OSA technical terms questions ???

snamvar · Post by **snamvar** » Wed Mar 16, 2005 9:49 pm

I have been using the Remstar Auto C-flex for the past few days along with Encore Pro software. I really like it
I have some questions on few indices:
1) What is "flow limitation" ?
2) What should my goal be for leaks?
3) What is the snore index?
Thanks in advance.

chrisp · Post by **chrisp** » Wed Mar 16, 2005 9:58 pm

Flow limitation = something less than a hypopnea. A minor restriction

leak goal = less than 1 lps . depending on method used to measure

Snore index = amplitude and lenght of snore

Ionizer · Post by **Ionizer** » Wed Mar 16, 2005 10:03 pm

Flow restriction = When the keg is running low

Leak index = How many times you take a leak in an hour

Snore index = how loud you snore after creating a flow restriction

Ionizer

rested gal · Post by **rested gal** » Wed Mar 16, 2005 11:58 pm

snamvar, the leak rate with my Remstar auto/c-flex touches 50 lpm sometimes, but averages around 25 lpm each night, and I feel fine each morning. Bear in mind that I'm a confirmed mouth breather and the tape edges sometimes work loose, which is what accounts for any jumps in leak rate for me, I think.

The Remstar's leaks are measured in leaks per minute. I think (can't remember for sure) that the 420E autopap is measured in leaks per second, so comparing the leak rate numbers for those two different machines would involve some math...even basic math is not my strong point.

I recently saw my uncle's Encore Pro data on exactly the same kind of autopap I have - the Remstar Auto/C-flex. His leak rate was way, way down - steadily low all night. His pressure stays around 7 or 8 - mine is usually in the 8-12 range. He's using an Activa nasal mask, no chin strap, no tape - just doesn't leak air out his mouth at all in his sleep, ever! I was happy for him, but I was green with envy!!

snamvar · Post by **snamvar** » Thu Mar 17, 2005 1:00 am

Thanks rested gal. My leak for the last few nights averaged about 60-70. I think the problem is that I don't have a hook on my headboard for the hose. The Breeze have a fairly lose grip on my head. In the middle of the night when I toss and turn, the hose pulls on the interface and it leaks. The other possibility is that my mouth my open. I'll experiment and fingure out why. It's good to have the Software

derek · Post by **derek** » Thu Mar 17, 2005 5:27 am

Rested,
L believe that the Respironics leaks are measured in litres per minute, not "leaks per minute" In other words it is the volume of air leaking. The value includes the normal exhaust port leakage as the baseline.
Regards,
derek

Mikesus · Post by **Mikesus** » Thu Mar 17, 2005 6:10 am

Well I have to admit that I still get the occasional LARGE LEAK indicator (Mirage Full Face Mask) But, I still wake up feeling good. Don't get too hung up on the numbers, make sure you are feeling good.

Flow limitations are used to determine if a pressure increase is needed.
it is defined on sleepnet as:

Flow Limitation – the partial closure of the upper airway impeding the flow of air into the lungs.

As for specifics: (quoted from the Encore help file)

Flow Limitation Index

Flow Limitation events are scaled on the left. The dates of therapy are displayed along the bottom of the graph.

Changes in flow limitation are recorded as events.

The Flow Limitation Index is calculated by the total number of Flow Limitation events per night divided by the hours of use.

NOTE: The average, displayed to the right of the graph, is calculated by taking the total number of events divided by the number of therapy days. This can be used to indicate if there has been a significant degradation in the flow signal, resulting in a pressure increase.

Leak

Liters per minute are scaled on the left. The dates of therapy are displayed along the bottom of the graph.

Displays the amount of air leakage per night of use. If the chart shows leakage at the “LL” level (large leak), this is an excessive leak that will compromise therapy. This could be the result of a poor mask fitting.

NOTE: The average, displayed to the right of the graph, is calculated by adding the daily averages and dividing by the number of therapy days.

Snore Index

Snoring events are scaled on the left. The dates of therapy are displayed along the bottom of the graph. The pressure signal is evaluated for the possibility of snores when the patient is inhaling.

The Snore Index displays the total number of snoring events per night divided by the hours of use.

NOTE: The average, displayed to the right of the graph, is calculated by taking the total number of events divided by the number of therapy days.

wading thru the muck! · Post by **wading thru the muck!** » Thu Mar 17, 2005 7:24 am

Keep in mind regarding the leak graph, that a good portion of what shows up is the "planned" leak through the exhaust holes. This will rise as your pressure rises, so that a person with a pressure of 12cm will automaticaly have more leak than a person at 8cm. In theory, as long as you stay below your machines "large leak" line, the machine is able to compensate for the leak rate.

RG, when you say "leaks per minute" are you refering to your machine or Ionizers definition?

littlebaddow · Post by **littlebaddow** » Thu Mar 17, 2005 8:28 am

Ionizer wrote:Leak index = How many times you take a leak in an hour

Ionizer

OK, can't resist, even though it might well be lost on many of you....

What's this got to do with my Welsh cousins

meister · Post by **meister** » Thu Mar 17, 2005 9:33 am

Some of my best nights when I wake up and can function during the
day are accompanied by the "High Leak in Last Session" message.
If I tighten down the mask more, then I get raw sore on my nose and
red marks all over my face. I sure hate answering the same question
everyday at work about my face. "Just my wife slapping me around,
again!" doesn't always go over well ...

My doctor is adament about patients have ABSOLUTELY NO access to
stats. He just wants to hear that you feel great or not. Me, I am a
tech jockey and data cruncher. I want those numbers and graphs, and
I want to achieve perfection! Meaning zero leaks. Maybe super glue
that hose right into my throat for zero leaks.

I am just hoping that some expert will step in and clarify whether that
"High Leak in Last Session" can just be safely ignored, or not. I need
to get an Oxygen saturation sensor to really know, I guess.

rested gal · Post by **rested gal** » Thu Mar 17, 2005 3:46 pm

Derek, thanks for the correction! I'm as bad at leak/litre definitions as I am in figuring out "what divides into what." I'm very glad you set my error straight.

Rested,
L believe that the Respironics leaks are measured in litres per minute, not "leaks per minute" In other words it is the volume of air leaking. The value includes the normal exhaust port leakage as the baseline.
Regards,
derek

Mikesus · Post by **Mikesus** » Thu Mar 17, 2005 5:12 pm

If you have the instructions that came with your mask, (and its a Resmed) there is a graph showing the leak rate at specific pressures. Check your graph on your instructions, then compare against your leak graph that should give you an idea of what is too much...

liz4cps · Post by **liz4cps** » Thu Mar 17, 2005 5:42 pm

meister wrote:Some of my best nights when I wake up and can function during the
day are accompanied by the "High Leak in Last Session" message.
If I tighten down the mask more, then I get raw sore on my nose and
red marks all over my face. I sure hate answering the same question
everyday at work about my face. "Just my wife slapping me around,
again!" doesn't always go over well ...

My doctor is adament about patients have ABSOLUTELY NO access to
stats. He just wants to hear that you feel great or not. Me, I am a
tech jockey and data cruncher. I want those numbers and graphs, and
I want to achieve perfection! Meaning zero leaks. Maybe super glue
that hose right into my throat for zero leaks.

I am just hoping that some expert will step in and clarify whether that
"High Leak in Last Session" can just be safely ignored, or not. I need
to get an Oxygen saturation sensor to really know, I guess.

I agree that it's helpful to have the stats, etc. They can be quite useful, especially since it can be difficult to get everything set up correctly so you can sleep right.

As far as leaks are concerned, you can't nor do you want them to be zero. The litres per minute reported include, as someone else mentioned, the air that escapes thru the exhaust port. That can't be zero as that would mean you were breathing in what you just exhaled which, of course, would not have enough oxygen in it.

Perfection is impossible to achieve in anything like this -- as much as I'd like it as well. You can tell if you are sleeping well though -- feeling good in the morning and if you're dreaming a lot, that's a good sign (though not necessary). Most untreated or under treated folks with sleep apnea don't sleep well enough to dream much if at all. When treatment is working and we are sleeping well, we have something they call "REM rebound" which means we start dreaming a lot. That doesn't last forever though it can last a while.

photogal · Post by **photogal** » Thu Mar 17, 2005 8:11 pm

As I am still researching and haven't purchased my Cpap yet, I find all of this very interesting. Meister, that's funny about your wife slapping you around. As a female, I can't say that I am enthusiastic about having red marks all over my face, either.
I'm hoping to order in the next couple of weeks. I've been really snowed. I've spent all week trying to get my tax stuff in order and still have another couple of days' work. I just have to take one thing at a time, get it done, then move to the next thing. The next thing will be the Cpap.
I actually had a decent night's sleep the other night, and woke feeling rested. That is so very rare that it was like, "Oh, this rings a dim bell of how I USED to feel!"
1. taxes
2. cpap
3. get written permission from two doctors that says my heart and asthma condition will allow anesthesia for shoulder surgery
4. Aughhhhhhh, shoulder surgery!!!!

OSA technical terms questions ???

OSA technical terms questions ???

I agree with Mikesus!

Re: I agree with Mikesus!

Machine	Mask