As I understand it, students apply for loans through the school's financial aid process. There are no specific CRNA-designated loans. The first step is to fill out that federal form- I think it is called an FAF. That will tell you how much federally supported money you can get, which accrues no interest until you leave school. For many people that money is not enough. Then you go to the supplemental loans. These do accrue interest during school, which you can pay as you go, or I believe there is a mechanism to let it pile up, and add to the total amount you start paying after graduation.
There is federal funding to some schools to support students, student nurse anesthetist traineeship grants. Programs that receive this money have different ways of distributing it. Ask about it when you apply.
Many people receive money from hospitals or groups that sponsor them throughout school. These students are "on contract" to their supporting employer, and have a legal committment to work for that employer for a specific amount of time after graduation. In return, the employer (usually) forgives the money. In some arrangements, the graduate pays back the money, but I think that is less common in these days of high demand for providers.
You will see discussion here about the pros and cons of contracting before graduation. The advantage of course, is the money. The disadvantage is that you are committed to a job before you have even had a chance to shop the market. Then again, employers are more than willing to "buy out" your contract, meaning they pay off the people that paid for your schooling, and now you are committed to the second employer instead of the first. How you feel about this depends on your personal ethics, but it does happen often.
Bottom line, if you want to go to school, are qualified and are accepted, finding the money will not hold you back.
Hope this helps,