Hi, the ENT that I went to sent me to a sleep specialist after I complained that my kids told me my snoring was very loud.. The first step was to get a night time or sleeping time pulse ox study. Mine were quite low--averaged around 70 while sleeping. I am pretty sure that they want it above 90. The sleep specialist ordered an overnight sleep study and that is where they discovered that I indeed had apnea and insomnia. I could have told them about the insomnia part, lol. Anyway, it was strongly recomended that I begin to use a CPAP which I agreed to. I was pretty heavy then; at least thirty pounds more than I am now. The CPAP has definately improved my quality of life. It is one of my hopes that if I get this weight off and keep it off, I can possibly get rid of the machine.. All the best to you as you approach surgery.