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Blood–gas Partition Coefficient
Blood–gas partition coefficient, also known as Ostwald coefficient for blood–gas, is a term used in pharmacology to describe the solubility of inhaled general anesthetics in blood. According to Henry's law, the ratio of the concentration in blood to the concentration in gas that is in contact with that blood, when the partial pressure in both compartments is equal, is nearly constant at sufficiently low concentrations. The partition coefficient is defined as this ratio and, therefore, has no units. The concentration of the anesthetic in blood includes the portion that is undissolved in plasma and the portion that is dissolved (bound to plasma proteins). The more soluble the inhaled anesthetic is in blood compared to in air, the more it binds to plasma proteins in the blood and the higher the blood–gas partition coefficient. It is inversely related to induction rate. Induction rate is defined as the speed at which an agent produces anesthesia. The higher the blood:gas partit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pharmacology
Pharmacology is a branch of medicine, biology and pharmaceutical sciences concerned with drug or medication action, where a drug may be defined as any artificial, natural, or endogenous (from within the body) molecule which exerts a biochemical or physiological effect on the cell, tissue, organ, or organism (sometimes the word ''pharmacon'' is used as a term to encompass these endogenous and exogenous bioactive species). More specifically, it is the study of the interactions that occur between a living organism and chemicals that affect normal or abnormal biochemical function. If substances have medicinal properties, they are considered pharmaceuticals. The field encompasses drug composition and properties,functions,sources,synthesis and drug design, molecular and cellular mechanisms, organ/systems mechanisms, signal transduction/cellular communication, molecular diagnostics, interactions, chemical biology, therapy, and medical applications and antipathogenic capabilities. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrous Oxide
Nitrous oxide (dinitrogen oxide or dinitrogen monoxide), commonly known as laughing gas, nitrous, or nos, is a chemical compound, an oxide of nitrogen with the formula . At room temperature, it is a colourless non-flammable gas, and has a slightly sweet scent and taste. At elevated temperatures, nitrous oxide is a powerful oxidiser similar to molecular oxygen. Nitrous oxide has significant medical uses, especially in surgery and dentistry, for its anaesthetic and pain-reducing effects. Its colloquial name, "laughing gas", coined by Humphry Davy, is due to the euphoric effects upon inhaling it, a property that has led to its recreational use as a dissociative anaesthetic. It is on the World Health Organization's List of Essential Medicines. It is also used as an oxidiser in rocket propellants, and in motor racing to increase the power output of engines. Nitrous oxide's atmospheric concentration reached 333 parts per billion (ppb) in 2020, increasing at a rate of abo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anesthesia
Anesthesia is a state of controlled, temporary loss of sensation or awareness that is induced for medical or veterinary purposes. It may include some or all of analgesia (relief from or prevention of pain), paralysis (muscle relaxation), amnesia (loss of memory), and unconsciousness. An individual under the effects of anesthetic drugs is referred to as being anesthetized. Anesthesia enables the painless performance of procedures that would otherwise cause severe or intolerable pain in a non-anesthetized individual, or would otherwise be technically unfeasible. Three broad categories of anesthesia exist: * General anesthesia suppresses central nervous system activity and results in unconsciousness and total lack of sensation, using either injected or inhaled drugs. * Sedation suppresses the central nervous system to a lesser degree, inhibiting both anxiety and creation of long-term memories without resulting in unconsciousness. * Regional and local anesthesia, which blo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enflurane
Enflurane (2-chloro-1,1,2-trifluoroethyl difluoromethyl ether) is a halogenated ether. Developed by Ross Terrell in 1963, it was first used clinically in 1966. It was increasingly used for inhalational anesthesia during the 1970s and 1980s but is no longer in common use. Enflurane is a structural isomer of isoflurane. It vaporizes readily, but is a liquid at room temperature. Physical properties Side effects Clinically, enflurane produces a dose-related depression of myocardial contractility with an associated decrease in myocardial oxygen consumption. Between 2% and 5% of the inhaled dose is oxidised in the liver, producing fluoride ions and difluoromethoxy-difluoroacetic acid. This is significantly higher than the metabolism of its structural isomer isoflurane. Enflurane also lowers the threshold for seizures, and should especially not be used on people with epilepsy. Like all potent inhalation anaesthetic agents it is a known trigger of malignant hyperthermia. Like the ot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methoxyflurane
Methoxyflurane, sold under the brand name Penthrox among others, is an inhaled medication primarily used to reduce pain following trauma. It may also be used for short episodes of pain as a result of medical procedures. Onset of pain relief is rapid and of a short duration. Use is only recommended with direct medical supervision. Common side effects include anxiety, headache, sleepiness, cough, and nausea. Serious side effects may include kidney problems, liver problems, low blood pressure, and malignant hyperthermia. It is unclear if it is safe in either pregnancy or breastfeeding. It is only recommended in those who have a normal level of consciousness and stable blood pressure and heart rate. It is classified as a volatile anaesthetic. It was first made in 1948 by William T. Miller and came into medical use in the 1960s. It was used as a general anesthetic from its introduction in 1960 until the late 1970s. In 1999, the manufacturer discontinued methoxyflurane in the U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Desflurane
Desflurane (1,2,2,2-tetrafluoroethyl difluoromethyl ether) is a highly fluorinated methyl ethyl ether used for maintenance of general anesthesia. Like halothane, enflurane, and isoflurane, it is a racemic mixture of (''R'') and (''S'') optical isomers ( enantiomers). Together with sevoflurane, it is gradually replacing isoflurane for human use, except in economically undeveloped areas, where its high cost precludes its use. It has the most rapid onset and offset of the volatile anesthetic drugs used for general anesthesia due to its low solubility in blood. Some drawbacks of desflurane are its low potency, its pungency and its high cost (though at low flow fresh gas rates, the cost difference between desflurane and isoflurane appears to be insignificant). It may cause tachycardia and airway irritability when administered at concentrations greater than 10 vol%. Due to this airway irritability, desflurane is infrequently used to induce anesthesia via inhalation techniques. Though ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sevoflurane
Sevoflurane, sold under the brand name Sevorane, among others, is a sweet-smelling, nonflammable, highly fluorinated methyl isopropyl ether used as an inhalational anaesthetic for induction and maintenance of general anesthesia. After desflurane, it is the volatile anesthetic with the fastest onset. While its offset may be faster than agents other than desflurane in a few circumstances, its offset is more often similar to that of the much older agent isoflurane. While sevoflurane is only half as soluble as isoflurane in blood, the tissue blood partition coefficients of isoflurane and sevoflurane are quite similar. For example, in the muscle group: isoflurane 2.62 vs. sevoflurane 2.57. In the fat group: isoflurane 52 vs. sevoflurane 50. As a result, the longer the case, the more similar will be the emergence times for sevoflurane and isoflurane. Medical uses It is one of the most commonly used volatile anesthetic agents, particularly for outpatient anesthesia,Livertox: Clinica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isoflurane
Isoflurane, sold under the brand name Forane among others, is a general anesthetic. It can be used to start or maintain anesthesia; however, other medications are often used to start anesthesia rather than isoflurane, due to airway irritation with isoflurane. Isoflurane is given via inhalation. Side effects of isoflurane include a decreased ability to breathe (respiratory depression), low blood pressure, and an irregular heartbeat. Serious side effects can include malignant hyperthermia or high blood potassium. It should not be used in patients with a history of malignant hyperthermia in either themselves or their family members. It is unknown if its use during pregnancy is safe for the fetus, but use during a cesarean section appears to be safe. Isoflurane is a halogenated ether. Isoflurane was approved for medical use in the United States in 1979. It is on the World Health Organization's List of Essential Medicines. Medical uses Isoflurane is always administered in con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halothane
Halothane, sold under the brand name Fluothane among others, is a general anaesthetic. It can be used to induce or maintain anaesthesia. One of its benefits is that it does not increase the production of saliva, which can be particularly useful in those who are difficult to intubate. It is given by inhalation. Side effects include an irregular heartbeat, respiratory depression, and hepatotoxicity. Like all volatile anesthetics, it should not be used in people with a personal or family history of malignant hyperthermia. It appears to be safe in porphyria. It is unclear whether use during pregnancy is harmful to the baby, and it is not generally recommended for use during a C-section. Halothane is a chiral molecule that is used as a racemic mixture. Halothane was discovered in 1955. It was approved for medical use in the United States in 1958. It is on the World Health Organization's List of Essential Medicines. Its use in developed countries has been mostly replaced by newer ane ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diethyl Ether
Diethyl ether, or simply ether, is an organic compound in the ether class with the formula , sometimes abbreviated as (see Pseudoelement symbols). It is a colourless, highly volatile, sweet-smelling ("ethereal odour"), extremely flammable liquid. It is commonly used as a solvent in laboratories and as a starting fluid for some engines. It was formerly used as a general anesthetic, until non-flammable drugs were developed, such as halothane. It has been used as a recreational drug to cause intoxication. Production Most diethyl ether is produced as a byproduct of the vapor-phase hydration of ethylene to make ethanol. This process uses solid-supported phosphoric acid catalysts and can be adjusted to make more ether if the need arises. Vapor-phase dehydration of ethanol over some alumina catalysts can give diethyl ether yields of up to 95%. Diethyl ether can be prepared both in laboratories and on an industrial scale by the acid ether synthesis. Ethanol is mixed with a stro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
General Anesthetic
General anaesthetics (or anesthetics, see spelling differences) are often defined as compounds that induce a loss of consciousness in humans or loss of righting reflex in animals. Clinical definitions are also extended to include an induced coma that causes lack of awareness to painful stimuli, sufficient to facilitate surgical applications in clinical and veterinary practice. General anaesthetics do not act as analgesics and should also not be confused with sedatives. General anaesthetics are a structurally diverse group of compounds whose mechanisms encompasses multiple biological targets involved in the control of neuronal pathways. The precise workings are the subject of some debate and ongoing research. General anesthetics elicit a state of general anesthesia. It remains somewhat controversial regarding how this state should be defined. General anesthetics, however, typically elicit several key reversible effects: immobility, analgesia, amnesia, unconsciousness, and reduced a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Desflurane
Desflurane (1,2,2,2-tetrafluoroethyl difluoromethyl ether) is a highly fluorinated methyl ethyl ether used for maintenance of general anesthesia. Like halothane, enflurane, and isoflurane, it is a racemic mixture of (''R'') and (''S'') optical isomers ( enantiomers). Together with sevoflurane, it is gradually replacing isoflurane for human use, except in economically undeveloped areas, where its high cost precludes its use. It has the most rapid onset and offset of the volatile anesthetic drugs used for general anesthesia due to its low solubility in blood. Some drawbacks of desflurane are its low potency, its pungency and its high cost (though at low flow fresh gas rates, the cost difference between desflurane and isoflurane appears to be insignificant). It may cause tachycardia and airway irritability when administered at concentrations greater than 10 vol%. Due to this airway irritability, desflurane is infrequently used to induce anesthesia via inhalation techniques. Though ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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