High flow nasal cannula oxygen has been proposed to perform preoxygenation in patients with acute respiratory failure requiring orotracheal intubation in intensive care units. However, its use for preoxygenation before the induction of general anaesthesia in operating room has never been evaluated in term of end tidal oxygen fraction which is the gold standard measurement during preoxygenation before general anaesthesia.

The goal of the present study is to measure end tidal oxygen after 3 min of preoxygenation using the recommended method (spontaneous breathing of 100% inhaled oxygen through a face mask) and using high flow nasal canula oxygen, in healthy volunteers.

High flow nasal cannula oxygen has been proposed to perform preoxygenation in patients with acute respiratory failure requiring orotracheal intubation in intensive care units. The results suggest that high flow oxygen could be superior to bag reservoir face mask in term of occurrence of severe hypoxemia during the intubation procedure.

At the present time its use for preoxygenation before the induction of general anaesthesia in operating room has never been evaluated in term of end tidal oxygen fraction which is the gold standard measurement ensuring that the functional residual capacity has been filled with oxygen.

We planned a randomised cross over study in healthy volunteers studying efficacy and tolerance of preoxygenation using spontaneous ventilation with 100% inhaled oxygen through a face mask connected to the anaesthesia machine and preoxygenation using high flow nasal cannula oxygen (60l/min).

Inclusion Criteria:

• healthy volunteers,
• signed contentment

Exclusion Criteria:

• any chronic or acute disease,
• pregnancy