In the United States, advanced practice nurses specializing in the provision of anesthesia care are known as certified registered nurse anesthetists (CRNAs). According to the American Association of Nurse Anesthetists, the 39,000 CRNAs in the US administer approximately 30 million anesthetics each year, roughly two thirds of the US total. 34% of nurse anesthetists practice in communities of less than 50,000. CRNAs start school with a bachelor's degree in nursing and at least 1 year of acute care nursing experience, and gain a masters degree in nurse anesthesia before passing the mandatory Certification Exam. Masters-level CRNA training programs range in length from 24 to 36 months.
CRNAs may work with podiatrists, dentists, anesthesiologists, surgeons, obstetricians and other professionals requiring their services. CRNAs administer anesthesia in all types of surgical cases, and are able to apply all the accepted anesthetic techniques—general, regional, local, or sedation. 34 states require physician supervision of a CRNA's practice, and hospitals can regulate what CRNAs can or cannot do based on local laws.
In the United States, the Centers for Medicare and Medicaid Services (CMS), a federal agency within the United States Department of Health and Human Services, determines the conditions for payment for all anesthesia services provided under the Medicare, Medicaid, and State Children's Health Insurance Program (SCHIP) programs. For the purposes of payment for anesthesiology services, CMS defines an anesthesia practitioner as a physician who performs the anesthesia service alone, a CRNA who is not medically directed, or a CRNA or AA who is medically directed. Under the QZ Anesthesia Claims Modifier, CMS allows payment to a CRNA for anesthesiology services provided under these programs without medical direction by a physician. Furthermore, under CMS regulations, anesthesia must be administered only by:
• a qualified doctor of medicine or osteopathic medicine, dentist, oral surgeon, or podiatrist;
• a CRNA who, unless exempted, is under the supervision of the operating practitioner or of an anesthesiologist;
• an anesthesiologist's assistant who is under the supervision of an anesthesiologist.
The aforementioned exemption for CRNAs is the State exemption (also referred to as an "opt-out"). Under the State exemption, if the State in which the hospital is located submits a letter to CMS requesting exemption from physician supervision of CRNAs, and that letter has been signed by the Governor of that State, then hospitals within that State may be exempted from the requirement for physician supervision of CRNAs. In 2001, CMS established this exemption for CRNAs from the physician supervision requirement by recognizing a Governor's written request to CMS attesting that it is in the best interests of the State's citizens to exercise this exemption. As of September 2010, sixteen states (California, Iowa, Nebraska, Idaho, Minnesota, New Hampshire, New Mexico, Kansas, North Dakota, Washington, Alaska, Oregon, South Dakota, Wisconsin, Montana and Colorado) have chosen to opt-out of the CRNA physician supervision regulation.