While an ASV device can automatically adjust pressure levels in real time, the device is often calibrated based on the results of an overnight sleep study. During the study, a sleep specialist makes sure your mask fits properly. They can also monitor how using the ASV affects your breathing ...
When I talked to my PPO and Medicare they told me that there was no need for a second sleep study... my doctor wanted one and I took one... big mistake, 500USD wasted... I 'failed' and a new diagnosis was given with an erroneous AHI number. A new sleep *titration* is good.....