Apnoea/hypopnea index (AHI)

 

Number of events per hour, calculated as:

 

Apnoeas (no airflow for 10 seconds or longer)
+
Hypopneas (shallow breathing where airflow reduced by at least 50% - lasting 10 seconds or longer)

 

A diagnosis of Obstructive Sleep Apnoea is based on:

  • AHI 5-15 - Mild Sleep Apnoea
  • AHI 15-30 - Moderate Sleep Apnoea
  • AHI >30 - Severe Sleep Apnoea