Vital capacity breath induction requires:

• Patient co-operation
• A tight sealing face mask (to ensure no atmospheric air is inhaled)
• Preferably, a large (3 L) bag on the anaesthetic breathing system

The bag is primed with a high concentration of volatile agent (e.g. 8 % sevoflurane) in oxygen. The patient first empties their lungs down to residual volume and then takes in a vital capacity breath, holding it for as long as possible before resuming normal tidal volume breathing.

As patient co-operation is required, this technique can only be used in older children and adults. However, it is quicker than the tidal volume inhalational method (but not as quick as intravenous induction).