Intrathoracic gas volumes

The term "intrathoracic gas volume" refers to the (residual) volume of gas, measured in litres, in the chest cavity that remains in the lungs after exhalation. The intrathoracic gas volume increases with age, body weight and height and is generally expressed as a percentage of the target value. An increase in the IGV occurs, for example, in pulmonary emphysema, where there is permanent over-inflation of the chest cavity. Furthermore, increased values are often found in obstructive ventilation disorders.