Sleep apnea means the absence of breathing while sleeping. It also refers to periods when a patient’s breathing becomes partially decreased or partially obstructed and is associated with a decrease in oxygen levels, arousal from stage of sleep as well as possibly elevated carbon dioxide levels.
Patients can be classified as having various forms of sleep apnea
Obstructive Apnea
This refers to a situation where patient is attempting to breathe but the airway is completely obstructed either as a result of significantly enlarged tonsils blocking the airway, a very pliant and collapsible upper airway or a relatively large tongue or small jaw causing obstruction in the upper airway. In children under the duration is 2 cycles of breathing.
Obstructive Hypopnea
This refers to a situation where the patient has a greater than 30% decrease in air flow associated with an ongoing effort to breathe. In this situation, the patient typically has a greater than 3% decline in the oxygen saturation levels as well as arousals from sleep.
Central Apnea
This refers to a situation where a patient has the absence of effort to breathe and typically results from the lack of signal from the brain stimulating the patient to breathe. In children the duration is greater than 2 cycles of breathing associated with a greater than 3% decrease in oxygen levels. If desaturations are not present then the duration is 20 seconds.
Mixed Apnea
This is a combination of both obstructive as well as central apnea. This occurs in a situation where both patterns run continuously into each other.
In children, the goal standard for diagnosis and obstructive sleep apnea or other forms of sleep apnea is an attended overnight sleep polysomnogram (Sleep study)