Sleep apnea severity was assessed with the apnea-hypopnea
index (AHI), which indicates severity based on the number of apneas (complete cessation of airflow) and hypopneas
(partial cessation of airflow) per hour of sleep.
Apnea was defined as a decrease in airflow amplitude to <25% of baseline lasting for at least 10 s; hypopnea
was defined as a decrease in airflow or chest wall movement amplitude to less than 60% of baseline lasting for at least 10 s, with both apneas and hypopneas
requiring an associated [greater than or equal to] 4% oxyhemoglobin desaturation.
index (AHI) is an index of severity that combines apneas and hypopneas
(slow or shallow breathing).
Apnea was defined as cessation of airflow for at least 10 seconds via mouth or nose, whereas hypopnea
was defined as at least 50% flow limitation with 3% desaturation.
Spanish researchers have studied men with obstructive sleep apnea and hypopnea
in order to study the link between this disorder an increased risk of cardiovascular disease and mortality.
OSA is characterized by repeated episodes of apnea (the cessation of breathing for at least 10 seconds) and/or hypopnea
(an airflow reduction of at least 30%), accompanied by a 4% drop in blood oxygen saturation level during sleep due to obstruction of the pharyngeal airway despite persistent respiratory efforts (Kryger, Roth, & Dement, 2000).
Alternatively, the airway may close partially, in a condition called hypopnea
, so the sleeper gets less than a full breath.
According to an earlier acute feasibility study, the device can reduce the apnea hypopnea
index by at least 50 percent.
Objective outcomes were measured on two scales: The apnea-hypopnea
index (AHI; the number of apnea or hypopnea
events per hour) and the oxygen desaturation index (ODI; the number of times per hour of sleep that the blood oxygen level drops by more than four percent).
Obstructive sleep apnea (OSA) is clinically defined by frequent episodes of apnea and hypopnea
Treatment for OSA is designed to alleviate symptoms of daytime somnolence, fatigue, irritability and ultimately reduce the incidence of apnea, hypopnea
and arousals caused by these events.
Patients were defined as having moderate to severe OSA if they had more than 20 apneas and hypopneas
per hour of sleep (their apnea-hypopnea
index was greater than 20).