Early night OA clusters true events, or awake breathing?

[ColoradoMom]

A brief history:
My teenage son has been using his CPAP for about 14 months, he is scheduled to have his 2nd titration study next month. His diagnostic sleep study showed mild to moderate OSA and hypoxia (I suspect his the diagnostic study underestimated his AHI because while not typical his treated AHI on occasion has been over 20). His last titration study (March 2018) showed that his AHI was considered to be treated at a pressure of 6, but they continued to raise the pressure and found a pressure of 9 increased his oxygen levels and resolved the hypoxia. In addition to OSA my son also has asthma, POTS, and is suspected to have a connective tissue disorder (likely Ehlers Danlos).
My son's sleep apnea seemed to be pretty well treated at a pressure of 9, but his average AHI has been gradually increasing over time (his AHI currently averages out at about 5). My son's doctor is hoping to be able to drop his pressure because at a pressure of 9 my son gets bad aerophagia. Because of my son's previous hypoxia and other health issues his doctor wants another titration study before deciding if changes should be made. Leading up to his titration study and follow up appointment I am hoping to get a better understanding of what is going on with his data. A recent pattern I have noticed is clustering of OA events early in the night, a period of breathing not detected, and an improvement later in the night. Before we raised my son's pressure from 6 to 9 he would often get clustering, but it was always later in the night. Which brings me to my question:
Are these early night clusters true events, or could they be awake breathing? Is his AHI increasing or is it possible that this is awake breathing therefore I shouldn't be concerned with the increased numbers?

[Sleeprider]

The streak of obstructive apnea looks positional from the point of view that the events are clustered. On the other hand, the breaths leading into it and during the events do not look flow-limited, so this may be more like some form of central apnea. The sleep study should help determine if there is breathing effort and the source of apnea Trying a soft cervical collar would at least eliminate the positional apnea possibility. I have not got particularly high confidence in the cause.

I recommend you discuss the addition of an oxygen bleed to the CPAP therapy http://www.apneaboard.com/wiki/index.php..._with_CPAP If your son is hypoxic, this is the answer, and he would qualify for it. If not prescribed, I would sure want to know the reason why.

[Gideon]

The flow rate shows sleep starting about 2300 and 2340 depending on which chart so yes the cluster at the start is SWJ.
The actual AHI that I see on the 26th is 1.6 11/7hrs  Fairly minor The other night even less.

Is BND common?  I was surprised to see it on both charts that you posted.

In the gaps of the BND I can see periods of VERY shallow breathing, enough so that it may not be accurate.  
Ask your doctor if these BND periods could be significant. 

Ask if the DeSATs could be measured at home?  There are many members here that do so.  Especially since they seem to be pressure dependent.

Looking at Tidal and Minute Volume charts may (only may) shed some light. as would looking at a zoomed view of the start and gaps of the BND periods (Events, Flow Rate,Tidal Volume, Minute Volume being the important charts to see in detail.  May also be good to ask your doctor about.  Do you have Sleepyhead on a laptop? if so consider taking it in to your doctor so he can examine the details himself.

Fred

[Sleeprider]

I agree with Fred's analysis and something I saw in the close-up charts is that some of the "apnea" start with an inhale, like holding breath. That is the case with all of these below, so SWJ is a plausible explanation.

[ColoradoMom]

Thank you Sleeprider and Fred, you have both been incredibly helpful! I have Sleepyhead on my laptop, and my son's doctor is always willing to take the time to look over Sleepyhead when we have concerns. I don't want to waste the doctors time with anything that is insignificant, so I really appreciate you both helping me to better understand what I am seeing!

To clarify about my son's hypoxia, it seems to be resolved at a pressure of 9. I have a recording oximeter, both my son's last titration study and our home oximeter show him only going under 88 for a minute or two over the course of the night since we raised the pressure to 9 (before CPAP he had desats into the 70s and was under 88 for over an hour). During his last titration study even after his AHI was good (at a pressure of 6) his O2 sats were still low and a he was having a high number of "unclassified" awakenings.  He had a wonderful sleep tech who believed the low O2 and awakenings were due to upper airway resistance, so she continued to try higher pressures and determined that at 9 his O2 improved and the awakenings decreased. My son's asthma is better treated now than it was at the time of his last titration study so his doctor is hoping the better asthma treatment may have improved his O2 levels and if that is the case we could lower the pressure a bit to address the aerophagia.

As far as the BND it, I see lengths of BND similar to the nights I posted about 2-3 per week. I always assumed it was the result of leaks, but that assumption is purely a guess. Here are some closer views of the BND Fred suggested I post, let me know if you see anything. Another thing I have noticed is on nights with lots of BND the AHI shown on his dreamstation screen is always higher than the AHI Sleepyhead reports (it seems the Dreamstation excludes the BND from the usage time). On the night I am posting the Dreamstation reported an AHI of 8.7.