Sleepyhead/Machine experiment. Interesting results!

[dooger54]

During the day today I decided to use my machine and mask to get a baseline read on leaks on my nasal pillows. I worked at getting the right size pillow to use by comparing the leak graph in Sleepyhead to make comparisons. It was very helpful.

While on the machine I decided to try a little experiment by holding my breath for about 15 seconds two different times. I was curious to see how it would be recorded. The machine recorded both instances as Obstructive Apneas. Interesting. So this begs the question - just how does the machine determine what is an apnea (obstructive,central,unknown) ? I obviously didn't have any obstruction, I just held my breath for 15 seconds.

[grayghost4]

it is a reflex to close your throat when you hold your breath ..

[dooger54]

it is a reflex to close your throat when you hold your breath ..

So how does the machine differentiate between obstructive and central (clear) apneas??

[englandsf]

It makes sense that holding your breath looks like OSA and mouth breathing looks like a leak or clear airway.

[Pugsy]

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

Page 8 of the manual.

For more information on how the FOT works you will need to go to the ResMed website.

Awake breathing irregularities (like holding your breath) make it difficult for the machine to distinguish what category to put the "event". I have done the same experiment and I have had it flag the "event" as a central.
This is why we have to disregard known wake time flagged events. One..they don't count for sleep apnea therapy evaluation because we aren't asleep and two....the machine doesn't always get it right when it comes to awake breathing irregularities.

[palerider]

it is a reflex to close your throat when you hold your breath ..

So how does the machine differentiate between obstructive and central (clear) apneas??

the things you can find on youtube: https://www.youtube.com/watch?v=fDhGpyeYb0c

you can *see* the difference if you zoom in on the flow and mask pressure traces. and compare what the machine flags as an obstructive and a central. it's subtle, but it shows up in sleepyhead graphs.

[dooger54]

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



Awake breathing irregularities (like holding your breath) make it difficult for the machine to distinguish what category to put the "event". I have done the same experiment and I have had it flag the "event" as a central.
This is why we have to disregard known wake time flagged events. One..they don't count for sleep apnea therapy evaluation because we aren't asleep and two....the machine doesn't always get it right when it comes to awake breathing irregularities.

Pugsy-

Are you aware of any data in Sleepyhead which can be an indication of wake time vs. sleep? Patterns we can look for perhaps?

[Pugsy]

Are you aware of any data in Sleepyhead which can be an indication of wake time vs. sleep? Patterns we can look for perhaps?

Some people will tell you they can tell by tidal or minute volume changes but I never could myself.
Sometimes I have a good idea by the change in flow rate.
Awake breathing is more irregular and tends to move around more....once asleep the flow rate becomes much more uniform and "boring" looking. I can usually spot the first sleep onset after I go to bed.
After that I find it harder to spot the difference in the middle of the night with arousals or whatever.
It's rare that I sleep so soundly that I don't remember a handful of awakenings that are very brief but I can't always spot them on the graphs.

SleepyHead can only report whatever the machine gathers...so if the machine can't determine if you are asleep or not then SH isn't going to be able to report something the machine doesn't gather.

But sometimes a person can get a reasonable idea by looking at the graphs once they have seen a lot of graphs.
Sometimes my flow rate change is so definitive that it's fairly easy assumption to make but sometimes it's not so easy and I end up with a WAG.

One of the nice things about the Respironics machines is the wave form flow rate graphs. It puts the flow rate at just the right level of scale and gives you a nice concise image of the entire night so that asleep breathing is much easier to see when we have the entire night flow rate easily seen.

With ResMed machines we have to do our own wave form graphs and thus we end up with lots of segments that aren't so easy to evaluate.

[archangle]

During the day today I decided to use my machine and mask to get a baseline read on leaks on my nasal pillows. I worked at getting the right size pillow to use by comparing the leak graph in Sleepyhead to make comparisons. It was very helpful.

While on the machine I decided to try a little experiment by holding my breath for about 15 seconds two different times. I was curious to see how it would be recorded. The machine recorded both instances as Obstructive Apneas. Interesting. So this begs the question - just how does the machine determine what is an apnea (obstructive,central,unknown) ? I obviously didn't have any obstruction, I just held my breath for 15 seconds.

The machine attempts to detect whether your airway is open or not. Most of us close off our airway when we hold our breath. Closed throat = obstructive apnea. It's hard to hold your breath without closing off the airway.

The machines attempt to detect clear airway apneas by varying the pressure a bit and looking for changes in the airflow. The changes in flow are different if the path to your lungs is open than if your throat is blocked.