User:Wyglif/Project


 * Good afternoon ladies and gentlemen.


 * The topic which I'd like to get to close with today is anesthesia, particularly the history of anesthesia. In this presentation i'm not going to concentrate on present forms of anesthesia. Instead I'm going topresent all forms of analgesics, anasthetics and so forth which were in use throughout history.


 * In opposition to my statement not to stick to very issiues of todays anesthesia, i'm obliged to describe at least meaning of the word anesthesia.

Anesthesia or anaesthesia (see spelling differences) has traditionally meant the process of blocking the perception of pain and other sensations. This allows patients to undergo surgery and other procedures without the distress and pain they would otherwise experience. It comes from the Greek roots an-, "not, without" and aesthētos, "perceptible, able to feel". The word was coined by Oliver Wendell Holmes, Sr. in 1846.

Today, the term  general anesthesia in its most general form can include:
 * Analgesia - blocking the conscious perception of pain
 * Hypnosis - producing unconsciousness
 * Amnesia - preventing memory formation
 * Relaxation - preventing unwanted movement or muscle tone
 * Homeostasis - preserving normal body functioning (e.g., maintaining blood pressure within normal physiological range)

Types
There are several forms of anaesthesia: - general anaesthesia &mdash; with reversible loss of consciousness and memory of unpleasant events - local anaesthesia &mdash; with reversible loss of sensation in a part of the body by localised administration of anaesthetic drugs at the affected site.

The administration of drugs to make a patient more comfortable or less anxious, but without inducing anaesthesia, is called sedation.


 * Let's now get to the heart of the matter.

Anesthesia was used as early back as the classical age. There are some references to anesthesia in ancient mythoology. In the East, in the 10th century work Shahnama, the author describes a Caesarean section performed on Rudaba, a mythological figure when giving birth, in which a special wine agent was prepared by a local 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.

Turning to non-mythological methods, Hypnotism and acupuncture have a long history of use as anaesthetic techniques. In China, Taoist medical practitioners developed anaesthesia by means of acupuncture. Chilling tissue (e.g. with ice) can temporarily cause nerve fibres (axons) to stop conducting sensation, while hyperventilation can cause brief alteration in conscious perception of stimuli including pain. In modern anaesthetic practice however, these techniques are seldom employed.

When it comes to herbal forms of anesthesia, The first herbal anaesthesia was administered in prehistory. Opium and Cannabis were two of the most important herbs used. They were ingested or burned and the smoke inhaled. Alcohol was also used, its vasodilatory properties being unknown. In early America preparations from datura and coca gave an effective anaesthetic -e scopolamine. In Medieval Europe various preparations of mandrake were tried as well as henbane, from which hyoscyamine was produced.

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

Along with time, more discoveries were made. In the West, the development of effective anaesthetics in the 19th century was, with techniques of Joseph Lister, one of the keys to successful surgery. Henry Hill Hickman experimented with carbon dioxide in the 1820s. The anaesthetic qualities of nitrous oxide (isolated by Joseph Priestley) were discovered by the British chemist Humphry Davy about 1795 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. The dentist was one of the first to use it in his practice. It was used in December 1844 for painless tooth extraction by American dentist Horace Wells. Demonstrating it the following year, at Massachusetts General Hospital, he made a mistake and the patient suffered considerable pain. This lost Wells any support.
 * As you can see, there were numerous attempts to ease the potential pain of a patient. Not all of them actually worked, and some of them may have even made things worse. The unquestionable advantage if them was progress in searching "the perfect anasthetic and analgesic".

Another dentist, William E. Clarke, performed an extraction in January 1842 using a different chemical, diethyl ether (discovered in 1540). In March 1842 in Danielsville, Georgia, Dr. Crawford Williamson Long was the first to use anaesthesia during an operation, giving it to a boy 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 undergoing an excision of a tumour from his neck. In a letter to Morton shortly thereafter, Oliver Wendell Holmes, Sr. proposed naming the procedure anæsthesia.

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.

Ether has a number of drawbacks, like its tendency to induce vomiting and its flammability. In England it was quickly replaced with chloroform. Discovered in 1831, its use in anaesthesia is usually linked to James Young Simpson, who, in a wide-ranging study of organic compounds, found chloroform's efficacy in 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, Duke of Albany. 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 anaesthetics at this time). This led to many deaths from the use of chloroform which (with hindsight) might have been preventable. The surgical amphitheater at Massachusetts General Hospital, or "ether dome" still exists today, although it is used for lectures and not surgery.


 * That's all about historical anesthesia I was going to say. Don't underestimate all the efforts of these people, who struggled on finding a remedy to serve patients better.


 * Join me on my next lecture, when I'm going to cover the topic of present-day anesthesiology, a branch of medicine dealing with the the all the issues mentioned today. See you then!