Before a person has an operation in hospital, he is given a drug or gas known as an anesthetic. This is to make him unconscious of pain while the operation is going on. It also makes the doctor's work much easier, as the patient is not struggling and frightened.
This state of unconsciousness is known as anesthesia from a Greek word meaning "loss of feeling". The discovery of anesthetics was one of the greatest in medicine and has prevented much suffering.
There are several methods of anesthesia: general, spinal, regional and local. A general anesthetic, which puts the patient to sleep, is given for all large operations. A spinal anesthetic is injected into the spinal canal and abolishes sensation in the lower part of the body. A regional or local anesthetic takes away the sensation of pain only in the part of the body that is operated on.
Before the middle of the 19th century, people who had to undergo an operation were given a lot of wine, or drugs made from plant juices, but the operation was always a very painful process. The discovery of anesthetics was the work of several people. In 1799 Sir Humphry Davy found that after breathing in nitrous oxide he became unconscious and had strange dreams. People who have been given this gas may laugh and behave as though they were drunk; for this reason it is often called laughing gas. Davy's pupil, Michael Faraday, suggested later that the liquid ether might be used to stop pain. It was not, however, used as an anesthetic until 1842, when Crawford W. Long, an American doctor, performed the first operation on a patient who had been made unconscious by breathing ether. Two years later another American, Horace Wells, used nitrous oxide when he was having a tooth removed.
In 1846 it began to be the custom of doctors and dentists in both Britain and America to use anesthetics for their operations.
The next step was when Sir James Young Simpson, a Scottish doctor, used ether to prevent pain in childbirth, but in 1847 he discovered that chloroform vapor is also an effective anesthetic. However, many people made an outcry against giving chloroform in childbirth, declaring that it was against religious teaching, for the Bible says "In sorrow thou shalt bring forth children". Then in 1853 Queen Victoria agreed to have an anesthetic at the birth of her son Prince Leopold and after this its use became more general. Later it was found that chloroform was sometimes dangerous, and it is therefore no longer used. Today nitrous oxide gas (with air or oxygen) and other anesthetic gases are also used to relieve pain in childbirth.
How Anesthetics are given
The person who has the special job of giving a patient an anesthetic is called the anesthetist. Before an important operation a patient has an injection to make him sleepy. Then, in a special anesthetic room, he is usually given an injection into a vein in the arm, which puts him to sleep. Afterwards the anesthetist puts a mask on the patient's face and through this he breathes in the anesthetic, which is kept in special containers. The anesthetic gas, which is usually nitrous oxide, cyclopropane or halothane, would kill the patient if it were used by itself for long, so oxygen has to given at the same time. It is also possible, during difficult operations, to relax all the muscles in the body by paralyzing them with drugs. While the body is paralyzed in this way, a machine (or the anesthetist) must do the work of the muscles which control breathing until the drugs' effects are reversed. For spinal anesthetics, special solutions are injected into the spinal canal of the backbone.
Local anesthetics are injected. Procaine and a chemical related to it are the ones most often used today. Such anesthetics can also be injected into a nerve to cut off all pain sensation in a limited region. Local anesthetics are often used in dentistry for the extraction of teeth and other treatment that would otherwise be painful.