Anesthetics Anesthesia is a partial or complete loss of sensation or feeling induced by the administration of various substances. For many decade, people have used one form of an anesthetic during surgical procedures. Some people also use some of these anesthetics as recreational drugs, e.g. laughing gas (a.k.a. Nitrous Oxide).
The term anesthetic literally means “without feeling”. There are many different types of anesthesia, but they are usually put into three groups. These groups are gene- ral anesthetics, local anesthetics, and spinal anesthetics. A general anesthetic causes a complete loss of consciousness. They are used when having a serious operation or in the case of an emergency operation. It works to the surgeon’s advantage because the anesthesia reacts with the body in a matter of seconds.
There are two different ways in which general anesthetics are administered, they are intravenous and inhalation. The most popular procedure is intravenous. This is where the anesthetic is put into the body by way of a needle in the vein, which is usually located in the hand or elbow. Although intravenous is more popular, it is usually used by itself during short procedures. In the case of longer procedures, intravenous anesthesia is also accompanied by inhalation anesthesia. Inhalation anesthesia is administered by way of a mask and in the form of gas.
Usually during long procedures, the mask will remain on while the fluids from the intravenous anesthesia work through your body. The second group of anesthesia is local anesthesia. Local anesthesia is used when a doctor wants to numb a certain part of the body while you maintain total consciousness. Local anesthetics are usually administered through a gel or cream on the surface of the skin, but can also be injected underneath the skin, e.g. lidocane.
If the anesthetic is placed on the surface of the skin than the numbing effect should take place within a few seconds. If injected underneath the skin, it can take up to a few minutes to take effect. Both forms of local anesthesia are used when dealing with minor surgery such as dentistry, etc. The third and last group of anesthetics is the topical group. This group is associated with childbirth, gynecological procedures, and spinal operations.
A spinal injection gives relief to pain, but at the same time allows for total consciousness. Usually the syringe is injected into the epidural layer of the spine. The effects of the spinal injection can be felt within minutes of the injection. As I have already discussed, there are three different methods of distribution among anesthetics, inhalant, intravenous, and infusion. An inhalant is an anesthetic in the form of a gas which is administered by way of a gas mask.
Intravenous anesthesia is administered by way of a needle into the vein. Infusion anesthetics are administered by way of a catheter. These three methods operate in four steps. The first of these steps is premedication or induction stage. This step involves the nurse or practitioner to administer a form of a sedative or muscle relaxant.
This step is not always required, only when having major surgery. The second stage is when the actual anesthesia is administered. The patient falls into a deep, pleasant state of unconsciousness. The third stage is when the drug is in full effect. The patient now experiences a loss of consciousness, although the patients reflexes still remain active and breathing is a little irregular. In the last stage, the fourth stage, the patient is totally unconscious.
Muscels are fully relaxed and breathing becomes regular and quiet. Anesthesia has a long history which started in the middle 1700’s. In 1769, an English chemist, Joseph Priestley discovered the first recognized anesthetic, nitrous oxide. Nitrous oxide is more commonly known as laughing gas. Although the gas was discovered in 1769, it wasn’t until 1844 when an American dentist by the name of Horace Wells, first put the nitrous oxide to use during a dentistry procedure.
The wonderful world of anesthesia was growing and becoming more and more popular throughout the United States as well as in England. The next important discovery took place in 1829. In 1829, an American, Micheal Faraday reported that the inhalation of ether caused a person to go into a state of unconsciousness. Using ether as an anesthetic was not very popular, though. It was first used in 1842 when, an American doctor, Crawford W. Long removed a tumor off of the neck of one of his patients.
The second recorded use of ether was by the American dentist, Thomas Green Morton in 1846. Morton along with the help of Charles Thomas Jackson, an American chemist, devel- oped a technique for painless tooth extraction with the assistance of diethyl ether. In 1831, an American physician and chemist, Samuel Guthrie was the first to discover chloroform and its uses. The first to use chloroform during a surgical procedure was Sir James Y. Simpson.
Simpson was a Scottish obstetrician whom was not satisfied with the action and reaction of ether. Simpson was the first to adopt chloroform as a useful anesthetic in surgical procedures. In 1884, Sigmund Freud was the first to report cocaine’s anesthetic properties. An Austrailian physician, Karl Koller, took this report of cocaine as an anesthetic and applied it to surgical procedures. Koller’s surgical procedure was even more important because it was the first procedure to take place while using what we now call “local anesthesia”.
Cocaine was the first local anesthesia to be discovered and used in a surgical procedure. William Stewart Halsted, a profesor of surgery at John Hopkins University in Baltimore, was the first to use cocaine to anesthetize whole areas of the body by directly injecting the cocaine into the nerve. In 1898, Karl Gustav Bier injected cocaine into vertebral canal and obtained paralysis of the lower extremities of the body. He used this method in surgical procedures. Since then this procedure that he discovered is know as spinal anesthesia and is widely used today.
At around 1901, J.L. Corning used cocaine to produce a useful spinal anesthetic, which in turn produced two important cocaine derivatives, novocaine and procaine. Many other important analgesics and their uses came about between 1800 to 1900. Ethyl chloride which was introduced to us in 1848, was too short lived. Surgeons needed an anesth- etic that was non-toxic and non-inflammable. So in 1929, cyclopropane was introduced to the medical world, but soon enough the medical world found out that the drug was inflammable. In 1934, trichloreth- ylene was first used.
This drug on the other hand came along with two advantages. It reduced the awareness of pain while maintaining full consciousness, which made the drug ideal for childbirth use. In 1874, Ore of Bordeaux, was the first to achieve an intravenous anesthesia. He used Chloral to achieve this intravenous anesthesia. In 1902, Emil Fischer performed a synthesis of Veronal.
The synthesis caused the use of intravenous anesthesia to be widely excepted and performed. After Veronal many other analgesics were produced and discovered. After 1945, two specific drugs came into use with anesthesia. These two drugs are curare and succinylcholine. Both of these drugs are used in anesthetics as a muscle relaxer. Curare prevents the nervous impulses fromreaching the muscels. Thus blocking the it at the neuromuscular junction where the nerve transmitter substance, acetylcholine, is stored.
The curare that is used in anesthesia is refered to as tubocurarine. Succinylcholine is used to neutralize the action of acetylcholine in the neuromuscular junction. These anesthetics and their derivatives are still used today. Another form of anesthetic used on the body is hypothermia. This is where the body temperature is lowered by about ten degrees. Hypothermia is achieved by cooling the patient with ice, wet sheets, and fans. Although this helps in cooling the body it does not stop the body’s natural responses to the cold. These responses are centered around the part of the brain called the hypothalamus.
Some of these responses are shivering, etc. The body has these responses because it is trying to keep the body’s heart, temperature, and blood pumping at a constant rate. In order to stop these responses doctors use a drug called chlorpromazine or they use promethazine, which also has a tranquilizing effect. This whole process is used because it lowers the amount of oxygen consumed by the tissues in the body. This also causes vital organs in the body to consume a lower amount of oxygen. The less oxygen the smaller amount of blood that is rushed to the brain and other vital organs within the body during surgery.
In turn the brain and other vital organs will still function just at a slower pace. This is an advantage to brain and heart surgery because these operations require more time and this allows for it without causing permanent damage to the body. There are many different effects of anesthesia on the body. There can be a dramatic drop or rise in blood pressure. A person’s blood pressure may also drop or rise if the patient goes into shock or has lost too much blood. Some anesthetics cause nausea and sickness. A rare reaction that sometimes occurs when administered general anesthesia is juandice. Doctors try to choose an anesthetic that induces unconsciousness rapidly and has the least …