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What is the relationship between leak rate and AHI reading? Last night I had a leak rate of 47 l/min and AHI average of 1.3 events per hr. Is that possible?
I've been wanting to ask that same question, since there tends to be an INVERSE relationship between my AHI scores and the leaks on the ResMed report, which makes no sense. Recent extreme examples: AHI 1.1, Leaks 60; AHI 3.3, Leaks 83; AHI 18.8, Leaks 8, AHI 10.4, Leaks 4.3. Actually, most of my AHI scores lately are around or under 5, and my O2 score on the finger monitor is near perfect each night, so I wonder if I should still worry about the high leak rate. (I am using the ResMed AirCurve10, V-Auto BiPap machine, with the Dreamwear nasal mask with a chinstrap. I use the cushion most nights, but alternate occasionally with the pillows, in hopes of getting lower leaks. They hurt my nose and don't really make much difference in the leak levels. This is the only mask I've found that lets me actually sleep through the night, and I've tried many, both nasal and full face.) I'd like to lower my average AHI's still more, but wonder if I have to give up the comfort and uninterrupted sleep of the Dreamwear mask, to accomplish that?
Sometimes when the mask is leaking high but AHI is normal may be during a time that you are not having as many events but it is an average of the overall night. While leak is important and ResMed machines do compensate for the leak better than most, what it cannot do is compensate for your positions during sleep. If you are on an Auto there will always be a time where there are more events in order to find the optimal pressure within the algorithm. If you go to your back and you have more events (or other positional increases) this will show in the scores but your leak may indeed be perfect. If there is a way that your DME can find what your average ending pressure is, and switch to normal BiPAP at that pressure. You will probably find that whatever pressure is ending you at 1.1 is going to continue to keep you at that AHI. I did this with my CPAP and as a result I always start and end at 18.0 with no ramp and no fluctuations. I am generally coming in around .5 AHI every night.
Airsense adjusts pressure and checks events. If you're leaking from your mouth AS could have a harder time maintaining pressure and then AHI would go up. If you're leaking around the mask then easier for AS to adjust the pressure and AHI would stabilize. As mentioned, changes in body positions can cause changes in this dynamic. A move from back to side might increase leaking and destabilize pressure - AHIs would go up. Minor variations in leakage and pressure should be within the range that the AS can adjust but major changes might take longer or be out of range.
sleeptech
+0 points
·
over 6 years
ago
Sleep
Enthusiast
When you say that the "Airsense adjusts pressure", do you mean actual pressure adjustment or just leak compensation? All CPAP machines have compensated for leak for years, but only and AirSense Auto will adjust its pressure. AirSense is the name of the entire current range of machines from ResMed, including autoset and fixed pressure.
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