subjects (61 men and 77 women). Consequently, during quiet breathing and deep breathing, the diaphragmatic thick and motions were 0.19±0.04cm and 1.4 ± 0.4cm, respectively. And the thickening fraction was 1.71 ± 0.58 and forced diaphragmatic motions were 5.1 ± 1.2cm, respectively. Since the motions were larger in men than in women, the gender should be taken into account. In addition, there were significant correlations between diaphragmatic thick or motions and demographic or anthropometric parameters. Interestingly, certain negative correlation between diaphragmatic motions and age is obtained(r=-0.243, P<0.05). Finally, the diaphragmatic thick and motions was significant correlated with respiratory muscle strength (r=0.484,r=0.489; P<0.05), suggesting that the diaphragmatic morphology could reflect diaphragm contractile force to some extent.Conclusions We obtained the reference values for diaphragmatic thick and motion as recorded by ultrasonography. Sex, height, weight may affect the diaphragmatic thick and motion to some extent. Moreover, age may affect diaphragmatic motion. And the diaphragmatic morphology could reflect diaphragm contractile force. It is valuable for application of ultrasonography to assessment of diaphragmatic function.