Complex Sleep Apnea - Hypopneas - Central or Obstructive

[Tonawanda]

I have been diagnosed with complex sleep apnea, and have been using my machine in the VPAP st mode. Depending on the pressure settings, my average AHI is about 10.

Are the hypopneas recorded on the sleepyhead report attached in conflict the diagnosis of Complex Sleep Apnea? If a central apnea is a (respiratory episode where there is no airflow and no effort to breathe because your brain doesn't send proper signals to the muscles that control your breathing) and a hyponea is caused by a partial obstruction of the airway, am I having central or obstructive apneas? If they are central apneas, does the Sleepyhead report somewhat indicate that?

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[TedVPAP]

I am not sure if I understand your question. The majority of events shown are hypopneas which means that you need higher pressure. The UA means that the machine was unable to determine if the apnea was due to obstruction or not.

[Pugsy]

It's not so much the machine couldn't determine OA or central but the fact that this particular model of machine simply doesn't distinguish between central vs obstructive apnea. One of the things I don't like about these high end ResMed machines.
We assume obstructive but can't prove it. Even in cpap mode it doesn't use FOT to decide open vs closed airway. You get UA flags.
I know because I had this machine to try and tried cpap mode.
Central apneas and obstructive apneas all get tossed in the generic "Apnea Basket"...so you get AI without any sub categories.
AHI is composed of AI plus the hyponea index and not the usual 3 categories.

If using ResScan it would be called "unclassified".

The hyponeas...most likely obstructive but would not be totally impossible for them to be central in nature.

And if obstructive most usually IPAP is what we look at but there's more than one way to obtain more IPAP than just increasing IPAP all by itself.
If we increase IPAP alone that increases PS and more PS might cause too much carbon dioxide blow off which could potentially make centrals worse.
If it were my report I would be increasing IPAP but I would do it by increasing EPAP so that it pushes IPAP up and not mess with PS.
All this after I zoomed in on the hyponeas to try to make sure they looked obstructive in nature and not central.

If new to therapy...and I assume has a follow up visit with the sleep doctor scheduled sometime soon...I would make sure that these results are brought to the attention of the sleep doctor.
If no follow up appointment is on the books for anytime soon...I would call them up and make one.

These settings aren't optimal and some adjustment is necessary. Ideally the sleep doctor should have his thumb on things and not let this slide.

[D.H.]

It looks like you either don't have Central Sleep Apnea, or that it's completely under control with this BiPAP.

You have too many Hypopneas, you need to work on that. You also need more than four hours of sleep. Most people need more than seven and less than nine.

Try increasing the pressure a little and see what happens. You need to be careful that you're not getting more Clear Airway or unclassified events when you do that. Sometimes, higher pressures can cause Central events, whether or not Central is part of the orignal diagnosis.

[Julie]

I think you might see a big difference in number of hypops by sleeping on your side IF you now sleep on your back... there are ways to keep you from flipping once asleep... does this sound like you?

[Tonawanda]

It's not so much the machine couldn't determine OA or central but the fact that this particular model of machine simply doesn't distinguish between central vs obstructive apnea. One of the things I don't like about these high end ResMed machines.
We assume obstructive but can't prove it. Even in cpap mode it doesn't use FOT to decide open vs closed airway. You get UA flags.
I know because I had this machine to try and tried cpap mode.
Central apneas and obstructive apneas all get tossed in the generic "Apnea Basket"...so you get AI without any sub categories.
AHI is composed of AI plus the hyponea index and not the usual 3 categories.

If using ResScan it would be called "unclassified".

The hyponeas...most likely obstructive but would not be totally impossible for them to be central in nature.

And if obstructive most usually IPAP is what we look at but there's more than one way to obtain more IPAP than just increasing IPAP all by itself.
If we increase IPAP alone that increases PS and more PS might cause too much carbon dioxide blow off which could potentially make centrals worse.
If it were my report I would be increasing IPAP but I would do it by increasing EPAP so that it pushes IPAP up and not mess with PS.
All this after I zoomed in on the hyponeas to try to make sure they looked obstructive in nature and not central.

If new to therapy...and I assume has a follow up visit with the sleep doctor scheduled sometime soon...I would make sure that these results are brought to the attention of the sleep doctor.
If no follow up appointment is on the books for anytime soon...I would call them up and make one.

These settings aren't optimal and some adjustment is necessary. Ideally the sleep doctor should have his thumb on things and not let this slide.

Thank You for this answer. It answers my primary question, central or obstructive, my understanding of the machines capability, and for the purposes of this machine what the AHI can be composed of.

I’ve had sleep apnea for 15 years. I’ve lost count of the number of sleep studies I’ve had (very fortunate to have great health insurance). Sleep Apnea started out mild and continued to get worse. I’ve never been able to comply with insurance company requirements in the past. I have no choice now, I have to make it work!

After 2 consecutive sleep studies, and a thorough consultation with a respected neurologist and sleep specialist, he prescribed the Bipap at a pressure of 10-16. Very effective pressure for almost 2 months usually reducing AHI to 5 or less. The issue though was I couldn’t keep the mask on, and asleep for 4 hours. I have a whole box of full face masks, and the one I’m using now works great for about 3 hours, and then its blast off. I had a follow up appointment about 2 weeks ago and the doctor reduced the ipap to 14. Much more comfortable, sleeping a little bit longer, but at the expense of much higher AHI. After 2 incremental increases, the current pressure is 15.2 resulting in an average of about 10 AHI. Looks like I’m heading back to 16. My doctor has been very accessible and is considering some other things on a one at a time basis.

The answers and explanations from you and the other forum members will be very helpful. I suspected more obstructive than central, and yes Julie, sleeping on my side has been somewhat helpful in the past, and along with my dealing with congestion due to allergies, I now have an additional approach to work on. One last thing, what does the abbreviation FOT represent?

Thanks again!

[Tonawanda]

I think you might see a big difference in number of hypops by sleeping on your side IF you now sleep on your back... there are ways to keep you from flipping once asleep... does this sound like you?

Absolutely! It will be a bit of a challenge, but I'll be working on that tonight. Thanks

[Tonawanda]

It looks like you either don't have Central Sleep Apnea, or that it's completely under control with this BiPAP.

You have too many Hypopneas, you need to work on that. You also need more than four hours of sleep. Most people need more than seven and less than nine.

Try increasing the pressure a little and see what happens. You need to be careful that you're not getting more Clear Airway or unclassified events when you do that. Sometimes, higher pressures can cause Central events, whether or not Central is part of the orignal diagnosis.

I agree, and I will. Thanks for your response.

[Tonawanda]

I am not sure if I understand your question. The majority of events shown are hypopneas which means that you need higher pressure. The UA means that the machine was unable to determine if the apnea was due to obstruction or not.

Yes, I do need a higher presssure, Thank You

[Mogy]

Hi Tonawanda,
Do you measure your SpO2?
The reason I ask is that a Hypopnea is scored when you have a 4% desaturation plus a flow reduction. Your machine is only measuring flow.
A definition of Hypopnea:
"Hypopnea is defined as reduction in ventilation of at least 50% that results in a decrease in arterial saturation of 4% or more"

Your machine is doing it's best to determine whether there is a Hypopnea, but without the oximetry data it is only measuring half of the information required.
If you had SpO2 data you would be much better informed about how to proceed.

[Pugsy]

FOT Forced Oscillation Technique...what ResMed uses to help it determine if the airway is open (central) or closed or partially closed (obstructive) when there is either a reduction or total lack of air flow.

https://sleep.tnet.com/home/files/resme ... -guide.pdf
page 8

[TedVPAP]

The more informed you are, the better you can help your doctor help you.
A higher pressure can certainly cause some discomfort but generally we get used to it.
Have you zoomed in on some of those H to see what they look like?
Examine your data just before you take the mask off. Maybe you will see a trend.

[CarpeNoctum]

the one I’m using now works great for about 3 hours, and then its blast off"

Hi Tonawanda,
People having to use higher pressures to treat their apnea sometimes have issues others do not. My guess would be that over those three hours of treatment, skin oils build up causing leaks. A small leak with an auto machine becomes a large leak fairly quickly.

A cloth gasket between mask and face can result in a better seal. And by obsorbing those skin oild can allow that seal to last longer too. I use old T shirt material and over time, have experimented using multiple layers (depends on thickness of fabric used).

It's easy enough to do and for me, it really improved things. I just cut a large oval and then cut out a nosehole. There are commercial versions that do an OK job.

It's little details that cummulatively allow cpap to work. Good luck...
CN

[Tonawanda]

Hi Tonawanda,
Do you measure your SpO2?
The reason I ask is that a Hypopnea is scored when you have a 4% desaturation plus a flow reduction. Your machine is only measuring flow.
A definition of Hypopnea:
"Hypopnea is defined as reduction in ventilation of at least 50% that results in a decrease in arterial saturation of 4% or more"

Your machine is doing it's best to determine whether there is a Hypopnea, but without the oximetry data it is only measuring half of the information required.
If you had SpO2 data you would be much better informed about how to proceed.

No I haven't, but I've been looking at oximeters online, and was going to start a topic asking for information and advice on the best way to proceed.

[Tonawanda]

the one I’m using now works great for about 3 hours, and then its blast off"

Hi Tonawanda,
People having to use higher pressures to treat their apnea sometimes have issues others do not. My guess would be that over those three hours of treatment, skin oils build up causing leaks. A small leak with an auto machine becomes a large leak fairly quickly.

A cloth gasket between mask and face can result in a better seal. And by obsorbing those skin oild can allow that seal to last longer too. I use old T shirt material and over time, have experimented using multiple layers (depends on thickness of fabric used).

It's easy enough to do and for me, it really improved things. I just cut a large oval and then cut out a nosehole. There are commercial versions that do an OK job.

It's little details that cummulatively allow cpap to work. Good luck...
CN

Thanks CarpeNoctum, I will give it a try!