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What is the apnea-hypopnea index? - April 23rd, 2020

The apnea-hypopnea index (AHI) is a scale that measures how serious your sleep disorder is. Used to test both apnea (when you stop breathing for 10 seconds or longer) and hypopnea (a partial loss of breath for 10 seconds or more), it determines how many times per hour of sleep you experience one of these events.

What do the numbers mean?

Your score is based on your average result, which is calculated by taking the number of times you experience hypopnea or apnea during the night and dividing this by your hours of sleep.

If you experience less than five events per hour, you are considered to have normal sleep. However, if you experience up to 14 events per hour, you fall into the ‘mild’ category. If you receive a moderate sleep apnea diagnosis, you experience 15 to 29 events per hour. Finally, if you have severe apnea, you experience 30 or more events.

Although children are less likely to have sleep apnea, doctors will consider an AHI above 1 as unusual. Generally, a child will require treatment if their AHI is more than 5.

How AHI is measured in a sleep study

During a sleep study, information is collected using a number of sensors designed to track your breathing patterns. These include nasal cannulas, oximeter clips and respiratory effort belts.

When will you need treatment?

If your AHI is normal, you won’t require treatment. However, continuous positive airway pressure (CPAP) masks are used for mild, moderate and severe sleep apnea. Most specialists will be looking for less than 5 events per hour, but if your baseline AHI is significant, such as 80 events per hour, even 8 events will be viewed as an excellent improvement.

Newer CPAP machines are able to track abnormal breathing events and generate an AHI. This information can then be used to manage your treatment. It’s important to remember that someone with a high AHI may not necessarily require a high CPAP pressure to resolve their condition as anatomy and lifestyle factors play a part too.

To find out more about the apnea-hypopnea index or CPAP machines, contact us at Apnea-Seal today.

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