Anesthesia
From Wikipedia, the free encyclopedia
Anesthesia, or anaesthesia (see spelling differences; from Greek αν-, an-, "without"; and αἴσθησις, aisthēsis, "sensation"),[1] traditionally meant the condition of having sensation (including the feeling of pain) blocked or temporarily taken away. It is a pharmacologically induced and reversible state of amnesia, analgesia, loss of responsiveness, loss of skeletal muscle reflexes or decreased stress response, or all simultaneously. These effects can be obtained from a single drug which alone provides the correct combination of effects, or occasionally a combination of drugs (such as hypnotics, sedatives, paralytics and analgesics) to achieve very specific combinations of results. This allows patients to undergo surgery and other procedures without the distress and pain they would otherwise experience. An alternative definition is a "reversible lack of awareness," including a total lack of awareness (e.g. a general anesthetic) or a lack of awareness of a part of the body such as a spinal anesthetic. The pre-existing word anesthesia was suggested by Oliver Wendell Holmes, Sr. in 1846 as a word to use to describe this state.[2]
Types of anesthesia include local anesthesia, regional anesthesia, general anesthesia, and dissociative anesthesia. Local anesthesia inhibits sensory perception within a specific location on the body, such as a tooth or the urinary bladder. Regional anesthesia renders a larger area of the body insensate by blocking transmission of nerve impulses between a part of the body and the spinal cord. Two frequently used types of regional anesthesia are spinal anesthesia and epidural anesthesia. General anesthesia refers to inhibition of sensory, motor and sympathetic nerve transmission at the level of the brain, resulting in unconsciousness and lack of sensation. Dissociative anesthesia uses agents that inhibit transmission of nerve impulses between higher centers of the brain (such as the cerebral cortex) and the lower centers, such as those found within the limbic system.
Anesthesia providers
Doctors specializing in perioperative care, development of an anesthetic plan, and the administration of anesthetics are known in the US as anesthesiologists and in the UK, Canada, Australia, and NZ as anaesthetists or anaesthesiologists. All anesthetics in the UK, Australia, New Zealand, Hong Kong and Japan are administered by doctors. Nurse anesthetists also administer anesthesia in 109 nations.[3] In the US, 35% of anesthetics are provided by physicians in solo practice, about 55% are provided by anesthesia care teams (ACTs) with anesthesiologists medically directing anesthesiologist assistants or certified registered nurse anesthetists (CRNAs), and about 10% are provided by CRNAs in solo practice.[4][5][3]
Physicians
Anesthesia students training with a patient simulator
In the strict sense, the term anesthetist refers to any individual who administers anesthesia. In the US, however, the term is most commonly employed to refer to registered nurses who have completed specialized education and training in anesthesia to become certified registered nurse anesthetists (CRNAs). In the US and Canada, medical doctors who specialize in anesthesiology are called anesthesiologists. Such physicians in the United Kingdom (UK), Australia and New Zealand are called anaesthetists.
In the US, a physician specializing in anesthesiology typically completes four years of college, four years of medical school, and four years of postgraduate medical training or residency[6] According to the American Society of Anesthesiologists, anesthesiologists provide or participate in more than ninety percent of the forty million anesthetics delivered annually.[7] In the UK, this training lasts a minimum of seven years after the awarding of a medical degree and two years of basic residency, and takes place under the supervision of the Royal College of Anaesthetists.[citation needed] In Australia and New Zealand, it lasts five years after the awarding of a medical degree and two years of basic residency, under the supervision of the Australian and New Zealand College of Anaesthetists.[8] Other countries have similar systems, including Ireland (the Faculty of Anaesthetists of the Royal College of Surgeons in Ireland), Canada and South Africa (the College of Anaesthetists of South Africa).
In the US, satisfactory completion of the written and oral Board examinations allows an anesthesiologist to be called a "Diplomate" of the American Board of Anesthesiology (or of the American Osteopathic Board of Anesthesiology, for osteopathic physicians). This is often referred to colloquially as being "Board Certified". In the UK, Fellowship of the Royal College of Anaesthetists (FRCA) is conferred upon medical doctors following satisfactory completion of the written and oral parts of the Royal College's examination.
The role of the anesthesiologist is no longer limited to the operation itself. Many anesthesiologists function as perioperative physicians, ensuring optimal analgesia and maintenance of physiologic homeostasis throughout the preoperative, intraoperative, and postoperative periods. Anesthesiologists may elect to subspecialize in anesthesia for particular types of surgery (cardiothoracic, obstetrical, neurosurgical, pediatric), regional anesthesia, acute or chronic pain medicine, or Intensive Care Medicine.
Anesthesia providers are often trained using full scale human simulators. The field was an early adopter of this technology and has used it to train students and practitioners at all levels for the past several decades. Notable centers in the United States can be found at the Johns Hopkins Medicine Simulation Center,[9] Harvard's Center for Medical Simulation,[10] Stanford,[11] The Mount Sinai School of Medicine HELPS Center in New York,[12] Duke University,[13]and the University of Utah. [14]
Nurse anesthetists
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 bachelors 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 can not 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