What measurement examines how effectively gas is being moved and how much blood is flowing around the alveoli for gas exchange?

The measurement that examines how effectively gas is being moved and how much blood is flowing around the alveoli for gas exchange is the V/Q ratio, which stands for ventilation/perfusion ratio. This ratio is a critical concept in understanding respiratory physiology.

In the context of gas exchange in the lungs, ventilation refers to the air that reaches the alveoli, while perfusion refers to the blood that reaches the alveoli via the pulmonary circulation. A healthy V/Q ratio indicates a good match between ventilation and perfusion, allowing for optimal gas exchange—where oxygen enters the blood and carbon dioxide is expelled.

When the V/Q ratio is abnormal, it can indicate problems such as a lack of airflow to well-perfused areas of the lung (as seen in conditions like asthma or COPD), or adequate airflow to poorly perfused areas (as seen in conditions like pulmonary embolism). Thus, the V/Q ratio is essential for evaluating lung function and understanding various respiratory disorders.

Other measures listed like pulse rate, peak flow, and oxygen saturation provide important information about cardiovascular and respiratory status but do not specifically assess the efficiency of gas exchange at the alveolar level in relation to blood flow in the lungs.