Anaesthesia Airway 2a681ae1 Endotracheal tube size in a full term infant? A 2.5 mm B 3.5 mm C 4.5 mm D 5.5 mm High-Yield Explanation Age Internal Diameter (mm) Cut length (cm) Full- term infant 3.5 12 Child 4+Age/4 12+Age/2 Adult Female 7.0-7.5 24 Male 7.5-9.0 24