Minute Volume is calculated as which of the following?

• A. Tidal volume divided by respiratory rate.
• B. Tidal volume times respiratory rate.
• C. Alveolar volume times respiratory rate.
• D. Inspiratory reserve volume times respiratory rate.

Answer: (B)

Minute volume (minute ventilation) is the total volume of air moved in and out of the lungs per minute. To get this, you need how much air is moved with each breath (tidal volume) and how many breaths occur each minute (respiratory rate). Multiply tidal volume by respiratory rate, giving a value in mL/min or L/min. For example, a tidal volume of 500 mL per breath and a rate of 12 breaths per minute equals 6,000 mL per minute (6 L/min). The other options don’t represent the total air moved per minute: dividing tidal volume by respiratory rate isn’t the flow per minute, using alveolar volume instead of tidal volume targets a different concept (alveolar ventilation, which ignores dead space), and using inspiratory reserve volume uses extra capacity not normally engaged in quiet breathing.