Accuracy of S9 Autoset statistics?

[soundersfootballclub]

I'm confused about the stats I am getting from my S9. Granted I have only been using it for 2 whole days but still. So far the Apnea Index lists that I have Central Apneas and almost no OSA. Now my sleep test showed I had OSA exclusively. Am I misunderstanding the S9 stats here? Is this machine more accurate than my sleep study results?

Another issue. I notice when I have tested it out during "naps" the last 2 days it is registering apnea occurances. The thing is I did not actually fall asleep either time I was just resting. So that has me wondering about the AHI stats in general, especially since the # of sleep pauses it's recording so far 6 and 8 an hour is significantly lower than the 18 an hour I had during my sleep test. I am also wondering if the occurrances it is recording means that those were occurrances that were both detected and also corrected by APAP??

And third. The data shows I have a maximum leak of 28.8. Now when it records these levels is it catching one of the times my mask has fallen off for a few seconds or is it telling me that a significant amount of the time my mask was leaking at that level or mouth was open. I am going to try sleeping with the chin strap I bought next and see how the leak rate changes.

Any insight from the experts here would be greatly appreciated. Thanks!

[Otter]

I'm confused about the stats I am getting from my S9. Granted I have only been using it for 2 whole days but still. So far the Apnea Index lists that I have Central Apneas and almost no OSA. Now my sleep test showed I had OSA exclusively. Am I misunderstanding the S9 stats here? Is this machine more accurate than my sleep study results?

The difference may be that the S9 can't tell whether or not you're trying to breathe, and the techs at the lab can. It also can't tell whether or not you're actually asleep.

Another issue. I notice when I have tested it out during "naps" the last 2 days it is registering apnea occurances. The thing is I did not actually fall asleep either time I was just resting.

It's very common for people to stop breathing while awake. You were probably rolling over or thinking, and unconsciously held your breath for a while. I sometimes find OAs in my data when I know I was a awake. Either I held my breath for a few seconds and was so stuffed up the s9 thought that was the cause, or I was swallowing.

So that has me wondering about the AHI stats in general, especially since the # of sleep pauses it's recording so far 6 and 8 an hour is significantly lower than the 18 an hour I had during my sleep test.

Your machine is not in the same league as the equipment at the sleep lab, but then, you don't need an assistant to help you get ready for bed every night either. It will not be as accurate, but I wouldn't get to upset about that yet. Just keep in mind where the data is coming from. Also, your not in the lab. Something as simple as the pillow you use could make a huge difference if it causes you to change your position.

I am also wondering if the occurrances it is recording means that those were occurrances that were both detected and also corrected by APAP??

It only scores the events that actually happen.

And third. The data shows I have a maximum leak of 28.8. Now when it records these levels is it catching one of the times my mask has fallen off for a few seconds or is it telling me that a significant amount of the time my mask was leaking at that level or mouth was open. I am going to try sleeping with the chin strap I bought next and see how the leak rate changes.

Ignore maximum leak rate. What you want to look at is the 95th percentile and median numbers. The display on the machine shows the 95% rate.

Any insight from the experts here would be greatly appreciated.

Oops. I'm no expert. But that took a while type, so I'll post it anyway.

If you post your summary numbers and detailed graphs, someone will probably offer you some insight.

[soundersfootballclub]

Otter thank you for responding. You said it only records the events that actually occur. So how do we know how effective the machine is in correcting the sleep pauses as they occur? Is that not recorded?

I also just redownloaded the data so it wasn't in summary format and now have the detailed graphs. I am a bit confused about the "Events" column. What do the numbers mean over each apnea event? Is it the # of seconds the pause lasted? One says 24. That is a long pause if that is what it means! Yeesh. Thanks again for responding to my questions. Take care.

[Otter]

Otter thank you for responding. You said it only records the events that actually occur. So how do we know how effective the machine is in correcting the sleep pauses as they occur?

Because you are having less apnea than you did in the lab without treatment, and, hopefully, you feel great.

Is that not recorded?

The machine can't record what doesn't happen. In auto mode, it does its best to predict obstructive events and head them off at the pass. You can tell it thought there was trouble coming because it increased the pressure. And you can look at the snore and flow limitation traces. But it can't record what it prevented any more than you can show your friends pictures of the kids you didn't have because you used a condom.

I also just redownloaded the data so it wasn't in summary format and now have the detailed graphs. I am a bit confused about the "Events" column. What do the numbers mean over each apnea event? Is it the # of seconds the pause lasted? One says 24. That is a long pause if that is what it means!

Afraid so.

[Pugsy]

What is your Central hourly index?
It is normal to have a few centrals during the night. Some might be scored at sleep onset or even if you hold your breath while turning over in bed.

[soundersfootballclub]

What is your Central hourly index?
It is normal to have a few centrals during the night. Some might be scored at sleep onset or even if you hold your breath while turning over in bed.

Pugsy I think it's 6.1 if you are asking what the # is next to "Central" under the "Apnea Index Column". "Obstructive" is only 0.3. This is actually data just from last night. I ended up deleting the first night's data because I thought something was wrong with my sd card.

Otter thanks again for the additional info. I think my doc is going to switch me to CPAP after my followup once he has an idea of what my pressure should be set at. It sounds like I might get better results under that setting. I noticed with my report that I seem to have pauses when I am in REM sleep especially the last few hours of sleep between 4-7am. I wonder if I can get away with only having to wear this thang for half the nite!

[Pugsy]

Pugsy I think it's 6.1 if you are asking what the # is next to "Central" under the "Apnea Index Column". "Obstructive" is only 0.3. This is actually data just from last night.

I would watch that Central number. Using the software look to see if the centrals are grouped together like when you first go to bed or maybe upon waking up. It is a little more than I would be comfortable with if I couldn't explain them away as sleep onset or turning over in bed.

You are using APAP? What pressure range? Is this the prescribed pressure from titration study?

If you could post that report showing the event scoring during the night it might help to determine if those centrals are anything to be concerned about. Especially if this continues.

Don't know how to post the report?
This is how I do it.


Open the image to full size so it is easily read.
I use Vista snipping tool to create a screen shot and crop the image at the same time.
Prt/scr key will also take a screen shot if using XP. If laptop is used sometimes the Fn key has to be pushed at the same time as the prt/scr key
I think windows 7 Home Premium has the snipping tool, Basic may not.
Once the screen shot is created save it in jpg format.
Upload the image to a host site. I use Photobucket it is free, there are others.
Once the image is uploaded then copy the ENTIRE IMG address. Be sure to include the opening and closing IMG in brackets. Paste that copied address into a post here.
Use the preview button. If you can't see the image try again because if you can't see it we can't.

[soundersfootballclub]

Pugsy I think it's 6.1 if you are asking what the # is next to "Central" under the "Apnea Index Column". "Obstructive" is only 0.3. This is actually data just from last night.

I would watch that Central number. Using the software look to see if the centrals are grouped together like when you first go to bed or maybe upon waking up. It is a little more than I would be comfortable with if I couldn't explain them away as sleep onset or turning over in bed.

You are using APAP? What pressure range? Is this the prescribed pressure from titration study?

If you could post that report showing the event scoring during the night it might help to determine if those centrals are anything to be concerned about. Especially if this continues.


.

Pugsy I did post my report. Here is the post. viewtopic/t67065/viewtopic.php?f=1&t=66 ... 50#p623450
If you have any insights I would love to hear them.

They couldn't find a pressure that worked during my split study so I was told to be on APAP with a pressure of 4 to 12 until my followup visit. I asked my doc if I definitely had OSA and not central and he said it was OSA.

[Pugsy]

Pugsy I did post my report. Here is the post. viewtopic/t67065/viewtopic.php?f=1&t=66945&p=623450#p623450
If you have any insights I would love to hear them.

Am I missing something? I see 3 images but they are of the sleep study. I would like to see the ResScan report from last night. The one with the graphs and the events showing the little numbers in the boxes above the events.

I didn't comment in your other thread because the other members had pretty much covered things.
Your situation of not being able to find suitable pressure during titration study is not uncommon.

[soundersfootballclub]

Pugsy I did post my report. Here is the post. viewtopic/t67065/viewtopic.php?f=1&t=66945&p=623450#p623450
If you have any insights I would love to hear them.

Am I missing something? I see 3 images but they are of the sleep study. I would like to see the ResScan report from last night. The one with the graphs and the events showing the little numbers in the boxes above the events.

I didn't comment in your other thread because the other members had pretty much covered things.
Your situation of not being able to find suitable pressure during titration study is not uncommon.

Oh sorry. I thought you asked about my sleep study report. I will figure out how and post the ResScan report.

[soundersfootballclub]

Ok Pugsy I figured out how to get the reports on here from last night. They look small on my screen I hope you can enlarge them with the magnifying tool. Thanks for taking the time to look at these.

http://s1124.photobucket.com/albums/l57 ... nt%3D2.jpg
http://s1124.photobucket.com/albums/l57 ... nt%3D1.jpg

Btw what the heck are Flow Limitation, Flow, Minute Ventilation? Why should I care?

Cheers.

[Pugsy]

It is a bit hard to see but it looks like those groupings with the centrals are associated with breaks in the scoring. In other words wakeups. Then you put the mask back on and have some more groups and these could be sleep onset events or even toss and turn arousal. The machine doesn't know if you are awake or not. It just calls them as it sees them.

You can zoom in on those and see for sure if the bulk of the groups are right after you turn the machine on and may still be awake or in transition to sleep. If this is the case they aren't hugely significant and if you were having a formal sleep study the tech wouldn't score them because they would show up maybe with an arousal or on the EEG part you weren't really asleep.

For now I would just watch those closely and see what kind of reports you get when you don't have sleep interruptions.

Btw what the heck are Flow Limitation, Flow, Minute Ventilation? Why should I care?

Flow is your breathing...the waxing and waning of the breathing rhythm during sleep. You can zoom in on the flow and see it in more detail.

Flow limitations..small decreases in the flow from whatever reason and they don't qualify for some other scoring.
Maybe Hyponea wannabe....maybe very small collapse in airway hindering flow just a little bit.

Minute ventilation? I don't use ResMed machine so I don't know how they define it. Is there a glossary in the software or an explanation in your clinical manual for it? Someone using a ResMed machine will have to explain its implications.

[Marcman]

I believe I saw somewhere else recently that minute ventilation is the measure of how much air you take in per minute. I tend not to graph it, because I don't think I've ever seen anyone explain how to interpret it. Presumably, a drop in minute ventilation is bad, but I don't know if I've ever seen drop significantly for a significant amount of time, but I tend not to look at it. I tend to look mainly at the events, flow, and flow limitation, because that's what I think I understand.

[jy2e71]

The minute ventilation is the amount of air a person breathes in one minute. The minute ventilation is calculated by multiplying tidal volume times respiratory rate.

[Bluecat]

But it can't record what it prevented any more than you can show your friends pictures of the kids you didn't have because you used a condom.

I love the comparison!!
You can more or less have an idea of the effectiveness of your treatment by comparing the results given by your machine to those of your sleep study.

Bluecat