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Inhalational anesthetic

January 01, 1970

An inhalational anesthetic is a chemical compound possessing general anesthetic properties that is delivered via inhalation. They are administered through a face mask, laryngeal mask airway or tracheal tube connected to an anesthetic vaporiser and an anesthetic delivery system. Agents of significant contemporary clinical interest include volatile anesthetic agents such as isoflurane, sevoflurane and desflurane, as well as certain anesthetic gases such as nitrous oxide and xenon.

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

List of inhalational anaesthetic agents edit

Currently-used agents edit

Previously-used agents edit

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:

Never-marketed agents edit

Volatile anaesthetics edit

Volatile anaesthetic agents share the property of being liquid at room temperature, but evaporating easily for administration by inhalation. The volatile anesthetics used in the developed world today include: Desflurane, isoflurane and sevoflurane. Other agents widely used in the past include ether, chloroform, enflurane, halothane, methoxyflurane. 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).[3]

The ideal volatile anaesthetic agent offers smooth and reliable induction and maintenance of general anaesthesia with minimal effects on non-target organ systems. In addition it is odorless or pleasant to inhale; safe for all ages and in pregnancy; not metabolised; rapid in onset and offset; potent; safe for exposure to operating room staff; and has a long shelf life. It is also cheap to manufacture; easy to transport and store; easy to administer and monitor with standard operating room equipment; stable to light, plastics, metals, rubber and soda lime; and 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.[4]

Gases edit

Other gases or vapors which produce general anaesthesia by inhalation include nitrous oxide, carbon dioxide, 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 odorless (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 people at standard atmospheric pressure, so it must be used as an adjunct anaesthetic, along with other agents.

Hyperbaric anaesthesia edit

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.[5][6] However, the minimum alveolar concentration (MAC) for nitrogen is not achieved until pressures of about 20 to 30 atm (bar) are attained.[7] 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.[8]

Endogenous analogous edit

Endogenous analogs of inhaled anesthetics are compounds that the body produces and that have the properties and similar mode of action of inhaled anesthetics.[9] Among the gases in the human body, carbon dioxide is among the most abundant and produces anesthesia from insects to humans.[10] CO2 anesthesia was first demonstrated to the king of france in the early 1800s by Henry Hill Hickman. Initially CO2 was thought to work through anoxia, but in the early 1900, increased CO2 in the lung showed a dramatic increase oxygenation of the brain disproving the anoxia argument. [11]Prior to the development of modern anesthetics, CO2 was used extensively by psychiatrists in a treatment called carbon dioxide inhalation therapy. [12]

Neurological theories of action edit

Main article: Theories of general anaesthetic 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.[13]

"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 edit

Paracelsus developed an inhalational anaesthetic in 1540.[14] He used sweet oil of vitriol (prepared by Valerius Cordus and named Aether by Frobenius):[14] used to feed fowl: “it was taken even by chickens and they fall asleep from it for a while but awaken later without harm”.[14] 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.[14]

In modern medicine, Dr. Horace Wells used nitrous oxide for his own dental extraction in 1844. However his attempt to replicate these results at Massachusetts General Hospital (MGH) resulted in a partial anesthetic and was deemed a failure.

William T.G. Morton is credited with successfully demonstrating surgical anesthesia for the first time on October 16, 1846, at MGH. Following this event, the use of ether and other volatile anesthetics became widespread in Western medicine.[15]

After the experiments and publications by the Scottish obstetrician James Young Simpson in late 1847, chloroform became the first widespread halocarbon anaesthetic. Chloroform is a much stronger and effective anaesthetic than ether, it is non-inflammable and it did not irritate the airways, unlike ether.

First non-gaseous inhalational anaesthetics such as ether and chloroform were inhaled from a handkerchief which the liquid was poured on and allowed to evaporate. Concerns about the dosage of chloroform lead to development of various inhalers.

See also edit

References edit

  1. ^ Tamburro CH (1978). "Health effects of vinyl chloride". Texas Reports on Biology and Medicine. 37: 126–44, 146–51. PMID 572591.
  2. ^ Oster RH, Carr CJ (July 1947). "Anesthesia; narcosis with vinyl chloride". Anesthesiology. 8 (4): 359–61. doi:10.1097/00000542-194707000-00003. PMID 20255056. S2CID 73229069.
  3. ^ Clar, D. T.; Patel, S.; Richards, J. R. (2022). "Anesthetic Gases". StatPearls. PMID 30725698.
  4. ^ Loscar, M.; Conzen, P. (2004). "Volatile anesthetics". Der Anaesthesist. 53 (2): 183–198. doi:10.1007/s00101-003-0632-6. PMID 14991199. S2CID 26029329.
  5. ^ Fowler, B; Ackles, KN; Porlier, G (1985). . Undersea Biomed. Res. 12 (4): 369–402. PMID 4082343. Archived from the original on October 26, 2008. Retrieved 2008-09-21.{{cite journal}}: CS1 maint: unfit URL (link)
  6. ^ Rogers, W. H.; Moeller, G. (1989). . Undersea Biomed. Res. 16 (3): 227–32. ISSN 0093-5387. OCLC 2068005. PMID 2741255. Archived from the original on 2009-09-01. Retrieved 2008-09-21.{{cite journal}}: CS1 maint: unfit URL (link)
  7. ^ Mekjavic, I. B.; Savic, S. A.; Eiken, O. (1995). "Nitrogen narcosis attenuates shivering thermogenesis". Journal of Applied Physiology. 78 (6): 2241–2244. doi:10.1152/jappl.1995.78.6.2241. PMID 7665424.
  8. ^ Burov, NE; Kornienko, Liu; Makeev, GN; Potapov, VN (November–December 1999). "Clinical and experimental study of xenon anesthesia". Anesteziol Reanimatol (6): 56–60. PMID 11452771. Retrieved 2008-11-03.
  9. ^ Lerner, Richard A. (9 December 1997). "A hypothesis about the endogenous analogue of general anesthesia". Proceedings of the National Academy of Sciences. 94 (25): 13375–13377. Bibcode:1997PNAS...9413375L. doi:10.1073/pnas.94.25.13375. PMC 33784. PMID 9391028.
  10. ^ Nilson, Theresa L.; Sinclair, Brent J.; Roberts, Stephen P. (October 2006). "The effects of carbon dioxide anesthesia and anoxia on rapid cold-hardening and chill coma recovery in Drosophila melanogaster". Journal of Insect Physiology. 52 (10): 1027–1033. doi:10.1016/j.jinsphys.2006.07.001. PMC 2048540. PMID 16996534.
  11. ^ Moriarty, John D. (April 1954). "Evaluation of Carbon Dioxide Inhalation Therapy". American Journal of Psychiatry. 110 (10): 765–769. doi:10.1176/ajp.110.10.765. PMID 13138755.
  12. ^ Moriarty, John D. (1954). "Evaluation of Carbon Dioxide Inhalation Therapy". American Journal of Psychiatry. 110 (10): 765–769. doi:10.1176/ajp.110.10.765. PMID 13138755.
  13. ^ John Travis, "Comfortably Numb, Anesthetics are slowly giving up the secrets of how they work," Science News. (July 3rd 2004). [1].
  14. ^ a b c d Terrell, RC (1986). "Future Development of Volatile Anesthetics". ZAK Zürich. Anaesthesiologie und Intensivmedizin / Anaesthesiology and Intensive Care Medicine. Vol. 188. pp. 87–92. doi:10.1007/978-3-642-71269-2_12. ISBN 978-3-642-71269-2. citing Fülöp-Miller R (1938) Triumph over pain. Literary Guild of America, New York.
  15. ^ "History of Anesthesia".

January 01, 1970
inhalational, anesthetic, inhalational, anesthetic, chemical, compound, possessing, general, anesthetic, properties, that, delivered, inhalation, they, administered, through, face, mask, laryngeal, mask, airway, tracheal, tube, connected, anesthetic, vaporiser. An inhalational anesthetic is a chemical compound possessing general anesthetic properties that is delivered via inhalation They are administered through a face mask laryngeal mask airway or tracheal tube connected to an anesthetic vaporiser and an anesthetic delivery system Agents of significant contemporary clinical interest include volatile anesthetic agents such as isoflurane sevoflurane and desflurane as well as certain anesthetic gases such as nitrous oxide and xenon Bottles of sevoflurane isoflurane enflurane and desflurane the common fluorinated ether anesthetics used in clinical practice These agents are colour coded for safety purposes Note the special fitting for desflurane which boils at room temperature Contents 1 List of inhalational anaesthetic agents 1 1 Currently used agents 1 2 Previously used agents 1 3 Never marketed agents 2 Volatile anaesthetics 3 Gases 4 Hyperbaric anaesthesia 5 Endogenous analogous 6 Neurological theories of action 7 History 8 See also 9 ReferencesList of inhalational anaesthetic agents editCurrently used agents edit Desflurane Isoflurane Nitrous oxide Sevoflurane Xenon Previously used agents edit 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 Acetylene Chloroethane ethyl chloride Chloroform Cryofluorane Cyclopropane Diethyl ether Divinyl ether Enflurane Ethylene Fluroxene Halothane still widely used in the developing world and is on the WHO Model List of Essential Medicines Methoxyflurane still used currently as an analgesic Methoxypropane Trichloroethylene Vinyl chloride 1 2 Never marketed agents edit Aliflurane Halopropane Norflurane Roflurane Synthane TefluraneVolatile anaesthetics editVolatile anaesthetic agents share the property of being liquid at room temperature but evaporating easily for administration by inhalation The volatile anesthetics used in the developed world today include Desflurane isoflurane and sevoflurane Other agents widely used in the past include ether chloroform enflurane halothane methoxyflurane 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 3 The ideal volatile anaesthetic agent offers smooth and reliable induction and maintenance of general anaesthesia with minimal effects on non target organ systems In addition it is odorless or pleasant to inhale safe for all ages and in pregnancy not metabolised rapid in onset and offset potent safe for exposure to operating room staff and has a long shelf life It is also cheap to manufacture easy to transport and store easy to administer and monitor with standard operating room equipment stable to light plastics metals rubber and soda lime and 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 4 Gases editOther gases or vapors which produce general anaesthesia by inhalation include nitrous oxide carbon dioxide 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 odorless 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 people at standard atmospheric pressure so it must be used as an adjunct anaesthetic along with other agents Hyperbaric anaesthesia editUnder 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 5 6 However the minimum alveolar concentration MAC for nitrogen is not achieved until pressures of about 20 to 30 atm bar are attained 7 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 8 Endogenous analogous editEndogenous analogs of inhaled anesthetics are compounds that the body produces and that have the properties and similar mode of action of inhaled anesthetics 9 Among the gases in the human body carbon dioxide is among the most abundant and produces anesthesia from insects to humans 10 CO2 anesthesia was first demonstrated to the king of france in the early 1800s by Henry Hill Hickman Initially CO2 was thought to work through anoxia but in the early 1900 increased CO2 in the lung showed a dramatic increase oxygenation of the brain disproving the anoxia argument 11 Prior to the development of modern anesthetics CO2 was used extensively by psychiatrists in a treatment called carbon dioxide inhalation therapy 12 Neurological theories of action editParts of this article those related to Important research from Scripps Research misses here need to be updated Please help update this article to reflect recent events or newly available information October 2021 Main article Theories of general anaesthetic 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 13 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 editParacelsus developed an inhalational anaesthetic in 1540 14 He used sweet oil of vitriol prepared by Valerius Cordus and named Aether by Frobenius 14 used to feed fowl it was taken even by chickens and they fall asleep from it for a while but awaken later without harm 14 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 14 In modern medicine Dr Horace Wells used nitrous oxide for his own dental extraction in 1844 However his attempt to replicate these results at Massachusetts General Hospital MGH resulted in a partial anesthetic and was deemed a failure William T G Morton is credited with successfully demonstrating surgical anesthesia for the first time on October 16 1846 at MGH Following this event the use of ether and other volatile anesthetics became widespread in Western medicine 15 After the experiments and publications by the Scottish obstetrician James Young Simpson in late 1847 chloroform became the first widespread halocarbon anaesthetic Chloroform is a much stronger and effective anaesthetic than ether it is non inflammable and it did not irritate the airways unlike ether First non gaseous inhalational anaesthetics such as ether and chloroform were inhaled from a handkerchief which the liquid was poured on and allowed to evaporate Concerns about the dosage of chloroform lead to development of various inhalers See also editA C E mixture a mixture of ethanol chloroform and diethyl ether Anaesthetic Concentration effect Second gas effectReferences edit Tamburro CH 1978 Health effects of vinyl chloride Texas Reports on Biology and Medicine 37 126 44 146 51 PMID 572591 Oster RH Carr CJ July 1947 Anesthesia narcosis with vinyl chloride Anesthesiology 8 4 359 61 doi 10 1097 00000542 194707000 00003 PMID 20255056 S2CID 73229069 Clar D T Patel S Richards J R 2022 Anesthetic Gases StatPearls PMID 30725698 Loscar M Conzen P 2004 Volatile anesthetics Der Anaesthesist 53 2 183 198 doi 10 1007 s00101 003 0632 6 PMID 14991199 S2CID 26029329 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 Archived from the original on October 26 2008 Retrieved 2008 09 21 a href Template Cite journal html title Template Cite journal cite journal a CS1 maint unfit URL link 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 Archived from the original on 2009 09 01 Retrieved 2008 09 21 a href Template Cite journal html title Template Cite journal cite journal a CS1 maint unfit URL link Mekjavic I B Savic S A Eiken O 1995 Nitrogen narcosis attenuates shivering thermogenesis Journal of Applied Physiology 78 6 2241 2244 doi 10 1152 jappl 1995 78 6 2241 PMID 7665424 Burov NE Kornienko Liu Makeev GN Potapov VN November December 1999 Clinical and experimental study of xenon anesthesia Anesteziol Reanimatol 6 56 60 PMID 11452771 Retrieved 2008 11 03 Lerner Richard A 9 December 1997 A hypothesis about the endogenous analogue of general anesthesia Proceedings of the National Academy of Sciences 94 25 13375 13377 Bibcode 1997PNAS 9413375L doi 10 1073 pnas 94 25 13375 PMC 33784 PMID 9391028 Nilson Theresa L Sinclair Brent J Roberts Stephen P October 2006 The effects of carbon dioxide anesthesia and anoxia on rapid cold hardening and chill coma recovery in Drosophila melanogaster Journal of Insect Physiology 52 10 1027 1033 doi 10 1016 j jinsphys 2006 07 001 PMC 2048540 PMID 16996534 Moriarty John D April 1954 Evaluation of Carbon Dioxide Inhalation Therapy American Journal of Psychiatry 110 10 765 769 doi 10 1176 ajp 110 10 765 PMID 13138755 Moriarty John D 1954 Evaluation of Carbon Dioxide Inhalation Therapy American Journal of Psychiatry 110 10 765 769 doi 10 1176 ajp 110 10 765 PMID 13138755 John Travis Comfortably Numb Anesthetics are slowly giving up the secrets of how they work Science News July 3rd 2004 1 a b c d Terrell RC 1986 Future Development of Volatile Anesthetics ZAK Zurich Anaesthesiologie und Intensivmedizin Anaesthesiology and Intensive Care Medicine Vol 188 pp 87 92 doi 10 1007 978 3 642 71269 2 12 ISBN 978 3 642 71269 2 citing Fulop Miller R 1938 Triumph over pain Literary Guild of America New York History of Anesthesia Retrieved from https en wikipedia org w index php title Inhalational anesthetic amp oldid 1219825207, wikipedia, wiki, book, books, library,

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