Anesthesiologist Assistants Ensure Same Surgical Outcomes as Nurse Anesthetists

Case Western Reserve University Master of Science in Anesthesia student intubating in simulation lab

Patients who undergo inpatient surgery experience no difference in death rates, length of hospital stay or costs between admission or discharge, whether their physician anesthesiologist is teamed with an anesthesiologist assistant or a nurse anesthetist, according to a new study published in Anesthesiology’s Online First, the electronic edition of the peer-reviewed medical journal of the American Society of Anesthesiologists. 

Both anesthesiologist assistants and nurse anesthetists are considered physician extenders in the practice of anesthesiology, meaning they collaborate with the physician anesthesiologist as key members of the anesthesia care team. Many institutions and insurance providers recognize no difference between anesthesiologist assistants and nurse anesthetists. In fact, there are only three key differences:

  • The training and licensure of the two groups is different. Anesthesiologist assistants have an undergraduate pre-medical degree and nurse anesthetists have an undergraduate nursing degree with a certain number of years’ experience before enrolling in an advanced program. Both professions have graduate degrees in anesthesia practice, and anesthesiologist assistants are licensed as anesthesia care providers by the state medical board.
  • Anesthesiologist assistants practice within an anesthesia care team and are always supervised by a physician anesthesiologist. In some instances, nurse anesthetists are supervised by other physicians and, in a small number of states, are able to administer anesthesia without physician supervision.
  • Anesthesiologist assistants practice in 18 jurisdictions and nurse anesthetists practice anywhere in the United States.

As the authors of the research reported, policymakers and researchers are considering alternative care models “in an effort to increase access and reduce healthcare spending,” and one solution is to expand the practice of anesthesiologist assistants to more states (1). This increase in “the use of non-physician providers could reduce costs [and,] in the face of predicted physician shortages, the expanded use of non-physician providers could increase access, particularly in underserved areas” (1).

The argument against expansion of anesthesiologist assistants’ practice has often centered on “the possibility that health outcomes may be worse when anesthesiologist assistants provide anesthesia care. Nonetheless, until now, it has not been known whether these concerns are warranted and whether there actually is a difference in outcomes depending on whether a physician anesthesiologist works with a nurse anesthetist or an anesthesiologist assistant,” said lead researcher Eric Sun, MD, PhD, and assistant professor of anesthesiology, perioperative and pain medicine at Stanford University Medical Center.

Dr. Sun and his co-authors were able to refute this claim through their research.

Using national claims data for 443,00 Medicare beneficiaries who underwent inpatient surgery between 2004 and 2011, the study illustrated that “the specific composition of the anesthesia care team—in other words, whether the physician anesthesiologist supervises a nurse anesthetist or an anesthesiologist assistant—is not likely to be associated with differences in patient outcomes” (8). Thus, anesthesiologist assistants are able to ensure the same surgical outcomes for patients as nurse anesthetists.

Given this conclusion, anesthesiologist assistants prove to be a key resource for expanding access to healthcare and reducing healthcare spending.

The project received funding from the American Society of Anesthesiologists. The full report can be viewed online.