Hypopnea

Hypopnea (or hypopnoea in British English) is a medical term for a disorder which involves episodes of overly shallow breathing or an abnormally low respiratory rate. Hypopnea is considered by some to be less severe than apnea (which is the complete obstruction of the airway), while other researchers have discovered hypopnea to have a "similar if not indistinguishable impact" on the negative outcomes of sleep breathing disorders. In sleep clinics, Obstructive Sleep Apnea Syndrome is normally diagnosed based on the frequent presence of apneas and/or hypopneas rather than differentiating between the two phenomena. Hypopnea is typically defined by a decreased amount of air movement into the lungs and can cause oxygen levels in the blood to drop. It commonly is due to partial obstruction of the upper airway.