False readings?

I have COPD along with sleep apnea. I was wondering if my AHI number is a true figure since I have both conditions? How does the machine know which condition is causing the breathing issues? Since I was put on Bi-level due to COPD I have problems exhaling I have many more central apneas. I never had centrals with C-pap.
Thanks

The firmware in the CPAP machine measures air flow and pressure.
It does not attempt to discern what caused any particular anomaly except it does try to tell the difference between an obstructive apnea and a clear airway apnea. Even then the classification may be in error because without the abdominal exertion sensors, such a classification cannot be certain.

What that leads to is the machine has no way of telling if a particular event was caused by your COPD, a "normal" apneac event, or just you temporarily stopping breathing while you roll over, etc.

The AHI you get is just a measure of how well things are going.

many more central apneas

How many are you having on a typical night and what is the most you have had on any night?

2-3 centrals . Most was 5

2-3 centrals during the night is nothing...Even 2-3 an hour may not be serious.

LSAT wrote:2-3 centrals during the night is nothing...Even 2-3 an hour may not be serious.

of course considering they are only 10 second long each

guest1 wrote:
of course considering they are only 10 second long each

It's the 12-second ones that kill you.

Thanks for that!

If you have an arousal during the night but don't completely wake up, the transition from sleep to partially awake back to sleep will frequently be accompanied with a "central apnea" that is just your body switching from awake breath control to sleeping breath control. In a sleep lab such an apnea will be ignored because it is actually meaningless. Your machine doesn't have access to the data that would allow it to make the same decision so it gets reported. In the sleep lab, they have EEG data and abdominal effort data so its easy for them to sort it out.

Folks who have no sleep apnea issues get these during the night. Your reported max of 5 during a single night amounts to less than 1 in the total AHI count for the night. Interesting to watch, nothing to spend any think time on, though.

If you stop breathing or slow down your breathing in your sleep for the required time and other qualifications, it's sleep apnea.

It doesn't matter if it's your tongue, your nose, your throat, tonsils, phlegm, COPD, your brain, asthma, alien parasites living in your throat, Darth Vader, etc.

I'm not sure COPD would trigger anything the machine would classify as an apnea. The definition of apnea seems to require a short term reduction in air flow from what it was a few minutes before. Does COPD tend to cause sudden reductions, or just generalized airflow reduction over a period of several minutes? Your breathing could be so restricted that you're having severe O2 deprivation, but if the airflow rate is reasonably constant, even if it's inadequate, it won't show up as an "apnea."

My Pulmonologist said my function test indicated my COPD is mild now but exhaling is my issue. Damage to lungs from smoking kills air sacs that cause dispelling air to be difficult.
Last night over half my events (7) were CAs ahi 2.74

Sometimes I think the switch from cpap to bilevel is the issue. Never had CAs with Cpap but struggled to exhale. i

If all you had were 7 events, you're doing great, and forget those 'CA's' - negligible!

If you stop breathing or slow down your breathing in your sleep for the required time and other qualifications, it's sleep apnea.

Medically speaking, sleep apnea is a disorder. The centrals that Sclark is seeing could be normal and therefore would not be classified as sleep apnea.

They are probably very short, but out of curiosity I would like to know how long they are.