handsomemans's Blog

Anesthesia

Anesthesia, or anaesthesia (see spelling differences; from Greek αν- an- “without” + αἲσθησις aisthesis “sensation”), has traditionally meant the condition of having sensation (including the feeling of pain) blocked. This allows patients to undergo surgery and other procedures without the distress and pain they would otherwise experience. The word was coined by Oliver Wendell Holmes, Sr. in 1846. Another definition is a "reversible lack of awareness", whether this is a total lack of awareness (e.g. a general anaesthestic) or a lack of awareness of a part of a the body such as a spinal anaesthetic or another nerve block would cause. Anesthesia differs from analgesia in blocking all sensation, not only pain.

Today, the term general anesthesia in its most general form can include:

• Analgesia: blocking the conscious sensation of pain;
• Hypnosis: produces unconsciousness without analgesia;
• Amnesia: preventing memory formation;
• Relaxation: preventing unwanted movement or muscle tone;
• Obtundation of reflexes, preventing exaggerated autonomic reflexes.

Patients undergoing surgery usually undergo preoperative evaluation. It includes gathering history of previous anesthetics, and any other medical problems, physical examination, ordering required blood work and consultations prior to surgery.

There are several forms of anesthesia. The following forms refer to states achieved by anesthetics working on the brain:

• General anesthesia: "Drug-induced loss of consciousness during which patients are not arousable, even by painful stimulation." Patients undergoing general anesthesia can often neither maintain their own airway nor breathe on their own. While usually administered with inhalational agents, general anesthesia can be achieved with intravenous agents, such as propofol.
• Deep sedation/analgesia: "Drug-induced depression of consciousness during which patients cannot be easily aroused but respond purposefully following repeated or painful stimulation." Patients may sometimes be unable to maintain their airway and breathe on their own.
• Moderate sedation/analgesia or conscious sedation: "Drug-induced depression of consciousness during which patients respond purposefully to verbal commands, either alone or accompanied by light tactile stimulation." In this state, patients can breathe on their own and need no help maintaining an airway.
• Minimal sedation or anxiolysis: "Drug-induced state during which patients respond normally to verbal commands." Though concentration, memory, and coordination may be impaired, patients need no help breathing or maintaining an airway.

The level of anesthesia achieved ranges on a continuum of depth of consciousness from minimal sedation to general anesthesia. The depth of consciousness of a patient may change from one minute to the next.

The following refer to states achieved by anesthetics working outside of the brain:

• Regional anesthesia: Loss of pain sensation, with varying degrees of muscle relaxation, in certain regions of the body. Administered with local anesthesia to peripheral nerve bundles, such as the brachial plexus in the neck. Examples include the interscalene block for shoulder surgery, axillary block for wrist surgery, and femoral nerve block for leg surgery. While traditionally administered as a single injection, newer techniques involve placement of indwelling catheters for continuous or intermittent administration of local anesthetics.
  • Spinal anesthesia: also known as subarachnoid block. Refers to a Regional block resulting from a small volume of local anesthetics being injected into the spinal canal. The spinal canal is covered by the dura mater, through which the spinal needle enters. The spinal canal contains cerebrospinal fluid and the spinal cord. The sub arachnoid block is usually injected between the 4th and 5th lumbar vertebrae, because the spinal cord usually stops at the 1st lumbar vertebra, while the canal continues to the sacral vertebrae. It results in a loss of pain sensation and muscle strength, usually up to the level of the chest (nipple line or 4th thoracic dermatome).
  • Epidural anesthesia: Regional block resulting from an injection of a large volume of local anesthetic into the epidural space. The epidural space is a potential space that lies underneath the ligamenta flava, and outside the dura mater (outside layer of the spinal canal). This is basically an injection around the spinal canal.
• Local anesthesia is similar to regional anesthesia, but exerts its effect on a smaller area of the body.

Contents 1 History 1.1 Herbal derivatives 1.2 Non-pharmacological methods 1.3 Early gases and vapours 1.4 Early local anesthetics 2 Anesthesia providers 2.1 Anesthesiologists (medically-trained physicians) 2.2 Nurse anesthetists 2.3 Anesthesiologist assistants 2.4 Anesthesia technicians 2.5 Veterinary anesthetists/anesthesiologists 3 Anesthetic agents 3.1 Local anesthetics 3.1.1 Adverse effects of local anaesthesia 3.2 Current inhaled general anesthetic agents 3.3 Current intravenous anesthetic agents (non-opioid) 3.4 Current intravenous opioid analgesic agents 3.5 Current muscle relaxants 3.5.1 Adverse effects of muscle relaxants 3.6 Current intravenous reversal agents 4 Anesthetic equipment 5 Anesthetic monitoring 6 Anesthesia record 7 Anesthesia Information Management System (AIMS) 8 Anesthesia in popular culture 9 See also 10 References 11 External links

//

History

Herbal derivatives

The first anesthesia (a herbal remedy) was administered in prehistory. Opium poppy capsules were collected in 4200 BC, and opium poppies were farmed in Sumeria and succeeding empires. The use of opium-like preparations in anaesthesia is recorded in the Ebers Papyrus of 1500 BC. By 1100 BC poppies were scored for opium collection in Cyprus by methods similar to those used in the present day, and simple apparatus for smoking of opium were found in a Minoan temple. Opium was not introduced to India and China until 330 BC and 600–1200 AD, but these nations pioneered the use of cannabis incense and aconitum. In the second century, according to the Book of Later Han, the physician Hua Tuo performed abdominal surgery using an anesthetic substance called mafeisan (麻沸散 "cannabis boil powder") dissolved in wine. Throughout Europe, Asia, and the Americas a variety of Solanum species containing potent tropane alkaloids were used, such as mandrake, henbane, Datura metel, and Datura inoxia. Classic Greek and Roman medical texts by Hippocrates, Theophrastus, Aulus Cornelius Celsus, Pedanius Dioscorides, and Pliny the Elder discussed the use of opium and Solanum species. In 13th century Italy Theodoric Borgognoni used similar mixtures along with opiates to induce unconsciousness, and treatment with the combined alkaloids proved a mainstay of anaesthesia until the nineteenth century. In the Americas coca was also an important anaesthetic used in trephining operations. Incan shamans chewed coca leaves and performed operations on the skull while spitting into the wounds they had inflicted to anaesthetize the site. Alcohol was also used, its vasodilatory properties being unknown. Ancient herbal anaesthetics have variously been called soporifics, anodynes, and narcotics, depending on whether the emphasis is on producing unconsciousness or relieving pain.

In Central Asia, in the 20th century work of Shahnameh, the author, Ferdowsi, describes a caesarean section performed on Rudaba when giving birth, in which a special wine agent was prepared as an anesthetic by a Zoroastrian priest, and used to produce unconsciousness for the operation. Although largely mythical in content, the passage does at least illustrate knowledge of anesthesia in ancient Persia.

The use of herbal anaesthesia had a crucial drawback compared to modern practice — as lamented by Fallopus, "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 famous locations (such as opium from the fields of Thebes in ancient Egypt). Anaesthetics 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 opium in standard chests, for example. In the 19th century, varying aconitum alkaloids from a variety of species were standardized by testing with guinea pigs. Despite these refinements, the discovery of morphine, a purified alkaloid that soon afterward could be injected by hypodermic for a consistent dosage, was enthusiastically received and led to the foundation of the modern pharmaceutical industry.

Another factor affecting ancient anaesthesia is that drugs used systemically in modern times were often administered locally, reducing the risk to the patient. Opium used directly in a wound acts on peripheral opioid receptors to serve as an analgesic, and a medicine containing willow leaves (salicylate, the predecessor of aspirin) would then be applied directly to the source of inflammation.

In 1804, the Japanese surgeon Seishū Hanaoka performed general anaesthesia for the operation of a breast cancer (mastectomy), by combining Chinese herbal medicine know-how and Western surgery techniques learned through "Rangaku", or "Dutch studies". His patient was a 60-year-old woman called Kan Aiya. He used a compound he called Tsusensan, based on the plants Datura metel, Aconitum and others.

Non-pharmacological methods

Hypnotism and acupuncture have a long history of use as anesthetic techniques. In China, Taoist medical practitioners developed anesthesia by means of acupuncture. Chilling tissue (e.g. with ice) can temporarily cause nerve fibers (axons) to stop conducting sensation, while hyperventilation can cause brief alteration in conscious perception of stimuli including pain (see Lamaze).

In modern anesthetic practice, these techniques are seldom employed.

Early gases and vapours

The works of Greek authors such as Dioscorides were well-known among the Persians in the Islamic Empire, and Persian/Iranian physicians such as al-Razi, Avicenna, and Abu al-Qasim wrote medical textbooks of great importance in the development of medicine in Europe and the Middle East. Arabic and Iranian anesthesiologists were the first to utilize oral as well as inhalant anesthetics. In Islamic Spain, Abu al-Qasim (Abulcasis) and Ibn Zuhr (Avenzoar), among other Muslim surgeons, performed hundreds of surgeries under inhalant anesthesia with the use of narcotic-soaked sponges. Abulcasis and Ibn Sina (Avicenna) wrote about anesthesia in their influential medical encyclopaedias, the al-Tasrif and The Canon of Medicine. These were precursors to the true narcotic derivatives which were not made until Dr. Janssen developed narcotics, except morphine, in the past 50 years.

Contemporary re-enactment of Morton's October 16, 1846, ether operation; daguerrotype by Southworth & Hawes.

In the West, the development of effective anesthetics in the 19th century was, with Listerian techniques, one of the keys to successful surgery. Henry Hill Hickman experimented with carbon dioxide in the 1820s. The anesthetic qualities of nitrous oxide (isolated in 1773 by Joseph Priestley) were discovered by the British chemist Humphry Davy about 1799 when he was an assistant to Thomas Beddoes, and reported in a paper in 1800. But initially the medical uses of this so-called "laughing gas" were limited — its main role was in entertainment. It was used on 30 September 1846 for painless tooth extraction upon patient Eben Frost by American dentist William Thomas Green Morton. Horace Wells of Connecticut, a traveling dentist, had demonstrated it the previous year 1845 at Massachusetts General Hospital. Wells made a mistake in choosing a particularly sturdy male volunteer, and the patient suffered considerable pain. This lost the colorful Wells any support. Later the patient told Wells he screamed in shock and not in pain. A subsequently drunk Wells died in jail, by cutting his femoral artery, after allegedly assaulting a prostitute with sulfuric acid.

Another dentist, William E. Clarke, performed an extraction in January 1842 using a different chemical, diethyl ether (discovered by Valerius Cordus in 1540). In March 1842 in Danielsville, Georgia, Dr. Crawford Long was the first to use anaesthesia during an operation, giving it to a boy (John Venables) before excising a cyst from his neck; however, he did not publicize this information until later.

On October 16, 1846, another dentist, William Thomas Green Morton, invited to the Massachusetts General Hospital, performed the first public demonstration of diethyl ether (then called sulfuric ether) as an anesthetic agent, for a patient (Edward Gilbert Abbott) undergoing an excision of a vascular tumor from his neck. In a letter to Morton shortly thereafter, Oliver Wendell Holmes, Sr. proposed naming the procedure anæsthesia.

Anesthesia pioneer Crawford W. Long

Despite Morton's efforts to keep "his" compound a secret, which he named "Letheon" and for which he received a US patent, the news of the discovery and the nature of the compound spread very quickly to Europe in late 1846. Here, respected surgeons—including Liston, Dieffenbach, Pirogoff, and Syme—undertook numerous operations with ether. An American-born physician, Boott—who had traveled to London—encouraged a leading dentist, Mr 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, Tasmania, that same year. Ether has a number of drawbacks, such as its tendency to induce vomiting and its flammability. In England it was quickly replaced with chloroform.

Discovered in 1831, the use of chloroform in anesthesia is usually linked to James Young Simpson, 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 Snow gave it to Queen Victoria during the birth of Prince Leopold. Unfortunately, chloroform is not as safe an agent as ether, especially when administered by an untrained practitioner (medical students, 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 (Hannah Greener) was recorded on 28 January 1848.

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 inhalational anesthesia.

The surgical amphitheatre at Massachusetts General Hospital, or "ether dome" still exists today, although it is used for lectures and not surgery. The public can visit the amphitheater on weekdays when it is not in use.

Early local anesthetics

The first effective local anesthetic was cocaine. Isolated in 1859, it was first used by Carl Koller, at the suggestion of Sigmund Freud, in ophthalmic surgery in 1884. Before that doctors had used a salt and ice mix for the numbing effects of cold, which could only have limited application. Similar numbing was also induced by a spray of ether or ethyl chloride. A number of cocaine derivatives and safer replacements were soon produced, including procaine (1905), Eucaine (1900), Stovaine (1904), and lidocaine (1943).

Opioids were first used by Racoviceanu-Piteşti, who reported his work in 1901.

Anesthesia providers

Physicians specialising in peri-operative care, development of an anesthetic plan, and the administration of anesthetics are known in the United States as anesthesiologists and in the UK and Canada as anaesthetists or anaesthesiologists. All anaesthetics in the UK, Australia, New Zealand and Japan are administered by physicians. 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 ACTs with anesthesiologists medically directing Anesthesiologist Assistants, CRNAs, and about 10% are provided by CRNAs in solo practice. - -

Anesthesiologists (medically-trained physicians)

In the US, medical doctors who specialize in anesthesiology are called anesthesiologists, and dentists who specialize in anesthesiology are called dental anesthesiologists. Such physicians in the UK, Canada and Australia are called anaesthetists or anaesthesiologists.

In the US, a physician specializing in anesthesiology completes 4 years of college, 4 years of medical school, 1 year of internship, and 3 years of residency. According to the American Society of Anesthesiologists, anesthesiologists provide or participate in more than 90 percent of the 40 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 Anaesthetists. 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 UK, Fellowship of the Royal College of Anaesthetists (FRCA), is conferred upon medical doctors following completion of the written and oral parts of the Royal College's examination. In the US, completion of the written and oral Board examinations by a physician anesthesiologist allows one to be called "Board Certified" or a "Diplomate" of the American Board of Anesthesiology (or of the American Osteopathic Board of Anesthesiology, for osteopathic physicians).

Other specialties within medicine are closely affiliated to anaesthetics. These include intensive care medicine and pain medicine. Specialists in these disciplines have usually done some training in anaesthetics. The role of the anaesthetist is changing. It is no longer limited to the operation itself. Many anaesthetists perform well as peri-operative physicians, and will involve themselves in optimizing the patient's health before surgery (colloquially called "work-up"), performing the anaesthetic,including specialized intraoperative monitoring (like transesophageal echocardiography), following up the patient in the post anesthesia care unit and post-operative wards, and ensuring optimal analgesia throughout.

It is important to note that the term anesthetist in the United States usually refers to registered nurses who have completed specialized education and training in nurse anesthesia to become certified registered nurse anesthetists (CRNAs). As noted above, the term anaesthetist in the UK and Canada refers to medical doctors who specialize in anesthesiology.

Nurse anesthetists

In the United States, advance 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 36,000 CRNAs in the US administer approximately 27 million anesthetics each year, roughly two thirds of the US total. Thirty-four percent 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. The average CRNA student has 5-7 years of nursing experience before entering a 27-36 month masters level anesthesia program.

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. CRNAs do not require Anesthesiologist supervision in any state and only require surgeon/dentist/podiatrists to sign the chart for medicare billing in all but 16 states.

Anesthesiologist assistants

In the US, 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 sixteen states through licensing, certification or physician delegation.

In the UK, a similar group of assistants are currently being evaluated. They are named Physician's Assistant (Anaesthesia). Their background can be nursing, operating department professional or another profession allied to medicine or a science graduate. Training is in the form of a post-graduate diploma and takes 27 months to complete. Once finished, a masters degree can be undertaken.

Anesthesiology assistants should be distinguished from anesthesia technicians.

Anesthesia technicians

Anesthesia technicians are specially trained biomedical technicians who assist anesthesiologists, nurse anesthetists, and anesthesiology assistants with monitoring equipment, supplies, and patient care procedures in the operating room.

In New Zealand, anaesthetic technicians complete a course of study recognized by the New Zealand Association of Anaesthetic Technicians and Nurses.

In the United Kingdom, personnel known as ODPs (operating department practitioners) or anaesthetic nurses provide support to the physician anaesthetist (anaesthesiologist).

Veterinary anesthetists/anesthesiologists Main article: Veterinary anesthesia

Veterinary anesthetists utilize much the same equipment and drugs as those who provide anesthesia to human patients. In the case of animals, the anesthesia must be tailored to fit the species ranging from large land animals like horses or elephants to birds to aquatic animals like fish. For each species there are ideal, or at least less problematic, methods of safely inducing anesthesia. For 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 animals, like cattle, can often be anesthetized for standing surgery 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 two-year residency in anesthesia and have qualified for certification by the American College of Veterinary Anesthesiologists.

Anesthetic agents

Local anesthetics Main article: Local anesthetic

• procaine
• amethocaine
• cocaine
• lidocaine
• prilocaine
• bupivacaine
• levobupivacaine
• ropivacaine
• dibucaine

Local anesthetics are agents which prevent transmission of nerve impulses without causing unconsciousness. They act by binding to fast sodium channels from within (in an open state). Local anesthetics can be either ester or amide based.

Ester local anesthetics (e.g., procaine, amethocaine, cocaine) are generally unstable in solution and fast-acting, and allergic reactions are common.

Amide local anesthetics (e.g., lidocaine, prilocaine, bupivicaine, levobupivacaine, ropivacaine and dibucaine) are generally heat-stable, with a long shelf life (around 2 years). They have a slower onset and longer half-life than ester anaesthetics, and are usually racemic mixtures, with the exception of levobupivacaine (which is S(-) -bupivacaine) and ropivacaine (S(-)-ropivacaine). These agents are generally used within regional and epidural or spinal techniques, due to their longer duration of action, which provides adequate analgesia for surgery, labor, and symptomatic relief.

Only preservative-free local anesthetic agents may be injected intrathecally.

Adverse effects of local anaesthesia

Adverse effects of local anesthesia are generally referred to as Local Anesthetic Toxicity.

Effects may be localized or systemic.

Examples of systemic effects of local anesthesia:

Local anesthetic drugs are toxic to the heart (where they cause arrhythmia) and brain (where they may cause unconsciousness and seizures). Arrhythmias may be resistant to defibrillation and other standard treatments, and may lead to loss of heart function and death.

The first evidence of local anesthetic toxicity involves the nervous system, including agitation, confusion, dizziness, blurred vision, tinnitus, a metallic taste in the mouth, and nausea that can quickly progress to seizures and cardiovascular collapse.

Toxicity can occur with any local anesthetic as an individual reaction by that patient. Possible toxicity can be tested with pre-operative procedures to avoid toxic reactions during surgery.

An example of localized effect of local anesthesia:

Direct infiltration of local anesthetic into skeletal muscle will cause temporary paralysis of the muscle.

Current inhaled general anesthetic agents Main article: General anaesthesia

• Desflurane
• Enflurane
• Halothane
• Isoflurane
• Nitrous oxide
• Sevoflurane
• Xenon (rarely used)

Volatile agents are specially formulated organic liquids that evaporate readily into vapors, and are given by inhalation for induction and/or maintenance of general anesthesia. Nitrous oxide and xenon are gases at room temperature rather than liquids, so they are not considered volatile agents. The ideal anesthetic vapor or gas should be non-flammable, non-explosive, lipid-soluble, and should possess low blood gas solubility, have no end organ (heart, liver, kidney) toxicity or side-effects, should not be metabolized, and should be non-irritant when inhaled by patients.

No anesthetic agent currently in use meets all these requirements. The agents in widespread current use are isoflurane, desflurane, sevoflurane, and nitrous oxide. Nitrous oxide is a common adjuvant gas, making it one of the most long-lived drugs still in current use. Because of its low potency, it cannot produce anesthesia on its own but is frequently combined with other agents. Halothane, an agent introduced in the 1950s, has been almost completely replaced in modern anesthesia practice by newer agents because of its shortcomings. Partly because of its side effects, enflurane never gained widespread popularity.

In theory, any inhaled anesthetic agent can be used for induction of general anesthesia. However, most of the halogenated anesthetics are irritating to the airway, perhaps leading to coughing, laryngospasm and overall difficult inductions. For this reason, the most frequently used agent for inhalational induction is sevoflurane. All of the volatile agents can be used alone or in combination with other medications to maintain anesthesia (nitrous oxide is not potent enough to be used as a sole agent).

Volatile agents are frequently compared in terms of potency, which is inversely proportional to the minimum alveolar concentration. Potency is directly related to lipid solubility. This is known as the Meyer-Overton hypothesis. However, certain pharmacokinetic properties of volatile agents have become another point of comparison. Most important of those properties is known as the blood:gas partition coefficient. This concept refers to the relative solubility of a given agent in blood. Those agents with a lower blood solubility (i.e., a lower blood–gas partition coefficient; e.g., desflurane) give the anesthesia provider greater rapidity in titrating the depth of anesthesia, and permit a more rapid emergence from the anesthetic state upon discontinuing their administration. In fact, newer volatile agents (e.g., sevoflurane, desflurane) have been popular not due to their potency (minimum alveolar concentration), but due to their versatility for a faster emergence from anesthesia, thanks to their lower blood–gas partition coefficient.

Current intravenous anesthetic agents (non-opioid)

While there are many drugs that can be used intravenously to produce anesthesia or sedation, the most common are:

• Barbiturates
  • Methohexital
  • Thiopental
• Benzodiazepines
  • Diazepam
  • Lorazepam
  • Midazolam
• Etomidate
• Ketamine
• Propofol

The two barbiturates mentioned above, thiopental and methohexital, are ultra-short-acting, and are used to induce and maintain anesthesia. However, though they produce unconsciousness, they provide no analgesia (pain relief) and must be used with other agents. Benzodiazepines can be used for sedation before or after surgery and can be used to induce and maintain general anesthesia. When benzodiazepines are used to induce general anesthesia, midazolam is preferred. Benzodiazepines are also used for sedation during procedures that do not require general anesthesia. Like barbiturates, benzodiazepines have no pain-relieving properties. Propofol is one of the most commonly used intravenous drugs employed to induce and maintain general anesthesia. It can also be used for sedation during procedures or in the ICU. Like the other agents mentioned above, it renders patients unconscious without producing pain relief. Because of its favourable physiological effects, "etomidate has been primarily used in sick patients". Ketamine is infrequently used in anesthesia practice because of the unpleasant experiences which sometimes occur upon emergence from anesthesia, which include "vivid dreaming, extracorporeal experiences, and illusions." However, like etomidate it is frequently used in emergency settings and with sick patients because it produces fewer adverse physiological effects. Unlike the intravenous anesthetic drugs previously mentioned, ketamine produces profound pain relief, even in doses lower than those which induce general anesthesia. Also unlike the other anesthetic agents in this section, patients who receive ketamine alone appear to be in a cataleptic state, unlike other states of anesthesia that resemble normal sleep. Ketamine-anesthetized patients have profound analgesia but keep their eyes open and maintain many reflexes.

Current intravenous opioid analgesic agents

While opioids can produce unconsciousness, they do so unreliably and with significant side effects. So, while they are rarely used to induce anesthesia, they are frequently used along with other agents such as intravenous non-opioid anesthetics or inhalational anesthetics. Furthermore, they are used to relieve pain of patients before, during, or after surgery. The following opioids have short onset and duration of action and are frequently used during general anesthesia:

• Alfentanil
• Fentanyl
• Remifentanil
• Sufentanil

The following agents have longer onset and duration of action and are frequently used for post-operative pain relief:

• Buprenorphine
• Butorphanol
• Diamorphine, (diacetyl morphine, also known as heroin, not available in U.S.)
• Hydromorphone
• Levorphanol
• Meperidine, also called pethidine in the UK, New Zealand, Australia and other countries
• Methadone
• Morphine
• Nalbuphine
• Oxycodone, (not available intravenously in U.S.)
• Oxymorphone
• Pentazocine

Current muscle relaxants

Muscle relaxants do not render patients unconscious or relieve pain. Instead, they are sometimes used after a patient is rendered unconscious (induction of anesthesia) to facilitate intubation or surgery by paralyzing skeletal muscle.

• Depolarizing muscle relaxants
  • Succinylcholine (also known as suxamethonium in the UK, New Zealand, Australia and other countries, "Celokurin" or "celo" for short in Europe)
• Non-depolarizing muscle relaxants
  • Short acting
    • Mivacurium
    • Rapacuronium
  • Intermediate acting
    • Atracurium
    • Cisatracurium
    • Rocuronium
    • Vecuronium
  • Long acting
    • Alcuronium
    • Doxacurium
    • Gallamine
    • Metocurine
    • Pancuronium
    • Pipecuronium
    • d-Tubocurarine

Adverse effects of muscle relaxants

Succinylcholine may cause hyperkalemia if given to burn patients, or paralyzed (quadraplegic, paraplegic) patients. The mechanism is reported to be through upregulation of acetylcholine receptors in those patient populations. Succinylcholine may also trigger malignant hyperthermia in susceptible patients.

Another potentially disturbing complication can be 'anesthesia awareness'. In this situation, patients paralyzed with muscle relaxants may awaken during their anesthesia, due to decrease in the levels of drugs providing sedation and/or pain relief. If this fact is missed by the anaesthesia provider, the patient may be aware of his surroundings, but be incapable of moving or communicating that fact. Neurological monitors are becoming increasingly available which may help decrease the incidence of awareness. Most of these monitors use proprietary algorithms monitoring brain activity via evoked potentials. Despite the widespread marketing of these devices many case reports exist in which awareness under anesthesia has occurred despite apparently adequate anesthesia as measured by the neurologic monitor.

Current intravenous reversal agents

• Flumazenil, reverses the effects of benzodiazepines
• Naloxone, reverses the effects of opioids
• Neostigmine, reverses the effects of non-depolarizing muscle relaxants

Anesthetic equipment Main article: Anaesthetic 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. Anesthesia practitioners must possess a comprehensive and intricate knowledge of the production and use of various medical gases, anaesthetic agents and vapours, medical breathing circuits and the variety of anaesthetic machines (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.

Anesthetic monitoring

Patients being treated under general anesthetics must be monitored continuously to ensure the patient's safety. For minor surgery, this generally includes monitoring of heart rate (via ECG or pulse oximetry), oxygen saturation (via pulse oximetry), non-invasive blood pressure, inspired and expired gases (for oxygen, carbon dioxide, nitrous oxide, and volatile agents). For moderate to major surgery, monitoring may also include temperature, urine output, invasive blood measurements (arterial blood pressure, central venous pressure), pulmonary artery pressure and pulmonary artery occlusion pressure, cerebral activity (via EEG analysis), neuromuscular function (via peripheral nerve stimulation monitoring), and cardiac output. In addition, the operating room's environment must be monitored for temperature and humidity and for buildup of exhaled inhalational anesthetics which might impair the health of operating room personnel.

Anesthesia record

The anesthesia record is the medical and legal documentation of events during an anesthetic. 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, urinary body fluids and data from physiologic monitors (Anesthetic monitoring, see above) during the course of an anesthetic. The anesthesia record may be written manually on paper; however, the paper record is increasingly replaced by an electronic record as part of an Anesthesia Information Management System (AIMS).

Anesthesia Information Management System (AIMS)

An AIMS refers to any information system that is used as an automated electronic anesthesia record keeper (i.e., connection to patient physiologic monitors and/or the Anaesthetic machine) and which also may allow the collection and analysis of anesthesia-related perioperative patient data.

Anesthesia in popular culture

The 1958 film Corridors of Blood, starring Boris Karloff, depicts an 1840's surgeon who experiments with anesthetic gases in an effort to make surgery pain free.

A bestseller by Robin Cook, Harmful Intent has an anesthesiologist as the main character, who uncovers a legal conspiracy aimed at his specialty.

The 1978 film Coma depicts a series of events at the Boston Memorial Hospital in which patients are intentionally put into a comatose state via anesthesia and their organs later sold.

Metallica has a song from their album Kill 'Em All called (Anesthesia) Pulling Teeth.

Awake, a 2007 suspense thriller, is about anaesthesia awareness.

References

1. ^ a b c d “Continuum Of Depth Of Sedation Definition Of General Anesthesia And Levels Of Sedation/Analgesia”, American Society of Anesthesiologists, ASA, 2004-10-27 
2. ^ Medicine throughout Antiquity. Benjamin Lee Gordon. 1949. p.306
3. ^ Utopian surgery: Early arguments against anaesthesiain surgery, dentistry and childbirth
4. ^ Dr. Kasem Ajram (1992). Miracle of Islamic Science, Appendix B. Knowledge House Publishers. ISBN 0911119434.
5. ^ Sigrid Hunke (1969), Allah Sonne Uber Abendland, Unser Arabische Erbe, Second Edition, p. 279-280:

   "The science of medicine has gained a great and extremely important discovery and that is the use of general anaesthetics for surgical operations, and how unique, efficient, and merciful for those who tried it the Muslim anaesthetic was. It was quite different from the drinks the Indians, Romans and Greeks were forcing their patients to have for relief of pain. There had been some allegations to credit this discovery to an Italian or to an Alexandrian, but the truth is and history proves that, the art of using the anaesthetic sponge is a pure Muslim technique, which was not known before. The sponge used to be dipped and left in a mixture prepared from cannabis, opium, hyoscyamus and a plant called Zoan."

   (cf. Prof. Dr. M. Taha Jasser, Anaesthesia in Islamic medicine and its influence on Western civilization, Conference on Islamic Medicine)
6. ^ Nurse anesthesia worldwide: practice, education and regulation (PDF). International Federation of Nurse Anesthetists. Retrieved on 2007-02-08.
7. ^ Is Physician Anesthesia Cost-Effective? (html). Anesth Analg (2007-02-01). Retrieved on 2007-02-15.
8. ^ When do anesthesiologists delegate? (html). Med Care (2007-02-01). Retrieved on 2007-02-15.
9. ^ Nurse anestheisa worldwide: practice, education and regulation (PDF). International Federation of Nurse Anesthetists. Retrieved on 2007-02-08.
10. ^ Surgical mortality and type of anesthesia provider (html). AANA (2007-02-25). Retrieved on 2007-02-25.
11. ^ Anesthesia Providers, Patient Outcomes, and Cost (pdf). Anesth Analg (2007-02-25). Retrieved on 2007-02-25.
12. ^ ASA Fast Facts: Anesthesiologists Provide Or Participate In 90 Percent Of All Annual Anesthetics (html). ASA. Retrieved on 2007-03-22.
13. ^ Television conferencing: Is it as effective as "in person" lectures for nurse anesthesia education? (PDF). AANA Journal (2006-02-01). Retrieved on 2007-02-05.
14. ^ Five facts about AAs (HTML). American Academy of Anesthesiologist Assistants. Retrieved on 2007-02-08.
15. ^ a b Townsend, Courtney (2004). Sabiston Textbook of Surgery. Philadelphia: Saunders, Chapter 17 – Anesthesiology Principles, Pain Management, and Conscious Sedation. ISBN 0721653685. 
16. ^ a b c d e f g h i j k l m n Miller, Ronald (2005). Miller's Anesthesia. New York: Elsevier/Churchill Livingstone. ISBN 0443066566. 
17. ^ Garfield JM, Garfield FB, Stone JG, et al: A comparison of psychologic responses to ketamine and thiopental-nitrous oxide-halothane anesthesia. Anesthesiology 1972; 36:329-338.
18. ^ Philbin DM, Rosow CE, Schneider RC, et al: Fentanyl and sufentanil anesthesia revisited: how much is enough?. Anesthesiology 1990; 73:5-11.
19. ^ Streisand JB, Bailey PL, LeMaire L, Ashburn MA, Tarver SD, Varvel J, Stanley TH: Fentanyl-induced rigidity and unconsciousness in human volunteers. Incidence, duration, and plasma concentrations. Anesthesiology 1993; 78:629-634.
20. ^ Stoelting RK, Miller RD: Basics of Anesthesia, 3rd edition, 1994.

Surgery A cardiothoracic surgeon performs a mitral valve replacement at the Fitzsimons Army Medical Center.

Surgery (from the Greek: χειρουργική cheirourgikē, via Latin: chirurgiae, meaning "hand work") is a 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, to help improve bodily function or appearance, or sometimes for some other reason. An act of performing surgery may be called a surgical procedure, operation, or simply surgery. In this context, the verb operating means performing surgery. The adjective surgical means pertaining to surgery; e.g. surgical instruments or surgical nurse. The patient or subject on which the surgery is performed can be a person or an animal. A surgeon is a person who performs operations on patients. Persons described as surgeons are commonly medical practitioners, but the term is also applied to podiatrists, dentists and veterinarians. Surgery can last from minutes to hours, but is typically not an ongoing or periodic type of treatment. The term surgery can also refer to the place where surgery is performed, or simply the office of a physician, dentist, or veterinarian.

Contents 1 Definitions of surgery 1.1 Types of surgery 1.2 Terminology 1.3 Description of surgical procedure 2 History 2.1 Modern surgery 3 Conditions treated by surgery 4 Common procedures 5 Surgical Specialties 6 See also 7 References 8 External links

//

Definitions of surgery

Surgery is a medical technology consisting of a physical intervention on tissues. As a general rule, a procedure is considered surgical when it involves cutting of a patient's tissues or closure of a previously sustained wound. Other procedures that do not necessarily fall under this rubric, such as angioplasty or endoscopy, may be considered surgery if they involve "common" surgical procedure or settings, such as use of a sterile environment, anesthesia, antiseptic conditions, typical surgical instruments, and suturing or stapling. All forms of surgery are considered invasive procedures; so-called "noninvasive surgery" usually refers to an excision that does not penetrate the structure being excised (i.e. laser ablation of the cornea) or to a radiosurgical procedure (i.e. irradiation of a tumor).

Types of surgery

Surgical procedures are commonly categorized by urgency, type of procedure, body system involved, degree of invasiveness, and special instrumentation.

Elective surgery is done to correct a non-life-threatening condition, and is carried out at the patient's request, subject to the surgeon's and the surgical facility's availability. Emergency surgery is surgery which must be done quickly to save life, limb, or functional capacity. Exploratory surgery is performed to aid or confirm a diagnosis. Therapeutic surgery treats a previously diagnosed condition.

Amputation involves cutting off a body part, usually a limb or digit. Replantation involves reattaching a severed body part. Reconstructive surgery, also commonly called plastic surgery, involves reconstruction of an injured, mutilated, or deformed part of the body. A subset of reconstructive surgery is cosmetic surgery, which is done to improve the appearance of an otherwise normal structure. Excision is the cutting out of an organ, tissue, or other body part from the patient. Transplant surgery is the replacement of an organ or body part by insertion of another from different human (or animal) into the patient. Removing an organ or body part from a live human or animal for use in transplant is also a type of surgery.

When surgery is performed on one organ system or structure, it may be classed by the organ, organ system or tissue involved. Examples include cardiac surgery (performed on the heart), gastrointestinal surgery (performed within the digestive tract and its accessory organs), and orthopedic surgery (performed on bones and/or muscles).

Minimally invasive surgery involves smaller outer incision(s) to insert miniaturized instruments within a body cavity or structure, as in laparoscopic surgery or angioplasty. By contrast, an open surgical procedure requires a large incision to access the area of interest. Laser surgery involves use of a laser for cutting tissue instead of a scalpel or similar surgical instruments. Microsurgery involves the use of an operating microscope for the surgeon to see small structures. Robotic surgery makes use of a surgical robot, such as the Da Vinci or the Zeus surgical systems, to control the instrumentation under the direction of the surgeon.

Terminology

• Excision surgery names often start with a name for the organ to be excised (cut out) and end in -ectomy.
• Procedures involving cutting into an organ or tissue end in -otomy. A surgical procedure cutting through the abdominal wall to gain access to the abdominal cavity is a laparotomy.
• Minimally invasive procedures involving small incisions through which an endoscope is inserted end in -oscopy. For example, such surgery in the abdominal cavity is called laparoscopy.
• Procedures for formation of a permanent or semi-permanent opening called a stoma in the body end in -ostomy.
• Reconstruction, plastic or cosmetic surgery of a body part starts with a name for the body part to be reconstructed and ends in -oplasty. Rhino is used as a prefix for "nose", so rhinoplasty is basically reconstructive or cosmetic surgery for the nose.

Description of surgical procedure

At a hospital, modern surgery is often done in an operating room using surgical instruments, an operating table for the patient, and other equipment. The environment and procedures used in surgery are governed by the principles of aseptic technique: the strict separation of "sterile" (free of microorganisms) things from "unsterile" or "contaminated" things. All surgical instruments must be sterilized, and an instrument must be replaced or re-sterilized if it becomes contaminated (i.e. handled in an unsterile manner, or allowed to touch an unsterile surface). OR staff must wear sterile attire (scrubs, a scrub cap, a sterile surgical gown, sterile latex or non-latex polymer gloves and a surgical mask), and they must scrub hands and arms with an approved disinfectant agent before each procedure.

Prior to surgery, the patient is given a medical examination, certain pre-operative tests, and an ASA score. If these results are satisfactory, the patient signs a consent form and is given a surgical clearance. If the procedure is expected to result in significant blood loss, an autologous blood donation may be made some weeks prior to surgery. If the surgery involves the digestive system, the patient may be instructed to perform a bowel prep by drinking a solution of polyethylene glycol the night before the procedure. Patients are also instructed to abstain from food or drink (an NPO order after midnight on the night before the procedure, to minimize the effect of stomach contents on pre-operative medications and reduce the risk of aspiration if the patient vomits during or after the procedure.

In the pre-operative holding area, the patient changes out of his or her street clothes and is asked to confirm the details of his or her surgery. A set of vital signs are recorded, a peripheral IV line is placed, and pre-operative medications (antibiotics, sedatives, etc) are given. When the patient enters the operating room, the skin surface to be operated on is cleaned and prepared by applying an antiseptic such as chlorhexidine gluconate or povidone-iodine to reduce the possibility of infection. If hair is present at the surgical site, it is clipped off prior to prep application. Sterile drapes are used to cover all of the patient's body except for the surgical site and the patient's head; the drapes are clipped to a pair of poles near the head of the bed to form an "ether screen", which separates the anesthetist/anesthesiologist's working area (unsterile) from the surgical site (sterile).

Anesthesia is administered to prevent pain from incision, tissue manipulation and suturing. Based on the procedure, anesthesia may be provided locally or as general anesthesia. Spinal anesthesia may be used when the surgical site is too large or deep for a local block, but general anesthesia may not be desirable. With local and spinal anesthesia, the surgical site is anesthetized, but the patient can remain conscious or minimally sedated. In contrast, general anesthesia renders the patient unconscious and paralyzed during surgery. The patient is intubated and is placed on a mechanical ventilator, and anesthesia is produced by a combination of injected and inhaled agents.

An incision is made to access the surgical site. Blood vessels may be clamped to prevent bleeding, and retractors may be used to expose the site or keep the incision open. The approach to the surgical site may involve several layers of incision and dissection, as in abdominal surgery, where the incision must traverse skin, subcutaneous tissue, three layers of muscle and then peritoneum. In certain cases, bone may be cut to further access the interior of the body; for example, cutting the skull for brain surgery or cutting the sternum for thoracic (chest) surgery to open up the rib cage.

Work to correct the problem in body then proceeds. This work may involve:

• excision - cutting out an organ, tumor, or other tissue.
• resection - partial removal of an organ or other bodily structure.
• reconnection of organs, tissues, etc., particularly if severed. Resection of organs such as intestines involves reconnection. Internal suturing or stapling may be used. Surgical connection between blood vessels or other tubular or hollow structures such as loops of intestine is called anastomosis.
• ligation - tying off blood vessels, ducts, or "tubes".
• grafts - may be severed pieces of tissue cut from the same (or different) body or flaps of tissue still partly connected to the body but resewn for rearranging or restructuring of the area of the body in question. Although grafting is often used in cosmetic surgery, it is also used in other surgery. Grafts may be taken from one area of the patient's body and inserted to another area of the body. An example is bypass surgery, where clogged blood vessels are bypassed with a graft from another part of the body. Alternatively, grafts may be from other persons, cadavers, or animals.
• insertion of prosthetic parts when needed. Pins or screws to set and hold bones may be used. Sections of bone may be replaced with prosthetic rods or other parts. Sometime a plate is inserted to replace a damaged area of skull. Artificial hip replacement has become more common. Heart pacemakers or valves may be inserted. Many other types of prostheses are used.
• creation of a stoma, a permanent or semi-permanent opening in the body
• in transplant surgery, the donor organ (taken out of the donor's body) is inserted into the recipient's body and reconnected to the recipient in all necessary ways (blood vessels, ducts, etc.).
• arthrodesis - surgical connection of adjacent bones so the bones can grow together into one. Spinal fusion is an example of adjacent vertebrae connected allowing them to grow together into one piece.
• modifying the digestive tract in bariatric surgery for weight loss.
• repair of a fistula, hernia, or prolapse
• other procedures, including:

• clearing clogged ducts, blood or other vessels
• removal of calculi (stones)
• draining of accumulated fluids
• debridement- removal of dead, damaged, or diseased tissue

• Surgery has also been conducted to separate conjoined twins.
• Sex change operations

Blood or blood expanders may be administered to compensate for blood lost during surgery. Once the procedure is complete, sutures or staples are used to close the incision. Once the incision is closed, the anesthetic agents are stopped and/or reversed, and the patient is taken off ventilation and extubated (if general anesthesia was administered).

After completion of surgery, the patient is transferred to the post anesthesia care unit and closely monitored. When the patient is judged to have recovered from the anesthesia, he/she is either transferred to a surgical ward elsewhere in the hospital or discharged home. During the post-operative period, the patient's general function is assessed, the outcome of the procedure is assessed, and the surgical site is checked for signs of infection. If removable skin closures are used, they are removed after 7 to 10 days post-operatively, or after healing of the incision is well under way.

Post-operative therapy may include adjuvant treatment such as chemotherapy, radiation therapy, or administration of medication such as anti-rejection medication for transplants. Other follow-up studies or rehabilitation may be prescribed during and after the recovery period.

History Main article: History of surgery

At least two prehistoric cultures had developed forms of surgery. The oldest for which we have evidence is trepannation, in which a hole is drilled or scraped into the skull, thus exposing the dura mater in order to treat health problems related to intracranial pressure and other diseases. Evidence has been found in prehistoric human remains from Neolithic times, in cave paintings, and the procedure continued in use well into recorded history. Surprisingly, many prehistoric and premodern patients had signs of their skull structure healing; suggesting that many survived the operation. In modern-day Pakistan, remains from the early Harappan periods of the Indus Valley Civilization (c. 3300 BC) show evidence of teeth having been drilled dating back 9,000 years. A final candidate for prehistoric surgical techniques is ancient Egypt, where a mandible dated to approximately 2650 BC shows two perforations just below the root of the first molar, indicating the draining of an abscessed tooth. Recent excavations of the construction workers of the Egyptian pyramids also led to possible evidence of brain surgery.

The oldest known surgical texts date back to ancient Egyptian about 3500 years ago. Surgeries were performed by priests, specialized in medical treatments similar to today. They documented their procedures on papyrus and were the first to describe patient case files which can nowadays be viewed in museums (i.e. Edwin Smith Papyrus). They medical expertise was later documented by Herodotus: "The practice of medicine is very specialized among them. Each physician treats just one disease. The country is full of physicians, some treat the eye, some the teeth, some of what belongs to the abdomen, and others internal diseases." Herodotus, Histories 2,84 For more information see also http://nefertiti.iwebland.com/timelines/topics/medicine.htm

Other ancient cultures to have surgical knowledge include ancient Greece - the Hippocratic Oath was an innovation of the Greek physician Hippocrates - and ancient China. However ancient Greek culture traditionally considered the practice of opening the body to be repulsive and thus left known surgical practices such as lithotomy to such persons as practice . In China, Hua Tuo was a famous Chinese physician during the Eastern Han and Three Kingdoms era. He was the first person to perform surgery with the aid of anesthesia, albeit a rudimentary and unsophisticated form.

In the Middle Ages, surgery was developed to a high degree in the Islamic world, with renowned practitioners such as Abulcasis (Abu al-Qasim Khalaf ibn al-Abbas Al-Zahrawi), an Andalusian-Arab physician and scientist who practised in the Zahra suburb of Córdoba. A great medieval surgeon, whose comprehensive medical texts shaped European surgical procedures up until the Renaissance. He is also often regarded as a Father Of Surgery.

In Europe, the demand grew for surgeons to formally study for many years before practicing; universities such as Montpellier, Padua and Bologna Universities were particularly renowned. By the fifteenth century at the latest, surgery had split away from physics as its own subject, of a lesser status than pure medicine, and initially took the form of a craft tradition until Rogerius Salernitanus composed his Chirurgia, laying the foundation for modern Western surgical manuals up to the modern time. Late in the nineteenth century, Bachelor of Surgery degrees (usually Ch.B.) began to be awarded with the (M.B.), and the mastership became a higher degree, usually abbreviated Ch.M. or M.S. in London, where the first degree was M.B.,B.S..

Basic surgical principles for asepsis ect are known as Halsteads principles

Modern surgery

Modern surgery developed rapidly with the scientific era. Ambroise Paré (sometimes spelled "Ambrose") pioneered the treatment of gunshot wounds, and the first modern surgeons were battlefield doctors in the Napoleonic Wars. Naval surgeons were often barber surgeons, who combined surgery with their main jobs as barbers. Three main developments permitted the transition to modern surgical approaches - control of bleeding, control of infection and control of pain (anaesthesia).

BleedingInfectionPain

Conditions treated by surgery

Surgery is used both as a treatment, and as an aspect of treatment, for many conditions, including:

• Physical trauma, e.g. wounds
• Anatomical Abnormalities
• Disorders of function
• Inflammation
• Ischaemia and infarction
• Metabolic disorders
• Neoplasia
• Other abnormalities of tissue growth, e.g. cysts, hyperplasia or Organ hypertrophy, as well as some cancers, if caught early enough
• Deformity and heavy scarring.
• Brain damage and nerve damage

Common procedures

Five of the most common surgical procedures in the United States are obstetric: episiotomy, repair of obstetric laceration, cesarean section, and artificial rupture of the amniotic membrane.

The most common non-obstetric surgical procedures include amputation, appendectomy, cataract surgery, circumcision, dental extraction and herniorraphy.

According to 1996 data from the US National Center for Health Statistics, 40.3 million inpatient surgical procedures were performed in the United States in 1996, followed closely by 31.5 million outpatient operations.

Surgical Specialties

• Cardiothoracic surgery
• Colon and Rectal surgery
• Dental Surgery
• General surgery
• Maxillofacial surgery
• Neurological surgery
• Ophthalmology
• Orthopaedic surgery
• Otolaryngology
• Paediatric surgery
• Plastic surgery
• Urology
• Vascular surgery

References

1. ^ (Capasso 2001)
2. ^ BBC NEWS | Science/Nature | Stone age man used dentist drill
3. ^ biography from Famousmuslims.com accessed 16 April 2007.
4. ^ http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=PubMed&list_uids=1558689&dopt=Abstract : Historical notes on pressure ulcers: the cure of Ambrose Paré
5. ^ Rabie E. Abdel-Halim, Ali S. Altwaijiri, Salah R. Elfaqih, Ahmad H. Mitwall (2003), "Extraction of urinary bladder described by Abul-Qasim Khalaf Alzahrawi (Albucasis) (325-404 H, 930-1013 AD)", Saudi Medical Journal 24 (12): 1283-1291 .

Medical The Rod of Asclepius, with its single snake, is an ancient Greek symbol associated with medicine. The American Medical Association, the American Osteopathic Association, the Royal Society of Medicine, the Australian Medical Association, the British Medical Association, and the World Health Organization display the Rod of Asclepius in their logos or emblems.

Medicine is the practice of maintaining and restoring human health through the study, diagnosis, and treatment of patients whose death it is the discipline's ultimate concern to avert. It has traditionally been regarded as both an art and a science: the term is derived from the Latin ars medicina meaning the art of healing. Whilst health science and biomedicine, clinical medicine, surgery and research are together the very bedrock of contemporary medicine, successful face-to-face relief of actual suffering resulting from disease and injury continues to require the intangible application of human feeling and compassion, what is referred to in English as "bedside manner."

Contents 1 History 2 Practice 2.1 Delivery systems 2.2 Delivery 2.3 Patient-physician-relationship 2.4 Clinical skills 3 Branches 3.1 Basic sciences 3.2 Specialties 3.2.1 Surgery 3.2.2 Medicine 3.2.3 Diagnostic specialties 3.2.4 Other 3.3 Interdisciplinary fields 4 Education 5 Legal restrictions 6 Criticism 7 See also 8 References 9 External links

//

History Physician treating a patient. Louvre Museum, Paris, France. Main article: History of medicine

The earliest type of medicine in most cultures was the use of empirical natural resources like plants (herbalism), animal parts and minerals. In all societies, including Western ones, there were also religious, ritual and magical resources. In aboriginal societies, there is a large scope of medical systems related to religious thinking, cultural experience, and natural resources. The religious ones more known are: animism (the notion of inanimate objects having spirits); spiritualism (here meaning an appeal to gods or communion with ancestor spirits); shamanism (the vesting of an individual with mystic powers); and divination (the supposed obtaining of truth by magic means). The field of medical anthropology studies the various medical systems and their interaction with society, while prehistoric medicine addresses diagnosis and treatment in prehistoric times.

The practice of medicine developed gradually in ancient Egypt, Babylonia, India, Sri Lanka, China, Greece, Persia, the Islamic world, medieval Europe and early modern period in Persia (Rhazes and Avicenna), Spain (Abulcasis and Avenzoar), Syria/Egypt (Ibn al-Nafis, 13th century), Italy (Gabriele Falloppio, 16th century), England (William Harvey, 17th century). Medicine as it is now practiced largely developed during the 19th and 20th centuries in Germany (Rudolf Virchow, Wilhelm Conrad Röntgen, Robert Koch), Austria (Karl Landsteiner, Otto Loewi), United Kingdom (Edward Jenner, Alexander Fleming, Joseph Lister, Francis Crick), New Zealand (Maurice Wilkins), Australia (Howard Floery, Frank Macfarlane Burnet), Russia (Nikolai Korotkov), United States (William Williams Keen, Harvey Cushing, William Coley, James D. Watson), Italy (Salvador Luria), Switzerland (Alexandre Yersin), Japan (Kitasato Shibasaburo), and France (Jean-Martin Charcot, Claude Bernard, Louis Pasteur, Paul Broca and others). The new "scientific" or "experimental" medicine (where results are testable and repeatable) replaced early Western traditions of medicine, based on herbalism, the Greek "four humours" and other pre-modern theories.

The Sumerian god Ningizzida was the patron of medicine. In the image he is accompanied by two gryphons. A similar image with two snakes coiling around a rod is called the Caduceus and, although historically inappropriate, appears in the logo/emblem of a significant number of private (rather than professional or academic) medical practices.

The focal points of development of clinical medicine shifted to the United Kingdom and the USA by the early 1900s (Canadian-born) Sir William Osler, Harvey Cushing). Possibly the major shift in medical thinking was the gradual rejection, especially during the Black Death in the 14th and 15th centuries, of what may be called the 'traditional authority' approach to science and medicine. This was the notion that because some prominent person in the past said something must be so, then that was the way it was, and anything one observed to the contrary was an anomaly (which was paralleled by a similar shift in European society in general - see Copernicus's rejection of Ptolemy's theories on astronomy). Physicians like Ibn al-Nafis and Vesalius led the way in improving upon or indeed rejecting the theories of great authorities from the past (such as Hippocrates, Galen and Avicenna), many of whose theories were in time discredited. Such new attitudes were made possible in Europe by the weakening of the Roman Catholic church's power in society, especially in the Republic of Venice.

Evidence-based medicine is a recent movement to establish the most effective algorithms of practice (ways of doing things) through the use of the scientific method and modern global information science by collating all the evidence and developing standard protocols which are then disseminated to healthcare providers. One problem with this 'best practice' approach is that it could be seen to stifle novel approaches to treatment.

Drug ampoules

Genomics and knowledge of human genetics is already having some influence on medicine, as the causative genes of most monogenic genetic disorders have now been identified, and the development of techniques in molecular biology and genetics are influencing medical practice and decision-making.

Pharmacology has developed from herbalism and many drugs are still derived from plants (atropine, ephedrine, warfarin, aspirin, digoxin, vinca alkaloids, taxol, hyoscine, etc). The modern era began with Robert Koch's discoveries around 1880 of the transmission of disease by bacteria, and then the discovery of antibiotics shortly thereafter around 1900. The first of these was arsphenamine / Salvarsan discovered by Paul Ehrlich in 1908 after he observed that bacteria took up toxic dyes that human cells did not. The first major class of antibiotics was the sulfa drugs, derived by French chemists originally from azo dyes. Throughout the twentieth century, major advances in the treatment of infectious diseases were observable in (Western) societies. The medical establishment is now developing drugs targeted towards one particular disease process. Thus drugs are being developed to minimize the side effects of prescribed drugs, to treat cancer, geriatric problems, long-term problems (such as high cholesterol), chronic diseases such as type 2 diabetes, lifestyle and degenerative diseases such as arthritis and Alzheimer's disease.

Practice

The practice of medicine combines both science as the evidence base and art in the application of this medical knowledge in combination with intuition and clinical judgment to determine the treatment plan for each patient.

Central to medicine is the patient-physician relationship established when a person with a health concern seeks a physician's help; the 'medical encounter'. Other health professionals similarly establish a relationship with a patient and may perform various interventions, e.g. nurses, radiographers and therapists.

Artificial insemination

As part of the medical encounter, the healthcare provider needs to:

• develop a relationship with the patient
• gather data (medical history, systems inquiry, and physical examination, combined with laboratory or imaging studies (investigations))
• analyze and synthesize that data (assessment and/or differential diagnoses), and then:
• develop a treatment plan (further testing, therapy, watchful observation, referral and follow-up)
• treat the patient accordingly
• assess the progress of treatment and alter the plan as necessary (management).

The medical encounter is documented in a medical record, which is a legal document in many jurisdictions.

Delivery systems

Medicine is practiced within the medical system, which is a legal, credentialing and financing framework, established by a particular culture or government. The characteristics of a health care system have significant effect on the way medical care is delivered.

Most industrialized countries and many developing countries deliver health care though a system of universal health care which guarantees health care for all through a system of compulsory private or co-operative health insurance funds or via government backed social insurance. This insurance, (in effect, a form of taxation) ensures the entire population has access to medical care on the basis of need rather than ability to pay. The delivery systems may be provided by private medical practices or by state owned hospitals and clinics, or by charities.

Most tribal societies but also some communist countries (e.g. China) and at least one industrialized capitalist country (the United States) provide no guarantee of health care for the population as a whole. In such societies, health care is available to those that can afford to pay for it or have self insured it (either directly or as part of an employment contract) or who may be covered by care financed by the government or tribe directly.

Transparency of information is another factor defining a delivery system. Access to information on conditions, treatments, quality and pricing greatly affects the choice by patients / consumers and therefore the incentives of medical professionals. While US health care system has come under fire for lack of openness, new legislation may encourage greater openness. There is a perceived tension between the need for transparency on the one hand and such issues as patient confidentiality and the possible exploitation of information for commercial gain on the other.

Delivery Painting of Henriette Browne

Medical care delivery is classified into primary, secondary and tertiary care.

Primary care medical services are provided by physicians or other health professionals who have first contact with a patient seeking medical treatment or care. These occur in physician offices, clinics, nursing homes, schools, home visits and other places close to patients. About 90% of medical visits can be treated by the primary care provider. These include treatment of acute and chronic illnesses, preventive care and health education for all ages and both sexes.

Secondary care medical services are provided by medical specialists in their offices or clinics or at local community hospitals for a patient referred by a primary care provider who first diagnosed or treated the patient. Referrals are made for those patients who required the expertise or procedures performed by specialists. These include both ambulatory care and inpatient services, emergency rooms, intensive care medicine, surgery services, physical therapy, labor and delivery, endoscopy units, diagnostic laboratory and medical imaging services, hospice centers, etc. Some primary care providers may also take care of hospitalized patients and deliver babies in a secondary care setting.

Tertiary care medical services are provided by specialist hospitals or regional centers equipped with diagnostic and treatment facilities not generally available at local hospitals. These include trauma centers, burn treatment centers, advanced neonatology unit services, organ transplants, high-risk pregnancy, radiation oncology, etc.

Modern medical care also depends on information - still delivered in many health care settings on paper records, but increasingly nowadays by electronic means.

Patient-physician-relationship

The examples and perspective in this article or section may not represent a worldwide view of the subject. Please improve this article or discuss the issue on the talk page.

This kind of relationship and interaction is a central process in the practice of medicine. There are many perspectives from which to understand and describe it.

An idealized physician's perspective, such as is taught in medical school, sees the core aspects of the process as the physician learning the patient's symptoms, concerns and values; in response the physician examines the patient, interprets the symptoms, and formulates a diagnosis to explain the symptoms and their cause to the patient and to propose a treatment. The job of a physician is similar to a human biologist: that is, to know the human frame and situation in terms of normality. Once the physician knows what is normal and can measure the patient against those norms, he or she can then determine the particular departure from the normal and the degree of departure. This is called the diagnosis.

The four great cornerstones of diagnostic medicine are anatomy (structure: what is there), physiology (how the structure/s work), pathology (what goes wrong with the anatomy and physiology) and psychology (mind and behavior). In addition, the physician should consider the patient in their 'well' context rather than simply as a walking medical condition. This means the socio-political context of the patient (family, work, stress, beliefs) should be assessed as it often offers vital clues to the patient's condition and further management.

A patient typically presents a set of complaints (the symptoms) to the physician, who then obtains further information about the patient's symptoms, previous state of health, living conditions, and so forth. The physician then makes a review of systems (ROS) or systems inquiry, which is a set of ordered questions about each major body system in order: general (such as weight loss), endocrine, cardio-respiratory, etc. Next comes the actual physical examination and often laboratory tests; the findings are recorded, leading to a list of possible diagnoses. These will be investigated in order of probability.

The next task is to enlist the patient's agreement to a management plan, which will include treatment as well as plans for follow-up. Importantly, during this process the healthcare provider educates the patient about the causes, progression, outcomes, and possible treatments of his ailments, as well as often providing advice for maintaining health. This teaching relationship is the basis of calling the physician doctor, which originally meant "teacher" in Latin. The patient-physician relationship is additionally complicated by the patient's suffering (patient derives from the Latin patior, "suffer") and limited ability to relieve it on his/her own. The physician's expertise comes from his knowledge of what is healthy and normal contrasted with knowledge and experience of other people who have suffered similar symptoms (unhealthy and abnormal), and the proven ability to relieve it with medicines (pharmacology) or other therapies about which the patient may initially have little knowledge.

The physician-patient relationship can be analyzed from the perspective of ethical concerns, in terms of how well the goals of non-maleficence, beneficence, autonomy, and justice are achieved. Many other values and ethical issues can be added to these. In different societies, periods, and cultures, different values may be assigned different priorities. For example, in the last 30 years medical care in the Western World has increasingly emphasized patient autonomy in decision making.

The relationship and process can also be analyzed in terms of social power relationships (e.g., by Michel Foucault), or economic transactions. Physicians have been accorded gradually higher status and respect over the last century, and they have been entrusted with control of access to prescription medicines as a public health measure. This represents a concentration of power and carries both advantages and disadvantages to particular kinds of patients with particular kinds of conditions. A further twist has occurred in the last 25 years as costs of medical care have risen, and a third party (an insurance company or government agency) now often insists upon a share of decision-making power for a variety of reasons, reducing freedom of choice of healthcare providers and patients in many ways.

The quality of the patient-physician relationship is important to both parties. The better the relationship in terms of mutual respect, knowledge, trust, shared values and perspectives about disease and life, and time available, the better will be the amount and quality of information about the patient's disease transferred in both directions, enhancing accuracy of diagnosis and increasing the patient's knowledge about the disease. Where such a relationship is poor the physician's ability to make a full assessment is compromised and the patient is more likely to distrust the diagnosis and proposed treatment. In these circumstances and also in cases where there is genuine divergence of medical opinions, a second opinion from another physician may be sought or the patient may choose to go to another doctor.

In some settings, e.g. the hospital ward, the patient-physician relationship is much more complex, and many other people are involved when somebody is ill: relatives, neighbors, rescue specialists, nurses, technical personnel, social workers and others.

Clinical skills Main articles: Medical history and Physical examination

A complete medical evaluation includes a medical history, a systems enquiry, a physical examination, appropriate laboratory or imaging studies, analysis of data and medical decision making to obtain diagnoses, and a treatment plan.

The components of the medical history are:

• Chief complaint (CC): the reason for the current medical visit. These are the 'symptoms.' They are in the patient's own words and are recorded along with the duration of each one. Also called 'presenting complaint.'
• History of present illness / complaint (HPI): the chronological order of events of symptoms and further clarification of each symptom.
• Current activity: occupation, hobbies, what the patient actually does.
• Medications (DHx): what drugs the patient takes including prescribed, over-the-counter, and home remedies, as well as alternative and herbal medicines/herbal remedies. Allergies are also recorded.
• Past medical history (PMH/PMHx): concurrent medical problems, past hospitalizations and operations, injuries, past infectious diseases and/or vaccinations, history of known allergies.
• Social history (SH): birthplace, residences, marital history, social and economic status, habits (including diet, medications, tobacco, alcohol).
• Family history (FH): listing of diseases in the family that may impact the patient. A family tree is sometimes used.

• Review of systems (ROS) or systems inquiry: a set of additional questions to ask which may be missed on HPI: a general enquiry (have you noticed any weight loss, fevers, lumps and bumps? etc), followed by questions on the body's main organ systems (heart, lungs, digestive tract, urinary tract, etc).

The physical examination is the examination of the patient looking for signs of disease ('Symptoms' are what the patient volunteers, 'Signs' are what the healthcare provider detects by examination). The healthcare provider uses the senses of sight, hearing, touch, and sometimes smell (taste has been made redundant by the availability of modern lab tests). Four chief methods are used: inspection, palpation (feel), percussion (tap to determine resonance characteristics), and auscultation (listen); smelling may be useful (e.g. infection, uremia, diabetic ketoacidosis). The clinical examination involves study of:

• Vital signs including height, weight, body temperature, blood pressure, pulse, respiration rate, hemoglobin oxygen saturation
• General appearance of the patient and specific indicators of disease (nutritional status, presence of jaundice, pallor or clubbing)
• Skin
• Head, eye, ear, nose, and throat (HEENT)
• Cardiovascular (heart and blood vessels)
• Respiratory (large airways and lungs)
• Abdomen and rectum
• Genitalia (and pregnancy if the patient is or could be pregnant)
• Musculoskeletal (spine and extremities)
• Neurological (consciousness, awareness, brain, cranial nerves, spinal cord and peripheral nerves)
• Psychiatric (orientation, mental state, evidence of abnormal perception or thought)

Laboratory and imaging studies results may be obtained, if necessary.

The medical decision-making (MDM) process involves analysis and synthesis of all the above data to come up with a list of possible diagnoses (the differential diagnoses), along with an idea of what needs to be done to obtain a definitive diagnosis that would explain the patient's problem.

The treatment plan may include ordering additional laboratory tests and studies, starting therapy, referral to a specialist, or watchful observation. Follow-up may be advised.

This process is used by primary care providers as well as specialists. It may take only a few minutes if the problem is simple and straightforward. On the other hand, it may take weeks in a patient who has been hospitalized with bizarre symptoms or multi-system problems, with involvement by several specialists.

On subsequent visits, the process may be repeated in an abbreviated manner to obtain any new history, symptoms, physical findings, and lab or imaging results or specialist consultations.

Branches

Working together as an interdisciplinary team, many highly-trained health professionals besides medical practitioners are involved in the delivery of modern health care. Examples include: nurses, emergency medical technicians and paramedics, laboratory scientists, (pharmacy, pharmacists), (physiotherapy,physiotherapists), respiratory therapists, speech therapists, occupational therapists, radiographers, dietitians and bioengineers.

The scope and sciences underpinning human medicine overlap many other fields. Dentistry and psychology, while separate disciplines from medicine, are considered medical fields.

A patient admitted to hospital is usually under the care of a specific team based on their main presenting problem, e.g. the Cardiology team, who then may interact with other specialties, e.g. surgical, radiology, to help diagnose or treat the main problem or any subsequent complications / developments.

Physicians have many specializations and subspecializations into certain branches of medicine, which are listed below. There are variations from country to country regarding which specialties certain subspecialties are in.

The main branches of medicine used in Wikipedia are:

• Basic sciences of medicine; this is what every physician is educated in, and some return to in biomedical research.
• Medical specialties
• interdisciplinary fields, where different medical specialties are mixed to function in certain occasions.

Basic sciences

• Anatomy is the study of the physical structure of organisms. In contrast to macroscopic or gross anatomy, cytology and histology are concerned with microscopic structures.
• Biochemistry is the study of the chemistry taking place in living organisms, especially the structure and function of their chemical components.
• Biostatistics is the application of statistics to biological fields in the broadest sense. A knowledge of biostatistics is essential in the planning, evaluation, and interpretation of medical research. It is also fundamental to epidemiology and evidence-based medicine.
• Cytology is the microscopic study of individual cells.
• Embryology is the study of the early development of organisms.
• Epidemiology is the study of the demographics of disease processes, and includes, but is not limited to, the study of epidemics.
• Genetics is the study of genes, and their role in biological inheritance.
• Histology is the study of the structures of biological tissues by light microscopy, electron microscopy and immunohistochemistry.
• Immunology is the study of the immune system, which includes the innate and adaptive immune system in humans, for example.
• Medical physics is the study of the applications of physics principles in medicine.
• Microbiology is the study of microorganisms, including protozoa, bacteria, fungi, and viruses.
• Neuroscience includes those disciplines of science that are related to the study of the nervous system. A main focus of neuroscience is the biology and physiology of the human brain and spinal cord.
• Nutrition is the study of the relationship of food and drink to health and disease, especially in determining an optimal diet. Medical nutrition therapy is done by dietitians and is prescribed for diabetes, cardiovascular diseases, weight and eating disorders, allergies, malnutrition, and neoplastic diseases.
• Pathology as a science is the study of disease—the causes, course, progression and resolution thereof.
• Pharmacology is the study of drugs and their actions.
• Physiology is the study of the normal functioning of the body and the underlying regulatory mechanisms.
• Toxicology is the study of hazardous effects of drugs and poisons.

Specialties Main article: Medical specialty

In the broadest meaning of "medicine", there are many different specialties. However, within medical circles, there are two broad categories: "Medicine" and "Surgery." "Medicine" refers to the practice of non-operative medicine, and most subspecialties in this area require preliminary training in "Internal Medicine". "Surgery" refers to the practice of operative medicine, and most subspecialties in this area require preliminary training in "General Surgery." There are some specialties of medicine that do not fit into either of these categories, such as radiology, pathology, or anesthesia, and those are also discussed further below.

Surgery

Surgical specialties employ operative treatment. In addition, surgeons must decide when an operation is necessary, and also treat many non-surgical issues, particularly in the surgical intensive care unit (SICU), where a variety of critical issues arise. Surgery has many subspecialties, e.g. general surgery, trauma surgery, cardiovascular surgery, neurosurgery, maxillofacial surgery, orthopedic surgery, otolaryngology, plastic surgery, oncologic surgery, vascular surgery, and pediatric surgery. In some centers, anesthesiology is part of the division of surgery (for logistical and planning purposes), although it is not a surgical discipline.

Surgical training in the U.S. requires a minimum of five years of residency after medical school. Sub-specialties of surgery often require seven or more years. In addition, fellowships can last an additional one to three years. Because post-residency fellowships can be competitive, many trainees devote two additional years to research. Thus in some cases surgical training will not finish until more than a decade after medical school. Furthermore, surgical training can be very difficult and time-consuming. A surgical resident's average work week is approximately 75 hours. Some subspecialties of surgery, such as neurosurgery, require even longer hours, and utilize an extension to the 80 hour regulated work week, allowing up to 88 hours per week. Many surgical programs still exceed this work hour limit. Attempts to limit the amount of hours worked has been difficult because of the large volume of patients who require surgical care, the limited amount of resources (including a shortage of people willing to enter into surgery as a career), the need to perform long operations and still provide care to all pre- and post-operative patients, and the need to provide constant coverage in the OR, ICU, and ER.

Medicine

• Internal medicine is concerned with systemic diseases of adults, i.e. those diseases that affect the body as a whole (restrictive, current meaning), or with all adult non-operative somatic medicine (traditional, inclusive meaning), thus excluding pediatrics, surgery, gynecology and obstetrics, and psychiatry. Practitioners of such specialties are referred to as physicians. There are several subdisciplines of internal medicine:

• • Cardiology
  • Critical care medicine
  • Endocrinology
  • Gastroenterology
  • Hepatology
  • Hematology
  • Infectious diseases
  • Nephrology
  • Oncology
  • Proctology
  • Pulmonology
  • Rheumatology
  • Neurology
  • Geriatrics

Generally, Pediatrics and Family Practice are also considered to fall under the category of "Medicine".

Medical training, as opposed to surgical training, requires three years of residency training after medical school. This can then be followed by a one to two year fellowship in the subspecialties listed above. In general, resident work hours in medicine are less than those in surgery, averaging about 60 hours per week.

Diagnostic specialties

• Clinical laboratory sciences are the clinical diagnostic services which apply laboratory techniques to diagnosis and management of patients. In the United States these services are supervised by a pathologist. The personnel that work in these medical laboratory departments are technically trained staff who do not hold medical degrees, but who usually hold an undergraduate medical technology degree, who actually perform the tests, assays, and procedures needed for providing the specific services. Subspecialties include Transfusion medicine, Cellular pathology, Clinical chemistry, Hematology, Clinical microbiology and Clinical immunology.
• Pathology as a medical specialty is the branch of medicine that deals with the study of diseases and the morphologic, physiologic changes produced by them. As a diagnostic specialty, pathology can be considered the basis of modern scientific medical knowledge and plays a large role in evidence-based medicine. Many modern molecular tests such as flow cytometry, polymerase chain reaction (PCR), immunohistochemistry, cytogenetics, gene rearrangements studies and fluorescent in situ hybridization (FISH) fall within the territory of pathology.
• Radiology is concerned with imaging of the human body, e.g. by x-rays, x-ray computed tomography, ultrasonography, and nuclear magnetic resonance tomography.
• Clinical neurophysiology is concerned with testing the physiology or function of the central and peripheral aspects of the nervous system. These kinds of tests can be divided into recordings of: (1) spontaneous or continuously running electrical activity, or (2) stimulus evoked responses. Subspecialties include Electroencephalography, Electromyography, Evoked potential, Nerve conduction study and Polysomnography. Sometimes these tests are performed by techs without a medical degree, but the interpretation of these tests is done by a medical professional.

Other

Following are some selected fields of medical specialties that don't directly fit into any of the above mentioned groups.

• Ophthalmology exclusively concerned with the eye and ocular adnexa. Combines conservative and surgical therapy, and has its own College.
• Dermatology is concerned with the skin and its diseases. In the UK, dermatology is a subspecialty of general medicine.
• Emergency medicine is concerned with the diagnosis and treatment of acute or life-threatening conditions, including trauma, surgical, medical, pediatric, and psychiatric emergencies.
• Obstetrics and gynecology (often abbreviated as OB/GYN) are concerned respectively with childbirth and the female reproductive and associated organs. Reproductive medicine and fertility medicine are generally practiced by gynecological specialists.
• Palliative care is a relatively modern branch of clinical medicine that deals with pain and symptom relief and emotional support in patients with terminal illnesses including cancer and heart failure.
• Pediatrics (AE) or paediatrics (BE) is devoted to the care of infants, children, and adolescents. Like internal medicine, there are many pediatric subspecialties for specific age ranges, organ systems, disease classes, and sites of care delivery.
• Physical medicine and rehabilitation (or physiatry) is concerned with functional improvement after injury, illness, or congenital disorders.
• Psychiatry is the branch of medicine concerned with the bio-psycho-social study of the etiology, diagnosis, treatment and prevention of cognitive, perceptual, emotional and behavioral disorders. Related non-medical fields include psychotherapy and clinical psychology.

Interdisciplinary fields

Interdisciplinary sub-specialties of medicine are:

• General practice, family practice, family medicine or primary care is, in many countries, the first port-of-call for patients with non-emergency medical problems.
• Many other health science fields, e.g. dietetics
• Bioethics is a field of study which concerns the relationship between biology, science, medicine and ethics, philosophy and theology.
• Biomedical Engineering is a field dealing with the application of engineering principles to medical practice.
• Clinical pharmacology is concerned with how systems of therapeutics interact with patients.
• Conservation medicine studies the relationship between human and animal health, and environmental conditions. Also known as ecological medicine, environmental medicine, or medical geology.
• Disaster medicine deals with medical aspects of emergency preparedness, disaster mitigation and management.
• Diving medicine (or hyperbaric medicine) is the prevention and treatment of diving-related problems.
• Evolutionary medicine is a perspective on medicine derived through applying evolutionary theory.
• Forensic medicine deals with medical questions in legal context, such as determination of the time and cause of death.
• Gender-based medicine studies the biological and physiological differences between the human sexes and how that affects differences in disease.
• Hospital medicine is the general medical care of hospitalized patients. Physicians whose primary professional focus is hospital medicine are called hospitalists in the USA.
• Medical humanities includes the humanities (literature, philosophy, ethics, history and religion), social science (anthropology, cultural studies, psychology, sociology), and the arts (literature, theater, film, and visual arts) and their application to medical education and practice.
• Medical informatics, medical computer science, medical information and eHealth are relatively recent fields that deal with the application of computers and information technology to medicine.
• Nosology is the classification of diseases for various purposes.
• Preventive medicine is the branch of medicine concerned with preventing disease.
  • Community health or public health is an aspect of health services concerned with threats to the overall health of a community based on population health analysis.
  • Occupational medicine's principal role is the provision of health advice to organizations and individuals to ensure that the highest standards of health and safety at work can be achieved and maintained.
  • Aerospace medicine deals with medical problems related to flying and space travel.
• Osteopathic medicine, a branch of the U.S. medical profession.
• Pharmacogenomics is a form of individualized medicine.
• Sports medicine deals with the treatment and preventive care of athletes, amateur and professional. The team includes specialty physicians and surgeons, athletic trainers, physical therapists, coaches, other personnel, and, of course, the athlete.
• Therapeutics is the field, more commonly referenced in earlier periods of history, of the various remedies that can be us