Age-based formula for selecting endotracheal tube size (internal diameter in mm)
Age-based formula for selecting endotracheal tube size (internal diameter in mm)
Cuffed tube*
Uncuffed tube
3.5 + (age in years/4)
4 + (age in years/4)
These formulas estimate the predicted cuffed (low-profile, thin-walled) and uncuffed endotracheal tube size for children ≥2 years of age. Additional tubes one size larger and one size smaller than calculated should also be available during endotracheal intubation.
* For younger children, use a 3.5 mm internal diameter cuffed endotracheal tube initially for children 8 months to <2 years of age and a 3.0 mm internal diameter cuffed endotracheal tube for children <8 months of age.
Reference:
Litman RS, Fiadjoe JE, Stricker PA, Coté CJ. The pediatric airway. In: A Practice of Anesthesia for Infants and Children, 5th ed, Coté CJ, Lerman J, Anderson BJ (Eds), Elsevier Saunders 2013.