Residual air volume / total lung ratio

Residual air volume is the volume of air remaining in the lungs after deep listening to air. Residual air volume / total lung ratio (RV / TLC) measurement can understand the status of lung ventilation. Increases are seen in emphysema and small airways are overclosing. Residual air volume and total lung volume increased significantly, suggesting chronic obstructive ventilation disorders, such as emphysema and pulmonary heart disease.