Who is behind the surgical drape? Understanding the role of anesthesiologist assistants

Author’s note: For several years, I worked for the American College of Surgeons’ (ACS) Division of Advocacy and Health Policy in Washington, DC, as the Quality Associate. Working with the ACS members provided an eye-opening view of what clinicians face on a daily basis—both the challenges and rewards of offering high-quality patient care. After almost four years in that position, I sought to put my interest in high-quality patient care and my premedicine educational background to use by becoming a health care professional. My time with the ACS specifically had sparked an interest in the care of surgical patients, and one surgeon in particular offered to help me discover firsthand the responsibilities that surgical professionals fulfill. Rahul Shah, MD, FACS, FAAP, pediatric otolaryngologist and medical director of perioperative services at Children’s National Medical Center, Washington, DC, offered to allow me to shadow him in the operating room (OR). Needless to say, I was hooked.

Though my day with Dr. Shah was spent observing surgeons performing operations, I was drawn to the other side of the surgical drape. I found fascinating the challenges and unknowns presented with each patient, the constant vigilance, and the complexities of physiology and pharmacology involved in anesthesiology. With that, I left the ACS in May 2011 to earn a master’s degree in anesthesiology and become an anesthesiologist assistant (AA).

As the completion of my graduate training draws near and I embark on this new career, I identify myself with anesthesia during the surgical “time-out” rather than as a representative of the ACS, as I did so many times in the past. Many surgeons have asked about the letters after my name: “AA-C—what does that mean? Who are you? What is your training?” This article is intended to educate surgeons about the role and training of the AAs who may be behind the drapes caring for their patients in the OR.

History of the profession

In response to the shortage of qualified anesthesia professionals in the mid-1960s, anesthesiologists Joachim S. Gravenstein, MD; John E. Steinhaus, MD; and Perry P. Volpitto, MD, performed a workforce analysis of all the qualities required to deliver safe, effective anesthesia care, including responsibility, education, and technical skill. The results of their investigation led to the creation of a new mid-level anesthesia provider, the “anesthesiologist assistant.”1 The AA would be a nonphysician health care professional with a premedical undergraduate background who would be trained in a graduate-level anesthesiology program.2 The AA would practice in an anesthesia care team (ACT) model, in which an anesthesiologist concurrently supervises up to four nonphysician providers, working together to provide quality anesthesia care to the surgical patient. Dr. Gravenstein and the coauthors described their vision for ending the anesthesia shortage as follows: “Responsibility and immediate care of the patient must remain within the province of the anesthesiologist; consequently, personnel could not work independently but only under the immediate direction of an anesthesiologist. An advantage in manpower for the anesthesiologist would result, as he could provide attention to several patients with the proper employment of the anesthesia team, described above.”1

AA education and training

As a result of their vision, the first AA program opened at Emory University, Atlanta, GA, in 1969. To date, nine AA programs that have been accredited by the Commission on Accreditation of Allied Health Education Programs (CAAHEP) exist in the U.S.:

  • Emory University
  • Case Western Reserve University, Cleveland, OH
  • South University, Savannah, GA
  • Nova Southeastern University, Ft. Lauderdale, FL
  • University of Missouri–Kansas City
  • Nova Southeastern University, Tampa, FL
  • Case Western Reserve University, Houston, TX
  • Case Western Reserve University, Washington, DC
  • University of Colorado School of Medicine, Aurora, CO

A new program will soon matriculate its first classes at Quinnipiac University, Hamden, CT. These programs are all affiliated with a university that has a medical school, and each has a board-certified, licensed anesthesiologist serving as medical director.3

According to Shane Angus, AA-C, program director of the newest school at Case Western Reserve University-DC, “The process of opening a new AA program in our nation’s capital involved meticulous planning in order to meet the high criteria for accreditation. Having high AA program credentialing requirements serves the growing surgical patient population by ensuring the graduation of exceptionally skilled AAs.” (Personal communication with the author, May 29, 2013.)

Competitive applicants must have a bachelor’s degree, all of the premedical coursework required by the typical American medical school, and must have taken either the Medical College Admissions Test or the Graduate Records Admission Test. The programs, which range from 24 to 28 months, include specialized didactic and clinical instruction in anesthesia-related courses. Students graduate with a master’s degree and more than 2,000 hours of clinical experience.4

According to Gina Scarboro, AA-C, chair of the Association of Anesthesiologist Assistant Program Directors, “The curriculum covered in an AA educational program is extremely rigorous. In the first year, students attend classes, participate in clinical education, and train using high-fidelity patient simulators. Unlike other graduate health care training, AA students participate in clinical rotations early in their curriculum, which leads to a tight temporal coupling between classroom instruction of the scientific concepts of anesthesia and their direct application in the operating room. Another unique aspect of AA education is the didactic instructional focus on anesthesia systems of delivery (machines) as well as instrumentation and monitoring that adds value to the anesthesiologist assistant’s role in the anesthesia care team.” (Personal communication with the author, April 26, 2013.)

The National Commission for Certification of Anesthesiologist Assistants, in collaboration with the National Board of Medical Examiners, administers a written certification examination for AAs. To maintain certification, AAs need to register for 40 hours of continuing medical education every two years and successfully complete a continued demonstration of qualifications examination every six years.5 AAs use the designation AA-C to indicate that they are currently certified.

Scope of practice

States with practicing AAs

District of Columbia
New Hampshire*
New Mexico
North Carolina
South Carolina
West Virginia*

*Delegatory authority (other states in list have licensure)

As members of the ACT, AAs work under the medical direction of an anesthesiologist. AAs are trained in all aspects of anesthesia care, including but not limited to:

  • Performing preoperative anesthetic evaluations
  • Establishing noninvasive and invasive monitoring
  • Applying and interpreting advanced monitoring techniques
  • Administering medication and delivering continuous anesthesia care during the perioperative period
  • Securing the airway, applying advanced life support practices
  • Performing and managing regional anesthetic techniques6

The specific responsibilities of AAs vary from practice to practice, as directed by the anesthesiologist.

AAs are either licensed by specific state statute or practice under provisions of the medical practice act that allow a licensed physician to delegate specific duties to a qualified practitioner. Howard Odom, MD, chair of the American Society of Anesthesiologists (ASA) Committee on AA Education and Practice, said, “Since defining the profession in the late 1960s, anesthesiologists have actively engaged in educating, advocating for practice, and employing AAs as our specialty-specific mid-level practitioner. Whether under delegation or statutory licensure, AAs have contributed to safe anesthesia care for more than 40 years under the medical direction of anesthesiologists.” (Personal communication with the author, April 29, 2013.)

AAs currently practice in 17 states and the District of Columbia (see table). Additionally, the federal government recognizes AAs, allowing them to practice at all Veterans Affairs hospitals under the TRICARE insurance program, which serves uniformed service members, retired military personnel, and their families.7 AAs practice in various surgical settings, including ambulatory surgery centers; however, according to the American Medical Association, “AAs are most commonly employed in larger facilities that perform procedures such as cardiac surgery, neurosurgery, transplant surgery, and trauma care, given the training in extensive patient monitoring devices and complex patients and procedures emphasized in AA educational programs.”8

Improved access and outcomes

In 2010, the RAND Corporation released a study that cited a shortage of 3,800 anesthesiologists and 1,282 nurse anesthetists as of 2007.9 This national shortage of anesthesia providers has increased due to various factors, including the growing number of procedures requiring anesthesia services, the rising number of surgeries required by the elderly population, and the rapid expansion of sites where surgery is performed. Furthermore, the shortage of anesthesia services is projected to continue until 2020. ASA past-president Mark Warner, MD, reflected on this disturbing shortage in a 2011 Physician’s Weekly article. “The projected shortage of anesthesiologists suggests that the U.S. will soon face a gap in anesthesiology services that will be just as important to Americans’ health as the projected physician gap for primary care services,” Dr. Warner wrote. “As more and more patients are projected to become older and sicker, healthcare facilities will need more anesthesiologists to provide the full scope of care that patients will need before, during, and after their surgeries and procedures.”10

With this alarming anesthesia professional shortage, operations may be delayed due to lack of qualified personnel, or, even worse, exhausted providers may be forced to care for surgical patients. The shortage of anesthesia professionals limits access to high-quality care and has an unnecessarily deleterious effect on patient safety. According to James Mesrobian, MD, chair of the ASA committee on practice management, “Anesthesiologist assistants fill the need for more midlevel providers in anesthesia services, particularly in rural areas where anesthesiologists are in short supply.”11

Whereas AAs increase access to the operative care for surgeons and their patients, they also increase the quality of anesthesia care provided to the surgical patient by functioning under the ACT model. Under this system, anesthesiologists medically direct two or more mid-level anesthesia providers at the same time. The shared skills, knowledge, and vigilance of the team allow for the ultimate collaboration to provide the most appropriate and high-quality care for the surgical patient. “I have worked with AAs for almost a decade and they provide outstanding care to patients as a member of the perioperative services team,” said Dr. Shah. (Personal communication with the author, April 27, 2013.) “They play an invaluable role in a niche position that will always provide value in the OR.  In the era of health care reform, the role of the AA will continue to be important, if not expand.”

The “observation synergism” of multiple providers in the ACT is further supported by the ability to rapidly respond during a crisis, leading to improved patient outcomes.12 In fact, “improved patient outcomes associated with care provided by anesthesia care teams and hybrid practices have been confirmed by a study of hospital characteristics and mortality after elective surgery.”13 An additional study also supports the premise that the physician-directed ACT model provides higher-quality patient care: “Both 30-day mortality rate and mortality rate after complications (failure-to-rescue) were lower when anesthesiologists directed anesthesia care. These results suggest that surgical outcomes in Medicare patients are associated with anesthesiologist direction, and may provide insight regarding potential approaches for improving surgical outcomes.”14

“With the ACT, the patient is assured that, with the anesthesiologist plus the AA, there are two anesthesia providers,” explained Rob Wagner, AA-C, MMSc, RRT, associate chair of the health science department and assistant professor at the AA program at Nova Southeastern University, Orlando, FL.15 “With the anesthesiologist and surgeon, there are two medical doctors. It is the highest standard of patient care.”15

AAs are the only anesthesia professionals who work exclusively in the ACT model. The unique dedication to this optimal mode of patient care is evident in the mission statement of the American Academy of Anesthesiologist Assistants (AAAA), which supports excellence through education, advocacy, and promotion of the ACT.16 “AAs are the sole nonphysician mid-level anesthesia providers that ensure an anesthesiologist-led delivery of safe anesthesia care,” said Saral Patel, AA-C, president of the AAAA. (Personal communication with the author, April 26, 2013.) “The AAAA promotes quality values during the delivery of anesthesia patient care, including teamwork, leadership, communication, professionalism, and mentorship.”

Anesthesiologists may supervise AAs in ratios defined in state law or board guidelines. The Centers for Medicare & Medicaid Services’ (CMS) requirements call for assigning up to four anesthetists to one anesthesiologist. The supervision ratios are usually between 2:1 and 4:1.

Support from anesthesiologists

The ASA has been a strong advocate for the AA profession since its inception. Not only does the ASA participate in the training, education, accreditation, and certification of AAs, but it also is one of the biggest proponents of the expansion of AAs in the workforce. In the March 2003 ASA NEWSLETTER, David C. Mackey, MD, clinical associate professor of anesthesiology, University of Florida College of Medicine, Gainesville, said, “The national emergence of the AA is long overdue. It is time to work with well-trained physician extenders who want to work with us and who are committed to the anesthesia care team concept.”17

Most recently, at the 2011 American Medical Association House of Delegates meeting in Chicago, “ASA unambiguously defined its position in full support of promoting the practice of AAs.”18 John M. Zerwas, MD, president of the ASA, member of the Texas House of Representatives, and past-president of Greater Houston Anesthesiology, has seen the implementation of AAs within the ACT model in Houston. “In both the hospital and ambulatory surgical setting, AAs have proven to be valuable, highly qualified members of the anesthesia care team in Texas.”19

The ASA, together with the AAAA, continues to support the growth of AA practice. Shared efforts include introduction of new state statutes that will enable AAs to practice in more states. “Anesthesiologists have always been and will continue to be medical leaders in innovation when it comes to patient safety, and AAs are proud to be part of the solution,” said Claire Chandler, AA-C, immediate past-president of the AAAA. (Personal communication with the author, April 21, 2013.) “It is uncommon to witness such a global bipartisan effort between physicians and advanced non-physician providers to promote the common goal of patient safety. This cooperative model is the future of quality health care.”

How surgeons can support AAs

The ACS has shown support for AA expansion in recent letters to state legislatures for AA licensing measures. “The ACS supports high-quality perioperative care of the surgical patient,” according to David B. Hoyt, MD, FACS, ACS Executive Director.  “The use of AAs in the anesthesia care team delivery system not only improves access for our surgeons, but also provides a value-driven team approach to patient care.”(Personal communication with the author, April 30, 2013.)

It is the hope of all of us who have chosen to serve as AAs that surgeons will continue to advocate for and support our efforts to provide high-quality anesthesia care to surgical patients. Surgeons can help bring AAs to their institutions by contacting their local ACS chapter and encouraging their leaders to write letters of support for AAs.

For more information about AAs, visit the AAAA website at www.anesthetist.org.


  1. Gravenstein JS, Steinhaus JE, Volpitto PP. Analysis of manpower in anesthesiology. Anesthesiology. 1970;33(3):350-357.
  2. Steinhaus JE, Evans JA, Frazier WT. The physician assistant in anesthesiology.  Anesthesia and Analgesia. 1973;52(5):794-799.
  3. Standards and Guidelines for the Accreditation of Educational Programs in Anesthesiologist Assistant. Commission on Accreditation of Allied Health Education Programs. Available at: http://www.anesthesiaprogram.com/pdfs/AA_Standards.pdf. Accessed April 6, 2013.
  4. Amburgey B, Fordham M, Payne B, Trebelhorn M. A study of anesthesiologist assistants. Research report No. 337. Kentucky Legislative Research Commission. Available at: http://www.anesthetist.org/factsaboutaas/AA_Study-RR337.pdf. Accessed April 26, 2013.
  5. National Commission for Certification of Anesthesiologist Assistants. Available at: http://www.aa-nccaa.org/. Accessed April 6, 2013.
  6. American Society of Anesthesiologists. Types of careers in anesthesiology. Careers in healthcare. Available at: http://www.asahq.org/for-the-public-and-media/about-profession/types-of-careers-in-anesthesiology.aspx. Accessed April 6, 2013.
  7. American Academy of Anesthesiologist Assistants. States with licensure. Facts about AAs. Available at: http://www.anesthetist.org/factsaboutaas/. Accessed April 6, 2013.
  8. American Medical Association. Anesthesiologist assistant. Health care careers directory 2008–2009. Available at: http://www.ama-assn.org/ama1/pub/upload/mm/40/aa0809.pdf.Accessed April 26, 2013.
  9. RAND Corporation. Is there a shortage of anesthesia providers in the United States? Available at: http://www.rand.org/pubs/research_briefs/2010/RAND_RB9541.pdf. Accessed April 26, 2013.
  10. Warner MA. Efforts needed to meet anesthesiologist demand. Physicians Weekly. Available at: http://www.physiciansweekly.com/efforts-needed-to-meet-anesthesiologist-demand/. Accessed April 26, 2013.
  11. Mesrobian JR. ASA: Need anesthesiology providers? Consider anesthesiologist assistants. Available at: http://www.kevinmd.com/blog/2012/05/asa-anesthesiology-providers-anesthesiologist-assistants.html. Accessed April 26, 2013.
  12. Cooper JB, Long CD, Newbower RS, Philip JH. Critical incidents associated with intraoperative exchanges of anesthesia personnel. Anesthesiology. 1982;56(6):456-461.
  13. Silber JH, Williams SV, Krakauer H, Schwartz JS. Hospital and patient characteristics associated with death after surgery. A study of adverse occurrence and failure to rescue. Med Care. 1992;30(7):615-629.
  14. Silber JH, Kennedy SK, Even-Shoshan O, Chen W, Koziol LFL, Showan AM, Longnecker DE. Anesthesiologist direction and patient outcomes. Anesthesiology. 2000; 93(1):152-163.
  15. Rothstein A. Anesthesiologist assistants: Making the operating room more accessible and manageable. Bull Am Coll Surg. 2006;91(8):24-26.
  16. American Academy of Anesthesiologist Assistants. Mission statement. Available at: http://www.anesthetist.org/aboutaaaa/. Accessed April 26, 2013.
  17. Frangou C. Anesthesiology assistants gain ground on physician extender map. Anesthesiol News. Available at: http://www.anesthetist.org/factsaboutaas/AN_Assts_Article.pdf. Accessed April 26, 2013.
  18. American Society of Anesthesiologists. Incorporating AAs into your practice. ASA NEWSLETTER. Available at: http://www.viewer.zmags.com/publication/dd2b8bfd#/dd2b8bfd/16. Accessed April 26, 2013.
  19. American Society of Anesthesiologists. State regulatory issues in AA practice. ASA NEWSLETTER. Available at: http://www.asahq.org/For-Members/Publications-and-Research/Periodicals/ASA-Newsletter.aspx?year=2003&ypp=1#archive. Accessed April 26, 2013.

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