Field Internship Student Data Acquisition Project. (FISDAP) Airway Practice Exam

What does the V/Q ratio measure?

1. The efficiency of heart function

2. The effectiveness of gas exchange versus blood flow

3. The level of oxygen in the blood

4. The respiratory rate of an individual

The correct answer is: The effectiveness of gas exchange versus blood flow

The V/Q ratio measures the effectiveness of gas exchange in relation to blood flow within the lungs. Specifically, it is the ratio of ventilation (V) to perfusion (Q). Ventilation refers to the air that reaches the alveoli and is available for gas exchange, while perfusion pertains to the blood flow through the pulmonary capillaries surrounding the alveoli. An optimal V/Q ratio indicates that there is a balance between the amount of air reaching the alveoli and the amount of blood flow in the surrounding capillaries, facilitating effective oxygen uptake and carbon dioxide removal. If this ratio is not balanced, either due to inadequate ventilation or insufficient blood flow, it can lead to conditions such as hypoxemia (low oxygen levels in the blood) or atelectasis (collapse of alveoli), which can compromise respiratory function and overall oxygen delivery to the tissues. In contrast, the other options relate to different physiological concepts: heart function, oxygen levels in the blood, and respiratory rate, none of which specifically measure the balance between ventilation and perfusion in the lungs. Thus, the V/Q ratio is a crucial metric in assessing pulmonary function and identifying potential respiratory issues.