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[Health] DreamStation AHI Math
#1
Question 
DreamStation AHI Math
Basics:

Diagnosed with severe obstructive apnea about 2 months ago
Sleep study result:  22 obstructive apneas, 56 central apneas, 87 hypopneas
Wallenberg Stroke 5 1/2 years ago
Using Phillips Respironics DreamStation BiPap machine w/full mask for about a month. Settings 21/17
Using DreamMapper App

Question(s):

The DreamMapper App math on my AHI doesn't seem to relate to my numbers of apneas. Also, when I try to reverse multiply the AHI with the time used, it doesn't match the sum of the apneas, or any combination of the apneas. How do they calculate the AHI, and are 'Clear Airway' apneas included in the calculation? Also, are Clear Airway apneas the same as central apneas?

Examples:

DATE          Clear Airway     Obstructive    Hypopneas   AHI   Usage
Sept 16            21                      2                12          4.4     7:56
Sept 17            32                      4                17          6.3     8:25
Sept 18            35                      7                14          7.1     7:54
Sept 19            42                      3                11          6.4     8:41
Sept 20            53                    10                19          9.5     8:37
Sept 21            43                      8                14          7.5     8:37
Sept 22            48                      3                12          7.6     8:20


Thanks for any help!
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#2
RE: DreamStation AHI Math
Add together all of the events and devide by time in hours.


So looking at sept 18

35+7+14=56 divided by time in hours I rounded up the hours and divided by 8 giving an AHI of 7

Which matches your machine stat of 7.1



Jason
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#3
RE: DreamStation AHI Math
Hi PaulKiser,
WELCOME! to the forum.!
Good luck with CPAP therapy.
Hang in there for more responses to your post.
trish6hundred
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#4
RE: DreamStation AHI Math
Unfortunately you got the fixed pressure BiPAP pro. With the BiPAP auto, EPAP would automatically increase to resolve OA and pressue support increase for hypopnea.

My impression is that your pressures are very high and you should consider a soft cervical collar to prevent physical obstruction of your airway from dropping your chin to chest and other head neck issues that cause airway occlusion.
Sleeprider
Apnea Board Moderator
www.ApneaBoard.com

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