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Friday, February 22, 2019

Surgery

From Wikipedia, the free encyclopedia

Surgeons repairing a ruptured Achilles tendon on a man
 
Surgery (from the Greek: χειρουργική cheirourgikē (composed of χείρ, "hand", and ἔργον, "work"), via Latin: chirurgiae, meaning "hand work") is a medical specialty that uses operative manual and instrumental techniques on a patient to investigate or treat a pathological condition such as a disease or injury, to help improve bodily function or appearance or to repair unwanted ruptured areas. 

The act of performing surgery may be called a "surgical procedure", "operation", or simply "surgery". In this context, the verb "operate" means to perform 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 practices surgery and a surgeon's assistant is a person who practices surgical assistance. A surgical team is made up of surgeon, surgeon's assistant, anesthesia provider, circulating nurse and surgical technologist. Surgery usually spans minutes to hours, but it is typically not an ongoing or periodic type of treatment. The term "surgery" can also refer to the place where surgery is performed, or, in British English, simply the office of a physician, dentist, or veterinarian.

Definitions

Surgery is a 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 (e.g. laser ablation of the cornea) or to a radiosurgical procedure (e.g. irradiation of a tumor).

Types of surgery

Surgical procedures are commonly categorized by urgency, type of procedure, body system involved, the degree of invasiveness, and special instrumentation.
  • Based on timing: 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. A semi-elective surgery is one that must be done to avoid permanent disability or death, but can be postponed for a short time. Emergency surgery is surgery which must be done promptly to save life, limb, or functional capacity.
  • Based on purpose: Exploratory surgery is performed to aid or confirm a diagnosis. Therapeutic surgery treats a previously diagnosed condition. Cosmetic surgery is done to subjectively improve the appearance of an otherwise normal structure.
  • By type of procedure: Amputation involves cutting off a body part, usually a limb or digit; castration is also an example. Resection is the removal of all of an internal organ or body part, or a key part (lung lobe; liver quadrant) of such an organ or body part that has its own name or code designation. Replantation involves reattaching a severed body part. Reconstructive surgery involves reconstruction of an injured, mutilated, or deformed part of the body. Excision is the cutting out or removal of only part 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.
  • By body part: 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 or muscles).
  • By degree of invasiveness of surgical procedures: 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 such as a laparotomy requires a large incision to access the area of interest.
  • By equipment used: 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 robotic 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", therefore a rhinoplasty is reconstructive or cosmetic surgery for the nose.
  • Repair of damaged or congenital abnormal structure ends in -rraphy.
  • Reoperation (return to the operating room) refers to a return to the operating theater after an initial surgery is performed to re-address an aspect of patient care best treated surgically. Reasons for reoperation include persistent bleeding after surgery, development of or persistence of infection.

Description of surgical procedure

Location

Inpatient surgery is performed in a hospital, and the patient stays at least one night in the hospital after the surgery. Outpatient surgery occurs in a hospital outpatient department or freestanding ambulatory surgery center, and the patient is discharged the same working day. Office surgery occurs in a physician's office, and the patient is discharged the same working day.

At a hospital, modern surgery is often performed in an operating theater using surgical instruments, an operating table for the patient, and other equipment. Among United States hospitalizations for non-maternal and non-neonatal conditions in 2012, more than one-fourth of stays and half of hospital costs involved stays that included operating room (OR) procedures. 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). Operating room 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.

Preoperative care

Prior to surgery, the patient is given a medical examination, receives certain pre-operative tests, and their physical status is rated according to the ASA physical status classification system. 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.

Some medical systems have a practice of routinely performing chest x-rays before surgery. The premise behind this practice is that the physician might discover some unknown medical condition which would complicate the surgery, and that upon discovering this with the chest x-ray, the physician would adapt the surgery practice accordingly. In fact, medical specialty professional organizations recommend against routine pre-operative chest x-rays for patients who have an unremarkable medical history and presented with a physical exam which did not indicate a chest x-ray. Routine x-ray examination is more likely to result in problems like misdiagnosis, over-treatment, or other negative outcomes than it is to result in a benefit to the patient. Likewise, other tests including complete blood count, prothrombin time, partial thromboplastin time, basic metabolic panel, and urinalysis should not be done unless the results of these tests can help evaluate surgical risk.

Staging for surgery

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, called the operating field, 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. The patient is assisted by an anesthesiologist or resident to make a specific surgical position, then sterile drapes are used to cover the surgical site or at least a wide area surrounding the operating field; 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 an 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. Choice of surgical method and anesthetic technique aims to reduce the risk of complications, shorten the time needed for recovery and minimize the surgical stress response.

Surgery

An incision is made to access the surgical site. Blood vessels may be clamped or cauterized 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 the 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. Whilst in surgery aseptic technique is used to prevent infection or further spreading of the disease. The surgeons' and assistants' hands, wrists and forearms are washed thoroughly for at least 4 minutes to prevent germs getting into the operative field, then sterile gloves are placed onto their hands. An antiseptic solution is applied to the area of the patient's body that will be operated on. Sterile drapes are placed around the operative site. Surgical masks are worn by the surgical team to avoid germs on droplets of liquid from their mouths and noses from contaminating the operative site.

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.
  • Reduction – the movement or realignment of a body part to its normal position. e.g. Reduction of a broken nose involves the physical manipulation of the bone or cartilage from their displaced state back to their original position to restore normal airflow and aesthetics.
  • 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. Sometimes 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
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 or reversed, and the patient is taken off ventilation and extubated (if general anesthesia was administered).

Post-operative care

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. There are several risk factors associated with postoperative complications, such as immune deficiency and obesity. Obesity has long been considered a risk factor for adverse post-surgical outcomes. It has been linked to many disorders such as obesity hypoventilation syndrome, atelectasis and pulmonary embolism, adverse cardiovascular effects, and wound healing complications. 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.

It is not uncommon for surgical drains to be required to remove blood or fluid from the surgical wound during recovery. Mostly these drains stay in until the volume tapers off, then they are removed. These drains can become clogged, leading to abscess

Postoperative 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.

The use of topical antibiotics on surgical wounds to reduce infection rates has been questioned. Antibiotic ointments are likely to irritate the skin, slow healing, and could increase risk of developing contact dermatitis and antibiotic resistance. It has also been suggested that topical antibiotics should only be used when a person shows signs of infection and not as a preventative. A systematic review published by Cochrane (organization) in 2016, though, concluded that topical antibiotics applied over certain types of surgical wounds reduce the risk of surgical site infections, when compared to no treatment or use of antiseptics. The review also did not find conclusive evidence to suggest that topical antibiotics increased the risk of local skin reactions or antibiotic resistance. 

Through a retrospective analysis of national administrative data, the association between mortality and day of elective surgical procedure suggests a higher risk in procedures carried out later in the working week and on weekends. The odds of death were 44% and 82% higher respectively when comparing procedures on a Friday to a weekend procedure. This “weekday effect” has been postulated to be from several factors including poorer availability of services on a weekend, and also, decrease number and level of experience over a weekend.

Epidemiology

United States

In 2011, of the 38.6 million hospital stays in U.S. hospitals, 29% included at least one operating room procedure. These stays accounted for 48% of the total $387 billion in hospital costs.

The overall number of procedures remained stable from 2001 to 2011. In 2011, over 15 million operating room procedures were performed in U.S. hospitals.

Data from 2003 to 2011 showed that U.S. hospital costs were highest for the surgical service line; the surgical service line costs were $17,600 in 2003 and projected to be $22,500 in 2013. For hospital stays in 2012 in the United States, private insurance had the highest percentage of surgical expenditure. in 2012, mean hospital costs in the United States were highest for surgical stays.

Special populations

Elderly people

Older adults have widely varying physical health. Frail elderly people are at significant risk of post-surgical complications and the need for extended care. Assessment of older patients before elective surgery can accurately predict the patients' recovery trajectories. One frailty scale uses five items: unintentional weight loss, muscle weakness, exhaustion, low physical activity, and slowed walking speed. A healthy person scores 0; a very frail person scores 5. Compared to non-frail elderly people, people with intermediate frailty scores (2 or 3) are twice as likely to have post-surgical complications, spend 50% more time in the hospital, and are three times as likely to be discharged to a skilled nursing facility instead of to their own homes. Frail elderly patients (score of 4 or 5) have even worse outcomes, with the risk of being discharged to a nursing home rising to twenty times the rate for non-frail elderly people.

Children

Surgery on children requires considerations which are not common in adult surgery. Children and adolescents are still developing physically and mentally making it difficult for them to make informed decisions and give consent for surgical treatments. Bariatric surgery in youth is among the controversial topics related to surgery in children.

Vulnerable populations

Doctors perform surgery with the consent of the patient. Some patients are able to give better informed consent than others. Populations such as incarcerated persons, people living with dementia, the mentally incompetent, persons subject to coercion, and other people who are not able to make decisions with the same authority as a typical patient have special needs when making decisions about their personal healthcare, including surgery.

In low- and middle-income countries

In 2014, the Lancet Commission on Global Surgery was launched to examine the case for surgery as an integral component of global health care and to provide recommendations regarding the delivery of surgical and anesthesia services in low and middle income countries. Among the conclusions in this study, two primary conclusions were reached:
  • Five billion people worldwide lack access to safe, timely, and affordable surgical and anesthesia care. Areas in which especially large proportions of the population lack access include Sub-Saharan Africa, the Indian Subcontinent, Central Asia and, to a lesser extent, Russia and China. Of the estimated 312.9 million surgical procedures undertaken worldwide in 2012, only 6.3% were done in countries comprising the poorest 37.3% of the world's population.
  • An additional 143 million surgical procedures are needed each year to prevent unnecessary death and disability.
Globally, 4.2 million people are estimated to die within 30 days of surgery each year, with half of these occurring in low- and middle-income countries. A prospective study of 10,745 adult patients undergoing emergency abdominal surgery from 357 centers across 58 countries found that mortality is three times higher in low- compared with high-human development index (HDI) countries even when adjusted for prognostic factors. In this study the overall global mortality rate was 1·6 per cent at 24 hours (high HDI 1·1 per cent, middle HDI 1·9 per cent, low HDI 3·4 per cent), increasing to 5·4 per cent by 30 days (high HDI 4·5 per cent, middle HDI 6·0 per cent, low HDI 8·6 per cent; P < 0·001). A sub-study of 1,409 children undergoing emergency abdominal surgery from 253 centers across 43 countries found that adjusted mortality in children following surgery may be as high as 7 times greater in low-HDI and middle-HDI countries compared with high-HDI countries. This translate to 40 excess deaths per 1000 procedures performed in these settings. Patient safety factors were suggested to play an important role, with use of the WHO Surgical Safety Checklist associated with reduced mortality at 30 days.

Human rights

Access to surgical care is increasingly recognized as an integral aspect of healthcare, and therefore is evolving into a normative derivation of human right to health. The ICESCR Article 12.1 and 12.2 define the human right to health as “the right of everyone to the enjoyment of the highest attainable standard of physical and mental health” In the August 2000, the UN Committee on Economic, Social and Cultural Rights (CESCR) interpreted this to mean “right to the enjoyment of a variety of facilities, goods, services, and conditions necessary for the realization of the highest attainable health”. Surgical care can be thereby viewed as a positive right – an entitlement to protective healthcare.

Woven through the International Human and Health Rights literature is the right to be free from surgical disease. The 1966 ICESCR Article 12.2a described the need for “provision for the reduction of the stillbirth-rate and of infant mortality and for the healthy development of the child” which was subsequently interpreted to mean “requiring measures to improve… emergency obstetric services”. Article 12.2d of the ICESCR stipulates the need for “the creation of conditions which would assure to all medical service and medical attention in the event of sickness”, and is interpreted in the 2000 comment to include timely access to “basic preventative, curative services… for appropriate treatment of injury and disability.”. Obstetric care shares close ties with reproductive rights, which includes access to reproductive health.

Surgeons and public health advocates, such as Kelly McQueen, have described surgery as “Integral to the right to health”. This is reflected in the establishment of the WHO Global Initiative for Emergency and Essential Surgical Care in 2005, the 2013 formation of the Lancet Commission for Global Surgery, the 2015 World Bank Publication of Volume 1 of its Disease Control Priorities “Essential Surgery”, and the 2015 World Health Assembly 68.15 passing of the Resolution for Strengthening Emergency and Essential Surgical Care and Anesthesia as a Component of Universal Health Coverage. The Lancet Commission for Global Surgery outlined the need for access to “available, affordable, timely and safe” surgical and anesthesia care; dimensions paralleled in ICESCR General Comment No. 14, which similarly outlines need for available, accessible, affordable and timely healthcare.

History

Plates vi & vii of the Edwin Smith Papyrus, an Egyptian surgical treatise

Trepanation

Surgical treatments date back to the prehistoric era. The oldest for which there is evidence is trepanation, 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.

Ancient Egypt

Prehistoric surgical techniques are seen in 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. Surgical texts from ancient Egypt date back about 3500 years ago. Surgical operations were performed by priests, specialized in medical treatments similar to today, and used sutures to close wounds. Infections were treated with honey.

India

Sushruta, the author of Sushruta Samhita, one of the oldest texts on surgery
 
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. Susruta was an ancient Indian surgeon commonly credited as the author of the treatise Sushruta Samhita. He is dubbed as the "founding father of surgery" and his period is usually placed between the period of 1200–600 BC. One of the earliest known mention of the name is from the Bower Manuscript where Sushruta is listed as one of the ten sages residing in the Himalayas. Texts also suggest that he learned surgery at Kasi from Lord Dhanvantari, the god of medicine in Hindu mythology. It is one of the oldest known surgical texts and it describes in detail the examination, diagnosis, treatment, and prognosis of numerous ailments, as well as procedures on performing various forms of cosmetic surgery, plastic surgery and rhinoplasty.

Ancient Greece

Hippocrates stated in the oath (c. 400 BC) that general physicians must never practice surgery and that surgical procedures are to be conducted by specialists
 
In ancient Greece, temples dedicated to the healer-god Asclepius, known as Asclepieia (Greek: Ασκληπιεία, sing. Asclepieion Ασκληπιείον), functioned as centers of medical advice, prognosis, and healing. In the Asclepieion of Epidaurus, some of the surgical cures listed, such as the opening of an abdominal abscess or the removal of traumatic foreign material, are realistic enough to have taken place. The Greek Galen was one of the greatest surgeons of the ancient world and performed many audacious operations – including brain and eye surgery – that were not tried again for almost two millennia.

Islamic World

Surgery was developed to a high degree in the Islamic world. Abulcasis (Abu al-Qasim Khalaf ibn al-Abbas Al-Zahrawi), an Andalusian-Arab physician and scientist who practiced in the Zahra suburb of Córdoba. His works on surgery, largely based upon Paul of Aegina's Pragmateia, were influential.

Early modern Europe

Ambroise Paré (c. 1510–1590), father of modern military surgery.
 
12th century medieval eye surgery in Italy
 
In Europe, the demand grew for surgeons to formally study for many years before practicing; universities such as Montpellier, Padua and Bologna were particularly renowned. In the 12th century, Rogerius Salernitanus composed his Chirurgia, laying the foundation for modern Western surgical manuals. Barber-surgeons generally had a bad reputation that was not to improve until the development of academic surgery as a specialty of medicine, rather than an accessory field. Basic surgical principles for asepsis etc., are known as Halsteads principles

There were some important advances to the art of surgery during this period. The professor of anatomy at the University of Padua, Andreas Vesalius, was a pivotal figure in the Renaissance transition from classical medicine and anatomy based on the works of Galen, to an empirical approach of 'hands-on' dissection. In his anatomic treatis De humani corporis fabrica, he exposed the many anatomical errors in Galen and advocated that all surgeons should train by engaging in practical dissections themselves. 

The second figure of importance in this era was Ambroise Paré (sometimes spelled "Ambrose"), a French army surgeon from the 1530s until his death in 1590. The practice for cauterizing gunshot wounds on the battlefield had been to use boiling oil; an extremely dangerous and painful procedure. Paré began to employ a less irritating emollient, made of egg yolk, rose oil and turpentine. He also described more efficient techniques for the effective ligation of the blood vessels during an amputation.

Modern surgery

The discipline of surgery was put on a sound, scientific footing during the Age of Enlightenment in Europe. An important figure in this regard was the Scottish surgical scientist, John Hunter, generally regarded as the father of modern scientific surgery. He brought an empirical and experimental approach to the science and was renowned around Europe for the quality of his research and his written works. Hunter reconstructed surgical knowledge from scratch; refusing to rely on the testimonies of others, he conducted his own surgical experiments to determine the truth of the matter. To aid comparative analysis, he built up a collection of over 13,000 specimens of separate organ systems, from the simplest plants and animals to humans. 

He greatly advanced knowledge of venereal disease and introduced many new techniques of surgery, including new methods for repairing damage to the Achilles tendon and a more effective method for applying ligature of the arteries in case of an aneurysm. He was also one of the first to understand the importance of pathology, the danger of the spread of infection and how the problem of inflammation of the wound, bone lesions and even tuberculosis often undid any benefit that was gained from the intervention. He consequently adopted the position that all surgical procedures should be used only as a last resort.

Other important 18th- and early 19th-century surgeons included Percival Pott (1713–1788) who described tuberculosis on the spine and first demonstrated that a cancer may be caused by an environmental carcinogen (he noticed a connection between chimney sweep's exposure to soot and their high incidence of scrotal cancer). Astley Paston Cooper (1768–1841) first performed a successful ligation of the abdominal aorta, and James Syme (1799–1870) pioneered the Symes Amputation for the ankle joint and successfully carried out the first hip disarticulation.

Modern pain control through anesthesia was discovered in the mid-19th century. Before the advent of anesthesia, surgery was a traumatically painful procedure and surgeons were encouraged to be as swift as possible to minimize patient suffering. This also meant that operations were largely restricted to amputations and external growth removals. Beginning in the 1840s, surgery began to change dramatically in character with the discovery of effective and practical anesthetic chemicals such as ether, first used by the American surgeon Crawford Long, and chloroform, discovered by Scottish obstetrician James Young Simpson and later pioneered by John Snow, physician to Queen Victoria. In addition to relieving patient suffering, anesthesia allowed more intricate operations in the internal regions of the human body. In addition, the discovery of muscle relaxants such as curare allowed for safer applications.

Infection and antisepsis

Unfortunately, the introduction of anesthetics encouraged more surgery, which inadvertently caused more dangerous patient post-operative infections. The concept of infection was unknown until relatively modern times. The first progress in combating infection was made in 1847 by the Hungarian doctor Ignaz Semmelweis who noticed that medical students fresh from the dissecting room were causing excess maternal death compared to midwives. Semmelweis, despite ridicule and opposition, introduced compulsory hand washing for everyone entering the maternal wards and was rewarded with a plunge in maternal and fetal deaths; however, the Royal Society dismissed his advice. 

Until the pioneering work of British surgeon Joseph Lister in the 1860s, most medical men believed that chemical damage from exposures to bad air was responsible for infections in wounds, and facilities for washing hands or a patient's wounds were not available. Lister became aware of the work of French chemist Louis Pasteur, who showed that rotting and fermentation could occur under anaerobic conditions if micro-organisms were present. Pasteur suggested three methods to eliminate the micro-organisms responsible for gangrene: filtration, exposure to heat, or exposure to chemical solutions. Lister confirmed Pasteur's conclusions with his own experiments and decided to use his findings to develop antiseptic techniques for wounds. As the first two methods suggested by Pasteur were inappropriate for the treatment of human tissue, Lister experimented with the third, spraying carbolic acid on his instruments. He found that this remarkably reduced the incidence of gangrene and he published his results in The Lancet. Later, on 9 August 1867, he read a paper before the British Medical Association in Dublin, on the Antiseptic Principle of the Practice of Surgery, which was reprinted in The British Medical Journal. His work was groundbreaking and laid the foundations for a rapid advance in infection control that saw modern antiseptic operating theaters widely used within 50 years. 

Lister continued to develop improved methods of antisepsis and asepsis when he realised that infection could be better avoided by preventing bacteria from getting into wounds in the first place. This led to the rise of sterile surgery. Lister introduced the Steam Steriliser to sterilize equipment, instituted rigorous hand washing and later implemented the wearing of rubber gloves. These three crucial advances – the adoption of a scientific methodology toward surgical operations, the use of anesthetic and the introduction of sterilized equipment – laid the groundwork for the modern invasive surgical techniques of today.

The use of X-rays as an important medical diagnostic tool began with their discovery in 1895 by German physicist Wilhelm Röntgen. He noticed that these rays could penetrate the skin, allowing the skeletal structure to be captured on a specially treated photographic plate.

Thursday, February 21, 2019

History of general anesthesia

From Wikipedia, the free encyclopedia

Re-enactment of the first public demonstration of general anesthesia by William T. G. Morton on October 16, 1846 in the Ether Dome at Massachusetts General Hospital, Boston. Surgeons John Collins Warren and Henry Jacob Bigelow are included in this daguerrotype by Southworth & Hawes.
 
The Bulfinch Building, home of the Ether Dome
 
Attempts at producing a state of general anesthesia can be traced throughout recorded history in the writings of the ancient Sumerians, Babylonians, Assyrians, Egyptians, Greeks, Romans, Indians, and Chinese. During the Middle Ages, which correspond roughly to what is sometimes referred to as the Islamic Golden Age, scientists and other scholars made significant advances in science and medicine in the Muslim world and Eastern world

The Renaissance saw significant advances in anatomy and surgical technique. However, despite all this progress, surgery remained a treatment of last resort. Largely because of the associated pain, many patients with surgical disorders chose certain death rather than undergo surgery. Although there has been a great deal of debate as to who deserves the most credit for the discovery of general anesthesia, it is generally agreed that certain scientific discoveries in the late 18th and early 19th centuries were critical to the eventual introduction and development of modern anesthetic techniques.
Two major advances occurred in the late 19th century, which together allowed the transition to modern surgery. An appreciation of the germ theory of disease led rapidly to the development and application of antiseptic techniques in surgery. Antisepsis, which soon gave way to asepsis, reduced the overall morbidity and mortality of surgery to a far more acceptable rate than in previous eras. Concurrent with these developments were the significant advances in pharmacology and physiology which led to the development of general anesthesia and the control of pain.

In the 20th century, the safety and efficacy of general anesthesia was improved by the routine use of tracheal intubation and other advanced airway management techniques. Significant advances in monitoring and new anesthetic agents with improved pharmacokinetic and pharmacodynamic characteristics also contributed to this trend. Standardized training programs for anesthesiologists and nurse anesthetists emerged during this period. The increased application of economic and business administration principles to health care in the late 20th and early 21st centuries led to the introduction of management practices such as transfer pricing to improve the efficiency of anesthetists.

Etymology of "anesthesia"

The word "anesthesia", coined by Oliver Wendell Holmes (1809–1894) in 1846 from the Greek ἀν-, an-, "without"; and αἴσθησις, aisthēsis, "sensation"), refers to the inhibition of sensation.

Antiquity

The first attempts at general anesthesia were probably herbal remedies administered in prehistory. Alcohol is the oldest known sedative; it was used in ancient Mesopotamia thousands of years ago.

Opium

Opium poppy, Papaver somniferum
 
The Sumerians are said to have cultivated and harvested the opium poppy (Papaver somniferum) in lower Mesopotamia as early as 3400 BC, though this has been disputed. The most ancient testimony concerning the opium poppy found to date was inscribed in cuneiform script on a small white clay tablet at the end of the third millennium BC. This tablet was discovered in 1954 during excavations at Nippur, and is currently kept at the University of Pennsylvania Museum of Archaeology and Anthropology. Deciphered by Samuel Noah Kramer and Martin Leve, it is considered to be the most ancient pharmacopoeia in existence. Some Sumerian tablets of this era have an ideogram inscribed upon them, "hul gil", which translates to "plant of joy", believed by some authors to refer to opium. The term gil is still used for opium in certain parts of the world. The Sumerian goddess Nidaba is often depicted with poppies growing out of her shoulders. About 2225 BC, the Sumerian territory became a part of the Babylonian empire. Knowledge and use of the opium poppy and its euphoric effects thus passed to the Babylonians, who expanded their empire eastwards to Persia and westwards to Egypt, thereby extending its range to these civilizations. British archaeologist and cuneiformist Reginald Campbell Thompson writes that opium was known to the Assyrians in the 7th century BC. The term "Arat Pa Pa" occurs in the Assyrian Herbal, a collection of inscribed Assyrian tablets dated to c. 650 BC. According to Thompson, this term is the Assyrian name for the juice of the poppy and it may be the etymological origin of the Latin "papaver".

The ancient Egyptians had some surgical instruments, as well as crude analgesics and sedatives, including possibly an extract prepared from the mandrake fruit. The use of preparations similar to opium in surgery is recorded in the Ebers Papyrus, an Egyptian medical papyrus written in the Eighteenth dynasty. However, it is questionable whether opium itself was known in ancient Egypt. The Greek gods Hypnos (Sleep), Nyx (Night), and Thanatos (Death) were often depicted holding poppies.

Prior to the introduction of opium to ancient India and China, these civilizations pioneered the use of cannabis incense and aconitum. c. 400 BC, the Sushruta Samhita (a text from the Indian subcontinent on ayurvedic medicine and surgery) advocates the use of wine with incense of cannabis for anesthesia. By the 8th century AD, Arab traders had brought opium to India and China.

Classical antiquity

In Classical antiquity, anesthetics were described by:

China

Hua Tuo, Chinese surgeon, c. AD 200
 
Bian Que (Chinese: 扁鵲, Wade–Giles: Pien Ch'iao, c. 300 BC) was a legendary Chinese internist and surgeon who reportedly used general anesthesia for surgical procedures. It is recorded in the Book of Master Han Fei (c. 250 BC), the Records of the Grand Historian (c. 100 BC), and the Book of Master Lie (c. AD 300) that Bian Que gave two men, named "Lu" and "Chao", a toxic drink which rendered them unconscious for three days, during which time he performed a gastrostomy upon them.

Hua Tuo (Chinese:華佗, c. AD 145–220) was a Chinese surgeon of the 2nd century AD. According to the Records of Three Kingdoms (c. AD 270) and the Book of the Later Han (c. AD 430), Hua Tuo performed surgery under general anesthesia using a formula he had developed by mixing wine with a mixture of herbal extracts he called mafeisan (麻沸散). Hua Tuo reportedly used mafeisan to perform even major operations such as resection of gangrenous intestines. Before the surgery, he administered an oral anesthetic potion, probably dissolved in wine, in order to induce a state of unconsciousness and partial neuromuscular blockade.

The exact composition of mafeisan, similar to all of Hua Tuo's clinical knowledge, was lost when he burned his manuscripts, just before his death. The composition of the anesthetic powder was not mentioned in either the Records of Three Kingdoms or the Book of the Later Han. Because Confucian teachings regarded the body as sacred and surgery was considered a form of body mutilation, surgery was strongly discouraged in ancient China. Because of this, despite Hua Tuo's reported success with general anesthesia, the practice of surgery in ancient China ended with his death.

The name mafeisan combines ma (, meaning "cannabis, hemp, numbed or tingling"), fei (, meaning "boiling or bubbling"), and san (, meaning "to break up or scatter", or "medicine in powder form"). Therefore, the word mafeisan probably means something like "cannabis boil powder". Many sinologists and scholars of traditional Chinese medicine have guessed at the composition of Hua Tuo's mafeisan powder, but the exact components still remain unclear. His formula is believed to have contained some combination of:
Others have suggested the potion may have also contained hashish, bhang, shang-luh, or opium. Victor H. Mair wrote that mafei "appears to be a transcription of some Indo-European word related to "morphine"." Some authors believe that Hua Tuo may have discovered surgical analgesia by acupuncture, and that mafeisan either had nothing to do with or was simply an adjunct to his strategy for anesthesia. Many physicians have attempted to re-create the same formulation based on historical records but none have achieved the same clinical efficacy as Hua Tuo's. In any event, Hua Tuo's formula did not appear to be effective for major operations.

Other substances used from antiquity for anesthetic purposes include extracts of juniper and coca.

Middle Ages and Renaissance

Arabic and Persian physicians may have been among the first to utilize oral as well as inhaled anesthetics. Ferdowsi (940–1020) was a Persian poet who lived in the Abbasid Caliphate. In Shahnameh, his national epic poem, Ferdowsi described a caesarean section performed on Rudaba. A special wine prepared by a Zoroastrian priest was used as an anesthetic for this operation. Although Shahnameh is fictional, the passage nevertheless supports the idea that general anesthesia had at least been described in ancient Persia, even if not successfully implemented.

In 1000, Abu al-Qasim al-Zahrawi (936–1013), an Arab physician described as the father of surgery. who lived in Al-Andalus, published the 30-volume Kitab al-Tasrif, the first illustrated work on surgery. In this book, he wrote about the use of general anesthesia for surgery. c. 1020, Ibn Sīnā (980–1037) described the use of inhaled anesthesia in The Canon of Medicine. The Canon described the "soporific sponge", a sponge imbued with aromatics and narcotics, which was to be placed under a patient's nose during surgical operations. Ibn Zuhr (1091–1161) was another Arab physician from Al-Andalus. In his 12th century medical textbook Al-Taisir, Ibn Zuhr describes the use of general anesthesia. These three physicians were among many who performed operations under inhaled anesthesia with the use of narcotic-soaked sponges. Opium made its way from Asia Minor to all parts of Europe between the 10th and 13th centuries.

Throughout 1200–1500 A.D. in England, a potion called dwale was used as an anesthetic. This alcohol-based mixture contained bile, opium, lettuce, bryony, henbane, hemlock and vinegar. Surgeons roused them by rubbing vinegar and salt on their cheekbones. One can find records of dwale in numerous literary sources, including Shakespeare's Hamlet, and the John Keats poem "Ode to a Nightingale". In the 13th century, we have the first prescription of the "spongia soporifica"—a sponge soaked in the juices of unripe mulberry, flax, mandragora leaves, ivy, lettuce seeds, lapathum, and hemlock with hyoscyamus. After treatment and/or storage, the sponge could be heated and the vapors inhaled with anasthetic effect.

Alchemist Ramon Llull has been credited with discovering diethyl ether in 1275. Aureolus Theophrastus Bombastus von Hohenheim (1493–1541), better known as Paracelsus, discovered the analgesic properties of diethyl ether around 1525. It was first synthesized in 1540 by Valerius Cordus, who noted some of its medicinal properties. He called it oleum dulce vitrioli, a name that reflects the fact that it is synthesized by distilling a mixture of ethanol and sulfuric acid (known at that time as oil of vitriol). August Sigmund Frobenius gave the name Spiritus Vini Æthereus to the substance in 1730.

18th century

Satirical cartoon by James Gillray showing a Royal Institution lecture, with Humphry Davy holding the bellows and Count Rumford looking on at extreme right.
 
Joseph Priestley (1733–1804) was an English polymath who discovered nitrous oxide, nitric oxide, ammonia, hydrogen chloride and (along with Carl Wilhelm Scheele and Antoine Lavoisier) oxygen. Beginning in 1775, Priestley published his research in Experiments and Observations on Different Kinds of Air, a six-volume work. The recent discoveries about these and other gases stimulated a great deal of interest in the European scientific community. Thomas Beddoes (1760–1808) was an English philosopher, physician and teacher of medicine, and like his older colleague Priestley, was also a member of the Lunar Society of Birmingham. With an eye toward making further advances in this new science as well as offering treatment for diseases previously thought to be untreatable (such as asthma and tuberculosis), Beddoes founded the Pneumatic Institution for inhalation gas therapy in 1798 at Dowry Square in Clifton, Bristol. Beddoes employed chemist and physicist Humphry Davy (1778–1829) as superintendent of the institute, and engineer James Watt (1736–1819) to help manufacture the gases. Other members of the Lunar Society such as Erasmus Darwin and Josiah Wedgwood were also actively involved with the institute.

During the course of his research at the Pneumatic Institution, Davy discovered the anesthetic properties of nitrous oxide. Davy, who coined the term "laughing gas" for nitrous oxide, published his findings the following year in the now-classic treatise, Researches, chemical and philosophical–chiefly concerning nitrous oxide or dephlogisticated nitrous air, and its respiration. Davy was not a physician, and he never administered nitrous oxide during a surgical procedure. He was, however, the first to document the analgesic effects of nitrous oxide, as well as its potential benefits in relieving pain during surgery:
As nitrous oxide in its extensive operation appears capable of destroying physical pain, it may probably be used with advantage during surgical operations in which no great effusion of blood takes place.

19th century

Eastern hemisphere

Takamine Tokumei from Shuri, Ryūkyū Kingdom, is reported to have made a general anesthesia in 1689 in the Ryukyus, now known as Okinawa. He passed on his knowledge to the Satsuma doctors in 1690 and to Ryūkyūan doctors in 1714.

Hanaoka Seishū, a Japanese surgeon of the 18th and 19th centuries
 
Hanaoka Seishū (華岡 青洲, 1760–1835) of Osaka was a Japanese surgeon of the Edo period with a knowledge of Chinese herbal medicine, as well as Western surgical techniques he had learned through Rangaku (literally "Dutch learning", and by extension "Western learning"). Beginning in about 1785, Hanaoka embarked on a quest to re-create a compound that would have pharmacologic properties similar to Hua Tuo's mafeisan. After years of research and experimentation, he finally developed a formula which he named tsūsensan (also known as mafutsu-san). Like that of Hua Tuo, this compound was composed of extracts of several different plants, including:
  • 2 parts bai zhi (Chinese:白芷Angelica dahurica);
  • 2 parts cao wu (Chinese:草烏Aconitum sp., monkshood or wolfsbane);
  • 2 parts chuān ban xia (Pinellia ternata);
  • 2 parts chuān xiōng (Ligusticum wallichii, Cnidium rhizome, Cnidium officinale or Szechuan lovage);
  • 2 parts dong quai (Angelica sinensis or female ginseng);
  • 1 part tian nan xing (Arisaema rhizomatum or cobra lily)
  • 8 parts yang jin hua (Datura stramonium, Korean morning glory, thorn apple, jimson weed, devil's trumpet, stinkweed, or locoweed).
The reader will note that five of these seven ingredients were thought to be elements of Hua Tuo's anesthetic potion, 1600 years earlier. Some sources claim that Angelica archangelica (often referred to as garden angelica, holy ghost, or wild celery) was also an ingredient.

The active ingredients in tsūsensan are scopolamine, hyoscyamine, atropine, aconitine and angelicotoxin. When consumed in sufficient quantity, tsūsensan produces a state of general anesthesia and skeletal muscle paralysis. Shutei Nakagawa (1773–1850), a close friend of Hanaoka, wrote a small pamphlet titled "Mayaku-ko" ("narcotic powder") in 1796. Although the original manuscript was lost in a fire in 1867, this brochure described the current state of Hanaoka's research on general anesthesia.

On 13 October 1804, Hanaoka performed a partial mastectomy for breast cancer on a 60-year-old woman named Kan Aiya, using tsūsensan as a general anesthetic. This is generally regarded today as the first reliable documentation of an operation to be performed under general anesthesia. Hanaoka went on to perform many operations using tsūsensan, including resection of malignant tumors, extraction of bladder stones, and extremity amputations. Before his death in 1835, Hanaoka performed more than 150 operations for breast cancer.

Western hemisphere

Gardner Quincy Colton, 19th-century American dentist
 
Horace Wells, 19th-century American dentist
 
Crawford W. Long, 19th-century American physician
 
William T. G. Morton, 19th-century American dentist
 
Friedrich Sertürner (1783–1841) first isolated morphine from opium in 1804; he named it morphine after Morpheus, the Greek god of dreams.

Henry Hill Hickman (1800–1830) experimented with the use of carbon dioxide as an anesthetic in the 1820s. He would make the animal insensible, effectively via almost suffocating it with carbon dioxide, then determine the effects of the gas by amputating one of its limbs. In 1824, Hickman submitted the results of his research to the Royal Society in a short treatise titled Letter on suspended animation: with the view of ascertaining its probable utility in surgical operations on human subjects. The response was an 1826 article in The Lancet titled "Surgical Humbug" that ruthlessly criticized his work. Hickman died four years later at age 30. Though he was unappreciated at the time of his death, his work has since been positively reappraised and he is now recognized as one of the fathers of anesthesia.

By the late 1830s, Humphry Davy's experiments had become widely publicized within academic circles in the northeastern United States. Wandering lecturers would hold public gatherings, referred to as "ether frolics", where members of the audience were encouraged to inhale diethyl ether or nitrous oxide to demonstrate the mind-altering properties of these agents while providing much entertainment to onlookers. Four notable men participated in these events and witnessed the use of ether in this manner. They were William Edward Clarke (1819–1898), Crawford W. Long (1815–1878), Horace Wells (1815–1848), and William T. G. Morton (1819–1868).

While attending undergraduate school in Rochester, New York, in 1839, classmates Clarke and Morton apparently participated in ether frolics with some regularity. In January 1842, by now a medical student at Berkshire Medical College, Clarke administered ether to a Miss Hobbie, while Elijah Pope performed a dental extraction. In so doing, he became the first to administer an inhaled anesthetic to facilitate the performance of a surgical procedure. Clarke apparently thought little of his accomplishment, and chose neither to publish nor to pursue this technique any further. Indeed, this event is not even mentioned in Clarke's biography.

Crawford W. Long was a physician and pharmacist practicing in Jefferson, Georgia in the mid-19th century. During his time as a student at the University of Pennsylvania School of Medicine in the late 1830s, he had observed and probably participated in the ether frolics that had become popular at that time. At these gatherings, Long observed that some participants experienced bumps and bruises, but afterward had no recall of what had happened. He postulated that diethyl ether produced pharmacologic effects similar to those of nitrous oxide. On 30 March 1842, he administered diethyl ether by inhalation to a man named James Venable, in order to remove a tumor from the man's neck. Long later removed a second tumor from Venable, again under ether anesthesia. He went on to employ ether as a general anesthetic for limb amputations and parturition. Long, however, did not publish his experience until 1849, thereby denying himself much of the credit he deserved.

On 10 December 1844, Gardner Quincy Colton held a public demonstration of nitrous oxide in Hartford, Connecticut. One of the participants, Samuel A. Cooley, sustained a significant injury to his leg while under the influence of nitrous oxide without noticing the injury. Horace Wells, a Connecticut dentist present in the audience that day, immediately seized upon the significance of this apparent analgesic effect of nitrous oxide. The following day, Wells underwent a painless dental extraction while under the influence of nitrous oxide administered by Colton. Wells then began to administer nitrous oxide to his patients, successfully performing several dental extractions over the next couple of weeks.

William T. G. Morton, another New England dentist, was a former student and then-current business partner of Wells. He was also a former acquaintance and classmate of William Edward Clarke (the two had attended undergraduate school together in Rochester, New York). Morton arranged for Wells to demonstrate his technique for dental extraction under nitrous oxide general anesthesia at Massachusetts General Hospital, in conjunction with the prominent surgeon John Collins Warren. This demonstration, which took place on 20 January 1845, ended in failure when the patient cried out in pain in the middle of the operation.

On 30 September 1846, Morton administered diethyl ether to Eben Frost, a music teacher from Boston, for a dental extraction. Two weeks later, Morton became the first to publicly demonstrate the use of diethyl ether as a general anesthetic at Massachusetts General Hospital, in what is known today as the Ether Dome. On 16 October 1846, John Collins Warren removed a tumor from the neck of a local printer, Edward Gilbert Abbott. Upon completion of the procedure, Warren reportedly quipped, "Gentlemen, this is no humbug." News of this event rapidly traveled around the world. Robert Liston performed the first amputation in December of that year. Morton published his experience soon after. Harvard University professor Charles Thomas Jackson (1805–1880) later claimed that Morton stole his idea; Morton disagreed and a lifelong dispute began. For many years, Morton was credited as being the pioneer of general anesthesia in the Western hemisphere, despite the fact that his demonstration occurred four years after Long's initial experience. Long later petitioned William Crosby Dawson (1798–1856), a United States Senator from Georgia at that time, to support his claim on the floor of the United States Senate as the first to use ether anesthesia.

In 1847, Scottish obstetrician James Young Simpson (1811–1870) of Edinburgh was the first to use chloroform as a general anesthetic on a human (Robert Mortimer Glover had written on this possibility in 1842 but only used it on dogs). The use of chloroform anesthesia expanded rapidly thereafter in Europe. Chloroform began to replace ether as an anesthetic in the United States at the beginning of the 20th century. It was soon abandoned in favor of ether when its hepatic and cardiac toxicity, especially its tendency to cause potentially fatal cardiac dysrhythmias, became apparent.

In 1871, the German surgeon Friedrich Trendelenburg (1844–1924) published a paper describing the first successful elective human tracheotomy to be performed for the purpose of administration of general anesthesia.

In 1880, the Scottish surgeon William Macewen (1848–1924) reported on his use of orotracheal intubation as an alternative to tracheotomy to allow a patient with glottic edema to breathe, as well as in the setting of general anesthesia with chloroform. All previous observations of the glottis and larynx (including those of Manuel García, Wilhelm Hack and Macewen) had been performed under indirect vision (using mirrors) until 23 April 1895, when Alfred Kirstein (1863–1922) of Germany first described direct visualization of the vocal cords. Kirstein performed the first direct laryngoscopy in Berlin, using an esophagoscope he had modified for this purpose; he called this device an autoscope. The death of Emperor Frederick III (1831–1888) may have motivated Kirstein to develop the autoscope.

20th century

The 20th century saw the transformation of the practices of tracheotomy, endoscopy and non-surgical tracheal intubation from rarely employed procedures to essential components of the practices of anesthesia, critical care medicine, emergency medicine, gastroenterology, pulmonology and surgery.

In 1902, Hermann Emil Fischer (1852–1919) and Joseph von Mering (1849–1908) discovered that diethylbarbituric acid was an effective hypnotic agent. Also called barbital or Veronal (the trade name assigned to it by Bayer Pharmaceuticals), this new drug became the first commercially marketed barbiturate; it was used as a treatment for insomnia from 1903 until the mid-1950s.

Until 1913, oral and maxillofacial surgery was performed by mask inhalation anesthesia, topical application of local anesthetics to the mucosa, rectal anesthesia, or intravenous anesthesia. While otherwise effective, these techniques did not protect the airway from obstruction and also exposed patients to the risk of pulmonary aspiration of blood and mucus into the tracheobronchial tree. In 1913, Chevalier Jackson (1865–1958) was the first to report a high rate of success for the use of direct laryngoscopy as a means to intubate the trachea. Jackson introduced a new laryngoscope blade that had a light source at the distal tip, rather than the proximal light source used by Kirstein. This new blade incorporated a component that the operator could slide out to allow room for passage of an endotracheal tube or bronchoscope.

Also in 1913, Henry H. Janeway (1873–1921) published results he had achieved using a laryngoscope he had recently developed. An American anesthesiologist practicing at Bellevue Hospital in New York City, Janeway was of the opinion that direct intratracheal insufflation of volatile anesthetics would provide improved conditions for otolaryngologic surgery. With this in mind, he developed a laryngoscope designed for the sole purpose of tracheal intubation. Similar to Jackson's device, Janeway's instrument incorporated a distal light source. Unique, however, was the inclusion of batteries within the handle, a central notch in the blade for maintaining the tracheal tube in the midline of the oropharynx during intubation and a slight curve to the distal tip of the blade to help guide the tube through the glottis. The success of this design led to its subsequent use in other types of surgery. Janeway was thus instrumental in popularizing the widespread use of direct laryngoscopy and tracheal intubation in the practice of anesthesiology.

Sodium thiopental, the first intravenous anesthetic, was synthesized in 1934 by Ernest H. Volwiler (1893–1992) and Donalee L. Tabern (1900–1974), working for Abbott Laboratories. It was first used in humans on 8 March 1934 by Ralph M. Waters in an investigation of its properties, which were short-term anesthesia and surprisingly little analgesia. Three months later, John Silas Lundy started a clinical trial of thiopental at the Mayo Clinic at the request of Abbott Laboratories. Volwiler and Tabern were awarded U.S. Patent No. 2,153,729 in 1939 for the discovery of thiopental, and they were inducted into the National Inventors Hall of Fame in 1986. 

In 1939, the search for a synthetic substitute for atropine culminated serendipitously in the discovery of meperidine, the first opiate with a structure altogether different from that of morphine. This was followed in 1947 by the widespread introduction of methadone, another structurally unrelated compound with pharmacological properties similar to those of morphine.

After World War I, further advances were made in the field of intratracheal anesthesia. Among these were those made by Sir Ivan Whiteside Magill (1888–1986). Working at the Queen's Hospital for Facial and Jaw Injuries in Sidcup with plastic surgeon Sir Harold Gillies (1882–1960) and anesthetist E. Stanley Rowbotham (1890–1979), Magill developed the technique of awake blind nasotracheal intubation. Magill devised a new type of angulated forceps (the Magill forceps) that are still used today to facilitate nasotracheal intubation in a manner that is little changed from Magill's original technique. Other devices invented by Magill include the Magill laryngoscope blade, as well as several apparatuses for the administration of volatile anesthetic agents. The Magill curve of an endotracheal tube is also named for Magill. 

The first hospital anesthesia department was established at the Massachusetts General Hospital in 1936, under the leadership of Henry K. Beecher (1904–1976). Beecher, who received his training in surgery, had no previous experience in anesthesia.

Sir Robert Reynolds Macintosh (1897–1989) achieved significant advances in techniques for tracheal intubation when he introduced his new curved laryngoscope blade in 1943. The Macintosh blade remains to this day the most widely used laryngoscope blade for orotracheal intubation. In 1949, Macintosh published a case report describing the novel use of a gum elastic urinary catheter as an endotracheal tube introducer to facilitate difficult tracheal intubation. Inspired by Macintosh's report, P. Hex Venn (who was at that time the anesthetic advisor to the British firm Eschmann Bros. & Walsh, Ltd.) set about developing an endotracheal tube introducer based on this concept. Venn's design was accepted in March 1973, and what became known as the Eschmann endotracheal tube introducer went into production later that year. The material of Venn's design was different from that of a gum elastic bougie in that it had two layers: a core of tube woven from polyester threads and an outer resin layer. This provided more stiffness but maintained the flexibility and the slippery surface. Other differences were the length (the new introducer was 60 cm (24 in), which is much longer than the gum elastic bougie) and the presence of a 35° curved tip, permitting it to be steered around obstacles.

Many new intravenous and inhalational anesthetics were developed and brought into clinical use during the second half of the 20th century. Paul Janssen (1926–2003), the founder of Janssen Pharmaceutica, is credited with the development of over 80 pharmaceutical compounds. Janssen synthesized nearly all of the butyrophenone class of antipsychotic agents, beginning with haloperidol (1958) and droperidol (1961). These agents were rapidly integrated into the practice of anesthesia. In 1960, Janssen's team synthesized fentanyl, the first of the piperidinone-derived opioids. Fentanyl was followed by sufentanil (1974), alfentanil (1976), carfentanil (1976), and lofentanil (1980). Janssen and his team also developed etomidate (1964), a potent intravenous anesthetic induction agent.

The concept of using a fiberoptic endoscope for tracheal intubation was introduced by Peter Murphy, an English anesthetist, in 1967. By the mid-1980s, the flexible fiberoptic bronchoscope had become an indispensable instrument within the pulmonology and anesthesia communities.

21st century

A modern anaesthetic machine. This particular machine is a "Flow-I" model, manufactured by Maquet.
 
The "digital revolution" of the 21st century has brought newer technology to the art and science of tracheal intubation. Several manufacturers have developed video laryngoscopes which employ digital technology such as the complementary metal–oxide semiconductor active pixel sensor (CMOS APS) to generate a view of the glottis so that the trachea may be intubated. The Glidescope video laryngoscope is one example of such a device.

Xenon has recently been approved in some jurisdictions as an anaesthetic agent which does not act as a greenhouse gas.

Algorithmic information theory

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