Final answer:
Obstructive sleep apnea is a frequent airway obstruction due to altered mental status, often caused by relaxation of throat muscles or obesity, with endotracheal intubation used to maintain an open airway during anesthesia.
Step-by-step explanation:
The most common airway obstruction due to altered mental status is often associated with obstructive sleep apnea, where the airway is blocked by relaxation of the tongue and throat muscles or by excess tissue in the case of obesity. Other significant causes include airway obstruction during anesthesia, where the tongue can relax and block the airway, necessitating endotracheal intubation to maintain an open airway. Blocking of the pharynx or trachea by foreign objects, especially in young children, is also common.