Sleep Apnea Information
Sleep apnea is a disorder where there is a reduction or pause in breathing while sleeping. Sleep apnea is common among adults and not children. The sleep disorder may be suspected based upon a person’s medical history and confirmed by testing. Treatment of sleep apnea may be surgical or non-surgical.
The technical definition of an apnea is when a person stops breathing completely or takes less than 25% of a normal breath for 10 seconds or more. Apnea may also be defined by at least a 4% drop in oxygen in the blood.
Apneas generally happen while a person is sleeping. The sleep is interrupted because of poor blood oxygen levels and inadequate breathing. The person may wake completely, but sometimes he comes out of a deep sleep into a more shallow state of sleep. Apneas are measured during sleep over a two hour period. The severity of apnea is estimated by dividing the number of apneas by the number of hours of sleep, providing an apnea index (AI). The greater the AI, the more severe the apnea.
Hypopneas are decreases in breathing that are not as severe as apneas. Hypopnea also occurs during sleep and is defined as 69% to 26% of a normal breath. Hypopneas are also defined as a 4% of greater drop in oxygen in the blood. Hypopneas often disrupt the level of sleep, similar to apneas. There is also a hypopnea index (HI) calculated by the number of hypopneas divided by the number of hours of sleep.
Sleep apnea is formally diagnosed if there is an apnea-hypopnea index of at least 15 occurrences per hour, or an episode once every four minutes, if no sleep apnea related problems are present in the patient. These medical problems include high blood pressure, stroke, daytime sleepiness, congestive heart failure, insomnia and mood disorders. If these medical issues are present, sleep apnea is diagnosed at five occurrences per hour.