Sharp spike in AHI for a short duration sleep

Hi All Not sure if anyone has experienced this and so i thought i will share and seek support. I have been using CPAP machine for more than 8+ years and 1 yr before i changed to APAP Fisher & Paykel SleepStyle machine which is incredibly silent and using a full face mask from ResMed Airfit. It is definitely effective than the previous one. But off late i observed that whenever i sleep for 1-2 hrs and get up i see a huge AHI reported of around 10.... If i continue sleeping for 8 hrs or so it avaerage to <5. My mask leak is low and my and jv a monthly average sleep of 7 hrs and avg AHI of 3.1.

And recently I also feel very tired whether I sleep for 2 hrs or 10 hrs. Not sure if this is a worrying sign of my health. I am also not doing much of exercise and not particularly careful with diet. I am.obese . was around 96 but not edging towards 100kg. Getting super stressed all the time.about this pattern any support frt this forum will.be really helpful Thanks

You should probably have a sleep study done to see what type of apnea you are having. There are a couple of issues with the F&P SleepStyle machine. First is that it does not collect data in a form that will allow it to be viewed by a software program called SleepyHead. SleepyHead has been replaced by another free program called OSCAR, but I am not sure that OSCAR supports the SleepStyle either. With the software you can get more information about your sleep apnea.

The other issue with the SleepStyle is that it does not distinguish between obstructive apnea and central apnea. If all you have is obstructive apnea then that is not a problem. If you have central apnea (airway not blocked, but not breathing) then the machine can make it worse. It will increase pressure when it sees a central apnea, and increasing pressure can make central apnea worse.

Keep in mind that if you get even a few apnea events in a short space of time it will show up as a high AHI. The normal acceptable treatment level is for AHI to average less than 5. That said, with CPAP many can achieve closer to 1 for AHI, especially if they AHI is mainly obstructive. With central apnea it is harder to get a real low number.

If you are having central apnea one possible way to address it while using the SleepStyle machine is to switch it to a fixed pressure instead of auto mode. That way central apnea events cannot trigger a pressure increase. The trick then is to find a pressure that is high enough to prevent the obstructive apnea while not so high as to trigger central apnea.

Hope that helps some,