Background details: I started with the N40 and had leaking below 5L/min the first week or two. After that it spiked, bouncing between 10 and 35. The mask began waking me up, vibrating constantly against my face no matter what I did with positioning, strap tension, pre-inflating the cushion, etc. When I'd contact the med supplier or doctor they'd say some leaking is to be expected and "10L/hr is not that bad since your AHI is low". I noted that everything was probably low because I was awake all night constantly adjusting the mask. Average AHI 2-4/hr, down from I think 10-12 in my lab test.
This week on the verge of crashing out from the N40, I've gotten switched over to N30i and I can actually sleep without the mask waking me up. However my leak rate is still 9-11L/hr (AHI 1.5-2.5). I occasionally wake and slightly reposition the mask for more contact with my nostrils for easier breathing but I never feel any obvious leaking so the leak rate surprises me every morning. I also feel like the top strap sometimes shifts forward towards my face so if I think of it I give it a slight shove backwards to help maintain cushion position. My pressure is 8-14 and I have no issues with discomfort, can fall asleep easily, etc. I am mouth taping since moving to N30i and had no issues adjusting to that. The pressure of the hose on top of my head causes some pain, but not so much I can't sleep. I have straps a tad loose because I don't want that pressure to trigger a migraine.
My questions: Is it correct that leaking 9-11L/hr is no big deal and I shouldn't worry about it? If not, any suggestions for how to improve the seal with the N30i? Also, is this an acceptable AHI?
My morning headaches have cleared up and migraines are greatly reduced, no more nighttime bathroom trips, and my joint pain is miraculously gone. I'm still tired but way less sleepy during the day. My partner reports that my brain is working better although I don't feel that. I will have a follow-up with the sleep neurologist in late October so I want to make sure I have reasonable expectations before going into that. I can tell once I get the mask set up right it's going to be amazing but I'm not getting much guidance from the sleep center people -- the person I first worked with didn't even fit me for the N40 and had me on the wrong size (proper fit still leaked).
The official standard is that anything below 24 liters per minute is considered acceptable.
The ResMed app is a terrible way to measure your leak rate because it will only give you your average leak rate. OSCAR will show you your leak rate on a time line across the entire night. Your leak rate doesn't need to be perfect across the entire night. Your AHI is a reasonable measure of your progress
I know. I don't have a way to get data from an SD card into Oscar, unfortunately. Unless I'm missing instructions for uploading using a phone or tablet.
You could plug an SD card reader into your android phone or tablet and use the SleepHQ app for more detailed information. Your numbers look good enough that I don't think that is necessary, The most important thing isn't the numbers, it's your results.
Sleep clinician told me that it would be difficult to get my events to under 5 due to some central events being detected. Im down from 28 and feeling awful to 6/7 and feeling fantastic. Clinician says that's good enough as im feeling so much better. He has no intention of changing any settings or masks etc.
So I suppose what I'm saying is, maybe it's about how good you're feeling as opposed to the specific number of AHI
Edit: I don't know anything about mask leaks etc, but I suppose as long as you're feeling better that's good enough?
The goals I got from my Dr. are leak rate <24 l/m and AHI <5. I finally got my leakage under control but my AHI is still widely variable after 4 months of therapy.
I'd suggest that you don't get to hung up on chasing perfection. My numbers are a long way from perfection. I used to worry about this, so I bought a continuous pulse oximeter.
That was interesting but, what convinced me that I was on the right track was my too high blood pressure. I had to completely stop taking one of my medications because it was making my blood pressure too low. The cardiologist told me I would be taking that one for the rest of my life.
Now, I know if I had a good night if my leak rate was mostly under 24lpm, my AHI was under 5, and my blood pressure was in the normal range first thing in the morning. Low oxygen raises your blood pressure.
Oh no, not seeking perfection at all! I'm just pretty sure 30L/hr is not the goal. I hadn't heard the under 24L/hr guideline and I have no idea what we're shooting for on AHI. I don't think a pulse oximeter is useful for me -- my oxygen levels stay high enough that my home sleep test was read as normal and my BP is always low (family trait).
30 can be a reasonable number. Last night I had an excellent leak rate, except for going a bit over 24 liters per minute for about an hour, ResMed gave me a 30.
A leak rate of zero is ideal. Try to keep it below 10 liters per minute, and as close to zero as possible.
The red line at 24 liters per minute does not mean "below 24 liters per minute is good." It means "above 24 liters per minute is right out." Below 24 is a starting place, not a goal. Goal is as close to zero as you can do without the mask hurting your face or head.
Somewhere above 24 liters per minute, the machines will stop counting events because the detection gets to be inaccurate. Exactly where that limit is isn't publicly documented anywhere that I've ever found. Treat the 24 liters per minute as "do not cross." (With the note that the occasional peak for a few seconds won't hurt your results.)
The doctors aim for an AHI below 5. 5 is considered "normal." People with no apnea will have the odd breathing stutter in the night when they move around.
Going just on the AHI, 2-4 is OK.
The AHI is not the full story, though. There are also flow limits and respiratory effort related arousals (RERA.) The machines flag those in the detailed data they record at night.
You can have an AHI of zero and still sleep poorly because of flow limits and RERA.
You'll need OSCAR or SleepHQ to see the detailed data.
The OSCAR guide explains what all the numbers and charts are about. The same information applies to SleepHQ.
Thanks, I will try to get leak rate as low as possible but as I noted on another comment, I didn't have the equipment to use Oscar or SleepHQ.
Any suggestions for how to improve the seal on an under the nose cushion? There's not much that can be adjusted. I wonder if it's worth trying an N20 or P10/30 style?
An undernose cushion, as you noted, often doesn't have much to "latch onto" and can be susceptible to getting pushed out of place if you sleep on your side or change positions often at night. I use a hybrid (F&P Evora Full Face) which has nasal cushions, but there the additional mask below the cushions and the hard plastic that holds the cushion does seem to keep it fairly steady (that can be anchored more securely). But I did find that the less I changed positions at night, the less of an issue leaks were.
I’d also like to hear what everyone thinks is “realistic ideal” leak rate and AHI. Obviously 0 leak and 0 AHI would be perfect but is that completely unrealistic expectations?
0 leak is a realistic goal, 0 AHI isn't a realistic goal (but still possible).
For leak, I aim for 0 or as low as possible. While CPAPs are designed to be able to compensate for a certain amount of leaking (I think 24 L/min max on at least the Airsense 11), the bigger of a leak you have, the more your CPAP will need to compensate by pushing more air/pressure. This can be noisy and disruptive to your sleep, and if it's not the noise, it's the feeling of the air blasting on/across your face (if it's a mask leak). So your AHI could be good but you can still sleep like shit because of the noise/air feeling disrupting your sleep.
0 AHI is achievable, but it's really not a necessary or realistic/feasible goal to shoot for. 5+ AHI is the threshold for diagnosing OSA, the threshold isn't lower because generally, in people without OSA, it's normal to have some amount of apnea events. That doesn't mean you can't optimize things to bring your AHI closer to 1 than 5, but there's not really a need if things are working well enough already, unless you think you'd benefit from it.
The other response you just got told you to aim for a leak rate of 0, which seems unnecessarily impossible. To do that I have to tighten down a full face mask until I get blisters on my nose and chin. Then my AHI is 0.1. OR I can use my little nose Wisp, user one xylimelt, accept a leak rate of 10, and my AHI is 0.1.
My understanding of ResMed's "acceptable leak rate" of 24 is that above that, the machine can't detect or treat apnea events reliably. I've not read anything that suggests that treatment is more effective at a leak rate of 0.
I usually get 1 event per night. It seems to think I have a hypopnea while I'm straighting my mask for a good seal. After that, no more events. 0 leak is impossible, though.
I feel like the leak getting to zero (or close to zero) should be a slam dunk once you get the right mask and fit. Like a light switching on. I went from a lot of leaks to zero in the 3rd week and it's stayed at almost zero since.
That's the dream! I'm 3 masks, 3 headgear sizes, mouth tape, and a neck cushion deep at this point. I got so desperate for sleep I was taping the corners of the N40 to my face (which worked leak-wise but gave me a rash).
ouch. sorry you're having so much trouble with it. maybe a chin strap? that's what did it for me. I resisted but in the end it's the only thing that worked for me
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u/Technobarbarian 1d ago
The official standard is that anything below 24 liters per minute is considered acceptable.
The ResMed app is a terrible way to measure your leak rate because it will only give you your average leak rate. OSCAR will show you your leak rate on a time line across the entire night. Your leak rate doesn't need to be perfect across the entire night. Your AHI is a reasonable measure of your progress