How is Minute Volume defined?

• A. Tidal volume divided by respiratory rate
• B. Tidal volume x respiratory rate
• C. Tidal volume plus respiratory rate
• D. Respiratory rate minus tidal volume

Answer: (B)

Minute volume is the total amount of air moved in or out of the lungs each minute. It is found by multiplying the air moved per breath (tidal volume) by the number of breaths taken per minute (respiratory rate). This gives a volume per minute, typically in milliliters or liters per minute. For example, tidal volume 500 mL multiplied by a respiratory rate of 12 breaths per minute equals 6000 mL per minute (about 6 L/min). The other options don’t yield a per-minute volume: dividing tidal volume by rate would not produce a meaningful ventilation value, and adding or subtracting tidal volume and rate mixes units (volume with a rate).