Distribution of regional ventilation during restricted chest wall movement determined by EIT

Abstract

Increased chest wall rigidity reduces the compliance of the whole respiratory system and affects the regional lung function. The objective of this study was to evaluate the distribution of regional lung ventilation during thoracic cage restrictions using electrical impedance tomography (EIT). The measurements were performed on ten healthy volunteers in the sitting, left and right lateral body positions. The chest compliance was restricted by external corsets. During unrestricted spontaneous breathing, the respired air was predominantly distributed to the dependent regions of the lungs in all postures. Thoracic restriction changed the topographical distribution of ventilation in both the left and right lateral postures because of a reduction of ventilation in the dependent lung regions. No significant changes were found in the non-dependent areas. In the right lateral position, the corresponding fractional ventilation of the dependent lung regions changed from 69.3 ± 15.4% to 57.2 ± 9.8% during breathing with non-restricted and restricted chest wall movements. In the left lateral position, the fractional ventilation of the dependent lung areas was reduced from 55.3 ± 11.4% to 36.4 ± 8.4%. Ventilation of the dependent lung regions is reduced by restricted chest wall movement in spontaneously breathing subjects. © Springer-Verlag 2007.