ResMed apnea type CA/OA recognition problem

pcstud wrote: ↑

Sun May 12, 2019 3:07 pm

palerider wrote: ↑

Sun May 12, 2019 2:04 pm

pcstud wrote: ↑

Sun May 12, 2019 11:05 am

I encountered a problem with incorrect recognition of the type of apnea at the pressure above 15cm H2O in AirCurve. Central apneas are mistakenly diagnosed as obstructive and the pressure rises, which exacerbates the problem even more.

What makes you think that? FOT is pretty accurate at differentiating between the two.

I always thought so. My observation is that the problem appears at a pressure higher than 15cm. That's why I asked here if anyone has similar observations.

There's nothing magical about 15cm pressure.

pcstud wrote: ↑

Sun May 12, 2019 3:06 pm

I have been following my results for a long time. There is a limit value above which I do not snore, I do not have hypopnea or apnea. This time the pressure was much higher, so I do not suspect obstruction. Well, unless too high pressure can cause obstructive apnea?

You've never been this old before, ya know? things change.

pcstud wrote: ↑

Sun May 12, 2019 4:16 pm

I don't think it's anything that's contributed to the discussion... but here you go.

Classic obstructives followed by recovery breaths.

I looked at your screenshots, and I see obstructive apnea and central apnea both flagged above 15cms. Are you thinking that they are all central? How can you be sure? A machine fault exclusively above 15cms is highly improbable. I think that it is more probable that something else has changed and the machine is reporting correctly.

palerider wrote: ↑

Sun May 12, 2019 4:27 pm

pcstud wrote: ↑

Sun May 12, 2019 4:16 pm

I don't think it's anything that's contributed to the discussion... but here you go.

Classic obstructives followed by recovery breaths.

How do you distinguish between OA and CA in this chart?

katestyles wrote: ↑

Sun May 12, 2019 4:30 pm

I looked at your screenshots, and I see obstructive apnea and central apnea both flagged above 15cms. Are you thinking that they are all central? How can you be sure? A machine fault exclusively above 15cms is highly improbable. I think that it is more probable that something else has changed and the machine is reporting correctly.

I'm not sure, that's why I asked if anyone has similar observations. It is strange for me to have OA at such high pressures and it is quite easy for me to explain CA. The logical explanation is the incorrect qualification of the type of apnea, which I did not observe at lower values. It's just a machine. Nobody realizes that he will never make a mistake.

pcstud wrote: ↑

Sun May 12, 2019 4:31 pm

palerider wrote: ↑

Sun May 12, 2019 4:27 pm

Classic obstructives followed by recovery breaths.

How do you distinguish between OA and CA in this chart?

pcstud wrote: ↑

Sun May 12, 2019 4:44 pm

pcstud wrote: ↑

Sun May 12, 2019 4:31 pm

palerider wrote: ↑

Sun May 12, 2019 4:27 pm

Classic obstructives followed by recovery breaths.

How do you distinguish between OA and CA in this chart?

There's more flow showing up due to FOT in the central flagged event, indicating that you've got an open airway.

You should be able to see a difference in the corresponding Mask Pressure chart too. they're not huge differences, they're subtle, but they're there.

Hey Kate...tell him about OAs happening at your pressures.
If he thinks 15 is high...tell him about yours.

IMHO...the zoomed in screen shot...the only thing that wasn't real was maybe the central/CA flagged event. That looks like arousal breathing to me. I think the cluster of OAs caused an arousal (may or may not remember waking up) and that central flagged was a not asleep central flagged because of a pause in the breathing because of being awake and the cluster of real OAs caused the arousal.
Just need more pressure at that time for some reason or other...and when that happens the 2 usual culprits....supine sleeping and REM or a combination of both causing someone to just need more pressure than they need at other times during the night.

OAs usually are followed by a big recovery breath...a big gulp of air as the body tries to recuperate from the apnea event. Reflex action more than anything else.
Central apneas don't normally have the big gulp of air so much.

Given the time of night (morning), I think it's possible that you've entered a period of disturbed sleep punctuated by arousals, maybe starting with an OA, which leads to arousals which leads to breath holding which the machine usually flags as CA. Events during light disturbed sleep with arousals are sometimes referred to as Sleep Wake Junk (SWJ). During these types of periods I have seen breath holding classified as OA instead of CA.

In a lab, events following an arousal would not be classified as either OA or CA.

Since you believe these events are caused by P greater than 15, why not limit Pmax to 15 and see what happens. You could decrease PS, to raise EPAP if you thought it necessary.

palerider wrote: ↑

Sun May 12, 2019 4:48 pm

You should be able to see a difference in the corresponding Mask Pressure chart too. they're not huge differences, they're subtle, but they're there.

I know the theory ... but I really do not see the difference on the graph.

Jay Aitchsee wrote: ↑

Sun May 12, 2019 4:53 pm

Given the time of night (morning), I think it's possible that you've entered a period of disturbed sleep punctuated by arousals, maybe starting with an OA, which leads to arousals which leads to breath holding which the machine usually flags as CA. Events during light disturbed sleep with arousals are sometimes referred to as Sleep Wake Junk (SWJ). During these types of periods I have seen breath holding classified as OA instead of CA.

In a lab, events following an arousal would not be classified as either OA or CA.

Since you believe these events are caused by P greater than 15, why not limit Pmax to 15 and see what happens. You could decrease PS, to raise EPAP if you thought it necessary.

This situation happened to me for the first time. I will make it exactly as you say. Thank you for your explanation. That sounds reasonable.
Where can I read more about these arousals?

Pugsy wrote: ↑

Sun May 12, 2019 4:51 pm

IMHO...the zoomed in screen shot...the only thing that wasn't real was maybe the central/CA flagged event. That looks like arousal breathing to me. I think the cluster of OAs caused an arousal (may or may not remember waking up) and that central flagged was a not asleep central flagged because of a pause in the breathing because of being awake and the cluster of real OAs caused the arousal.
Just need more pressure at that time for some reason or other...and when that happens the 2 usual culprits....supine sleeping and REM or a combination of both causing someone to just need more pressure than they need at other times during the night.

OAs usually are followed by a big recovery breath...a big gulp of air as the body tries to recuperate from the apnea event. Reflex action more than anything else.
Central apneas don't normally have the big gulp of air so much.

Thank you for your explanation. Probably you both are right that it can be arousal which results in pressure increase.Where can I read more about it?

palerider wrote: ↑

Sun May 12, 2019 4:48 pm

There's more flow showing up due to FOT in the central flagged event, indicating that you've got an open airway.

pcstud wrote: ↑

Sun May 12, 2019 4:57 pm

I know the theory ... but I really do not see the difference on the graph

If the scale if decreased to enlarge the FOT wave and then The FOT from the Flow rate graph is compared to the corresponding FOT from the Mask Pressure graph, there is usually a phase shift apparent with one type of apnea and not the other. I forget which now.

pcstud wrote: ↑

Sun May 12, 2019 5:03 pm

Where can I read more about these arousals?

viewtopic.php?f=1&t=113409&st=0&sk=t&sd=a#p1094245

viewtopic/t114197/Flow-Rate-Waveform-Ex ... l#p1104979

https://www.bing.com/search?q=sleep+wak ... 92b9a4eea2