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