Newbie question on numbers, especially leaks

[Bonnie corgi lover]

I have slept just 3 nights with CPAP, usage hours of 23. I just figured out how to get my nightly data, so I only have 1 night's worth. Reading various posts and collected wisdom is helping, but I still don't have a clue on how to interpret the leak rate.

Leak = 0.14 L/S
AHI = 3.6
AI = 0.4
HI = 3.2

So, I think AI number means that my apnea events (no breathing) were 0.4 per hour (pretty good). The HI number means my hypopnea events (decreased breathing) were 3.2 per hour (OK, but not great). AHI is just the total. 3.6 is less than 5, which is normal. But lower, like less than 3 might be even better. Also, ResMed machines may be more "sensitive" in detecting/reporting HI.

But I'm still very confused about how to interpret the leak rate. Is my mask leaking a lot or not much? If it's too high, the other data may not be accurate, right? The mask seems to develop a few, sporadic leaks during the night, but I sure can't tell what's happening when I'm sleeping! I would welcome any input or corrections.

Pressure is 13.0 and EPR is 3. I'm using a ResMed S8 Elite II CPAP with an intergrated heated humidifer and the Respironic's Comfort Gel Full mask. Humidity is set to 3 for now.

This board has been a wonderful resource. Much, much more helpful than my doc or DME. Thanks everyone for participating!

[grandmma]

Bump.

I'm not an expert, there are others who'll give you advice. But personally I find that my leak numbers are kinda irrelevant if my AI and HI (AHI) results are good.

I would imagine with some advice here, you could get that AHI further down. The lower the AHI, the better you feel daily, that's for sure.

Good luck, and you've come to the right place for help.

[Goofproof]

Bump.

I'm not an expert, there are others who'll give you advice. But personally I find that my leak numbers are kinda irrelevant if my AI and HI (AHI) results are good.

I would imagine with some advice here, you could get that AHI further down. The lower the AHI, the better you feel daily, that's for sure.

Good luck, and you've come to the right place for help.

It's really the other way around, if the leak numbers are to high the data numbers are useless. Jim

[GumbyCT]

Yes, If the leaks are too high your machine may not sense events you are still having. Also the pressure drops bc of leaks and is no longer therapeutic.

[Goofproof]

To measure you leak rate correctly, your machine has to be set to the mask. The leak shown to you is the leak rate over what your machine thinks is normal for your mask.

My machine allows me to do the math, that way it's always correct, I just subtract what the mask is supposed to vent from the machine reading, and if my pencil doesn't make a mistake the number will be the excessive leak.

Also Resmed's tend to score HI's higher than other machines, so you want the AI to be as low as possible, and let the HI's follow. Jim

[grandmma]

Guys, had no idea - obviously and literally.

My machine's not set to my mask, neither is my software. No idea re that either - sad I know. But the leak average is usually in the mid to high thirties, as is my mask rate, so I'm covered I guess.

And whilst I used to obsess over my leak rates, once I got it all under control, I stopped worrying too much. I do check, and the average is low, but I did not know if high it affects the #s.

Thanks a bunch.

[Goofproof]

Guys, had no idea - obviously and literally.

My machine's not set to my mask, neither is my software. No idea re that either - sad I know. But the leak average is usually in the mid to high thirties, as is my mask rate, so I'm covered I guess.

And whilst I used to obsess over my leak rates, once I got it all under control, I stopped worrying too much. I do check, and the average is low, but I did not know if high it affects the #s.

Thanks a bunch.

Your Remstar doesn't have to be set, If the numbers you get are close to the numbers that came with the mask you are OK! In the mid to high 30's your leak rate is OK! The numbers won't be affected. jim

[RiverDave]

Bonnie - A leak rate of 0.14 l/s is not too, too bad. If it were me, I wouldn't want it any higher, though. I think the goal should be(and is for me) to get it as low as possible. It is fairly difficult, but very possible to consistently get a zero leak rate. Do make sure your machine is set to the right mask - if it were me, I'd use the "full" setting.

Grandmma - if your machine is a Respironics, there is no mask setting feature - I think it's unique to ResMed's.


Good Luck

[Goofproof]

Grandmma - if your machine is a Respironics, there is no mask setting feature - I think it's unique to ResMed's.Good Luck

Like the picky D/C power issue. Jim

[Bonnie corgi lover]

Thanks, everyone. I really do appreciate all the help. However, I’m still confused about my leak rates.

Now I have 2 days of efficiency data:

leak rate 0.14, 0.14
AHI 3.3, 3.6
AI: 0.2, 0.4
HI: 3.2, 3.1

The ResMed mask setting menu doesn't seem to list the Respironics Comfort Gel mask, so it's set to "standard." I've seen the graph that came with the mask, and the table at the link below, but I'm still not sure how to interpret the numbers.

http://www.internetage.com/cpapinfo/leak-rates-1.html

The table reads 34 at my pressure of 13. From the graph that comes with my mask, it looks to be closer to 30.

The literature with my mask also has a little table:

Pressure Drop cm H20 (hPa)
50 LPM 100 LPM
All Cushion Sizes : 0.4 1.0
P-S-M-L 0.1 0.25

I’m not sure about what the subtracting the intentional from actual leak rates means with my machine – isn’t that already done with the ResMed?

Remember, I’m a newbie. I’m just trying to figure out if I’m doing well or not. AI, HI and AHI numbers seem acceptable IF I’m not leaking too much to make them inaccurate. I especially don’t understand why my machine reports 0.14. Do I need to move the decimal or do some other conversion? I understand 0 leaks would be ideal, but just how bad is 0.14? Also, should I chose some other mask than “standard” on my machine? No other masks listed seem even close.

[Snoredog]

Thanks, everyone. I really do appreciate all the help. However, I’m still confused about my leak rates.

Now I have 2 days of efficiency data:

leak rate 0.14, 0.14
AHI 3.3, 3.6
AI: 0.2, 0.4
HI: 3.2, 3.1

The ResMed mask setting menu doesn't seem to list the Respironics Comfort Gel mask, so it's set to "standard." I've seen the graph that came with the mask, and the table at the link below, but I'm still not sure how to interpret the numbers.

http://www.internetage.com/cpapinfo/leak-rates-1.html

The table reads 34 at my pressure of 13. From the graph that comes with my mask, it looks to be closer to 30.

The literature with my mask also has a little table:

Pressure Drop cm H20 (hPa)
50 LPM 100 LPM
All Cushion Sizes : 0.4 1.0
P-S-M-L 0.1 0.25

I’m not sure about what the subtracting the intentional from actual leak rates means with my machine – isn’t that already done with the ResMed?

Remember, I’m a newbie. I’m just trying to figure out if I’m doing well or not. AI, HI and AHI numbers seem acceptable IF I’m not leaking too much to make them inaccurate. I especially don’t understand why my machine reports 0.14. Do I need to move the decimal or do some other conversion? I understand 0 leaks would be ideal, but just how bad is 0.14? Also, should I chose some other mask than “standard” on my machine? No other masks listed seem even close.

Your AHI data looks fine, I wouldn't change anything on the machine.

Leak rate=0.14 that value shown by the machine is given in Liters Per Second (L/s), the flow chart that comes with most
masks is rated in Liters Per Minute (L/m), so to see how you are doing, you have to do a little math to that machine
result, you take the 0.14 x 60 seconds = 8.4 Liters per Minute (L/m).

If you take that 8.4 Liters per minute and now compare it to the "graph" flow chart that came with your mask for 13 cm
pressure it should give you something in the range of 28 to 34 L/m intentional leak.

The 8.4 L/m is what the machine is seeing as external leak and I think you are good to go if you keep external leak at or below 12 L/m. Note: That machine has a learn mode where you can fine tune the leak for the ***** star ranking of your leak. Consult your manual
and calibrate it for your particular mask (think it is called Mask Fitting Feature) and it will give you more accurate data on the leak aspect,
this also where it learns your current mask leak rate.

On the Resmed machines it includes a library which knows the intentional leak rate (i.e. Resmed masks), while you can pick
a similar mask the result can be off unless calibrated. When you use a non-Resmed mask you have to select "Std" and use that
mask fitting feature so it can learn your leak rate.

Basically you put on the mask, switch to Std mask type, select Mask fitting feature and press the button,
it brings up pressure to like 10 cm and you breathe normally, once it learns the leak rate of your mask
it will display each morning how your leak rate was. If there is a problem with leak it will let you know (I am
recalling this from my old days with the Spirit so it could have changed in the S8). If you haven't
calibrated the leak for your mask the leak data you are looking at may be off only because it doesn't
know what it is. I don't see a problem with the 8.4 L/m even if it is off, but it doesn't jive with
the flow chart data seen (suggest using that Mask fitting feature). If you have already done that
then the 8.4 is only external leak and very good, based upon your low AHI I'd say it is the latter.

[echo]

And how are you feeling? Low leak and AHI is meaningless if you're still feeling crappy... but a slightly high AHI is OK if you're noticing significant improvement (and your AI is pretty good, so it seems like you're good to go!)

[taberge]

So let's get this straight,

All masks have a given leak rate depending on the model and pressure setting?

Here I am thinking I need a perfect seal with zero leak rates from all the modifications made to some masks posted on this site.

I don't think my machine has a mask setting from reading the manual last night. i have a Remstar Pro M series CPAP w/CFLEX with Resmed Ultra Mirage II nasal mask. From the chart, I am assuming that the listed leak rates should be the avg rate the machine is reporting or below?

For my first night of use I really didnt feel leaks around my mask where it contacted my skin. The air rushing out of the front of the mask did make me keep checking the mask for a while because the air would hit the pillow and bed and whirl back up into my face making me think the mask had shifted. I wish they had a more optimal system to vent so if you feel air around your face you KNOW you have a leak.

I don't have the card reader or the software yet but the first night numbers are leaks 33.7 L/M and an AHI of 0.9 at a pressure setting of 10. I think I need to remind myself to power off the machine before pulling the mask off and I need to turn off that auto on feature in that it may add to the leak numbers.. The machine cranks right up before I get the mask situated.

[Bonnie corgi lover]

Thanks for the advice. My machine does have a "mask fit" feature, which I will check out. My worry is that there may be minimal leaks when I start out, but the mask may move or start leaking while I'm sleeping. When I go to sleep, I can't feel any leaks, but I wake up several times and change positions, which seems to set off some leaks. I'm anxious that I get the most benefit from the therapy.

I feel very good, but I felt fine before CPAP. I'm not using it because I felt bad. I didn't feel excessively tired or sleepy before. I had a heart attack which woke me middle of the night. I knew that I snored, but had no idea I had sleep apenea. While in the hospital, I kept setting off the oxygenation alarms at night. The docs there strongly suggested I be evaluated for sleep apnea. I spent five days in the CCU and my family had to came in from all over the country. Not something I want to go through again! At 46 years of age, a pre-menopausal women, with no other major risk factors for heart disease, I am convinced that sleep apnea was the major contributory factor to my heart attack. From my subsequent sleep studies, I was told I had severe sleep apnea, with oxygenation dropping to as low as 54% and more than 40 apnea episodes per hour.

I've actually been afraid to go to sleep each night. So, I'm paranoid that I'm getting the benefits from CPAP. All the issues like rainout and strap marks are secondary to me and can be worked on over time. Next steps will be to get a card reader and try to borrow a pulse oximeter. Sorry to get off on a rant.

[bigk]

Hmm. Where is slinky when you need her?

The mask fit feature doesn't calibrate the mask so far as I can tell - It merely helps you determine when your mask is fitting properly.

I BELIEVE that the standard setting has a known leak allowance of 30l/min? so if you convert your l/s leak rate by multiplying by 60 and ADD 30 to it, that will give you your mask leak rate and you can compare that to the table for your mask.

I wouldn't be worried about a leak rate of 0.14l/s - the machine will compensate right up to a leak rate of around 0.4l/s. Obviously, the lower the better of course.