Ventilation/perfusion ratio

In respiratory physiology, the ventilation/perfusion ratio (or V/Q ratio) is a measurement used to assess the efficiency and adequacy of the matching of two variables:

VQ Ratio can therefore be defined as: the ratio of the amount of air reaching the alveoli to the amount of blood reaching the alveoli. These two variables, V & Q, constitute the main determinants of the blood oxygen (O2) and carbon dioxide (CO2) concentration.