mask leak vs AHI

My wife is using a Resmed system with a Dreamwear mask. Her AHI score is <5 consistently, but she frequently has a mask seal score that is excessive (>24 L/min). It seems like her mask seal is totally independent of her AHI score for the night. Even when she has an excellent mask seal, her AHI does not change much.

I have the same setup, and my mask seal stays below 5 L/min; and my AHI only goes about 1.0 about once a month; and, it, too seems to be independent of the mask seal.

I think the answer may be a kind of yes and no thing. My AHI was affected by my L/Min rate. At over 100 L/Min, my AHI went up significantly. Under 80 L/Min, not so much. Not sure how I could extrapolate a theory on this from my own experience but just a guess to say that perhaps your missus L/Min isn't high enough to make a huge difference in AHI but may account for a bit higher AHI score. I don't know the Dreamwear mask but using the correct size mask is critical to getting a good seal. Perhaps trying a different type mask would also be instructive.

Hi wiscman. Most newer machines can compensate for some amount of mask leak, so the AHI remains controlled even if mask leak increases a bit. There is also something called "intentional leak" that should always be present. This leak is the air that is intentionally blown out of the exhalation valve (small holes or port) of the mask so that you do not re-breath your carbon dioxide. This might be why the AHI remains consistent even when the mask seal score changes. Best wishes!