* indication of immediate tracheal intubation * significant acute progressive circulatory insufficiency * impaired alertness, confusion, restlessness * body mass index\> 40 kg / m2 * chest trauma or other contraindication to prone position * pneumothorax * vulnerable person: safeguard of justice * pregnant or lactating woman

* indication of immediate tracheal intubation * significant acute progressive circulatory insufficiency * impaired alertness, confusion, restlessness * body mass index\> 40 kg / m2 * chest trauma or other contraindication to prone position * pneumothorax * vulnerable person: safeguard of justice * pregnant or lactating woman

- indication of immediate tracheal intubation - significant acute progressive circulatory insufficiency - impaired alertness, confusion, restlessness - body mass index> 40 kg / m2 - chest trauma or other contraindication to prone position - pneumothorax - vulnerable person: safeguard of justice - pregnant or lactating woman

- indication of immediate tracheal intubation - significant acute progressive circulatory insufficiency - impaired alertness, confusion, restlessness - body mass index> 40 kg / m2 - chest trauma or other contraindication to prone position - pneumothorax - vulnerable person: safeguard of justice - pregnant or lactating woman