Definitions

Respiratory minute volume

Respiratory minute volume (or minute ventilation, or flow of gas) is the volume of air which can be inhaled (inhaled minute volume) or exhaled (exhaled minute volume) from a person's lungs in one minute. This is normally registered when a person has a ventilator supporting the person's breathing due to a sickness or injury.

Minute volume is calculated by taking the tidal volume and multiplying the respiratory rate (the number of breaths per minute a person is taking). The higher the minute volume the more carbon dioxide (CO2) the person is releasing, the converse is the lower the minute volume the lower the amount of carbon dioxide the person is releasing. For example a person who is hyperventilating would have an increased minute volume.

A normal minute volume would be 5–8 liters per minute.

The symbol used to represent minute volume is $dot\left\{V\right\}$ or MV.

Relationship to other Physiological Rates

Minute volume is closely related to both alveolar ventilation and dead space ventilation. That is;

$dot\left\{V\right\} = dot\left\{V\right\}_A + dot\left\{V\right\}_D$

Where $dot\left\{V\right\}_A$ is alveolar ventilation, and $dot\left\{V\right\}_D$ represents dead space ventilation