Apnea–hypopnea index


The Apnea–Hypopnea Index or Apnoea–Hypopnoea Index is an index used to indicate the severity of sleep apnea. It is represented by the number of apnea and hypopnea events per hour of sleep. The apneas must last for at least 10 seconds and be associated with a decrease in blood oxygenation. Combining AHI and oxygen desaturation gives an overall sleep apnea severity score that evaluates both the number of sleep disruptions and the degree of oxygen desaturation.
The AHI is calculated by dividing the number of apnea events by the number of hours of sleep. The AHI values for adults are categorized as:
For children, because of their different physiology, an AHI in excess of 1 is considered abnormal. Pediatric patients presenting with AHI of 2 or greater will often be referred for treatment.