ABSTRACT
Sleep disordered breathing refers to a continuum of disease from snoring to frank sleep apnea. Simply defined, sleep disordered breathing refers to upper airway partial or total obstruction and the partial or complete cessation of airflow. There can be respiratory effort (obstructive) or no respiratory effort (central) associated with this airway obstruction. These events while the individual is asleep are a normal phenomenon, but when the number of events rises during the sleep period above a certain threshold, they are considered pathologic. In sleep disordered breathing that entails obstructive events, there are two types of airflow limitation. There is a hypopnea, which is defined as noncomplete cessation of airflow with either an associated arousal from sleep or a significant desaturation from baseline. Apnea is near complete cessation (>90%) of airflow, with no need for an associated desaturation. Snoring to frank apneas is a continuum of upper airway patency (Figure 21.1).
