minuteventilation

Minute ventilation, often abbreviated VE, is the total volume of air inhaled or exhaled from the lungs per minute. It is calculated as the product of tidal volume (the amount of air moved per breath) and respiratory rate (breaths per minute): VE = VT × f. In healthy adults at rest, typical values are a tidal volume of about 0.5 liters and a respiratory rate of 12–20 breaths per minute, resulting in a minute ventilation of roughly 6–8 liters per minute.

Ventilation can be distinguished into alveolar ventilation and dead space ventilation. Alveolar ventilation refers to the portion of ventilation that reaches the gas-exchanging units, and it is given by VE_A = (VT − VD) × f, where VD is the physiologic dead space. Anatomical dead space in an adult is typically around 150 mL per breath. Increased dead space, as seen in certain lung diseases or pulmonary embolism, reduces effective alveolar ventilation even if VE remains high.

Ventilation varies with activity and physiologic state. At rest VE is relatively low; during exercise, VE increases substantially to meet higher metabolic demands, potentially reaching well over 60 L/min in intense effort, depending on fitness and efficiency of gas exchange.

Measurement and clinical relevance: VE can be estimated from spirometry measurements of VT and f, or monitored directly in clinical settings using respiratory flow sensors and ventilator readouts. Alveolar ventilation and gas exchange are of clinical interest in anesthesia, critical care, and respiratory diseases, as inadequate VE can lead to hypercapnia or hypoxemia. Regulation of minute ventilation is driven by brainstem respiratory centers, with chemoreceptors responding to CO2 and pH, as well as peripheral O2 sensors influencing ventilatory drive.