It is represented by the number of apnea and hypopnea events per hour of sleep.
Apneas (pauses in breathing) must last for at least 10 seconds and be associated with a decrease in blood oxygenation to be considered.
Underage pediatric patients presenting with AHI of 2 or greater will often be referred for treatment.
[3] The Apnea-Hypopnea Index has been criticized for being too simplistic to accurately rate apnea and hypopnea events for their severity.
[4][5] In one study, mean apnea-hypopnea duration and not AHI was found to be associated with worse hypertension.