AHI stands for what in sleep study metrics?

• A. Apnea Severity Index
• B. Apnea Hypopnea Index
• C. Apnea Hypoxic Index
• D. Arterial Hypopnea Index

Answer: (B)

The main idea is to know what AHI represents in sleep studies. AHI stands for Apnea-Hypopnea Index, the rate of breathing disruption events per hour of sleep. It combines two types of events: apneas, which are complete cessations of airflow for at least 10 seconds, and hypopneas, which are partial reductions in airflow accompanied by a drop in oxygen or an arousal. To get the AHI, you add up all apneas and hypopneas and divide by the total sleep time in hours, giving a value in events per hour. This index is used to categorize sleep apnea severity: typically mild, moderate, or severe based on the per-hour rate. The other terms aren’t standard metrics: focusing only on apneas would miss the hypopneas, a hypoxic-only index would emphasize desaturation rather than total event count, and Arterial Hypopnea Index isn’t a recognized sleep metric.