@lisalucier Thank you for the welcome! I personally don't have sleep apnea. I have been a registered sleep technologist for about 9 years. I run sleep studies and do PAP titrations when indicated. I speak from observation. When patients return with breakthrough symptoms it is often an issue with the mask. Either the mask is not the proper size, not tightened with a good seal, or there is oral breathing while using a nasal mask. Apneas, in general, tend to be worse during REM sleep and also while sleeping on your back. It is a possibility during the titration study, minimally REM or back sleeping was seen. It is also very important to note the original amount of apneas before treatment compared to the number after therapy. The goal of PAP therapy is a great improvement rather than "perfect"...if that makes sense.