Admin thread warning to new CPAP patients: This thread contains information concerning CPAP mask modifications which may be dangerous if attempted without seeking professional help from a qualified sleep doctor. Disclaimer: Patients are free to do as they wish, however Apnea Board does not condone these types of inherently risky mask modifications. Thanks.
Have read through many of the threads but have not seen much discussion on CO2, triggers and central apneas.
I had two sleep studies done. First one showed AHI of 35, 50/50 CAs/OAs. Second one was for titration on the CPAP. Recommendation was for 9cm. I got a new cpap machine Respironics System One I think it is called, used it for a week or two and had the rep read the SD card. OAs came down a bit, but CAs not reduced. Rep sent data to Dr. who prescribed a Bipap at 14/10 settings. Got one, used it a week or two and had rep read the SD card. OAs down as before, but CAs not reduced.
I began a little research on CAs. Found they often start and/or increase with use of cpap. Although they can be related to heart trouble, basic mechanism for breathing/not breathing i.e. CA is CO2 concentration in the blood; if too high, triggers breathing response. If too low, no breathing response i.e. CAs. Read several research studies done on adding CO2 mixtures into face masks and in adding “dead space” to a mask to increase breathing residence time in the mask thereby increasing CO2 concentrations and it directly affects CAs.
So my theory is: even though the cpap/bipap machine controls pressure at settings, the flow rate of air thru the mask is controlled by the amount of openings in the mask. The more openings, the higher the air flow required to maintain the pressure settings. With higher flows, the O2 concentrations and saturations are high which is desirable, but it also reduces the CO2 perhaps below the threshold/trigger point for breathing in particularly sensitive individuals. This may explain why cpap use causes/increases CAs in some people.
I began my own research by closing off certain openings and controlling the remaining openings to slow down flow rate but keep pressure settings, thereby lowering O2 and increasing CO2. I was aware of going too far and getting into trouble, but have been able to survive and see on my SD card data that the CAs came down below 5, OAs controlling around 5 also based on pressures. I'm still tweaking settings trying to get good readings and be comfortable. I have a Dr. appt. in a week and will discuss (and I’m sure get reprimanded) but has anyone else got any info on this ? Thanks for any ideas and suggestions.