Endotracheal Intubation

Endotracheal intubation is performed to provide a definitive airway and to assist in breathing and ventilation.

When the tube is inserted through the mouth, it is referred to as endotracheal intubation.1 When it is inserted through the nose, it is known as nasotracheal intubation.2

There are a variety of different reasons someone may be intubated, and the method used depends on the purpose.

Endotracheal (through the mouth) intubation is used in most emergency situations. That's because the tube that gets placed through the mouth is larger and easier to insert than the one inserted through the nose.

Endotracheal intubation may be used to:1

Nasotracheal (through the nose) intubation is used to:2

  • Protect the airway if there is an impending threat of obstruction

  • Deliver anesthesia for surgeries involving the mouth, head, or neck (including dental surgery)


Endotracheal intubation is typically used in emergencies. It also supports breathing in people with severe breathing problems due to disease or trauma. Nasotracheal intubation is more commonly used to deliver anesthesia, but it can also protect the airways if there is a risk of obstruction.

Choosing Endotracheal Tube Size


    • The endotracheal tube (ETT) size formula, (age/4) + 3.5, with a cuffed tube makes more sense anatomically. Why does this matter? Classic teaching is that we should use the formula (16+age)/4 or (age/4) + 4 to calculate the uncuffed pediatric ETT size.


    • Female: average size ETT is 7.0 - 7.5

    • Male: average size ETT is 7.5 - 8.0