42 CFR §410.69

1. (a)Basic rule. Medicare Part B pays for anesthesia services and related care furnished by a certified registered nurse anesthetist or an anesthesiologist's assistant who is legally authorized to perform the services by the State in which the services are furnished.
2. (b)Definitions. For purposes of this part—
   1. (1)Works under the direction of an anesthesiologist;
   2. (2)Is in compliance with all applicable requirements of State law, including any licensure requirements the State imposes on nonphysician anesthetists; and
   3. (3)Is a graduate of a medical school-based anesthesiologist's assistant educational program that—
      1. (A)Is accredited by the Committee on Allied Health Education and Accreditation; and
      2. (B)Includes approximately two years of specialized basic science and clinical education in anesthesia at a level that builds on a premedical undergraduate science background.
         1. (1)Is licensed as a registered professional nurse by the State in which the nurse practices;
         2. (2)Meets any licensure requirements the State imposes with respect to non-physician anesthetists;
         3. (3)Has graduated from a nurse anesthesia educational program that meets the standards of the Council on Accreditation of Nurse Anesthesia Programs, or such other accreditation organization as may be designated by the Secretary; and
         4. (4)Meets the following criteria:
            1. (i)Has passed a certification examination of the Council on Certification of Nurse Anesthetists, the Council on Recertification of Nurse Anesthetists, or any other certification organization that may be designated by the Secretary; or
            2. (ii)Is a graduate of a program described in paragraph (3) of this definition and within 24 months after that graduation meets the requirements of paragraph (4)(i) of this definition.
         5. (5)For certified registered nurse anesthetist services, the certified registered nurse anesthetist may review and verify (sign and date), rather than re-document, notes in a patient's medical record made by physicians; residents; nurses; medical, physician assistant, and advanced practice registered nurse students; or other members of the medical team, including, as applicable, notes documenting the certified registered nurse anesthetist's presence and participation in the service.