In most states, AAs would have to be a licensed provider, just like an MD or an RN. That is normally done through some sort of enabling legislation, whether that be a "free-standing" AA Practice Act, or some additional language added to a state's medical practice act. In some cases, PA legislation is amended and modified to include AAs. Georgia is unique in licensing AAs as PAs, because they were way ahead of the curve in passing PA legislation nearly 50 years ago that had language allowing for "specialty PA's" as they were developed. The AAs in Georgia are the only group that ever took hold with that concept.
It would be nice if the medical board could add AAs on their own. I'm not sure that's possible in any state. The exception is for the few states that allow AAs to practice under "delegatory authority" of a physician, something that would have to be allowed under the state's medical practice act. The best example of this is in Texas, where several hundred AAs practice, with the blessing and knowledge of the medical board. (Of course CRNAs oppose licensure of AAs in Texas each and every time it comes up in the legislature). Delegatory authority allows a physician to delegate certain medical acts to appropriately trained individuals. So, they can't take someone off the street and teach them anesthesia OJT, but they can delegate to an AA with a master's degree in anesthesiology.
While the number of states allowing AA practice creeps up (I think Indiana is the most recent), the number of practices open to hiring AAs has mushroomed over the last decade. I'm sure politics plays a part in this. But hey - if a CRNA wants to claim they're the equal or better than an anesthesiologist - and an anesthesiologist chooses to hire an AA instead - do you think I'm going to complain? Demand for AAs is high - there is virtually 100% job placement.
For those practices that want to remain all-MD - more power to you. We don't discourage that at all. But for those practices that want to utilize a true anesthesia care team practice where every patient has an anesthesiologist personally involved in their care, it's hard to beat AAs.