Can diaphragmatic mobility be measured by chest wall volumes?

e do Esporte – CEFID, Florianópolis, SC, Brasil Abstract Background : The evaluation of the diaphragm muscle is important in clinical practice as a way to investigate its relationship with lung volumes. This allows the knowledge of pulmonary variations via different equipment, enabling the accessibility of the ventilatory evaluation. Objective : To investigate the relationship between chest wall volumes and diaphragmatic mobility in the sitting position and dorsal decubitus at 30° of trunk inclination. Methods : 40 participants of both sexes, aged between 20 and 50 years, were submitted to measurements of volume changes in three chest wall compartments by optoelectronic plethysmography. Diaphragmatic mobility (DM) was assessed by ultrasonography. Statistical analysis: univariate analysis was performed using Spearman´s rank correlation, followed by linear regression to determine the influence of lung volume changes in each compartment on DM. Significance was set at ≤5%. Results : DM was correlated with the volume of the abdominal rib cage (Vrca) at 30° (r=0.33, p=0.03) and with abdominal volume (Vab) in both sitting position and at 30° inclination, respectively (r=0.62, p<0.001; r=0.61, p<0.001). However, in multivariate analysis, Vab contributed to 68% and 50% of DM variance while sitting and at 30º, respectively. Conclusion : Abdominal volume (Vab) can be used as an indirect measure of DM in men and women in the sitting position and at