I just finished MS-3, and what from I have seen/experienced in my interactions and learning from anesthesia is that when I ask a CRNA any question the least bit in-depth about physiology or underlying mechanisms behind whatever procedure they might be doing at that moment, the CRNAs never know the answer (not even the most experienced CRNAs). they can't even fathom having those concepts in mind while they're doing it. It's like, I'm asking something they never even heard of, and it's pretty elementary stuff--I mean, things a third-year med student would ask and that any resident would know.
When I discovered this, I realized that CRNAs will never ever be able to work independently of MDAs. CRNAs are trained to be technicians. They go through the motions without any understanding of the underlying physiology. Of course, when you practice the motions over and over again, like a recipe, you can eventually do that independently and more adeptly than some residents, but if anything goes the least bit wrong, a CRNA WILL NOT KNOW WHAT TO DO unless they know the science behind the motions. And they do not, as I have seen personally. CRNAs, if you want the science, you not only have to go through med school, but you have to have the science background from undergrad (i.e. pre-med classes), b/c CRNA school does not teach this.
Thus, not having an MDA around is a complete DANGER to the patient. CRNAs should not even desire to practice alone. That's unfair to the patient and putting the pts lives at risk, just to satisfy CRNAs pride.