什么是 Ventilation？

Pulmonary ventilation is the volume of air moved into and out of the lungs per minute: the volume of one breath (the tidal volume) multiplied by the number of breaths per minute (the respiratory rate). At rest, about $0.5\,\mathrm{L}$ twelve to fifteen times a minute: $6\text{ to }8\,\mathrm{L}/\mathrm{min}$. In the lungs the air reaches some 300 million alveoli, thin-walled sacs wrapped in capillaries, where oxygen passes into the blood and carbon dioxide out of it.