I'm not familiar with Complex sleep apnea but I saw in the information that one of the alternative treatments is a bi-level pap (bi-pap). I just recently started using one after having a c-pap for 3 years and it has been a game changer for me. The pressures can be set for both the inhales and exhales. It took me almost 3 years to understand and be able to articulate what was happening. I would wake up feeling like I was being suffocated with a lot of pressure and tightness in my chest. (Heart issues were eliminated) Within just a few minutes of use I could tell the difference and knew that we had found the answer. When I was able to explain that I couldn't push out a breath, was when the pulmonologist suggested I try the bi-pap. I have energy again and sleep comfortably all night. I hope you find an answer soon.