Q; Size of ET Tube (Endotracheal Tube) represents what? (choose one)

A) Internal diameter of ETT

B) External diameter of ETT

Answer: Internal diameter of ETT

The “size” of an ET tube refers to its internal diameter. Therefore a “size 7 ” ET tube, means one with an internal diameter of 7 mm. ET tubes are usually labeled as ID (internal diameter) and OD (outside diameter).