Inhalation anesthetics (also known as volatile anesthetics) are those that enter the body through inhalation into the lungs. After inhalation of anesthesia are distributed throughout the tissues of the body via the bloodstream. In most cases, the brain is the principle target when inhalation anesthetics are administered.
History of inhalation
Inhaled anesthetics used in the first Islamic kingdom, and consisted of sponges soaked in drug site. Fungus was held in front of an individual who had surgery patients.
The use of inhaled anesthetics and surgical success in the modern world is based on two discoveries: the development of sterile surgical techniques Joseph Lister and the discovery of the anesthetic properties of nitrous oxide.
The first modern inhaled anesthetics were carbon dioxide and nitrous oxide. While carbon dioxide has never really came into regular use as an anesthetic by inhalation, nitrous oxide is widespread, and in fact is still in use today.
The effect of nitrous oxide as an inhaled anesthetic gas was first noticed in public by the British chemist Humphry Davy, who published a paper on the subject in 1800. But it was several decades before the use of nitrous oxide was widespread. One of the first successful applications of gas painful tooth extraction was performed by William Thomas Green Morton, an American dentist, was not recorded until the 1846th
Also during the 1840s, another inhaled anesthetic known as diethyl ether is shown publicly for first time use during a tooth extraction procedure. Chloroform has also been developed in the previous decade, despite the well documented dangers of two chloroform and ether, the two have had a reasonably widespread use in Britain for a while.
Between 1930 and 1940, inhalation anesthetics such as cyclopropane, trichlorethylene, and isopropenyl acrylate was developed. However, the development of halothane in 1951, and the use of this anesthetic in clinical practice, five years after most of the past by inhalation expired.
During the 1960s and 1970s were a small number of new inhalation synthesized. Among them were enflurane, isoflurane, sevoflurane, desflurane and methoxyflurane. With the exception of methoxyflurane, which was withdrawn from the market due to nephrotoxicity, many inhalation developed during this period are still in use today.
Inhaled anesthetics are currently used
The most inhalational anesthetics are used halogen-containing volatile anesthetics have been developed in the years 1960 and 1970. These include isoflurane, sevoflurane, desflurane and enflurane. Halothane, developed in the 1950s, is still in use.
Nitrous oxide, developed over a hundred years ago, is also in regular use as an anesthetic by inhalation. Colloquially known as "laughing gas", the best known medical use in dentistry.
Another type of non-volatile inhalational anesthetics, which may eventually become a more regular use of xenon. Currently, xenon is more expensive to use than other inhalation anesthetics, and this has limited its use a little '. However, xenon is interesting because it is about 50% more effective than nitrous oxide, and because it is a greenhouse gas, is also more environmentally friendly.
Mode of action
Inhaled anesthetics are administered anesthesia machine, which uses the generator for the production of breathing gas to liquid version of the anesthesia. When inhaled, the gas is distributed throughout the body via the bloodstream at a rate that depends on the dose of anesthesia used, and in more detail the factors that depend on the patient receives anesthesia.
Inhalation anesthetics typically operate through two ways: increasing the inhibitory function, or a decrease in excitatory transmission in the nerve endings in the brain. In ideal situations, leading to inhalation anesthesia quickly, and the emergence of the anesthetized state is rapid once the anesthesia stimulus is removed.
The body tries to inhalation anesthetics in two ways: through metabolism, and by exhalation. Inhalation anesthetics ideals are those that are broken only at low levels. The metabolic rate varies considerably among different anesthetics: halothane, for example, is metabolized at a rate of 10% to 20%, whereas enflurane has a metabolic rate about 2.5% and nitrous oxide has a rate of 0%, and is not metabolized at all.
During a surgical procedure that tends to accumulate inhalation in adipose tissue, which means that patients with higher percentages of body fat awakens drugged state more slowly than patients with less body fat .
Possible side effects and toxic effects
Most of the inhalation agents produce a variety of side effects. Some side effects occur in only one or two different anesthetics, while other side effects are common to almost all. Some of the most common side effects include:
Cardiovascular effects include high blood pressure decreased (in all inhalation anesthetics except nitrous oxide and increased heart rate (isoflurane and halothane).
Pulmonary effects include increased respiratory rate. This increase is dose-dependent and is common to all inhalation anesthetics.
Renal and hepatic impairment after administration of all the inhalation anesthetics. Very rare cases (one from 6000 and one in 35,000), necrosis of the liver may be caused by halothane administration. Nephrotoxicity, while the use of methoxyflurane therefore quite common, is sometimes seen after high doses of sevoflurane.
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