Tidal volume is the lung volume representing the normal volume of air displaced between normal inspiration and expiration when extra effort is not applied.
Typical values are around 500ml or 7ml/kg bodyweight.

Mechanical Ventilation

The volume of gas moved during the respiratory cycle in mechanical ventilation

Mechanical ventilation

In medicine, mechanical ventilation is a method to mechanically assist or replace spontaneous breathing. This may involve a machine called a ventilator or the breathing may be assisted by a physician, respiratory therapist or other suitable person compressing a bag or set of bellows...

 where control (or at least appreciation) of tidal volume is necessary to ensure adequate ventilation without causing barotrauma. Measurement can be affected (usually over-estimated) by leaks in the breathing circuit or the introduction of additional gas, for example during the introduction of nebulized

Nebulizer

In medicine, a nebulizer is a device used to administer medication in the form of a mist inhaled into the lungs....

 drugs.

Acute Respiratory Distress Syndrome

There is evidence that limiting tidal volume to below 6ml/kg may be beneficial in the management of ARDS.