1. What is Central Apnea Index?

The Central Apnea Index (CAI) measures the frequency of central apneas per hour of sleep. Central apneas occur when the brain fails to send proper signals to the muscles that control breathing during sleep.

2. How Does the Calculator Work?

The calculator uses the CAI formula:

Where:

• Central Apneas — Total number of central apnea events recorded
• Sleep Hours — Total duration of sleep in hours

Explanation: The index provides a standardized measure of central apnea severity by accounting for variations in sleep duration.

3. Importance of CAI Calculation

Details: CAI is a key metric in sleep studies for diagnosing central sleep apnea, determining its severity, and monitoring treatment effectiveness. Higher values indicate more severe central sleep apnea.

4. Using the Calculator

Tips: Enter the total number of central apnea events and the total sleep duration in hours. Both values must be valid (central apneas ≥ 0, sleep hours > 0).

5. Frequently Asked Questions (FAQ)

Q1: What is considered a normal CAI value?
A: A CAI less than 5 events per hour is generally considered normal in adults. Values between 5-15 indicate mild central sleep apnea, 15-30 moderate, and above 30 severe.

Q2: How does CAI differ from AHI?
A: CAI measures only central apneas, while the Apnea-Hypopnea Index (AHI) includes both obstructive and central events plus hypopneas.

Q3: When should CAI be measured?
A: CAI is typically measured during an overnight sleep study (polysomnography) in a sleep lab or with a home sleep test device.

Q4: What causes high CAI values?
A: High CAI can be caused by heart failure, opioid use, neurological disorders, or sleeping at high altitudes. It can also occur in treatment-emergent central sleep apnea.

Q5: How is central sleep apnea treated?
A: Treatment depends on the underlying cause and may include addressing medical conditions, adaptive servo-ventilation (ASV), CPAP, or supplemental oxygen.