Well, first the second sleep study (called the titration study) has to determine what type of machine you need. The study may also determine whether or not you are a mouth breather. They don't always determine that, but if it's obvious, they will likely test you with a full face mask, covers the nose and mouth. They typically start testing you with a nasal mask (covers only the nose), then if there are other problems, they may try a different type. If you have any significant problems using the mask they test you with, tell them, maybe they can try a different one.
Most people are prescribed a straight cpap machine. But there are times when they might decide to prescribe something called a bipap, or maybe even an auto cpap. Bipaps (also called a bilevel machine) are typically used for those who require higher pressures or have some other problems. An auto cpap is rarely recommended, only if there are difficulties in determining a pressure. But most likely you will be prescribed with a straight cpap.
The doctor writes the prescription, after the second sleep study. Hopefully he will talk to you about it first, but you never know. And the process varies depending on your insurance. They may send you to a local DME (durable medical equipment store) to get your equipment. My insurance sucked, they only paid for equipment provided by one out-of-town company and my equipment was sent to me. But most get theirs through a local equipment store.
The DMEs usually tell you that you need the basic model. Ask about the others. There are things to consider when getting a machine, things I wish I knew about when I got mine. Some have other features and your insurance may not cover the cost of a more expensive model, don't know. But some have something called c-flex (called something else in another brand, forget the name) which offers a kind of relief for exhale that many people find is comfortable.
Also, different models record different things. All of them I believe record compliance, there's a computer card in the machine that records data that the DME can read. Some basic models only record compliance (how often you use it, how many hours). Some machines record more data than that, like how many apneas you are experiencing, how bad of a mask leak you are having. If that info matters to you, you might want to ask about it.
As to masks, first you need to know if a nose-only mask is all you need. Perhaps your sleep study will determine that. If you use a nose-only mask, there are more options, such as nasal mask, or nasal pillows (they are small short insertions into your nostrils, not over the nose). Ask to try different ones. Also, ask what is their exchange or return policy, if they have one. Also, ask how often will your insurance pay for a new mask. They always check with your insurance, so they will know. Insurance companies will typically pay for a new mask after 6 months, for some even after 3 months.
You might also ask the process, if they want you to rent to own. Many do that (mine didn't, my insurance paid for it outright). That might be a good idea if they push that, for it gives you an easier opportunity to switch machines should you need to (not likely but it happens). If you are told you are a mouth breather and need a full face mask, there are fewer options, so be sure to ask to see all the available ones. And you might want to review our mask section for people's thoughts on different masks. The hybrid is a new mask, and insurance may not pay for all of it because it's expensive. It's a new type, for it is a combination full face mask and nasal pillows. It covers the mouth, and has the little nasal pillows that rest inside your nostrils. Some people feel a little claustrophobic with a full face mask that covers both the nose and the mouth, but many do just fine with that.
Oh, you should have a heated humidifier. They are typically provided, but look for that. Often the doc has to include it in the prescription in order for insurance to cover the cost. And be sure it's a heated humidifier, not just a cool passover kind. The heated humidifier can be used both ways, and it's best to have the option.
Gosh, I've given you a lot to think about, sorry. I've sure rambled on and on. Let me know if you have questions.
