Leakage Rates too Low

I have a history of having extreme trouble finding a mask that will seal at my normal pressure of about 17cm H20.

Recently I have been tryin to use a Phillips Respironics Comfort 2 (Not gel) full face mask. On about 4 nights of maybe the 7 different nights I have used it, I have had the ResMed S9 Auto Vpap machine I use tell me that it has recorded between 0-3 liters/minute average leakage. This happened last night, and I recall that I was able to get the mask to seal really, really well. When I breathed the mask seal was expanding and contracting without any hint of leak at all. I also put the SD card of the S9 machine in my computer and looked at the data in the ResScan software and it did confirm that I had really that low average leakage for those 4 nights.

But here is the rub. On those 4 nights when the leakage was that low, I have awakened and felt absolutely rotten, tired and sleepy and worn out for the entire day. This is compared to my quattro mask which has a typical leakage of around 30 liters/min. I have also had days with the Comfort 2 when I have averaged around 30 liters/min leakage. With the quattro or the Comfort 2, when I am having around 30 liters/min leakage, I typically feel that I slept reasonably well (with cpap, however I never have felt a totally good sleep), and certainly not awful like the days I've shown the leakage around 0-2liters/min average.

But wait, on top of that, the Phillips charts that show the leakage rates from the exhaust port from the Comfort 2 mask http://www.healthcare.philips.com/asset ... 111027.pdf, indicate that I should expect a MINIMUM, NORMAL LEAKAGE OF ABOUT 34 liters/min at a pressure of 15 cmH2O (remember I'm at 17) from the exhaust port on the Comfort 2 mask.

THEREFORE, there is no way I should be getting an average leakage rate down around 0-2 liters/min.

So something funny is going on here.

Can someone figure out why?

Thanks.

ResMed machines subtract the vent rate BEFORE reporting it on the LCD screen or it gets recorded on the SD card to be used with the software. The machine doesn't know exactly which mask you are using so they use a generic vent rate adjusted for the pressure you use. It isn't 100% accurate but it is very close.

ResMed says that they can compensate for leaks up to 24 L/min. Above that amount and they say therapy and scoring of events can be impaired. ResScan has a red line at the 24 L/min mark on their software reports.

If you are feeling horrible after the nights with minimal leak then it isn't the leak that is the problem but might be something else. The nights with 30 L/min....well, if you spend a lot of the night with a leak that much then we can't even trust the data to be accurate.

ResMed machine users try to get as far below that 24 L/min line as they can. Less than 10 L/min is more what you want. You sure don't want to spend much time above 24 L/min.

What is your AHI (and the breakdown to categories) when you have the minimal leak?

I have to put the card in the computer to review it, but my recollection is that the AHI was below 10.

Will tell you later tomorrow, up too late because of Patriot's game today.

No matter what the AHI is, I was definitely feeling awful.

I suspect what I should be doing is getting a new sleep study with the respironics mask. I'm betting that with a good seal, my pressures may be too high, or something else is going on.

charlestek wrote:my recollection is that the AHI was below 10

I feel pretty awful with an AHI of 5 even. Industry standard is to get AHI below 5.

You might post one of your daily detailed reports here for comments..Perhaps we can spot something that needs some work. Also...need to know the Central index part of any AHI.

Pugsy,

Here is the latest report from my machine. http://www.skytomic.com/Report_1-27-12.pdf

I've been using my medium quattro for the last few nights which burps a lot no matter how I tighten it down. Still did not sleep well last night, even though the average leakage was around 14l/min.

Maybe you need to get a mask liner for that Quattro FX to stop the leaks.

Squid,

This is a regular quattro. I use a quattro medium or large, or the respironics comfort2 (non gel)
On the quattro's I have a pad a cheek liner that I may or may not use, sometime it helps, sometimes not.
I also have tried a quietus liner, which didn't help as well as remzzz's

It is really hard to evaluate a single night's leak from the summary graph. We can't see the peaks and the valleys. Can you post a single night daily detailed report showing the leak on an hour by hour thing?

In general from the summary reports your leaks are showing all over the place with some night's venturing into large leak territory but we can't tell how long you spent in large leak from these summary reports.

If leaks (even small ones) are waking you up for any reason then they are messing with your sleep cycles and in turn will mess with how you feel the next day. Anything that wakes us up for any reason is messing with our chance of feeling improvement.

Pugsy,

I will try to get that data a little later this evening. Last time I tried to tell the program to do a single day's report, I couldn't later get it to revert to the summary report.

Ok, here are some detailed reports:
Last night, the 27th, I awoke and found one of the mask strap clasps disconnected from the mask, so I snapped it back on, as the detailed report showed, I had high leakage for a number of hours, then it dropped back after I fixed the mask. The report for the 24th, shows very little leakage, but I remember feeling awful the next day.

Also last night, on the recommendation of a gastroenterologist, I used a wedge to raise my head so that I would not get acid reflux. Despite the fact that the mask leaked a lot, I feel a little better today, still tired, but not zonked.

http://www.skytomic.com/1-27-2012.pdf

http://www.skytomic.com/DetailedReport_1-26-12.pdf

http://www.skytomic.com/1-24-2012.pdf

Here is a detailed report for last night, where I used the respironics mask and tightened it down hard. There was very little leakage: http://www.skytomic.com/1-28-2012.pdf

Unfortunately, today I felt considerably worse than normal, that is considerably worse then when I have average leakage around 30l/min. This seems to happen when the mask has very little leakage at night.
I can't function when feeling this badly exhausted all day. I am at a loss here, as it just seems to confirm that cpap is a very poor treatment for me. I am considering mandible advancement, and I guess this pushes me further toward that. I'm looking for work and would have to wait at least 3 months to get the operation, and it would be at least a month after the operation before I could be able to interview and accept a job, so that is a huge issue.

If you had zero leak and slept horribly due to mask pain....you are going to feel horrible the next day even if the AHI is 0.0 and the leak line was perfectly straight with no leak blips. Anything that messes with your sleep messes with how you feel. So we keep trying different masks till we find something that is comfortable and doesn't leak like crazy. Sometimes we have to make a few compromises.
Give up a little leak so the mask doesn't create pain and disrupt our sleep.

I could easily crank my nasal pillows down so that my leak was non existent but the price I would pay in horrible sleep due to pain simply isn't worth it.

It sucks....if the masks leak too much then the leaks will wake us up and thus mess with sleep quality and we feel like crap.
Tighten the mask up so it doesn't leak (so the leaks don't wake us) and then we can't sleep well due to the pain or discomfort from the over tight mask. We still end up feeling like crap.
So we compromise. Find an acceptable leak level that doesn't wake us up fiddling with leaks and mask loose enough to be comfortable and not cause pain which also wakes us up.

A person has to get good quality sleep to ever hope to feel better from sleep apnea.

The mask is the most problematic part of cpap therapy. We just keep trying masks till we find one that lets us control the leaks and doesn't cause pain.

Since the port leakage for my mask at 17cmH2O pressure should be around 36l/min, I would expect subtracting off 24l/min, that the lowest leakage I could get would be 12l/min???

You most certainly can and will have leak rates reported down to 0.0 or 0.5 or 0.10 BECAUSE
ResMed machines do the math for you THEN they report the excess leak. You are never going to see a total leak report on your machine for you to subtract the vent rate from. You aren't supposed to do the math. You would only use the vent tables if you had a machine like mine.

ResMed will take a generic number from your mask choice in your setup menu for your average pressure and subtract it from the total leak (internal) and then report excess leak. I say generic number because these machines don't have every mask's vent rate computed stored in its memory. So it likely will not be a perfect number but will be very close.

ResMed says that they can handle excess leaks up to 24 L/min (the red line on ResScan leak graphs).

You don't go subtracting 24 L/min or anything from what you see being reported. What you already see is excess leak. That 24 L/min number is just an imaginary line in the sand where ResMed has chosen to draw the line and say that above this line....we may not be able to do a good job.

Now for my machine that reports Total Leak (Vent rate + excess leak) I would use this graph to subtract the vent rate at my pressure to get the excess rate. 24 L/min never comes into my factors at all. That is a ResMed line in the sand number. The only way I would ever use it is if my vent rate was 24 and I was mentally subtracting it to get excess leak.
Respironics line in the sand is roughly around 90 L/min. We are never given a set number to go on.

IF you had a machine like mine...here is an example of what might happen if your average pressure and average vent rate was 36 L/min.
Respironics machine reports and average leak rate of 50 L/min... Vent rate is 36 L/min...So we subtract 36 from 50 and get 14 L/min excess leak. We don't use the same 24 L/min excess leak line that you use.
Instead we use a total leak line around 90...so we compare the total leak of 50 to that 90 and we see that we are well within acceptable limits.

You need to be cautious. You may be acquiring high rates of CO2. Other than that, I really haven't a bit of advice to offer. Just sounds hinky to me.

charlestek wrote:I have a history of having extreme trouble finding a mask that will seal at my normal pressure of about 17cm H20.

Recently I have been tryin to use a Phillips Respironics Comfort 2 (Not gel) full face mask. On about 4 nights of maybe the 7 different nights I have used it, I have had the ResMed S9 Auto Vpap machine I use tell me that it has recorded between 0-3 liters/minute average leakage. This happened last night, and I recall that I was able to get the mask to seal really, really well. When I breathed the mask seal was expanding and contracting without any hint of leak at all. I also put the SD card of the S9 machine in my computer and looked at the data in the ResScan software and it did confirm that I had really that low average leakage for those 4 nights.

But here is the rub. On those 4 nights when the leakage was that low, I have awakened and felt absolutely rotten, tired and sleepy and worn out for the entire day. This is compared to my quattro mask which has a typical leakage of around 30 liters/min. I have also had days with the Comfort 2 when I have averaged around 30 liters/min leakage. With the quattro or the Comfort 2, when I am having around 30 liters/min leakage, I typically feel that I slept reasonably well (with cpap, however I never have felt a totally good sleep), and certainly not awful like the days I've shown the leakage around 0-2liters/min average.

But wait, on top of that, the Phillips charts that show the leakage rates from the exhaust port from the Comfort 2 mask http://www.healthcare.philips.com/asset ... 111027.pdf, indicate that I should expect a MINIMUM, NORMAL LEAKAGE OF ABOUT 34 liters/min at a pressure of 15 cmH2O (remember I'm at 17) from the exhaust port on the Comfort 2 mask.

THEREFORE, there is no way I should be getting an average leakage rate down around 0-2 liters/min.

So something funny is going on here.

Can someone figure out why?

Thanks.