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Impact of Mask Leaks on AHI? - Ron AKA - 04-14-2018
With my unsuccessful trial of the Mirage Quattro full face mask, I am soldiering on with my AirFit P10 nasal pillow mask. I am currently trying a no EPR setup. Last night I thought I had a great night, with minimal leaks. I have been having trouble with the straps on the mask staying in place. But last night went great, I thought. Then I get the scolding report from SleepyHead about major leaks. So my question for others that have experience in this is whether or not mask leaks are a serious problem? Is it just an annoyance, or does it impact the flagging of events, and in particular affect AHI? Daily report capture is below.
RE: Impact of Mask Leaks on AHI? - Apnea Infant - 04-14-2018
Well, I think masks leaks do impact on the numbers.
You have much centrals and it may be useful to lower EPR slowly in an effort to reduce those if you haven't already.
For me, slow reduction of EPR was what was needed together with the slow lowering of pressure which helped with the leaks.
RE: Impact of Mask Leaks on AHI? - MitchS - 04-14-2018
While it wouldn’t hurt to continue to work on your leaks, I don’t think your leaks are high enough, at 5% over redline, to affect your treatment. Your 95% leak rate is acceptable. I would love to have your Med. leak rate. As long as the leaks aren’t affecting your sleep quality, I wouldn’t worry too much about them.
Due to my fine hair, I have a problem with slippage with the P10 head gear, as well. I have found that wearing them under my Ruby style chin strap works great at stopping the slippage.
RE: Impact of Mask Leaks on AHI? - Walla Walla - 04-14-2018
The large leak rate on the Resmed starts at 24l/min but it's not like a light switch. It gradually degrades the machines ability to recognize events until around a leak rate of 30 l/min where it can't detect anything. If your just above 24l/min you probably can get by but as it goes higher it really starts hurting your treatment. Not being able to see events is why many people with large leaks think they're getting low AHI numbers. In reality the events may be there but the machine can't detect them.
RE: Impact of Mask Leaks on AHI? - Hojo - 04-14-2018
I've noticed the higher the leak the worse I feel in the morning and my AHI tends to reflect it.
RE: Impact of Mask Leaks on AHI? - Ron AKA - 04-14-2018
(04-14-2018, 09:19 AM)Apnea Infant Wrote: Well, I think masks leaks do impact on the numbers.
You have much centrals and it may be useful to lower EPR slowly in an effort to reduce those if you haven't already.
For me, slow reduction of EPR was what was needed together with the slow lowering of pressure which helped with the leaks.
I don't have a lot of data, but with the scant data I do have with EPR on, Central Incidence averaged 2.5, and Obstructive 1.8. Now after only two nights Centrals averaged 1.9, and Obstructive 0.7. So far the No EPR option is working better, and the lower pressures SHOULD be easier on the mask sealing. But that part is not real apparent yet... For me, I think centrals will remain a big problem, and I am not going to get real low AHI numbers with the current machine I have. I am trying not to let it distract me for now, and will give it two to three months to hopefully improve. I am focusing on the bringing the OA events down first.
RE: Impact of Mask Leaks on AHI? - Ron AKA - 04-14-2018
(04-14-2018, 09:58 AM)Walla Walla Wrote: The large leak rate on the Resmed starts at 24l/min but it's not like a light switch. It gradually degrades the machines ability to recognize events until around a leak rate of 30 l/min where it can't detect anything. If your just above 24l/min you probably can get by but as it goes higher it really starts hurting your treatment. Not being able to see events is why many people with large leaks think they're getting low AHI numbers. In reality the events may be there but the machine can't detect them.
While last night was not a good example, I have seen cases where the leak occurs and then when it ends, there is a whole series of flagged events. It is kind of like the machine thinks everything is OK and it does not increase pressure, and perhaps even reduces it, and then when the leaks end the floodgate opens and the events occur due to the pressure being too low. Here is an example from Wednesday night below.
The alternate explanation might be that the leak woke me up, I fixed the mask and the events then occur from me huffing and puffing and cursing the mask...
Thoughts on which it may be? From the example below, I sure do not see anything that I would flag during the grey leak portion. To me I look sound asleep with pretty regular breathing.
RE: Impact of Mask Leaks on AHI? - Walla Walla - 04-14-2018
The machine isn't reading any disruption in the flow due to the leak. Your looking at the flow chart and not seeing anything. That's exactly the problem the machine has with leaks. It's recording a normal flow because it's running blind. When that happens you don't know if there was events or not because the machine thinks the flow is normal and without disruption. About all you can assume is that there may well be events in the large leak area that the machine didn't record in the flow chart.
RE: Impact of Mask Leaks on AHI? - SarcasticDave94 - 04-14-2018
Walla Walla's take would be similar to mine. The higher the leak rate, the more inaccurate the chart and event flagging will be. Like he said, it's flying blind. If the machine can't detect events due to leaks, it can't flag or address what it can't see.
RE: Impact of Mask Leaks on AHI? - Ron AKA - 04-14-2018
(04-14-2018, 05:19 PM)SarcasticDave94 Wrote: Walla Walla's take would be similar to mine. The higher the leak rate, the more inaccurate the chart and event flagging will be. Like he said, it's flying blind. If the machine can't detect events due to leaks, it can't flag or address what it can't see.
That was my first thought too. However, I have looked through quite a few of these high leak grayed out area sections, and the thing that seems consistent is that the pressure and flow waveform during the gray area looks identical to the area prior to the gray area. The big change comes in right after the end of the gray area. Almost always there is a big disruption in flow and pressure, the leak gets stopped, and the rough irregular breathing starts, and events get flagged. I think I am leaning towards a wake up to fix the leak, and then events get flagged when I am in that semi awake state of irregular sporadic breathing. I can believe that somehow a leak mask the events, but it doesn't seem possible for the machine to recreate the pressures and flow pattern that was in place before the event. Just don't think the machine is that smart...