AHI higher on CPAP than without it

I was diagnosed with mild apnea (AHI 5.1 on home test), had an in-lab titration study, and now have a DreamStation CPAP machine with humidifier and nose mask and chin strap. Just started using it about a week and a half ago. I would say that my daytime sleepiness is partially reduced; I adjusted to sleeping with all the hardware on my face and head with no problem, and my provider has reviewed my machine's records with no concern at all about any of the numbers.

The issue is that the AHI reading -- EVERY night -- has ranged from 7 to 15, with no specific pattern. We'd at first thought it was a mouth breathing issue, since I was waking up with a dry mouth -- something that doesn't happen without CPAP -- which is why I now have the chin strap. Also, I'm a side sleeper who never stays on my back for very long.

My husband has about the same level of apnea as mine, uses exactly the same kinds of equipment (minus chin strap), and his AHI reading is almost always below 1 and never above 3.

My provider thinks the mouth breathing causes unreliable readings with a nose mask, and was just part of my adjustment period to wearing the equipment. The chin strap does seem to prevent it; I don't wake up with a dry mouth now. But those AHI numbers still stay higher than they were without CPAP, and my daytime sleepiness is only slightly reduced. Has anyone else had this experience?


  • EB_BryanEB_Bryan Posts: 32 mod

    Are you using a fixed pressure CPAP machine or one that Auto-Titrates? Most people need a variety of pressures throughout the night as you move around and hit different cycles of sleep. Auto-Titrating CPAP machines take these movements and cycles into account and adjust the pressures based on your needs. This might help to lower your AHI (if the cause is simply that you need different pressures as you move around).

    Along with that there are some settings in your Dreamstation you may be able to change to help with the readouts. If you make sure the mask type is set to x1 you may see a reduction in your AHI. The x1 setting is meant for nasal masks specifically, as opposed to full face, or nasal pillow masks.

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