Pre-oxygenation before induction: the core idea

This page is demonstration content, prepared to show the clinical-notes format. Before publication it must be checked against standard texts and reviewed by a qualified anaesthetist.

The idea in one sentence

Pre-oxygenation replaces the nitrogen in the patient's functional residual capacity with oxygen, creating an oxygen reservoir that buys time between induction and a secured airway.

Practical points commonly examined

• Adequate pre-oxygenation is usually defined by an end-tidal oxygen fraction above a threshold rather than by time alone.
• Positioning, a well-fitted mask and a tight seal matter more than flow rate.
• Special situations, including pregnancy and obesity, reduce safe apnoea time and deserve explicit attention in viva answers.

This is a teaching scaffold, not a protocol. Local institutional guidance always governs practice.