Question regarding CPAP machine not recognizing central events

[imagineapuddle]

Hello and sorry for the long post, I bolded my actual questions,

I was hoping someone here might have some insights into this question as I've asked a few doctors and have only been told the machines aren't too accurate with central events. I was using a CPAP machine(REMstar pro c-flex+) for around a year with little improvements, but the machine data showed I had nearly 0 events per night and near full compliance. After not feeling much improvement, I had another sleep study which showed I had a higher AHI(16) than I initially had(6.6) and nearly all of the events were central. I don't understand why the CPAP machine wasn't able to recognize that I was still having central apnea events. I now use an ASV device that was titrated successfully, but I still haven't noticed an improvement over the CPAP. Is it possible my new machine isn't recognizing some apnea events either?

My symptoms are severe and seem to be much worse than my low AHI initially suggested and I have been using CPAP/ASV rather unsuccessfully for 3 years now. I was just told I most likely have idiopathic hypersomnia, but I was also told this before my second sleep study that diagnosed me with either central apnea or complex apnea.

Any explanation on how the first machine couldn't recognize I stopped breathing, but the second machine(Aircurve 10 ASV) can, would be appreciated. Thanks

[LSAT]

An AHI of 16 is not categorized as severe.....5-14 is mild.....15-29 is moderate and 30+ is severe. Older machines did not recognize centrals and some newer models miss some occasionally. A sleep study is more accurate. Chances are , an untreated AHI of 16 with mostly centrals is not Central Sleep Apnea..especially is your CPAP was taking care of reducing them Regular CPAPs cannot get rid of CAs.

[Wulfman...]

Hello and sorry for the long post, I bolded my actual questions,

I was hoping someone here might have some insights into this question as I've asked a few doctors and have only been told the machines aren't too accurate with central events. I was using a CPAP machine(REMstar pro c-flex+) for around a year with little improvements, but the machine data showed I had nearly 0 events per night and near full compliance. After not feeling much improvement, I had another sleep study which showed I had a higher AHI(16) than I initially had(6.6) and nearly all of the events were central. I don't understand why the CPAP machine wasn't able to recognize that I was still having central apnea events. I now use an ASV device that was titrated successfully, but I still haven't noticed an improvement over the CPAP. Is it possible my new machine isn't recognizing some apnea events either?

My symptoms are severe and seem to be much worse than my low AHI initially suggested and I have been using CPAP/ASV rather unsuccessfully for 3 years now. I was just told I most likely have idiopathic hypersomnia, but I was also told this before my second sleep study that diagnosed me with either central apnea or complex apnea.

Any explanation on how the first machine couldn't recognize I stopped breathing, but the second machine(Aircurve 10 ASV) can, would be appreciated. Thanks

You were using a straight-pressure CPAP machine. No straight-pressure CPAP machine has ever had the ability to detect (and avoid) central apneas. You would have needed an APAP in a range of pressures for it to detect centrals. The algorithms and sensors in those machines make it possible for them to back off pressures when they detect POSSIBLE centrals.


Den

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[Julie]

Also, is it possible there's anything else health-wise going on to keep you from feeling better? When's the last time you had a work-up for e.g. cardiac issues, thyroid problems, sugar etc?

[jnk...]

I've asked a few doctors

Not all are experts on the subtleties of treatment machines.

told the machines aren't too accurate with central events.

Well, yes, and no. They are excellent at identifying that an apnea of some sort has occurred. But they are not the definitive word on whether the apnea was primarily a central one or an obstructive one. Sometimes the airway closes during a central apnea, for example. But there is no way for a machine to miss that some sort of apnea has occurred unless there is a very large unintended leak happening at the time.

another sleep study . . . showed . . . nearly all of the events were central.

Was this a lab/center attended PSG? If so, those events were very likely truly central in nature.

Is it possible my new machine isn't recognizing some apnea events either?

Highly unlikely if you are masked up properly.

I have been using CPAP/ASV rather unsuccessfully for 3 years now.

Posting data here may help increase likelihood of success.

Any explanation on how the first machine couldn't recognize I stopped breathing, but the second machine(Aircurve 10 ASV) can, would be appreciated. Thanks

Both machines should recognize when you aren't breathing. But an ASV has ways of keeping breathing regular and evened-out in such a way that centrals can be prevented for many users, which is particularly useful if centrals of unknown origin are disturbing sleep and/or impacting oxygenation.

[ChicagoGranny]

Any explanation on how the first machine couldn't recognize I stopped breathing, but the second machine(Aircurve 10 ASV) can, would be appreciated. Thanks

Just to make one thing clear, your CPAP machine should recognize and report all apneas. But, it cannot distinguish between obstructive and central apneas. If it truly wasn't recognizing some apneas, then the machine was defective.

Your ASV machine should recognize all apneas and distinguish between obstructive and central. It will react appropriately to the two different types of apneas. If it doesn't recognize and respond, it is defective.

[ChicagoGranny]

I have been using CPAP/ASV rather unsuccessfully for 3 years

You said your AHI with the CPAP was near zero. What has your AHI been with the ASV over the last two years?

My symptoms are severe

What are your symptoms? Do you sleep throughout the night? Do you feel like you have hypersomnia during the day? Any other symptoms?

What medications do you take? How is your sleep hygiene, diet and exercise? Are there major stressors not related to sleep in your life?

[imagineapuddle]

Hello and thanks for all the replies. I think my major question was why my first CPAP machine didn't recognize any centrals, but the follow up sleep study did. I'm aware that the machine shouldn't be able to differentiate between central and obstructive events, but I was under the impression it should at least be able to tell that there was an event. Unfortunately, I've had pretty much all of the common tests done(ie thyroid, bloodwork, etc.) and have had two MSLTs that had sleep latency of 7.3 and 5.2 respectively, but no REM sleep. My AHI on both the CPAP and the ASV has been below 2. I believe my current data has it at around 1.2 and I think on CPAP it was below 1. I experienced minor improvements after starting with CPAP therapy initially, but my symptoms still feel extreme and are severely impacting my life. My confusion is why the CPAP wasn't recognizing apnea events, even though the sleep study showed they were still occurring even though the nightly machine data wasn't showing anything.

My symptoms are exhaustion, fatigue, execessive daytime sleepiness, constant headaches, cognitive difficulties(difficulty concentrating, impaired memory, difficulty focusing, etc.) and generally feel like I haven't slept at all after 6-7.5 hours a night. I constantly feel exhausted and sore like previously did a full body workout, even though I'm not that active. I also seem to have very vivid dreams(usually nightmares) and what appear to be hypnagogic hallucinations. My sleep hygiene is fine according to the sleep therapist I was sent to. I was previously getting 7.5 hours of uninterrupted sleep, before I realized this wasn't making a positive impact, so now it is consistently between 6.5-7.5 hours. I don't particular nap during the day that I'm aware of, but when I do fall asleep, I wake up feeling worse than before.

I am not currently on any medications, but have used Aderall, Nuvigil, and Provigil all without any success. My symptoms sound a lot like narcolepsy, but I didn't go into REM sleep during the MSLTs, which is why I was told it was most likely Idiopathic Hypersomnia, which has similar symptoms.

I've spoken with several doctors at my local sleep clinic, and with two of the doctors I have seen at Stanford's sleep clinic that I was referred to. First doctor I saw at Stanford believed I was still suffering from obstructive apnea and was the one that told me that the machines aren't always that accurate and that they don't always see the entire picture. The second doctor I saw after another sleep study and told me that it was IH. I'm trying to decide if it's worth it to try to get another appointment with the first doctor and see if he has anything further to say about the apnea, or if I should just accept the IH diagnosis.

I've never had a sleep study with the ASV beyond the initial titration, which is my main point in asking the question. Initially I was told the CPAP therapy was working correctly and there was nothing more they could do, then I had another study and found I was having a bunch of centrals. Does anyone think it might be helpful for me to do another sleep study with the ASV, or would it be a waste of money. Also, none of the MSLTs I had were with a CPAP device, could this have effected my REM sleep during them? I know during my initial sleep study in 2015, I never entered REM sleep and my deep sleep were sporadic, so I'm wondering if not having a CPAP on could have effected the MSLT results.

[ChicagoGranny]

My confusion is why the CPAP wasn't recognizing apnea events, even though the sleep study showed they were still occurring even though the nightly machine data wasn't showing anything.

When a CPAP successfully treats your apnea, there are no events to show.

If your sleep study was without being hooked up to CPAP, it would show any events that occur.

My sleep hygiene is fine according to the sleep therapist I was sent to.

You are a rare individual.

sore like previously did a full body workout, even though I'm not that active

That sounds like something besides sleep apnea. Do you have RLS?