First, a little of my history:
I've been tooling along for the past four years with my trusty PRS1 560 APAP set to a range of 4-20 cm/H2O, figuring I'd let the machine do its thing. My original doc, who I only saw for my initial sleep study and diagnosis, had me set for a range of 4-6 cm/H2O, which was nowhere near adequate IMHO. I've been religious in my use of the machine when sleeping, I very, very, very rarely sleep without it--usually only because a URI has my nasal passages completely blocked--and have enjoyed AHIs hovering around 2.1 over the past 4 years.
About 5 months after my initial OSA diagnosis, I started having problems with atrial fibrillation and high blood pressure, which I'm pretty sure are related to my OSA. Both are well controlled with medication.
Fast forward to last month, and I finally get around to finding a local sleep doc, having moved away from the area the old one was in about 3 yrs ago. New doc grabs a download from my SD card, agrees that things look decent, but has me narrow the pressure range to 10-15 cm/H2O and orders an overnight oximetry test to ensure that my treatment is as effective as the Encore numbers looked.
Turns out that it isn't.
The oximetry test revealed that my was Sp02 below 90% a good 40% of the night, with an average of 14 desaturations per hour and a lowest measured SpO2 of 81%. My baseline SpO2 was only 90% to begin with, so it had to drop very little to register as hypoxemic. Indeed, my average low SpO2 was only 88.3% so it really didn't drop that much. In truth, it was below 88% only 16 minutes out of the entire night, so I'm not sure why that's so alarming. Most of the night, it varied between 88-93%. (I should mention that I live at an elevation of about 4700 ft)
Nonetheless, my doc's conclusion was that sleep-disordered breathing is still present despite current therapy, and he wants me to do a titration study in hopes that a pressure setting can be found that will keep my SpO2 sats up where they should be.
I've attached the SleepyHead data from the night of the oximetry test in hopes that the experts on here might be able to help identify areas of concern. Right off the bat, the one thing I suspect is my tidal volume, though I'm not sure what normal values would be there. I'm a big guy, 6'2", 300+ lbs, with a max lung capacity between 4-5 liters. My normal breathing when awake is somewhat shallow due to my weight, and I suspect this is also true while I sleep. I have read about Obesity Hypoventilation Syndrome and suspect this might be at play to some degree as well.
Would appreciate anyone taking a look and offering any observations!
