high AHI; low pressure

[hegel]

I'm one of those people who get a higher ahi when I go into deeper rem sleep. So I often feel more rested when I have a higher ahi reading in the morning--for example today, with a 2.9 reading. But I notice that my 90% pressure reading will often stay low, even with these higher readings. Today it was 9.00, which is a tad below average for me. Shouldn't my 90% show a bump up in response to more events?

[LSAT]

I'm one of those people who get a higher ahi when I go into deeper rem sleep. So I often feel more rested when I have a higher ahi reading in the morning--for example today, with a 2.9 reading. But I notice that my 90% pressure reading will often stay low, even with these higher readings. Today it was 9.00, which is a tad below average for me. Shouldn't my 90% show a bump up in response to more events?

90% means that 90% of the time your pressure was at or below 9. 2.9 is not considered a high reading...in fact, after 8 years on CPAP my average reading is between 1.0 and 2.0, with an occasional 3+ reading. The main consideration is how are you sleeping and how do you feel.

[hegel]

thanks lsat; I know of all of that. Still, shouldn't my pressure reading show a bump to address the higher number of events indicated by a higher ahi? I mean, I often get a 90% reading of 10 and an ahi of 1.3, for example. It's almost as if the machine was being lazy.

[Pugsy]

Is the higher AHI primarily OA or Clear Airway? Remember the machine can't/won't respond to Clear Airway events.

90% numbers often lie and you can't really base expectations on just the 90% number.
It would be better to evaluate the actual details...pressure line vs events that are clustered probably in REM and see what is really happening.

I am personally familiar with OSA being worse in REM sleep....documented to be about 5 times worse in REM than in non REM sleep on my sleep study.
Also lots of personal experience with wild 90% numbers because of those REM events and that's why I say that 90% number are easily skewed and thus not nearly as reliable as people want them to be.

[fj62]

While I wait to get my sleep study I am trying to get my AHI's down by increasing the pressure. This morning my AHI was over 45.5 so I Upped the pressure on cpap to 8. I took an hour nap today at the higher Pressure and had 22 AHI. I plan on checking AHI's for the next days to se if I sleep better. If my AHI's improve I will be tempted to increase my pressure to see if I can get my numbers to look better.

[Julie]

Don't just keep raising your pressure... there are too many other factors involved and until you understand them all, and see what SleepyHead says, it's not a good idea to just raise it higher, esp. if you don't leave it in one place for a few days at a time to see results... one night's just not enough to base anything on.

[hegel]

Just to be clear, in my earlier post I meant that it seemed like my machine was being lazy when I had a higher ahi and a low pressure reading last night.

So 90% pressure readings can lie! or in any case be inaccurate, or inconsistent. That's becoming my experience. I haven't had the time yet to download last nights' info. But it just seems intuitive that, when I have one of those great, deep rem sleep nights, and my events go up, I should see a higher 90% pressure reading the following morning. I want the pressure up, intercepting the OA's and all the rest! Stupid machine!

Quiet, it might hear you....

Still, I can't really complain about a reading of 2.7 or thereabouts.

Hey, I slept well; I'm good.

[Pugsy]

Quiet, it might hear you....

Or the aliens will hear you and pay you a visit.

Once you get the software up and running you will understand what I mean about 90/95 % numbers.
Sometimes they are good useful tools and sometimes useless.

And remember the machine won't respond to Clear Airway events so if your AHI has many CAs then you are blaming the machine for not responding but it isn't supposed to.

When you see the software reports you may see some clustering of OA events during probable REM sleep and you may need to increase that minimum pressure just a bit to break up the clustering.

[fj62]

I raised my pressure to 8 from 7 last night. When I woke up in the middle of the night I had a slight headache and couldn't fall back asleep. I changed my setting back to 7. The AHI read 19.1 when I reset the pressure. My machine also read an AHI of 19.1 this morning. I feel less tired today. I am also thinking of going back to my old Resmed M series cpap with the malfunctioning humidifier because I was less tired when I was using it.