General anesthesia is a state of controlled unconsciousness during which patient doesn't feel anything and may be described as 'anesthetized'. During general anesthesia, anesthetic medications are injected into a vein, or anesthetic gases may be breathed into the lungs. When these medications are carried to the brain by the blood, they effectively "numb" the brain, and produce unconsciousness.
Regional anesthesia is the specialized use of local anesthetic to numb a part of the body. Regional anesthesia can be used for operations on larger or deeper parts of the body. Local anesthetic drugs are injected near to the bundles of nerves which carry signals from that area of the body to the brain. The most common regional anesthetics (also known as regional 'blocks') are spinal and epidural anesthetics. These can be used for operations on the lower body.
Use of anesthesia has been recorded since prehistory,where Opium poppy capsules were used in Sumeria and succeeding empires. Simple apparatus for smoking of opium were used for adminstration of anesthesia. Contries like India and China initially used cannabis incense and aconitum. As per the Book of Later Han, the physician Hua Tuo performed abdominal surgery using an anesthetic substance called mafeisan, which literally means cannabis boil powder, dissolved in wine. Other variants like Solanum species containing potent tropane alkaloids , Coca and Alcohol were also used in these initial days.
The use of above herbal anaesthesia had a crucial drawback compared to modern practice in context of standardisation, as described on Wikepedia by Fallopus that "when soporifics are weak they are useless, and when strong, they kill". This drawback was tried to overcome by, standardizing production as much as possible, with taking 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.
Later, use of gases and vapours was also notice during mid 1800. Henry Hill Hickman experimented with carbon dioxide in the 1820s. British chemist Humphry Davy in 1799 used nitrous oxide .Effective general anessthesia for surgery begin in 1846, when a dentist, William Thomas Green Morton, gave diethyl ether at Massachusetts General Hospital, in the first public demonstration of diethyl ether as an anesthetic agent. It was then, Oliver Wendell Holmes, Sr. proposed naming the procedure ansthesia.Anesthesia gained good public repute when Queen Victoria accepted chloroform a la reine from Dr. John Snow during the birth of prince Leopold in 1857.
Local anaesthesia originated with the