Basic Definitions & Information

Certified anesthesiologist assistants (CAAs) are highly skilled allied health professionals who work under the direction of licensed anesthesiologists to implement anesthesia care plans. CAAs work exclusively within the anesthesia care team environment as described by the American Society of Anesthesiologists (ASA). All CAAs possess a premedical background, a baccalaureate degree, and also complete a comprehensive didactic and clinical program at the graduate school level. CAAs are trained extensively in the delivery and maintenance of quality anesthesia care as well as advanced patient monitoring techniques. The goal of CAA education is to guide the transformation of qualified student applicants into competent health care practitioners who aspire to practice in the anesthesia care team.

Certified Anesthesiologist Assistants and certified registered nurse anesthetists are both defined as "non-physician anesthetists" within the Centers for Medicare & Medicaid Services section of the Code of Federal Regulations.

In the 1960s, three anesthesiologists, Joachim S. Gravenstein, John E. Steinhaus, and Perry P. Volpitto, were concerned with the shortage of anesthesiologists in the country. These academic department chairs analyzed the spectrum of tasks required during anesthesia care. The tasks were individually evaluated based on the level of professional responsibility, required education and necessary technical skill. The result of this anesthesia workforce analysis was to introduce the concept of team care and to define a new mid-level anesthesia practitioner linked to a supervising anesthesiologist. This new professional - the certified anesthesiologist assistant or CAA - had the potential to at least partially alleviate the shortage of anesthesiologists.

The new type of anesthetist would function in the same role as the nurse anesthetist under anesthesiologist direction. An innovative educational paradigm for anesthetists was created that built on a pre-med background during college and led to a Master’s degree. This pathway placed CAAs on an anesthesia “career ladder.” Some CAAs have leveraged their premed background, Master’s degree and clinical experience to successfully apply to medical school. A few have returned to anesthesia to become the physician leader of the care team that launched their professional career.

Although CAAs and physician assistants (PAs) are both allied health professionals, they do not perform the same functions. Each has its own separate educational curriculum, standards for accreditation, and its own agency for certification. PAs receive a generalist education and may practice in many different fields under the supervision of a physician in that field. The scope of practice of a PA is much broader than that of an CAA, and in some states the PA works under less supervision than the CAA.

A CAA may not practice outside of the field of anesthesia or without the supervision of an anesthesiologist. An CAA may not practice as a physician’s assistant unless the CAA has also completed a PA training program and passed the National Commission for the Certification of Physician Assistants (NCCPA) exam.

Likewise a PA may not identify him- or herself as an CAA unless he or she has completed an accredited CAA program and passed the National Commission for the Certification of Anesthesiologist Assistants (NCCAA) exam. The exact scope of practice authority for CAAs and PAs in any individual state can only be ascertained by referring to the laws or board of medicine guidelines of the state in question.

Although both are considered to be equivalent clinical non-physician anesthesia providers and may serve as physician extenders in the delivery of anesthesia, CAAs and NAs are very different with regard to their educational background, training pathway and certification process.

According to the Council on Accreditation (COA) of Nurse Anesthesia Educational Programs, a typical applicant to an NA program must have attained a bachelor’s degree in either nursing or another appropriate area.  Until recently, nurses with only an associate’s degree in nursing also were accepted.  Additionally, the applicant must be licensed to practice as a registered nurse and take either the Graduate Record Exam (GRE) or the Miller Analogies Test (MAT) prior to matriculation.  Finally, one year of nursing experience is required in an “acute care setting.”

In order to be admitted to an CAA program, the applicant must have achieved a bachelor’s degree with prescribed prerequisites typical of premedical course work.  Specific requirements include general and organic chemistry, advanced college math, general and advanced biology, and physics.  Applicants must then take either the (MCAT) or the (GRE).  Although many applicants who are from allied health backgrounds such as respiratory therapy and emergency medical technology may have years of clinical experience, a clinical background is not an absolute requirement.  In no instance does such work experience substitute for the required academic background of sufficient course content and quality.  Nurses who meet the premed coursework prerequisites have been admitted to CAA programs.

NA training programs must include a minimum of 24 months in a Master’s level program accredited by the COA.  The training programs may be based at any college or university offering a Master’s level degree.  Many nurse anesthetists do not possess a Master’s degree as this was not required until 1998.  Nurse anesthetist programs do not require involvement of a medical school or academic physician faculty.  Community hospitals may serve as main clinical sites.  A minimum of 450 hours of classroom/laboratory education, 800 hours of clinical anesthesia education, and administration of 450 anesthetics, including all types of surgery, must be achieved for the student to successfully complete the training program.

CAA training programs must include a minimum of 24 months in a Master’s level program accredited by the Commission for the Accreditation of Allied Health Educational Programs (CAAHEP).  The programs must be based at, or in collaboration with, a university that has a medical school and academic anesthesiologist physician faculty.  Main clinical sites must be academic medical centers.  An average of 600 hours of classroom/laboratory education, 2600 hours of clinical anesthesia education, and more than 600 anesthetics administered, including all types of surgery, are typically required to successfully complete CAA training.

Upon completion of an accredited nurse anesthetist program, a student may become certified by passing the Council for Certification of Nurse Anesthetists certification exam.  This examination is an adaptive computer examination consisting of 90-160 questions.  Forty hours of approved Continuing Education Units (CEU) are required every two years in order to recertify.  To be recertified, nurse anesthetists do not take an additional exam.

Upon completion of an accredited CAA program, a student may become certified by passing the NCCAA examination that consists of 200 questions.  This examination is co-validated by the National Board of Medical Examiners.  To re-certify, an CAA must complete 40 hours of CME every two years.  Additionally, CAAs must take the Continuing Demonstration of Qualification Exam every six years.  The CDQ exam follows the same format as the initial certification exam.

The professional organization for CAAs is the American Academy of Anesthesiologist Assistants (AAAA).  AAAA was founded in 1975 and serves the various educational, advocacy and national organizational needs of the CAA profession. Their website may be found at:

CAAs and CAA students, as well as NAs and NA students, are eligible for ASA membership. They join under the category of “Educational Members” and are entitled to all of the educational benefits of ASA memberships, including free registration at the ASA Annual Meeting and a subscription to Anesthesiology.

Educational members are nonvoting members and cannot run for office. However at the invitation of the President, CAAs can and do serve on committees and attend Reference Committee and House of Delegates meetings. Dues for Educational Members are currently the same as for Affiliate Members. Applications for membership may be obtained from the ASA website.

Education & Certification

As of May 2017, there are 12 accredited CAA educational programs.

According to the latest standards established by the Commission on Accreditation of Allied Health Education Programs (CAAHEP), accredited Anesthesiologist Assistant educational program must be supported by an anesthesiology department of a medical school that is accredited by the Liaison Committee on Medical Education or its equivalent. The anesthesiology department must have the educational resources internally or through educational affiliates that would qualify it to meet the criteria of the Accreditation Council for Graduate Medical Education (ACGME), or its equivalent for sponsorship of an anesthesiology residency program. CAAHEP rules also allow for consortium sponsorship utilizing the combined resources of an academic anesthesiology department and an accredited college with appropriate allied health faculty and degrees.

Although the standards recognize the importance of a basic science education within a clinically oriented academic setting, it is also recognized that some of the supervised clinical practice components of the curriculum may be carried out in affiliated community hospitals that have the appropriate affiliation agreements specifying the requisite teaching faculty and staffing ratios for the clinical experience.

The Commission on Accreditation of Allied Health Education Programs (CAAHEP) accredits CAA training programs. ASA is a CAAHEP member and participates in the accreditation processes for three health professions – certified anesthesiologist assistant, respiratory therapy and emergency medical technician-paramedic. CAAHEP is the largest accreditor in the health sciences field. In collaboration with its Committees on Accreditation, CAAHEP reviews and accredits over 2000 educational programs in nineteen health science occupations. CAAHEP is recognized by the Council for Higher Education Accreditation (CHEA).

CAAHEP re-approved the “Standards and Guidelines for Anesthesiologist Assistant Education” most recently in 2004. These standards are composed and submitted by the Accreditation Review Committee on Education for the Anesthesiologist Assistant (ARC-AA). ARC-AA in turn is composed of representatives from the American Academy of Anesthesiologist Assistants (AAAA), and the American Society of Anesthesiologists (ASA). Anesthesiologists from ASA work along with CAA representatives from AAAA to define the educational process that produces a competent CAA graduate. This partnership of professional organizations has ensured an integral role for anesthesiologists in CAA education. This in turn echoes the anesthesiologist/CAA relationship in the anesthesia care team.

Additional information on accreditation may be found at the CAAHEP website.

According to CAAHEP standards for CAA programs, the depth and duration of the total program, and particularly the clinical experience, shall be sufficient to assure the potential employer that the newly graduated CAA will be able to perform entry-level functions. The number, content and length of courses shall be appropriate to the training of an assistant to the anesthesiologist. The CAA curriculum is based on an advanced graduate degree model, and at least two full academic years are required. The current programs are 24 to 28 months long. Graduates from all CAA educational programs earn a masters-level degree.

Qualified student applicants must possess a baccalaureate degree and complete all of the premedical course work required by the typical American medical school.

Though minor differences between programs may exist, generalized admission requirements for students seeking entrance into an CAA program include:

  • Bachelor’s degree from an accredited institution with a premedical sciences track
  • Two semesters of biology with laboratory
  • Two semesters of vertebrate anatomy and physiology (or other advanced biology) with laboratory
  • Two semesters of general chemistry; one semester of organic chemistry; a second semester of organic chemistry or biochemistry with laboratory
  • Two semesters of general physics with laboratory
  • Two semesters of advanced college mathematics including calculus
  • Either the Medical College Admissions Test (MCAT) or the Graduate Records Admission Test (GRE)

According to CAAHEP standards, the program must include faculty who are qualified through academic preparation and experience to teach assigned subjects. Faculty members for the basic sciences are university-based professors and instructors. Faculty for the supervised clinical practice portion of the educational program must include physicians and CAAs based within the department of anesthesiology, but also may include other health professionals who are experienced in their disciplines. All faculty members should possess at least clinical appointments within the affiliated medical school. Although anesthesiology residents and fellows may be involved in CAA training, they should not play a predominant role.

The National Commission for Certification of Anesthesiologist Assistants (NCCAA) was founded in July 1989 to develop and administer the certification process for CAAs in the United States. The NCCAA consists of Commissioners representing ASA, AAAA, and at-large physician and CAA members.

Graduates or senior students in their last semester in an CAA educational program that has been accredited by CAAHEP may apply for initial certification. Initial certification is awarded to an CAA who has successfully completed the Certifying Examination for Anesthesiologist Assistants administered by NCCAA in collaboration with the National Board of Medical Examiners (NBME). Certified AAs are permitted to use the designation CAA to indicate that they are currently certified.

The content for the Certifying Examination for Anesthesiologist Assistants is based on knowledge and skills required for anesthetist practice. NCCAA has contracted with NBME to serve as a consultant for the development and ongoing administration of the Certifying Examination. A Test Committee of anesthesiologists and AAs is responsible for writing and evaluating test questions for the examinations as well as for an item bank containing material that will be used in future years. The first Certifying Examination was administered in 1992.

The NCCAA annually publishes a list of Certified Anesthesiologist Assistants (CAA). This public document is made available to state boards of medicine and other bodies responsible for credentialing health care professionals.

More information on CAA certification may be found at the NCCAA website.

CAAs must maintain certification after passing the initial examination. The ongoing process requires that AAs submit documentation to NCCAA every two years that they have completed 40 hours of continuing medical education (CME). In addition, every six years they must pass the Examination for Continued Demonstration of Qualifications (CDQ). This ongoing certification cycle is depicted below.

NCCAA Certification Process
Year 0 Certifying Examination
Year1 None
Year 2 CME Registration
Year 3 None
Year 4 CME Registration
Year 5 None
Year 6 CME Registration & CDQ Examination


The CDQ Examination was first administered in 1998, making CAAs the first anesthesia profession to require passage of a written examination as part of the recertification process. Failure to meet any of the above CME or examination requirements results in withdrawal of certification for the CAA.

CAA Practice

According to the ASA statement on the Anesthesia Care Team, anesthesia care personally performed or medically directed by an anesthesiologist constitutes the practice of medicine. Certain aspects of anesthesia care may be delegated to other properly trained and credentialed professionals. These professionals, medically directed by the anesthesiologist, comprise the Anesthesia Care Team.

The Care Team statement (last amended on October 21, 2009 ) says, “Such delegation and direction should be specifically defined by the anesthesiologist and also be consistent with state law or regulations and medical staff policy. Although selected tasks of overall anesthesia care may be delegated to qualified members of the Anesthesia Care Team, overall responsibility and direction for the Anesthesia Care Team and the patients' safety rests with the anesthesiologist.”

Members of the medically directed anesthesia care team may include anesthesiology residents as well as non-physicians such as certified anesthesiologist assistants and nurse anesthetists.

The scope of CAA clinical practice is generally the same as that of nurse anesthetists on the Anesthesia Care Team.

Specifically, the local scope of practice of CAAs is usually defined by

  • the medically directing anesthesiologist,
  • the hospital credentialing body,
  • the state’s board of medicine
  • any applicable state statute or regulation.

States may also require a practice agreement between the sponsoring anesthesiologist and the CAAs who are medically directed.

The specific job descriptions and duties of CAAs may differ according to local practice.  State law or board of medicine regulations or guidelines may further define the job descriptions of CAAs.  The constant ingredient no matter what the local variation is that CAAs always practice under the medical direction of a qualified anesthesiologist.  

As part of defining the educational goal of CAA training programs, the CAAHEP accreditation Standards include a template CAA job description.   The excerpt is included below.   Wherever the term ‘assisting’ occurs, it is understood that such assistance may be actual performance of the stated task by the CAA as part of duties directed by the supervising anesthesiologist.  

“Under the direction of a qualified anesthesiologist, the certified anesthesiologist assistant's  functions include, but are not limited to, the following:

  • Making the initial approach to a patient of any age in any setting to obtain an appropriate and accurate preanesthetic health history, perform an appropriate physical examination and record pertinent data in an organized and legible manner. These activities help to define the patient's current physical status as it relates to the planned anesthetic.
  • Performing or assisting in the conduct of diagnostic laboratory and related studies as appropriate, such as drawing arterial and venous blood samples.
  • Establishing non-invasive and invasive routine monitoring modalities, as delegated by the responsible anesthesiologist.
  • Assisting in the application and interpretation of advanced monitoring techniques such as pulmonary artery catheterization, electroencephalographic spectral analysis, echocardiography and evoked potentials.
  • Assisting in the induction, maintaining and altering anesthesia levels, administering adjunctive treatment and providing continuity of anesthetic care into and during the post-operative recovery period.
  • Assisting in the use of advanced life support techniques, such as high frequency ventilation and intra-arterial cardiovascular assist devices.
  • Assisting in making post-anesthesia patient rounds by recording patient progress notes, compiling and recording case summaries, and by transcribing standing and specific orders.
  • Performing evaluation and treatment procedures essential to responding to life-threatening situations, such as cardiopulmonary resuscitation, on the basis of established protocols (basic life support, advance cardiac life support, and pediatric advanced life support).
  • Assisting in the performance of duties in intensive care units, pain clinics and other settings, as appropriate.
  • Training and supervising personnel in the calibration, trouble shooting and use of patient monitors.
  • Performing delegated administrative duties in an anesthesiology practice or anesthesiology department in such areas as the management of personnel, supplies and devices.
  • Assisting in the clinical instruction of others.”

The complete Standards for Accreditation of Anesthesiologist Assistant Education  are available from CAAHEP at CAA standards.

CAAs are permitted to perform regional anesthesia techniques and place invasive monitors.  These aspects of CAA practice depend on the discretion of the supervising anesthesiologist, policies and procedures of the Department of Anesthesiology, standards set by the facility credentialing committee, and applicable state law.  As always, performance of any such patient care task is under the medical direction of an anesthesiologist.

Certified anesthesiologist assistants may be either licensed as CAAs or practice under the license of an anesthesiologist under the principle of delegation.  Anesthesiologists may delegate those tasks or duties involved in the practice of anesthesiology to qualified individuals such as CAAs as long as the anesthesiologist is immediately available and the anesthesiologist retains ultimate responsibility for the care of the patient.  The exact details regarding delegation and licensing of CAAs are different from state to state, and an anesthesiologist seeking to employ CAAs should consult the board of medicine of the state in which he or she practices.

Anesthesiology practices in many states presently employ CAAs. Inclusion of CAAs in anesthesia care team practices across the country is a dynamic and evolving situation. To get the latest and most accurate information, please contact your state board of medicine or the ASA Washington Office for any questions on the licensure and practice locations of CAAs.

Another excellent resource is maintained by the American Academy of Anesthesiologist Assistants (AAAA). A list of states where CAAs currently practice may be obtained by contacting AAAA at their website.

Licensure for CAAs is created by legislation that is enacted and codified into state law or through regulation adopted by the board of medicine.

Delegatory authority may take the form of either recognition and action by the board of medicine or expressed in a delegation enabling statute such as the state’s medical practice act. It is well accepted in various medical specialties, including anesthesiology, that the board of medicine may grant a physician the authority to delegate tasks or duties related to the practice of medicine to qualified individuals so long as the physician: 1) remains ultimately responsible to the patient and 2) assures that the individual performing the tasks is qualified to do so. An anesthesiologist seeking to employ CAAs under the principle of delegatory authority should seek input from the board of medicine of their specific state.

Licensure for CAA practice, although sometimes more difficult to achieve, better defines and anchors the practice of CAAs in a state than does the simpler delegatory authority.

In all states CAA practice falls under the auspices of the board of medicine. In contrast, nurse anesthetists’ practice is regulated by state boards of nursing.

Practice Management of CAAs

If your state does not presently provide the legislative or delegatory option of CAA practice, consultation should take place with the board of medicine or other governing body to explore the specific legal implications of CAA practice in your state. General information on the steps to establish CAA practice is available from the ASA's Office of Governmental and Legal Affairs.  You may also inquire of other state societies as to their local advocacy and procedural steps that have led to gaining the option to hire CAAs.   

Also, the American Academy of Anesthesiologist Assistants is a valuable resource on suggested methods of licensing and establishing practice of CAAs drawn from various states. You can contact AAAA at: (678) 222-4233 or

Finally, you can also contact the educational programs directly as listed in the question titled, "Where are CAA education programs located?" above.

In addition to the practical issues that limit how many anesthetists may be supervised by an anesthesiologist at any one time, ratios are also often specified as contract requirements from payers. For instance in order to meet CMS requirements for medical direction, no more than 4 anesthetists (CAAs or NAs) may be concurrently directed by an anesthesiologist.

The supervision ratio may also be defined in state law or Board of Medicine guidelines and is usually between 2:1 and 4:1. Check the regulations in your state for the applicable standard. It is important to note that in states where statutes specify a supervision ratio of CAAs to anesthesiologists at less than 4:1, the anesthesiologist may also concurrently supervise NAs up to a total combined ratio of 4:1 for both non-physician anesthetists.

CMS recognizes both CRNAs and CAAs as non-physician anesthesia providers. Similarly, commercial insurance payers make no distinction between the two anesthetist types with regard to payments for services provided under medical direction by an anesthesiologist.

According to the United States Code of Federal Regulations ( 42 C.F.R. § 482.52 Condition of participation: Anesthesia services)

“If the hospital furnishes anesthesia services, they must be provided in a well-organized manner under the direction of a qualified doctor of medicine or osteopathy. The service is responsible for all anesthesia administered in the hospital.

Standard: Organization and staffing. The organization of anesthesia services must be appropriate to the scope of the services offered. Anesthesia must be administered only by:

  • A qualified anesthesiologist;
  • A doctor of medicine or osteopathy (other than an anesthesiologist);
  • A dentist, oral surgeon, or podiatrist who is qualified to administer anesthesia under State law;
  • A certified registered nurse anesthetist (CRNA), as defined in § 410.69(b) of the Federal Register, who is under the supervision of the operating practitioner or of an anesthesiologist who is immediately available if needed; or
  • An anesthesiologist's assistant, as defined in § 410.69(b) of the Federal Register, who is under the supervision of an anesthesiologist who is immediately available if needed.”


When employed within the same department and when possessing the same job description and experience level within the anesthesia care team, CAAs and NAs are compensated with identical salary and benefit packages.