Apnea-Hypopnea Index Calculator
Enter the number of apnea and hypopnea events observed during a sleep study plus the total hours of sleep to determine OSA severity.
How to Use This Calculator
Gather sleep study data
Use results from a home sleep apnea test or polysomnogram including total apneas, hypopneas, and actual sleep time.
Enter counts and sleep duration
Type the number of events observed and the hours slept. The calculator automatically computes events per hour.
Review severity and next steps
Discuss the result with a sleep specialist. Treatment decisions depend on symptoms, daytime impairment, and comorbidities.
Formula
The apnea-hypopnea index quantifies obstructive sleep apnea severity by averaging respiratory events per hour of actual sleep. Ensure apneas and hypopneas are scored using AASM criteria.
Full Description
The apnea-hypopnea index (AHI) is a cornerstone metric in sleep medicine. It combines full airway collapses (apneas) and partial obstructions with oxygen desaturation or arousals (hypopneas) to assess obstructive sleep apnea severity. Higher AHI scores are associated with daytime sleepiness, cardiovascular disease, insulin resistance, and increased accident risk.
Management options include positive airway pressure therapy, mandibular advancement devices, positional therapy, weight loss, alcohol moderation, and upper airway surgery. AHI should be interpreted alongside symptoms, oxygen saturation metrics, and arousal indices to guide treatment.
Frequently Asked Questions
Do I need an in-lab study for accurate AHI?
Home sleep apnea tests estimate AHI from limited channels and can underestimate severity. Polysomnography provides the most comprehensive data, especially for complex sleep apnea or comorbid insomnia.
Can AHI vary night to night?
Yes. Sleep position, alcohol intake, nasal congestion, and REM sleep proportion can change event counts. Clinical decisions consider typical patterns rather than a single night.
What if my symptoms are severe but AHI is mild?
Some patients experience significant daytime sleepiness with only mild OSA. Treat based on symptom burden, oxygen saturation, and comorbid risk rather than AHI alone.
Does treatment reduce AHI?
Continuous positive airway pressure (CPAP) can normalise AHI. Oral appliances, weight loss, and positional therapy also decrease events, though follow-up testing is recommended to confirm efficacy.