WordNet

tending to vary often or widely; "volatile stocks"; "volatile emotions"
a volatile substance; a substance that changes readily from solid or liquid to a vapor; "it was heated to evaporate the volatiles"
evaporating readily at normal temperatures and pressures; "volatile oils"; "volatile solvents"
a drug that causes temporary loss of bodily sensations (同)anaesthetic, anesthetic_agent, anaesthetic agent
characterized by insensibility; "the young girls are in a state of possession--blind and deaf and anesthetic"; "an anesthetic state" (同)anaesthetic

PrepTutorEJDIC

(液体が)揮発性の,揮発しやすい / (人・性格が)変わりやすい,気まぐれの / 不安定な;爆発しやすい / 怒りやすい,短気な

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/08/10 11:51:39」(JST)

wiki en

[Wiki en表示]

Bottles of sevoflurane, isoflurane, enflurane, and desflurane, the common fluorinated ether anaesthetics used in clinical practice. These agents are colour-coded for safety purposes. Note the special fitting for desflurane, which boils at room temperature.

An inhalational anaesthetic is a chemical compound possessing general anaesthetic properties that can be delivered via inhalation. They are administered by anaesthetists (a term which includes anaesthesiologists, nurse anaesthetists, and anaesthesiologist assistants) through an anaesthesia mask, laryngeal mask airway or tracheal tube connected to an anaesthetic vaporiser and an anaesthetic delivery system. Agents of significant contemporary clinical interest include volatile anaesthetic agents such as isoflurane, sevoflurane and desflurane, as well as certain anaesthetic gases such as nitrous oxide and xenon.

List of inhalational anaesthetic agents

Currently-used agents

Desflurane
Isoflurane
Nitrous oxide
Sevoflurane
Xenon

Previously-used agents

Although some of these are still used in clinical practice and in research, the following anaesthetic agents are primarily of historical interest in developed countries:

Chloroethane (ethyl chloride)
Chloroform
Cryofluorane
Cyclopropane
Diethyl ether
Enflurane
Ethylene
Fluroxene
Halothane
Methoxyflurane
Methoxypropane
Trichloroethylene
Vinyl ether

Never-marketed agents

Aliflurane
Halopropane
Norflurane
Roflurane
Synthane
Teflurane

Volatile anaesthetics

Volatile anaesthetic agents share the property of being liquid at room temperature, but evaporating easily for administration by inhalation. All of these agents share the property of being quite hydrophobic (i.e., as liquids, they are not freely miscible with water, and as gases they dissolve in oils better than in water). The ideal volatile anaesthetic agent offers smooth and reliable induction and maintenance of general anaesthesia with minimal effects on other organ systems. In addition it is odourless or pleasant to inhale; safe for all ages and in pregnancy; not metabolised; rapid in onset and offset; potent; and safe for exposure to operating room staff. It is also cheap to manufacture; easy to transport and store, with a long shelf life; easy to administer and monitor with existing equipment; stable to light, plastics, metals, rubber and soda lime; non-flammable and environmentally safe. None of the agents currently in use are ideal, although many have some of the desirable characteristics. For example, sevoflurane is pleasant to inhale and is rapid in onset and offset. It is also safe for all ages. However, it is expensive (approximately 3 to 5 times more expensive than isoflurane), and approximately half as potent as isoflurane.

Gases

Other gases or vapors which produce general anaesthesia by inhalation include nitrous oxide, cyclopropane and xenon. These are stored in gas cylinders and administered using flowmeters, rather than vaporisers. Cyclopropane is explosive and is no longer used for safety reasons, although otherwise it was found to be an excellent anaesthetic. Xenon is odourless and rapid in onset, but is expensive and requires specialized equipment to administer and monitor. Nitrous oxide, even at 80% concentration, does not quite produce surgical level anaesthesia in most persons at standard atmospheric pressure, so it must be used as an adjunct anaesthetic, along with other agents.

Hyperbaric anaesthesia

Under hyperbaric conditions (pressures above normal atmospheric pressure), other gases such as nitrogen, and noble gases such as argon, krypton, and xenon become anaesthetics. When inhaled at high partial pressures (more than about 4 bar, encountered at depths below about 30 metres in scuba diving), nitrogen begins to act as an anaesthetic agent, causing nitrogen narcosis.^[1]^[2] However, the minimum alveolar concentration (MAC) for nitrogen is not achieved until pressures of about 20 to 30 atm (bar) are attained.^[3] Argon is slightly more than twice as anaesthetic as nitrogen per unit of partial pressure (see argox). Xenon however is a usable anaesthetic at 80% concentration and normal atmospheric pressure.^[4]

Neurological theories of action

The full mechanism of action of volatile anaesthetic agents is unknown and has been the subject of intense debate. "Anesthetics have been used for 160 years, and how they work is one of the great mysteries of neuroscience," says anaesthesiologist James Sonner of the University of California, San Francisco. Anaesthesia research "has been for a long time a science of untestable hypotheses," notes Neil L. Harrison of Cornell University.^[5]

"Most of the injectable anesthetics appear to act on a single molecular target," says Sonner. "It looks like inhaled anesthetics act on multiple molecular targets. That makes it a more difficult problem to pick apart."

The possibility of anaesthesia by the inert gas argon in particular (even at 10 to 15 bar) suggests that the mechanism of action of volatile anaesthetics is an effect best described by physical chemistry, and not a chemical bonding action. However, the agent may bind to a receptor with a weak interaction . A physical interaction such as swelling of nerve cell membranes from gas solution in the lipid bilayer may be operative. Notably, the gases hydrogen, helium, and neon have not been found to have anaesthetic properties at any pressure. Helium at high pressures produces nervous irritation ("anti-anaesthesia"), suggesting that the anaesthetic mechanism(s) may be operated in reverse by this gas (i.e., nerve membrane compression). Also, some halogenated ethers (such as flurothyl) also possess this "anti-anaesthetic" effect, providing further evidence for this theory.

History

The concept was first used by Paracelsus in 1540.^[6] He used sweet oil of vitriol (prepared by Valerius Cordus and named Aether by Frobenius):^[6] used to feed fowl: “it was taken even by chickens and they fall asleep from it for a while but awaken later without harm”.^[6] Subsequently, about 40 years later, in 1581, Giambattista Delia Porta demonstrated the use of ether on humans although it was not employed for any type of surgical anesthesia.^[6]

References

^ Fowler, B; Ackles, KN; Porlier, G (1985). "Effects of inert gas narcosis on behavior—a critical review.". Undersea Biomed. Res. 12 (4): 369–402. PMID 4082343. Retrieved 2008-09-21.
^ Rogers, W. H.; Moeller, G. (1989). "Effect of brief, repeated hyperbaric exposures on susceptibility to nitrogen narcosis". Undersea Biomed. Res. 16 (3): 227–32. ISSN 0093-5387. OCLC 2068005. PMID 2741255. Retrieved 2008-09-21.
^ [1]
^ Burov, NE; Kornienko, Liu; Makeev, GN; Potapov, VN (November–December 1999). "Clinical and experimental study of xenon anesthesia". Anesteziol Reanimatol (6): 56–60. Retrieved 2008-11-03.
^ John Travis, "Comfortably Numb, Anesthetics are slowly giving up the secrets of how they work," Science News. (July 3rd 2004). [2].
^ ^a ^b ^c ^d Terrell, RC (1986). "Future Development of Volatile Anesthetics". ZAK Zürich Anaesthesiologie und Intensivmedizin / Anaesthesiology and Intensive Care Medicine 188: 87–92. doi:10.1007/978-3-642-71269-2_12. citing Fülöp-Miller R (1938) Triumph over pain. Literary Guild of America, New York.

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

1. 麻酔および麻酔剤選択の概要 overview of anesthesia and anesthetic choices
2. 悪性高熱症の易罹患性 susceptibility to malignant hyperthermia
3. 周術期の投薬マネージメント perioperative medication management
4. 非心臓手術施行時の肥満患者に対する麻酔 anesthesia for the obese patient undergoing non cardiac surgery
5. 末梢神経ブロックの概要 overview of peripheral nerve blocks

English Journal

Comparative presynaptic effects of the volatile anesthetics sevoflurane and isoflurane at the mouse neuromuscular junction.

Castro Fonseca MD1, Da Silva JH1, Ferraz VP2, Gomez RS3, Guatimosim C1.
Muscle & nerve.Muscle Nerve.2015 Nov;52(5):876-84. doi: 10.1002/mus.24589. Epub 2015 Aug 13.
INTRODUCTION: Sevoflurane and isoflurane are anesthetics that cause muscle relaxation and potentiate the effects of neuromuscular blocking agents. Their presynaptic mechanisms of action are not understood completely, especially at the motor nerve terminal.METHODS: We compared the presynaptic effects
PMID 25656419

Endoplasmic reticulum stress pathway mediates isoflurane-induced neuroapoptosis and cognitive impairments in aged rats.

Ge HW1, Hu WW2, Ma LL3, Kong FJ4.
Physiology & behavior.Physiol Behav.2015 Nov 1;151:16-23. doi: 10.1016/j.physbeh.2015.07.008. Epub 2015 Jul 8.
Postoperative cognitive dysfunction (POCD) is increasingly being recognized as an important clinical syndrome. Although it has been documented that volatile anesthetics induce neuronal apoptosis and cognitive deficits in several aged animal models, the underlying mechanisms are not well understood.
PMID 26162760

Bronchoconstriction induced by inhaled methacholine delays desflurane uptake and elimination in a piglet model.

Kretzschmar M1, Kozian A2, Baumgardner JE3, Schreiber J4, Hedenstierna G5, Larsson A6, Hachenberg T7, Schilling T8.
Respiratory physiology & neurobiology.Respir Physiol Neurobiol.2015 Oct 3. pii: S1569-9048(15)30051-3. doi: 10.1016/j.resp.2015.09.014. [Epub ahead of print]
Bronchoconstriction is a hallmark of asthma and impairs gas exchange. We hypothesized that pharmacokinetics of volatile anesthetics would be affected by bronchoconstriction. Ventilation/perfusion (V̇A/Q̇) ratios and pharmacokinetics of desflurane in both healthy state and during inhalational admin
PMID 26440992

Japanese Journal

3SA2-08 物理化学的手法によるリン脂質単分子膜への揮発性麻酔薬の作用機構(3SA2 麻酔作用の分子機構 : 生物物理から明らかにされる生体分子と麻酔薬の相互作用,第47回日本生物物理学会年会)

山本靖
生物物理 49(SUPPLEMENT_1), S18, 2009-09-20
NAID 110008101045

Pharmacological preconditioning in type 2 diabetic rat hearts: the roles of mitochondrial ATP-sensitive potassium channels and the phosphatidylinositol 3-kinase-Akt pathway.

Matsumoto Shuhei,Cho Sungsam,Tosaka Shinya,Ureshino Hiroyuki,Maekawa Takuji,Hara Tetsuya,Sumikawa Koji
Cardiovascular Drugs and Therapy 23(4), 263-270, 2009-08
… PURPOSE: The authors examined whether olprinone, a phosphodiesterase type 3 inhibitor, or isoflurane, a volatile anesthetic, could protect the heart against myocardial infarction in type 2 diabetic rats and whether the underlying mechanisms involve protein kinase C (PKC), mitochondrial ATP-sensitive potassium (m-K(ATP)) channels, or the phosphatidylinositol 3-kinase (PI3K)-Akt pathway. …
NAID 120001609353

Related Pictures

★リンクテーブル★

リンク元	「gaseous anesthetic」「inhalation anesthetic」「揮発性麻酔薬」「揮発性吸入麻酔薬」「inhalational anesthetic」
関連記事	「anesthetic」「volatile」