minutventilation

Minute ventilation, sometimes misspelled as minutventilation, is the volume of air inhaled or exhaled per unit time. It is calculated as the product of tidal volume (the amount of air moved per breath) and respiratory rate (breaths per minute): minute ventilation = tidal volume × respiratory rate. This measure reflects the overall air exchange performed by the lungs in a given moment.

In a healthy adult at rest, tidal volume is about 0.5 liters and the respiratory rate is around 12 to 20 breaths per minute, giving a typical minute ventilation of about 6 to 8 liters per minute. Minute ventilation does not equal alveolar ventilation, which accounts for the dead space in the airways where gas exchange does not occur. Alveolar ventilation can be approximated as (tidal volume minus dead space) times the respiratory rate and is usually lower than total minute ventilation, particularly when dead space is increased.

Measurement of minute ventilation can be done directly at the mouth or nose with spirometry or inferred from readings on ventilators and capnography. Clinically, minute ventilation is used to assess respiratory status in anesthesia, critical care, and respiratory therapy. It can indicate hypoventilation or hyperventilation and informs adjustments to ventilatory support, especially in patients with airway, neuromuscular, or metabolic conditions.

Factors influencing minute ventilation include metabolic demand, body size, age, sleep state, physical activity, pain, and medications. Diseases affecting airway resistance, lung compliance, or respiratory drive—such as COPD, obesity, neuromuscular disorders, or central nervous system depressants—can alter minute ventilation significantly.