Can you trust the data from the machine?

mhacker · Post by **mhacker** » Sat Jun 16, 2007 9:36 am

This almost sounds paranoid but the more I learn, the less I trust the data.

Consider this chart. When I woke up to go to the bathroom at about 5 hours into sleep, I shut off the machine and pulled the hose. Now I have a max leak reading that is not real. Same with the OA just as I was turning off the machine to get up. I had been laying there petting the cats and was not asleep so I know it is a false reading. How are people getting a 0.0 AHI when the data can be so easily skewed?
I reviewed several weeks of data and I see a lot of this type of errors. I think I want to edit the data to remove the false indicators.

This is another reason to own the software and not rely on summaries or someone just giving you numerical readings.

bdp522 · Post by **bdp522** » Sat Jun 16, 2007 10:32 am

Could it be that the OAs are what woke you in the first place? Could it be that when you were waking you held your breath till you shut off the machine, making it look like an OA?
Leak rate for your mask is about 26 at your pressure(10.3). You have leaks that are way to high. I would worry less about the occasional Max leak rate at this point. You may have disconnected the hose before the machine was fully off. But you need to get those leaks under control. Could you be mouth breathing or mouth leaking?
Although with an AHI of 0.7 you might want to just leave it all as it is!

Brenda

Guest · Post by **Guest** » Sat Jun 16, 2007 11:21 am

I agree with Brenda.
You don't breathe the same when you're awake as when you're asleep.
I've also wondered, in my own case, if some of the reported hypopneas result from when I'm turning over during the night......I can't turn over without holding my breath.

I take the numbers with a grain of salt....it ain't perfect, but at least they're a yardstick to go by......better than making repeated trips to the doctor only to be asked "How do you feel?"

You're also using a long ramp time, too. I would suggest shortening the ramp time or doing without it. Your pressure isn't that high to warrant it.

But, your numbers are good.

Den

mhacker · Post by **mhacker** » Sat Jun 16, 2007 11:59 am

bdp522 wrote:Could it be that the OAs are what woke you in the first place?

More than likely as I laid there for a few minutes - that one I figure is real

bdp522 wrote:Could it be that when you were waking you held your breath till you shut off the machine, making it look like an OA?

Yep, I am positive of that, which is why I have gone back and looked at several nights of data. I edited the .XML file and removed several "questionable" events. The overall averages did not change much. I am still at 1.1 AHI for the month - better than the 92.7 AHI I was diagnosed with.

bdp522 wrote:Leak rate for your mask is about 26 at your pressure(10.3). You have leaks that are way to high. I would worry less about the occasional Max leak rate at this point. You may have disconnected the hose before the machine was fully off.

My normal pressure is 11.0 and the ramp up skews that average - two 45 minute ramps in 7 hours. I figure I did a quick disconnect but at 4 in the morning, who is going to sit there and wait for the machine to stop? If I edit that one event, my max is 70 (which is what EPA shows) not 110 like EP shows. Obviously Jim's program takes events like this into account.

bdp522 wrote:But you need to get those leaks under control. Could you be mouth breathing or mouth leaking?
Although with an AHI of 0.7 you might want to just leave it all as it is!

I have been spending a lot of time on the leak issue. Taped, glued, mouth guard, all have made small changes - thinking of getting piercings and bolting things together....
Since I have nights with an AHI of .2 and a 30 day average of 1.2 AHI, I am not worried about the average numbers. But I am looking deeper into the numbers since at a casual glance they may look good but on the mornings I feel like cr@p - the leaks and OAI are extremely high.

I am amazed that the little machine can even do this, maybe I am to hard on it by wishing for perfect data and interpretation.

Snoredog · Post by **Snoredog** » Sat Jun 16, 2007 12:24 pm

well to me it looks like:

you used Ramp when you started.
you took a short break a little after therapy hour 5 then used Ramp again.

During that break period, after therapy hour 5 you had a large leak seen. Can be many causes of that, either you developed a leak which was what caused you to awaken for the break in the first place or you removed the mask before turning off the machine, or that leak was associated with the anti-asphaxia flapper valve slamming shut after turning on the machine if using a full face mask.

In any case, that momentary mask leak is irrelevant to your therapy, it wasn't enough to register as even Max leak. Your avg. leak is only 43 L/m, so if the interface you are using is avg. 30L/m or so, that is not bad. Could be improved upon but not bad.

If anything these machines are overly sensitive vs. missing events.

DrowzyDave · Post by **DrowzyDave** » Sat Jun 16, 2007 12:34 pm

mhacker wrote:
bdp522 wrote:But you need to get those leaks under control. Could you be mouth breathing or mouth leaking?
Although with an AHI of 0.7 you might want to just leave it all as it is!
Since I have nights with an AHI of .2 and a 30 day average of 1.2 AHI, I am not worried about the average numbers. But I am looking deeper into the numbers since at a casual glance they may look good but on the mornings I feel like cr@p - the leaks and OAI are extremely high.

Wouldn't a high leak rate affect the machine's ability to accurately measure apneas and hypopneas? Since it is measuring limitations in airflow, if there is a large leak happening, wouldn't a lot of airflow restrictions in the patients's airway go undetected and result in an underestimated AHI? I am wondering if that is the case for me as well. I have an average leak rate in the low 40s. I have the mask type set in my machine for a FF mask. I believe the machine subtracts the intended leak rate since when I have the mask on and machine running the displayed leak rate is 0. To get the displayed leak rate to read 40, I have to create a pretty large leak. Yet my nightly and average AHIs are between 7 and 9 but I too feel like cr@p some mornings.

Dave

mhacker · Post by **mhacker** » Sat Jun 16, 2007 2:24 pm

Well I feel better that other people see the same holes in the data. I had not thought about:

"You're also using a long ramp time, too. I would suggest shortening the ramp time or doing without it."

Interesting that reviewing the data in a timeline - I usually have 1 to 2 "snores" during my initial ramp but not on subsequent ramps. It is possible that starting the ramp at 4 is too low also. It must be the default setting and the RT did not think of setting it or telling me - or it did not register that it was a convenance setting for me to adjust.

I suspect that there are extra apnea events because of coughing, yawning, rolling over, etc. If I had an excessive amount, I would try to eliminate each by finding something to blame. Since my events are few, I will just live with it, knowing that a measured 0.0 AHI is never going to happen. A real 0.0 AHI may have happened during my two 2 event nights or my 3 event night.

Goofproof · Post by **Goofproof** » Sat Jun 16, 2007 2:58 pm

I trust mine! The first thing you need to know.

The Three states of Matter:

Matter, the building blocks of the Universe

Anti-Matter, The reverse of the building blocks of the Universe, These must be kept apart at all costs.

Don't Matter, This Covers Almost Everything Else, Especally data from XPAP machines, as it is only a indicator of treatment, it's not like shooting a rifle, it's closer to shooting a shotgun. The trends of your treatment are what count, along with you feeling better. Jim

JimW · Post by **JimW** » Sat Jun 16, 2007 3:02 pm

mhacker wrote:...It is possible that starting the ramp at 4 is too low also. It must be the default setting and the RT did not think of setting it or telling me - or it did not register that it was a convenance setting for me to adjust.

I would not be able to tolerate a starting pressure of less than 5.5 or 6 very well. Raising that starting ramp pressure might be helpful.

jennmary · Post by **jennmary** » Sat Jun 16, 2007 4:17 pm

My ramp starts at 6. I usually only set the ramp for about 10-15 min though. My pressure is at 14 so it can be hard for me to just start at that. So I use the ramp for 10 min.....or even 5 sometimes. For me the ramp isnt about falling asleep before the pressure hits, it is just easer to gradually increase then to jump right in at 14. I am usuallly still quite awake when ramp is over.
My RT made sure to ask me when I was trying on my mask and getting machine if that 6 starting point felt ok. She would have changed it if it wasnt, but it worked for me. I dont feel hardly any pressure and it almost feels like it is off when I exhale. I also have exhilation relief on my machine.

Guest · Post by **Guest** » Sat Jun 16, 2007 5:08 pm

mhacker wrote:Well I feel better that other people see the same holes in the data. I had not thought about:
"You're also using a long ramp time, too. I would suggest shortening the ramp time or doing without it."
Interesting that reviewing the data in a timeline - I usually have 1 to 2 "snores" during my initial ramp but not on subsequent ramps. It is possible that starting the ramp at 4 is too low also. It must be the default setting and the RT did not think of setting it or telling me - or it did not register that it was a convenance setting for me to adjust.

I suspect that there are extra apnea events because of coughing, yawning, rolling over, etc. If I had an excessive amount, I would try to eliminate each by finding something to blame. Since my events are few, I will just live with it, knowing that a measured 0.0 AHI is never going to happen. A real 0.0 AHI may have happened during my two 2 event nights or my 3 event night.

Not necessarily. Over the last two years, I've had about a dozen.....some on the forum report several in a week or month. On the night of the 11th of this month, I had a 0.0 in all three categories.....Apneas, Hypopneas AND Snores. It was the zero snores that surprised me.

Give it time......you've got a good start.

Den

John_M · Post by **John_M** » Sat Jun 16, 2007 5:31 pm

bdp522 wrote:..

But you need to get those leaks under control. Could you be mouth breathing or mouth leaking?
Although with an AHI of 0.7 you might want to just leave it all as it is!

Brenda,
This is the situation I am facing too. My AHI's look good, typically around 1.0, occasionally 0.0. But my leak rate is kinda high, in the low 40's lpm.

What do we need to do to bring down the leaks? What's the best approach?
What kind of strategies to go the last miles. I have tried Velcro, Panty tights, Pad cheeks, pping masks, tightening straps, loosning straps etc.

Do you think Puresleep would help?

John

Guest · Post by **Guest** » Sat Jun 16, 2007 5:58 pm

John,

If you're using the Comfortfull 2 as is showing in your profile, I'd try a different full face mask......maybe the UMFF or the new Quattro. Leaks in the low 40's aren't bad.....depending on what your pressure is.
I just couldn't get the Comfortfull 2 to work for me......but some people do.

Den

Snoredog · Post by **Snoredog** » Sat Jun 16, 2007 6:13 pm

you are on CPAP, leaks don't mean squat to that machine unless they become so bad it can no longer maintain your 10cm pressure. If leak were so bad that it caused that, you should be seeing solid black tics across the top of the Leak graph. I see none.

Looks like a 30-45 minute Ramp period, I see nothing wrong with that, it is more important that you get to sleep using any means necessary including using a Ramp, it is WHY they added that feature to nearly all machines.

Starting Ramp pressure: Looks like you are starting at 4cm, which may be a problem, too low and you be starving for air just to breathe. But after 5 minutes it will already be at 4.5cm pressure, then 5cm after 10 minutes and 6cm by the time 20 minutes have elapsed. So depending on what mask you are using, the air may feel a bit stuffy for the first 20 minutes. Once you reach 6cm, you start getting enough pressure to properly flush out exhaled CO2 from the mask.

If having and using a Ramp (even at 4cm starting pressure) were a problem, we should be seeing a bunch more OSA tics on that report during that period, but we don't.

Again, this is a CPAP it doesn't care as much as an auto about leaks, there is nothing it would do about them anyway.

Your numbers look fine, I don't see how you can improve on that any.

mhacker · Post by **mhacker** » Sat Jun 16, 2007 6:38 pm

I pulled out my initial sleep study - it will be one year next week - from the notes - "Tech to start CPAP at 5.0 Due to OSA, OSH & Snores"

Ya think a ramp start of 4 might be a bit low. I shortened the time and raised the pressure. Will let it stay for a week before I change anything else.

Also just noted that my AHI was 4.6 with the CPAP at the sleep study so in 9 months I have had a 75% improvement.

it's not like shooting a rifle, it's closer to shooting a shotgun. The trends of your treatment are what count, along with you feeling better.

Jim, yeppers, even though I feel better, lost weight, off all medications, BP down, my over-all sense of feeling "well" is just not there yet. I guess I am expecting too much and want to find a reason for "why not?".

But then I got three wild pigs this weekend with three shots so I have this OCD of "need it perfect or it's not good enough" Going to be a big BBQ on the 4th!!