WordNet

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
the act of inhaling; the drawing in of air (or other gases) as in breathing (同)inspiration, aspiration, intake, breathing in

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吸入;〈C〉吸入剤

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/05/06 13:36:00」(JST)

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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 some type of 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

isoflurane
desflurane
nitrous oxide
sevoflurane

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:

aliflurane
chloroethane
chloroform
cyclopropane
diethyl ether
enflurane
ethylene
halothane
methoxyflurane
methoxypropane
roflurane
teflurane
trichloroethylene
vinyl ether

Future agents

xenon

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 vapours 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 specialised 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 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. Cite uses deprecated parameters (help)
^ 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

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1. 全身麻酔の導入 induction of general anesthesia
2. ハロタン肝炎 halothane hepatitis
3. Cardiovascular problems in the post-anesthesia care unit (PACU)
4. 外科手術における神経モニタリングおよび麻酔 neuromonitoring in surgery and anesthesia
5. 頸動脈内膜剥離術および頸動脈ステント留置術の麻酔 anesthesia for carotid endarterectomy and carotid stenting

English Journal

Adsorption of fluorinated anesthetics within the pores of a molecular crystal.

Chen TH1, Kaveevivitchai W, Jacobson AJ, Miljanić OŠ.
Chemical communications (Cambridge, England).Chem Commun (Camb).2015 Sep 1;51(74):14096-8. doi: 10.1039/c5cc04885k.
Commonly used inhalation anesthetics-enflurane, isoflurane, sevoflurane, halothane, and methoxyflurane-are adsorbed within the pores of a porous fluorinated molecular crystal to the tune of up to 73.4(±0.2)% by weight. Uptake of all studied anesthetics is quite fast, typically reaching saturation i
PMID 26252729

Genetic inactivation and prolonged pharmacologic inhibition of monoacylglycerol lipase have opposite effects on anesthetic sensitivity to propofol.

Petrenko AB1, Yamazaki M2, Sakimura K2, Kano M3, Baba H4.
European journal of pharmacology.Eur J Pharmacol.2015 Aug 26. pii: S0014-2999(15)30224-7. doi: 10.1016/j.ejphar.2015.08.048. [Epub ahead of print]
Monoacylglycerol lipase (MGL) is a major enzyme involved in degradation of the endocannabinoid 2-arachidonoylglycerol (2-AG). Selective inhibitors of MGL are regarded as promising analgesics and anticancer agents. To gain insight into the possible consequences of their prolonged administration for a
PMID 26318148

[Anesthesia management in implantation of baroreceptor stimulators].

Werner T1, Lebar L, Wittmann S, Keyser A, Fischer M, Schmidli J, Graf BM, Zausig YA.
Der Anaesthesist.Anaesthesist.2015 Aug 15. [Epub ahead of print]
Baroreceptor stimulators are novel implantable devices that activate the carotid baroreceptor reflex. This results in a decrease in activity of the sympathetic nervous system and inhibition of the renin-angiotensin-aldosterone system. In patients with drug-resistant hypertension, permanent electrica
PMID 26275386

Japanese Journal

ラリンジアルマスク,プロポフォールtarget-controlled infusion(TCI)および軟性気管支鏡にて気管ステントを留置した1例

仲田庄志
気管支学 : 日本気管支研究会雑誌 34(2), 154-158, 2012-03-25
背景.悪性気道狭窄に対するステント留置は,標準的な治療である.留置するステントの種類により,麻酔法(全身麻酔か吸入麻酔,静脈麻酔)や気道確保の仕方は各施設により様々な方法で行われている.今回プロポフォールTCIにより適切な麻酔深度を維持,ラリンジアルマスクを挿入し,軟性気管支鏡で気道ステントを留置した.症例.82歳女性で,食道癌の再発による喀血で受診した.精査で,腫瘍は声帯下4cmから5cm長にわ …
NAID 110009437397

新たな吸入麻酔薬 : デスフルラン : セボフルランとの比較

正木英二
日本歯科麻酔学会雑誌 40(1), 1-6, 2012-01-15
NAID 10030283194

NARCOBIT-A Newly Developed Inhalational Anesthesia System for Mice

MATSUDA Yoshikazu,OHSAKA Kazumasa,YAMAMOTO Hidekazu,JIYOURAKU Kouzou,NATSUME Katsuhiko,HIRABAYASHI Shirokazu,KOUNOIKE Masayoshi,INOUE Masaaki
Experimental Animals 56(2), 131-137, 2007
… NARCOBIT is the first anesthetic system for mice and rats to incorporate a ventilator. … In this study, we used NARCOBIT for inducing inhalational anesthesia in mice and evaluated the changes in their hemodynamic parameters. … Since the use of NARCOBIT enables the anesthetic concentration of isoflurane to be easily changed, a suitable anesthesia depth can be obtained for experimental purposes. …
NAID 130000068043