As for MDA being "in-house", w/ or w/out CRNA's. The delivery of anesthesia can be w/ only CRNA. In many rural areas anesthesia is only CRNA's and can practice anywhere w/out a MDA. The surgeons/ob's/ MD performing the case become the In-house doc, but it is still the anesthesia provider or is resposible, be that a CRNA or MDA. A good example would be those DDS who have employ CRNA's at their practice or Plastic's who have only CRNA's.
I have been married to a CRNA for 11 years, who has work in every practice enviroment, CRNA only and mixed. I think when all said and done most anesthesia providers like having a second pair of hands around, whose focus is anesthesia.
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