True about endotracheal intubation is:

A i.e. It reduces the normal anatomical dead space - Endotracheal tube decreases the anatomical dead space (150 ml) to as less as 25 ml. - Endotracheal intubation increases the resistance to respiration; obstruction from kinking, foreign body or secretions fuher increase resistance. Subglottic edema, though a complication, is not the most common one.