Great oxygen and AHI scores despiite high leakage rate

My sleep doctor can't figure out how I could have perfect 10 oxygen scores most nights with my wrist oximeter, low AHI (from 0.5 up to 5) with leakage scores ranging from high 40's to 100 on the ResMed report, never below 40. I have not been able to find a mask I could actually sleep with besides my very comfortable Dreamwear, alternating between the cushion and nasal pillows, and using a chinstrap off and on, with equally high leakage scores. My machine is the ResMed AirCurve10 V-Auto BiPap, with settings of 8/11. I know the oximeter is working because on the rare nights when I was unable to use the BiPap machine for some reason, but did use the wrist monitor, the O2 printout is full of deep red spikes and the score is dramatically lower. I sometimes have a night with an unusually high AHI score, such as 17.9, but still a perfect 10 on the oxygen, which makes no sense, if an apnea event is by definition a pause in breathing of 10 seconds or more. My sleep doctor is as puzzled as I am over this strange phenomenon. Either my machine is wildly exaggerating the leakage rate, or increasing the pressure levels to compensate and maintain an airway, or underestimating the AHI rate, but if it's the latter the apnea events should be reflected in much lower oxygen readings. Does anyone have a clue to this mystery? Curious Fox

Your best bet would be to download OSCAR and have a look at what is going on in detail during the night. OSCAR is free to download, but needs a PC or Mac to run the software, and a SD card reader to get the data from the machine to the PC.

I love the Dreamwear Nasal Pillow mask. I do find it sliding off some nights not as much since I switched to all automatic settings. I am a historical mouth breather and have worked hard to train myself to position my tongue resting in the top of my mouth which over time has made an amazing difference. I always struggled with a traditional chin strap. I have stumbled on something new that I think is going to work great. I just ordered a new strap for my Dreamwear Nasal Pillow mask. I curiously read some of the reviews. One person's review suggested that this mask should come from the manufacturer with two sets of straps. One that could be used as a chin strap as it keeps the mask from coming off throughout the night and is a a very comfortable chin strap. When my new strap arrived, I tried it with my old strap and it worked perfectly! What a concept!