[CPAP] What Changed to explain high AHI only part of night?

[HosedPrincess]

        I’ve been on CPAP for about 4 weeks. My sleep test AHI was 27. I’ve been learning and trying things, with pretty good results. I have a nightly habit of removing my mask, but putting it back on after an hour or so. Last night, I had three sessions on my CPAP. The first two were representative of the past week. The last session of the night is unlike anything I’ve seen yet. If I separate them out, my AHIs are:

#1       .78
#2     1.54
#3    23.44

In Session 3, I spent 12.5 minutes in apnea, which is 8% of that 2.5 hours. 

I can’t figure out what changed. Any ideas?

[Sleeprider]

Clusters of events are usually traced to a positional issue involving chin-tucking. It may have resulted from a change in pillows, or maybe because you are sleeping differently due to the mask. It could have been there all along. Many members have dealt with this pattern. The place to start is with these two wikis. Try the self-tests described in the articles and compare your charts to the examples.
Positional Apnea http://www.apneaboard.com/wiki/index.php...onal_Apnea
Soft Cervical Collar http://www.apneaboard.com/wiki/index.php...cal_Collar

[HosedPrincess]

I wear a cervical collar every night due to a neck injury, so I was already wearing one. When I awoke, it was in place. If I get more nights like this, how often is acceptable with my cervical collar on?

I wonder if it is due to my jaw misalignment. When I bring my teeth together, my jaw is pushed back, out of alignment. It’s a small amount, but enough to give me a headache. I work hard to sleep with my jaw relaxed, below my teeth. Maybe last night I clenched my teeth. Maybe I need one of those anti snoring things to bring my jaw forward, even though I don’t snore?

[Sleeprider]

I would not worry about it unless it becomes a common trend. You did great from 21:00 to 01:30, then after about a 1-1/2 hour break it looks like things were very different. It's probably best to let it go for now and if the pattern continues, we can start doing some detective work. It looks like 6.0 may be a bit low for your minimum pressure, and with EPR at 3, a minimum of 7 is usually better, but again, we don't have much to go on from this one night.

[staceyburke]

Your chart shows positional apnea. In other words you cut off your airway in the way you slept. Many times it happens when sleeping on your back or change of pillow height. I don’t believe it it a real problem because earlier you did not have those events. I don’t think you need a collar but reading about it may help you understand “chin tucking”. See the link for collar at this button of the post.

[SevereApnea]

Hello HosedPrincess

I love the way Oscar allows us to dissect each sleep session and look at the stats.

My own experience (only 1 year so far) is that I more often have worse events towards the end of the night: 4 AM to wake-up time. One reason would be that is when we enter more REM sleep, more relaxed, more likely for airways to narrow.

Another reason would be positional, despite using a Soft Cervical Collar (SCC). Yes, I know you already use a Neck Brace, I don't know how yours works or if this is just as useful for your sleep problems as your neck problems.

I include 2 charts for your interest. In both I am using a SCC size Medium.

First chart:
[attachment=29474]

When I woke just before 3 AM I was shocked at my OSA score (6!), despite me having the SCC in place. Panic, so
I immediately replaced my oximeter. The notes from that night included the following comment: 

Sleep Pattern:

#1:  22:39 – 02:54 (4.3) AHI 6.1 5.1 0.2 ! Yikes what is going on here? Must be positional and collar too loose, too comfy, maybe?
Plan Tonight: New firm cervical collar. Use Oximeter again in case we have the same events and see what happens.  
Min EPAP 5.4. Max IPAP 13.0 PS 3.0 Ti Max 3.0. 

Notice how high the pressures went and how they maxed out. Machine can't do anything against anatomical obstruction.

Next night with a new firmer SCC same size Medium.

[attachment=29475]

The old collar (just a cheap one from the local Pharmacy) had got too soft and comfy, and not doing its job anymore. Clearly I had changed position while asleep, neck too flexed, either supine or even side sleeping in fetal position maybe. The new one (same cheap one from the pharmacy, just new and still firm) is now my go-to collar. Still looking for that perfect collar, not there yet. If I can still tuck my chin inside the collar it is too loose.
If it squashes down it is too soft.

For me, this PAP therapy is a journey and not a quick fix.

Each night is different!

[HosedPrincess]

Oh SevereApnea, this is encouraging in a sad discouraging way! Before the CPAP machine, I’d been through multiple neck braces in the past year trying to sleep comfortably with my neck injury. The best SCC allowed my neck to feel better, but made me snore. The neurologist shrugged. My primary care doctor ordered the sleep study because of high blood pressure, and I didn’t go for almost a full year. I finally went because my husband said it would solve my dry nasal passages! Imagine my shock when I had sleep apnea. I had no idea.

So, if I get these kinds of numbers too much, I guess the factors for determining if I have the best collar for me will have to take into consideration both positional apnea as well as sleep comfort. In the past month, which is how long I’ve been on CPAP, my neck has improved a lot. I was in physical therapy and said many times, “If I could just sleep comfortably, I’d be happy.” The CPAP is less annoying than the neck pain, so I’ll keep an eye on the numbers and adjust my head as needed!

[Sleeprider]

Most of our members are using a soft cervical collar. I was thinking you might be using a more rigid collar. Can you describe what you have?

[HosedPrincess]

Hi SleepRider, I use the OTC Cervical Collar, Large, Narrow 2.5 depth that I order from Amazon. I've tried different lengths and widths, and this is most comfortable. I'm pretty short, so I have a short neck.

Pre-CPAP, I had also used various travel pillows to stop my head from moving sideways, but not forward. They didn't make me snore, but they didn't stabilize my neck enough, either.