Pulmonary ventilation - perfusion ratio
From WikiLectures
The ratio of pulmonary ventilation and perfusion is a quantity that expresses the ratio of alveolar ventilation [V A ] = l/min and capillary flow in the lungs [Q] = l/min. This ratio can be applied to the lungs as a whole, or to specific parts of the lungs. If we consider total alveolar ventilation and total pulmonary flow, we get values approximately VA/Q= 5l/min