**6.3 Intra-operative assessment and impact of anesthesia on OSA patients**

During anesthesia; alteration of muscle activity results in upper airway collapse more at the level of retro-lingual. Such obstructive events require active intervention to arouse spontaneously, which is an important defense mechanism that occurs during natural sleep to overcome airway obstruction.

The administration of anesthetic agents exacerbates the upper airway collapse, alter the tone of the pharyngeal musculature, result in delay of the restoration of airway patency, therefore, in general the tendency for airway obstruction occurs out of proportion to the level of achieved sedation [22].
