Sleep Apnea and Definition of AHI
Definition
Sleep apnea is defined as a sleep apnea that is defined as a Stop for more than 10s;
Hypopnea means that the respiratory airflow decreases by more than 50% of the normal airflow intensity during sleep, and the blood oxygen saturation decreases by ≥4% compared with the basic level.
Sleep apnea syndrome refers to repeated episodes of apnea more than 30 times during 7 hours of sleep per night, or sleep apnea/hypopnea index
AHI: the average hourly The number of apnea + hypopnea during sleep is greater than or equal to 5 times/h.
There are three types of sleep apnea syndrome:
1) Obstructive type: no airflow through the mouth and nose during sleep, but chest and abdominal breathing still exists;
2) Central type: during sleep, the airflow of the mouth and nose and the breathing movement of the chest and abdomen are suspended at the same time, and the activities of the diaphragm and intercostal muscles are stopped;
3) Mixed Type: refers to an apnea process that begins with a central type of apnea, followed by an obstructive type of apnea at the same time. According to the apnea/hypopnea index (AHI), the condition of sleep apnea syndrome is divided into three grades: mild, moderate and severe
that is, those with AHI between 5 and 20 are mild
21~40 is moderate
more than 40 is severe
The lowest SaO2 at night is 85%~90%, 80%~84%, <80%, respectively
