Anesthesia, or
anaesthesia (see
spelling differencesOne of the ways in which American English and British English differ is in spelling.-Historical origins:In the early 18th century, English spelling was not standardized. Differences became noticeable after the publishing of influential dictionaries...
; from
GreekGreek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
,
an-, "without"; and ,
aisthēsis, "sensation"), traditionally meant the condition of having sensation (including the feeling of
painPain is an unpleasant sensation often caused by intense or damaging stimuli such as stubbing a toe, burning a finger, putting iodine on a cut, and bumping the "funny bone."...
) blocked or temporarily taken away. It is a
pharmacologicallyPharmacology is the branch of medicine and biology concerned with the study of drug action. More specifically, it is the study of the interactions that occur between a living organism and chemicals that affect normal or abnormal biochemical function...
induced and reversible state of
amnesiaAmnesia is a condition in which one's memory is lost. The causes of amnesia have traditionally been divided into categories. Memory appears to be stored in several parts of the limbic system of the brain, and any condition that interferes with the function of this system can cause amnesia...
,
analgesiaAn analgesic is any member of the group of drugs used to relieve pain . The word analgesic derives from Greek an- and algos ....
, loss of responsiveness, loss of
skeletal muscleSkeletal muscle is a form of striated muscle tissue existing under control of the somatic nervous system- i.e. it is voluntarily controlled. It is one of three major muscle types, the others being cardiac and smooth muscle...
reflexes or decreased stress response, or all simultaneously. This allows patients to undergo
surgerySurgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...
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
awarenessAwareness is the state or ability to perceive, to feel, or to be conscious of events, objects or sensory patterns. In this level of consciousness, sense data can be confirmed by an observer without necessarily implying understanding. More broadly, it is the state or quality of being aware of...
(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.Oliver Wendell Holmes, Sr. was an American physician, professor, lecturer, and author. Regarded by his peers as one of the best writers of the 19th century, he is considered a member of the Fireside Poets. His most famous prose works are the "Breakfast-Table" series, which began with The Autocrat...
in 1846 as a word to use to describe this state.
Types of anesthesia include
local anesthesiaLocal anesthesia is any technique to induce the absence of sensation in part of the body, generally for the aim of inducing local analgesia, that is, local insensitivity to pain, although other local senses may be affected as well. It allows patients to undergo surgical and dental procedures with...
,
regional anesthesiaRegional anaesthesia is anaesthesia affecting only a large part of the body, such as a limb or the lower half of the body. Regional anaesthetic techniques can be divided into central and peripheral techniques. The central techniques include so called neuraxial blocks...
,
general anesthesiaGeneral anaesthesia is a state of unconsciousness and loss of protective reflexes resulting from the administration of one or more general anaesthetic agents...
, and dissociative anesthesia. Local anesthesia inhibits
sensory perceptionIn a sensory system, a sensory receptor is a sensory nerve ending that responds to a stimulus in the internal or external environment of an organism...
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 cordThe spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...
. Two frequently used types of regional anesthesia are
spinal anesthesiaSpinal anaesthesia , also called spinal analgesia or sub-arachnoid block , is a form of regional anaesthesia involving injection of a local anaesthetic into the subarachnoid space, generally through a fine needle, usually 9 cm long...
and
epidural anesthesiaThe term epidural is often short for epidural analgesia, a form of regional analgesia involving injection of drugs through a catheter placed into the epidural space...
. General anesthesia refers to inhibition of sensory, motor and sympathetic nerve transmission at the level of the brain, resulting in
unconsciousnessUnconsciousness is the condition of being not conscious—in a mental state that involves complete or near-complete lack of responsiveness to people and other environmental stimuli. Being in a comatose state or coma is a type of unconsciousness. Fainting due to a drop in blood pressure and a...
and lack of sensation. Dissociative anesthesia uses agents that inhibit transmission of nerve impulses between higher centers of the brain (such as the
cerebral cortexThe cerebral cortex is a sheet of neural tissue that is outermost to the cerebrum of the mammalian brain. It plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness. It is constituted of up to six horizontal layers, each of which has a different...
) and the lower centers, such as those found within the
limbic systemThe limbic system is a set of brain structures including the hippocampus, amygdala, anterior thalamic nuclei, septum, limbic cortex and fornix, which seemingly support a variety of functions including emotion, behavior, long term memory, and olfaction. The term "limbic" comes from the Latin...
.
Plant derivatives
Throughout Europe, Asia, and the Americas a variety of
SolanumSolanum, the nightshades, horsenettles and relatives, is a large and diverse genus of annual and perennial plants. They grow as forbs, vines, subshrubs, shrubs, and small trees, and often have attractive fruit and flowers. Many formerly independent genera like Lycopersicon or Cyphomandra are...
species containing potent
tropane alkaloidTropane alkaloids are a class of alkaloids and secondary metabolites that contain a tropane ring in their chemical structure...
s were used, such as
mandrakeMandrake is the common name for members of the plant genus Mandragora, particularly the species Mandragora officinarum, belonging to the nightshades family...
, henbane,
Datura metelDatura metel is a shrub-like perennial herb, commonly known as angel's trumpet, devil's trumpet, and metel.Datura metel grows in the wild in all the warmer parts of the world, and is cultivated worldwide for its chemical and ornamental properties...
, and
Datura inoxiaDatura inoxia is a species in the family Solanaceae. It is native to Central and South America, and introduced in Africa, Asia, Australia and Europe. The scientific name is often cited as D. innoxia...
. Ancient Greek and Roman medical texts by
HippocratesHippocrates of Cos or Hippokrates of Kos was an ancient Greek physician of the Age of Pericles , and is considered one of the most outstanding figures in the history of medicine...
,
TheophrastusTheophrastus , a Greek native of Eresos in Lesbos, was the successor to Aristotle in the Peripatetic school. He came to Athens at a young age, and initially studied in Plato's school. After Plato's death he attached himself to Aristotle. Aristotle bequeathed to Theophrastus his writings, and...
,
Aulus Cornelius CelsusAulus Cornelius Celsus was a Roman encyclopedist, known for his extant medical work, De Medicina, which is believed to be the only surviving section of a much larger encyclopedia. The De Medicina is a primary source on diet, pharmacy, surgery and related fields, and it is one of the best sources...
,
Pedanius DioscoridesPedanius Dioscorides was a Greek physician, pharmacologist and botanist, the author of a 5-volume encyclopedia about herbal medicine and related medicinal substances , that was widely read for more than 1,500 years.-Life:...
, and
Pliny the ElderGaius Plinius Secundus , better known as Pliny the Elder, was a Roman author, naturalist, and natural philosopher, as well as naval and army commander of the early Roman Empire, and personal friend of the emperor Vespasian...
discussed the use of opium and
Solanum species. In 13th century Italy,
Theodoric BorgognoniTheodoric Borgognoni , also known as Teodorico de'Borgognoni, and Theodoric of Lucca, was an Italian who became one of the most significant surgeons of the medieval period...
used similar mixtures along with opiates to induce unconsciousness, and treatment with the combined alkaloids proved a mainstay of anesthesia until the nineteenth century. In the Americas
cocaCoca, Erythroxylum coca, is a plant in the family Erythroxylaceae, native to western South America. The plant plays a significant role in many traditional Andean cultures...
was also an important anesthetic used in trephining operations.
IncanThe Andean civilizations made up a loose patchwork of different cultures that developed from the highlands of Colombia to the Atacama Desert. The Andean civilizations are mainly based on the cultures of Ancient Peru and some others such as Tiahuanaco. The Inca Empire was the last sovereign...
shamansShamanism is an anthropological term referencing a range of beliefs and practices regarding communication with the spiritual world. To quote Eliade: "A first definition of this complex phenomenon, and perhaps the least hazardous, will be: shamanism = technique of ecstasy." Shamanism encompasses the...
chewed coca leaves and performed operations on the skull while spitting into the wounds they had inflicted to anesthetize the site.
AlcoholEthanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...
was also used, its
vasodilatoryVasodilation refers to the widening of blood vessels resulting from relaxation of smooth muscle cells within the vessel walls, particularly in the large arteries, smaller arterioles and large veins. The process is essentially the opposite of vasoconstriction, or the narrowing of blood vessels. When...
properties being unknown. Ancient herbal anesthetics have variously been called
soporificsHypnotic drugs are a class of psychoactives whose primary function is to induce sleep and to be used in the treatment of insomnia and in surgical anesthesia...
,
anodyneIn medicine before the 20th century, an anodyne was a medicine that was believed to relieve or soothe pain by lessening the sensitivity of the brain or nervous system In medicine before the 20th century, an anodyne was a medicine that was believed to relieve or soothe pain by lessening the...
s, and
narcoticThe term narcotic originally referred medically to any psychoactive compound with any sleep-inducing properties. In the United States of America it has since become associated with opioids, commonly morphine and heroin and their derivatives, such as hydrocodone. The term is, today, imprecisely...
s, depending on whether the emphasis is on producing unconsciousness or relieving pain.
The use of herbal anesthesia had a crucial drawback compared to modern practice—as lamented by
FallopiusGabriele Falloppio , often known by his Latin name Fallopius, was one of the most important anatomists and physicians of the sixteenth century....
, "When soporifics are weak, they are useless, and when strong, they kill." To overcome this, production was typically standardized as much as feasible, with production occurring from specific locations (such as opium from the fields of
ThebesThebes is the Greek name for a city in Ancient Egypt located about 800 km south of the Mediterranean, on the east bank of the river Nile within the modern city of Luxor. The Theban Necropolis is situated nearby on the west bank of the Nile.-History:...
in ancient Egypt). Anesthetics were sometimes administered in the "spongia somnifera", a sponge into which a large quantity of drug was allowed to dry, from which a saturated solution could be trickled into the nose of the patient. At least in more recent centuries, trade was often highly standardized, with the drying and packing of
opiumOpium is the dried latex obtained from the opium poppy . Opium contains up to 12% morphine, an alkaloid, which is frequently processed chemically to produce heroin for the illegal drug trade. The latex also includes codeine and non-narcotic alkaloids such as papaverine, thebaine and noscapine...
in standard chests, for example. In the 19th century, varying aconitum alkaloids from a variety of species were standardized by testing with
guinea pigThe guinea pig , also called the cavy, is a species of rodent belonging to the family Caviidae and the genus Cavia. Despite their common name, these animals are not in the pig family, nor are they from Guinea...
s. Trumping this method was the discovery of
morphineMorphine is a potent opiate analgesic medication and is considered to be the prototypical opioid. It was first isolated in 1804 by Friedrich Sertürner, first distributed by same in 1817, and first commercially sold by Merck in 1827, which at the time was a single small chemists' shop. It was more...
, a purified alkaloid that could be injected by
hypodermic needleA hypodermic needle is a hollow needle commonly used with a syringe to inject substances into the body or extract fluids from it...
for a consistent dosage. The enthusiastic reception of morphine led to the foundation of the modern pharmaceutical industry.
The first effective local anesthetic was
cocaineCocaine is a crystalline tropane alkaloid that is obtained from the leaves of the coca plant. The name comes from "coca" in addition to the alkaloid suffix -ine, forming cocaine. It is a stimulant of the central nervous system, an appetite suppressant, and a topical anesthetic...
. Isolated in 1859, it was first used by
Karl KollerKarl Koller was an Austrian ophthalmologist who began his medical career as a surgeon at the Vienna General Hospital, and was a colleague of Sigmund Freud.Koller introduced cocaine as a local anaesthetic for eye surgery...
, at the suggestion of
Sigmund FreudSigmund Freud , born Sigismund Schlomo Freud , was an Austrian neurologist who founded the discipline of psychoanalysis...
, in
eye surgeryEye surgery, also known as orogolomistician surgery or ocular surgery, is surgery performed on the eye or its adnexa, typically by an ophthalmologist.-Preparation and precautions:...
in 1884. German surgeon
August BierAugust Karl Gustav Bier was a German surgeon and a pioneer of spinal anaesthesia. After professorships in Greifswald and Bonn, Bier became a professor at the Charité in Berlin.-Spinal anesthesia:...
(1861–1949) was the first to use cocaine for
intrathecalIntrathecal is an adjective that refers to something introduced into or occurring in the space under the arachnoid membrane of the brain or spinal cord...
anesthesia in 1898. Romanian surgeon Nicolae Racoviceanu-Piteşti (1860–1942) was the first to use
opioidAn opioid is a psychoactive chemical that works by binding to opioid receptors, which are found principally in the central and peripheral nervous system and the gastrointestinal tract...
s for intrathecal analgesia; he presented his experience in Paris in 1901. A number of newer local anesthetic agents, many of them derivatives of cocaine, were synthesized in the 20th century, including eucaine (1900),
amylocaineAmylocaine was the first synthetic local anesthetic. It was synthesized and patented under the name Stovaine by Ernest Fourneau at the Pasteur Institute in 1903. It was formerly used mostly in spinal anesthesia.-External links:...
(1904),
procaineProcaine is a local anesthetic drug of the amino ester group. It is used primarily to reduce the pain of intramuscular injection of penicillin, and it was also used in dentistry. Owing to the ubiquity of the trade name Novocain, in some regions procaine is referred to generically as novocaine...
(1905), and
lidocaineLidocaine , Xylocaine, or lignocaine is a common local anesthetic and antiarrhythmic drug. Lidocaine is used topically to relieve itching, burning and pain from skin inflammations, injected as a dental anesthetic or as a local anesthetic for minor surgery.- History :Lidocaine, the first amino...
(1943).
Early inhalational anesthetics
The first physician to use
diethyl etherDiethyl ether, also known as ethyl ether, simply ether, or ethoxyethane, is an organic compound in the ether class with the formula . It is a colorless, highly volatile flammable liquid with a characteristic odor...
as an anesthetic was
Crawford LongCrawford Williamson Long was an American surgeon and pharmacist best known for his first use of inhaled diethyl ether as an anesthetic...
, who administered it on 30 March 1842 during a surgical procedure to remove a
tumorA tumor or tumour is commonly used as a synonym for a neoplasm that appears enlarged in size. Tumor is not synonymous with cancer...
from a patient. He subsequently used it on multiple occasions afterward, but did not publish anything regarding the trials until 1849.
William Thomas Green Morton, a Boston dentist, conducted the first public demonstration of the inhalational anesthetic. Morton, who was unaware of Long's previous work, was invited to the Massachusetts General Hospital to demonstrate his new technique for painless surgery. After Morton had induced anesthesia, surgeon
John Collins WarrenJohn Collins Warren , of Boston, was one of the most renowned American surgeons of the 19th century. In 1846 he gave permission to William T.G. Morton to provide ether anesthesia while Warren performed a minor surgical procedure...
removed a tumor from the neck of Edward Gilbert Abbott. This occurred in the surgical amphitheater now called the
Ether DomeThe Ether Dome is an amphitheater in the Bulfinch Building at Massachusetts General Hospital in Boston. It served as the hospital's operating room from its opening in 1821 until 1867. It was the site of the first use of inhaled ether as a surgical anesthetic on 16 October 1846. William Thomas...
. The previously skeptical Dr. Warren was impressed and stated "Gentlemen, this is no humbug." In a letter to Morton shortly thereafter, physician and writer
Oliver Wendell Holmes, Sr.Oliver Wendell Holmes, Sr. was an American physician, professor, lecturer, and author. Regarded by his peers as one of the best writers of the 19th century, he is considered a member of the Fireside Poets. His most famous prose works are the "Breakfast-Table" series, which began with The Autocrat...
proposed naming the state produced "anesthesia", and the procedure an "anesthetic".
Morton at first attempted to hide the actual nature of his anesthetic substance, referring to it as Letheon. He received a US patent for his substance, but news of the successful anesthetic spread quickly by late 1846. Respected surgeons in Europe including
ListonRobert Liston was a pioneering Scottish surgeon, and the son of the Scottish minister and inventor Henry Liston, whose father was also a Robert Liston, Moderator of the General Assembly of the Church of Scotland....
,
DieffenbachJohann Friedrich Dieffenbach was a German surgeon who specialized in skin transplantation and plastic surgery. His work in rhinoplastic and maxillofacial surgery established many modern techniques of reconstructive surgery. He endeavours comprehended subcutaneous operations such as tenotomy, the...
, Pirogov, and
SymeJames Syme was a pioneering Scottish surgeon.-Early life:He was born on 7 November in Edinburgh. His father was a writer to the signet and a landowner in Fife and Kinross, who lost most of his fortune in attempting to develop the mineral resources of his property...
, quickly undertook numerous operations with ether. An American-born physician, Boott, encouraged London dentist James Robinson to perform a dental procedure on a Miss Lonsdale. This was the first case of an operator-anesthetist. On the same day, 19 December 1846, in Dumfries Royal Infirmary, Scotland, a Dr. Scott used ether for a surgical procedure. The first use of anesthesia in the Southern Hemisphere took place in
Launceston, TasmaniaLaunceston is a city in the north of the state of Tasmania, Australia at the junction of the North Esk and South Esk rivers where they become the Tamar River. Launceston is the second largest city in Tasmania after the state capital Hobart...
, that same year. Drawbacks with ether such as excessive
vomitingVomiting is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose...
and its
flammabilityFlammability is defined as how easily something will burn or ignite, causing fire or combustion. The degree of difficulty required to cause the combustion of a substance is quantified through fire testing. Internationally, a variety of test protocols exist to quantify flammability...
led to its replacement in England with
chloroformChloroform is an organic compound with formula CHCl3. It is one of the four chloromethanes. The colorless, sweet-smelling, dense liquid is a trihalomethane, and is considered somewhat hazardous...
.
Discovered in 1831, the use of chloroform in anesthesia is linked to
James Young SimpsonSir James Young Simpson was a Scottish doctor and an important figure in the history of medicine. Simpson discovered the anaesthetic properties of chloroform and successfully introduced it for general medical use....
, who, in a wide-ranging study of organic compounds, found chloroform's efficacy on 4 November 1847. Its use spread quickly and gained royal approval in 1853 when
John SnowJohn Snow was an English physician and a leader in the adoption of anaesthesia and medical hygiene. He is considered to be one of the fathers of epidemiology, because of his work in tracing the source of a cholera outbreak in Soho, England, in 1854.-Early life and education:Snow was born 15 March...
gave it to Queen Victoria during the birth of
Prince LeopoldThe Prince Leopold, Duke of Albany was the eighth child and fourth son of Queen Victoria and Prince Albert of Saxe-Coburg and Gotha. Leopold was later created Duke of Albany, Earl of Clarence, and Baron Arklow...
. Unfortunately, chloroform is not as safe an agent as ether, especially when administered by an untrained practitioner (
medical studentsA medical school is a tertiary educational institution—or part of such an institution—that teaches medicine. Degree programs offered at medical schools often include Doctor of Osteopathic Medicine, Bachelor/Doctor of Medicine, Doctor of Philosophy, master's degree, or other post-secondary...
, nurses, and occasionally members of the public were often pressed into giving anesthetics at this time). This led to many deaths from the use of chloroform that (with hindsight) might have been preventable. The first fatality directly attributed to chloroform anesthesia was recorded on 28 January 1848 after the death of Hannah Greener.
John Snow of London published articles from May 1848 onwards "On Narcotism by the Inhalation of Vapours" in the London Medical Gazette. Snow also involved himself in the production of equipment needed for the administration of
inhalational anestheticsAn inhalational anaesthetic is a chemical compound possessing general anaesthetic properties that can be delivered via inhalation. They are administered by anaesthetists through an anaesthesia mask, laryngeal mask airway or tracheal tube connected to some type of anaesthetic vaporiser and an...
.
Anesthesia providers
Doctors specializing in perioperative care, development of an anesthetic plan, and the administration of anesthetics are known in the United States as
anesthesiologists and in the United Kingdom and Canada 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. 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.
Physicians
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 According to the
American Society of AnesthesiologistsThe American Society of Anesthesiologists is an association of physicians, primarily anesthesiologists, that share a common goal of raising the standard of the medical specialty of anesthesiology and the improvement of patient care by fostering and encouraging education through research and...
,
anesthesiologistAn anesthesiologist or anaesthetist is a physician trained in anesthesia and peri-operative medicine....
s provide or participate in more than ninety percent of the forty million anesthetics delivered annually. 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 AnaesthetistsThe Royal College of Anaesthetists is "the professional body responsible for the specialty of anaesthesia throughout the United Kingdom". It sets standards in anaesthesia, critical care, pain management, and for the training of anaesthetists, physician assistants - and practising critical care...
. 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. 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
homeostasisHomeostasis is the property of a system that regulates its internal environment and tends to maintain a stable, constant condition of properties like temperature or pH...
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, Harvard's Center for Medical Simulation, Stanford, The Mount Sinai School of Medicine HELPS Center in New York, and Duke University.
Nurse anesthetists
In the United States,
advanced practice nurseAn advanced practice registered nurse is a nurse with advanced didactic and clinical education, knowledge, skills, and scope of practice in nursing....
s specializing in the provision of anesthesia care are known as Certified Registered
Nurse anesthetistA nurse anesthetist is a nurse who specializes in the administration of anesthesia.In the United States, a Certified Registered Nurse Anesthetist is an advanced practice registered nurse who has acquired graduate-level education and board certification in anesthesia...
s (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 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,
anesthesiologistAn anesthesiologist or anaesthetist is a physician trained in anesthesia and peri-operative medicine....
s, 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
sedationSedation is the reduction of irritability or agitation by administration of sedative drugs, generally to facilitate a medical procedure or diagnostic procedure...
. 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 ServicesThe Centers for Medicare & Medicaid Services , previously known as the Health Care Financing Administration , is a federal agency within the United States Department of Health and Human Services that administers the Medicare program and works in partnership with state governments to administer...
(CMS), a federal agency within the
United States Department of Health and Human ServicesThe United States Department of Health and Human Services is a Cabinet department of the United States government with the goal of protecting the health of all Americans and providing essential human services. Its motto is "Improving the health, safety, and well-being of America"...
, determines the conditions for payment for all anesthesia services provided under the
MedicareMedicare is a social insurance program administered by the United States government, providing health insurance coverage to people who are aged 65 and over; to those who are under 65 and are permanently physically disabled or who have a congenital physical disability; or to those who meet other...
,
Medicaid Medicaid is the United States health program for certain people and families with low incomes and resources. It is a means-tested program that is jointly funded by the state and federal governments, and is managed by the states. People served by Medicaid are U.S. citizens or legal permanent...
, and
State Children's Health Insurance ProgramThe State Children's Health Insurance Program – later known more simply as the Children's Health Insurance Program – is a program administered by the United States Department of Health and Human Services that provides matching funds to states for health insurance to families with children...
(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.
Anesthesiologist assistants
In the United States, anesthesiologist assistants (AAs) are graduate-level trained specialists who have undertaken specialized education and training to provide anesthesia care under the direction of an anesthesiologist. AAs typically hold a masters degree and practice under anesthesiologist supervision in 18 states and the District of Columbia through licensing, certification or physician delegation.
In the UK, a similar group of assistants are currently being evaluated. They are referred to as "
physician assistantA physician assistant/associate ' is a healthcare professional trained and licensed to practice medicine with limited supervision by a physician.-General description:...
(anaesthesia)" (PAA). Their background can be nursing, operating department practice, another of the allied medical professions, or even one of the natural sciences. Training is in the form of a postgraduate diploma and takes 27 months to complete.
Operating department practitioners
In the United Kingdom, operating department practitioners provide assistance and support to the anesthetist or anesthesiologist. They can also assist the surgeon with surgical procedures and provide postoperative care to patients emerging from anesthesia. ODPs can be found in the operating department, accident and emergency department, intensive care unit, high dependency unit and in radiology, cardiology and endoscopy suites which require anesthesia support. They may also work with organ transplantation teams, as well as provide pre-hospital care to trauma victims. They are state-registered in the UK. The ODP is a
mid-levelThe term mid-level practitioner is an identifier used by the United States Drug Enforcement Administration to monitor and control the diversion of controlled substances in the U.S...
practitionerA practitioner is someone who engages in an occupation, profession, religion, or way of life.Practitioner may refer to:* Medical practitioner* Justice practitioner* Solitary practitioner, in Wicca and Paganism...
of
perioperative medicineThe term perioperative medicine describes the consultation, care, or co-management of a patient undergoing surgery that is provided by an anesthesiologist, an internal medicine generalist or hospitalist.-Background:...
. ODPs also function as lecturers and trainers in
cardiopulmonary resuscitationCardiopulmonary resuscitation is an emergency procedure which is performed in an effort to manually preserve intact brain function until further measures are taken to restore spontaneous blood circulation and breathing in a person in cardiac arrest. It is indicated in those who are unresponsive...
, and work in management positions in operating departments.
Veterinary anesthetists/anesthesiologists
Much of the equipment and drugs utilized by veterinary anesthetists is similar or identical to that used in anesthesia for human patients. There are vast differences in the physiology of different animal species, which may influence the choice of anesthetic agents and delivery systems in organisms ranging in diversity from (for example)
annelidThe annelids , formally called Annelida , are a large phylum of segmented worms, with over 17,000 modern species including ragworms, earthworms and leeches...
s to elephants. For many wild animals, anesthetic drugs must often be delivered from a distance by means of remote projector systems ("dart guns") before the animal can even be approached. Large domestic livestock can often be anesthetized for certain types of surgery in the standing position using only local anesthetics and sedative drugs. While most clinical veterinarians and veterinary technicians routinely function as anesthetists in the course of their professional duties, veterinary anesthesiologists in the U.S. are veterinarians who have completed a three year residency in anesthesia and have qualified for certification by the American College of Veterinary Anesthesiologists.
Other personnel
Anesthesia techniciansAn anaesthetic technician or anesthesia technician is an allied healthcare worker who assists with the administration and monitoring of anaesthesia and has an extensive knowledge of anaesthesia techniques, instruments, supplies, and technology.Anaesthetic technicians are mainly employed by...
are specially trained
biomedical techniciansA Bio-Medical Equipment Technician, also referred to as a Biomed, Biomedical Engineering Technologist , Biomed Equipment Technician, a Biomedical Equipment Specialist or Electronics and Biomedical Engineer is a highly skilled electromechanical technologist that ensures that medical equipment is...
. They do not administer anesthesia, but rather they assist anesthesia providers similar to the way in which
scrub techniciansA surgical technologist, also called "scrub tech," "surgical technician," or "operating room technician", is an allied health professional working as a part of the team delivering surgical care in some countries. They possess knowledge and skills in sterile and aseptic techniques...
assist surgeons. Commonly these services are collectively called perioperative services, and thus the term perioperative service technician (PST) is used interchangeably with anesthesia technician. In the United States, an anesthesia technician can become a
Certified Anesthesia TechnicianCertified Anesthesia Technician is a title granted to an individual that successfully meets the experience and examination requirements of the certification...
(Cer.A.T.), followed by becoming a
Certified Anesthesia TechnologistCertified Anesthesia Technologist is a title granted to an individual that successfully meets the experience and examination requirements of the certification...
(Cer.A.T.T.) through
American Society of Anesthesia Technologists & TechniciansThe American Society of Anesthesia Technologists & Technicians, or ASATT, based in Oak Creek, Wisconsin, is a non-profit, educational organization responsible for the standards of technologist/technician competency in all areas of anesthesia....
(ASATT). In New Zealand, an anesthetic technician completes a course of study recognized by the
New Zealand Anaesthetic Technicians SocietyThe New Zealand Anaesthetic Technicians' Society - A body representing Anaesthetic Technicians' in New Zealand.Anaesthetic Technicians are healthcare workers employed in the New Zealand health service. Anaesthetic Technicians work as a member of a multi-disciplinary team that includes doctors,...
.
Anesthetic agents
An anesthetic agent is a drug that brings about a state of anesthesia. A wide variety of drugs are used in modern anesthetic practice. Many are rarely used outside of anesthesia, although others are used commonly by all disciplines. Anesthetics are categorized in to two categories:
general anestheticsA general anaesthetic is a drug that brings about a reversible loss of consciousness. These drugs are generally administered by an anaesthesia provider to induce or maintain general anaesthesia to facilitate surgery...
cause a reversible loss of consciousness (
general anesthesiaGeneral anaesthesia is a state of unconsciousness and loss of protective reflexes resulting from the administration of one or more general anaesthetic agents...
), while
local anestheticA local anesthetic is a drug that causes reversible local anesthesia, generally for the aim of having local analgesic effect, that is, inducing absence of pain sensation, although other local senses are often affected as well...
s cause reversible
local anesthesiaLocal anesthesia is any technique to induce the absence of sensation in part of the body, generally for the aim of inducing local analgesia, that is, local insensitivity to pain, although other local senses may be affected as well. It allows patients to undergo surgical and dental procedures with...
and a loss of
nociceptionNociception is defined as "the neural processes of encoding and processing noxious stimuli." It is the afferent activity produced in the peripheral and central nervous system by stimuli that have the potential to damage tissue...
.
Anesthetic equipment
In modern anesthesia, a wide variety of medical equipment is desirable depending on the necessity for portable field use, surgical operations or intensive care support, and the type(s) of anesthetic(s) to be administered. Anesthesia practitioners must possess a comprehensive and intricate knowledge of the production and use of various medical gases, anesthetic agents and vapors, medical breathing circuits and the variety of
anesthetic machineThe anaesthetic machine is used by anaesthesiologists and nurse anaesthetists to support the administration of anaesthesia...
s (including vaporizers, ventilators and pressure gauges) and their corresponding safety features, hazards and limitations of each piece of equipment, for the safe, clinical competence and practical application for day to day practice.
The risk of transmission of infection by anesthetic equipment has been a problem since the beginnings of anesthesia. Although most equipment that comes into contact with patients is disposable, there is still a risk of contamination from the anesthetic machine itself or because of bacterial passage through protective filters.
Anesthetic monitoring
Patients under general anesthesia must undergo continuous physiological monitoring to ensure safety. In the US, the
American Society of AnesthesiologistsThe American Society of Anesthesiologists is an association of physicians, primarily anesthesiologists, that share a common goal of raising the standard of the medical specialty of anesthesiology and the improvement of patient care by fostering and encouraging education through research and...
(ASA) have established minimum monitoring guidelines for patients receiving general anesthesia, regional anesthesia, or sedation. This includes electrocardiography (ECG), heart rate, blood pressure, inspired and expired gases, oxygen saturation of the blood (pulse oximetry), and temperature. In the UK the Association of Anaesthetists (AAGBI) have set minimum monitoring guidelines for general and regional anesthesia. For minor surgery, this generally includes monitoring of
heart rateHeart rate is the number of heartbeats per unit of time, typically expressed as beats per minute . Heart rate can vary as the body's need to absorb oxygen and excrete carbon dioxide changes, such as during exercise or sleep....
,
oxygen saturationOxygen saturation or dissolved oxygen is a relative measure of the amount of oxygen that is dissolved or carried in a given medium. It can be measured with a dissolved oxygen probe such as an oxygen sensor or an optode in liquid media, usually water.It has particular significance in medicine and...
,
blood pressureBlood pressure is the pressure exerted by circulating blood upon the walls of blood vessels, and is one of the principal vital signs. When used without further specification, "blood pressure" usually refers to the arterial pressure of the systemic circulation. During each heartbeat, BP varies...
, and inspired and expired concentrations for
oxygenOxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
,
carbon dioxideCarbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
, and inhalational anesthetic agents. For more invasive surgery, monitoring may also include temperature, urine output, blood pressure,
central venous pressureCentral venous pressure describes the pressure of blood in the thoracic vena cava, near the right atrium of the heart...
,
pulmonary artery pressurePulmonary artery pressure is a measure of the blood pressure found in the pulmonary artery. Mean pulmonary arterial pressure is normally 9 - 18 mmHg.It is usually higher than the pulmonary wedge pressure....
and pulmonary artery occlusion pressure,
cardiac outputCardiac output is the volume of blood being pumped by the heart, in particular by a left or right ventricle in the time interval of one minute. CO may be measured in many ways, for example dm3/min...
, cerebral activity, and neuromuscular function. In addition, the operating room environment must be monitored for ambient temperature and humidity, as well as for accumulation of exhaled inhalational anesthetic agents, which might be deleterious to the health of operating room personnel.
Effective July 1, 2011, the ASA implemented updated standards for patient monitoring.
Anesthesia record
The anesthesia record is the medical and legal documentation of events while a patient is under anesthesia. It reflects a detailed and continuous account of drugs, fluids, and blood products administered and procedures undertaken, and also includes the observation of cardiovascular responses, estimated blood loss, urine output and data from physiologic monitors (see "Anesthetic monitoring" section above) while a patient is under anesthesia.
Traditionally handwritten on paper, the anesthesia record is increasingly being replaced by an electronic record as part of an Anesthesia Information Management System (AIMS), especially since 2007. An AIMS is any
information systemAn information system - or application landscape - is any combination of information technology and people's activities that support operations, management, and decision making. In a very broad sense, the term information system is frequently used to refer to the interaction between people,...
that is used as an automated electronic anesthesia record keeper (i.e., connection to patient physiologic monitors and/or the
anesthetic machineThe anaesthetic machine is used by anaesthesiologists and nurse anaesthetists to support the administration of anaesthesia...
) and which also may allow the collection and
analysisAnalysis is the process of breaking a complex topic or substance into smaller parts to gain a better understanding of it. The technique has been applied in the study of mathematics and logic since before Aristotle , though analysis as a formal concept is a relatively recent development.The word is...
of anesthesia-related perioperative patient
dataThe term data refers to qualitative or quantitative attributes of a variable or set of variables. Data are typically the results of measurements and can be the basis of graphs, images, or observations of a set of variables. Data are often viewed as the lowest level of abstraction from which...
gathered from monitors and/or the anesthesia machine. These systems typically run on medical-grade hardware in the operating room. AIMS can be stand-alone systems or integrated modules of a
hospital information systemThere are various titles and acronyms which all declare similar approaches to managing the information flow and storage in hospital routine services, as*Hospital Information System , or*Healthcare Information System, or...
. AIMS have several benefits to the anesthesia departments as well to the hospital administration as documented in the scientific literature:
- Reducing anesthesia-related drug costs
- Increased anesthesia billing and capture of anesthesia-related charges
- Increased hospital reimbursement through improved hospital coding
- Improvement of the data quality of the intraoperative anesthesia record
- Support training and education of the anesthesia workforce
- Support of clinical decision-making
- Support of patient care and safety
- Enhancement of clinical studies
- Enhancement of clinical quality improvement programs
- Support of clinical risk management
- Monitoring for diversion of controlled substances
See also
- Allergic reactions during anesthesia
- Anesthesia awareness
Anesthesia awareness, or unintended intra-operative awareness occurs during general anesthesia, on the operating table, when the patient has not been given enough of the general anesthetic or analgesic to render the patient unconscious during general anesthesia...
- ASA physical status classification system
- Cardiothoracic anesthesiology
Cardiothoracic anesthesiology is a subspeciality of the medical practice of anesthesiology devoted to the preoperative, intraoperative, and postoperative care of adult patients undergoing cardiothoracic surgery and related invasive procedures...
- Geriatric anesthesia
Geriatric anesthesia is the branch of medicine that studies anesthesia approach in elderly.- Origin :The perioperative care of elderly patients differs from that of younger patients for a number of reasons. Some of these can be attributed to the changes that occur in the process of aging, but many...
- Intraoperative neurophysiological monitoring
Intraoperative neurophysiological monitoring or intraoperative neuromonitoring is the use of electrophysiological methods such as electroencephalography , electromyography , and evoked potentials to monitor the functional integrity of certain neural structures during surgery...
- The Helsinki Declaration for Patient Safety in Anaesthesiology
The Helsinki Declaration for Patient Safety in Anaesthesiology is a document prepared jointly by the two principal anaesthesiology organizations in Europe, The European Board of Anaesthesiology and the European Society of Anaesthesiology . It was launched in June 2010 at the Euroanaesthesia...
- Patient safety
Patient safety is a new healthcare discipline that emphasizes the reporting, analysis, and prevention of medical error that often leads to adverse healthcare events. The frequency and magnitude of avoidable adverse patient events was not well known until the 1990s, when multiple countries reported...
- Perioperative mortality
Perioperative mortality is mortality in relation to surgery, often defined as death within two weeks of a surgical procedure. An important consideration in the decision to perform any surgical procedure is to weigh the benefits against the risks...
- Second gas effect
During induction of general anesthesia when a large volume of nitrous oxide is taken up from alveoli into pulmonary capillary blood, the concentration of gases remaining in the alveoli is increased. This results in effects known as the "concentration effect" and the "second gas effect". These...
Further reading
- Wolf, Jacqueline H. Deliver Me from Pain: Anesthesia and Birth in America (Johns Hopkins University Press, 2009) 277pp; covers 1840s to 21st century; ISBN 978-0-8018-9110-6
External links