Desflurane

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Desflurane
Desflurane2.svg
Desflurane-3D-balls.png
Systematic (IUPAC) name
2-(difluoromethoxy)-1,1,1,2-tetrafluoro-ethane
Clinical data
Legal status ?
Pharmacokinetic data
Metabolism Not metabolized
Half-life Elimination dependent on minute ventilation
Identifiers
CAS number 57041-67-5 YesY
ATC code N01AB07
PubChem CID 42113
DrugBank DB01189
ChemSpider 38403 YesY
UNII CRS35BZ94Q YesY
KEGG D00546 YesY
ChEBI CHEBI:4445 YesY
ChEMBL CHEMBL1200733 N
Chemical data
Formula C3H2F6O 
Mol. mass 168.038 g/mol
 N (what is this?)  (verify)

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 and Sevoflurane, 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 the third world, 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. 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 it vaporises very readily, it is a liquid at room temperature. Anaesthetic machines are fitted with a specialized anaesthetic vaporiser unit that heats liquid desflurane to a constant temperature. This enables the agent to be available at a constant vapor pressure, negating the effects fluctuating ambient temperatures would otherwise have on its concentration imparted into the fresh gas flow of the anesthesia machine.

Desflurane, along with enflurane and to a lesser extent isoflurane, has been shown to react with the carbon dioxide absorbent in anesthesia circuits to produce detectable levels of carbon monoxide through degradation of the anesthetic agent. The CO2 absorbent, Baralyme, when dried, is most culpable for the production of carbon monoxide from desflurane degradation, although it is also seen with soda lime absorbent as well. Dry conditions in the carbon dioxide absorbent are conducive to this phenomenon, such as those resulting from high fresh gas flows.[1]

Physical properties[edit]

Boiling point : 23.5 °C or 74.3 °F (at 1 atm)
Density : 1.465 g/cm³ (at 20 °C)
Molecular Weight : 168
Vapor pressure: 88.5 kPa 672 mmHg (at 20 °C)
107 kPa 804 mmHg (at 24 °C)
Blood:Gas partition coefficient: 0.42
Oil:Gas partition coefficient : 19
MAC : 6 vol %

Global-warming potential[edit]

Desflurane is a greenhouse gas. Anesthesia gases used globally contribute the equivalent of 1 million cars to global warming.[2] The twenty-year global-warming potential, GWP(20), for desflurane is 3714,[3] meaning that one tonne of desflurane emitted is equivalent to 3714 tonnes of carbon dioxide in the atmosphere, much higher than sevoflurane or isoflurane. Taking into account the different amounts typically used in 1 hour of anesthesia (1 minimal alveolar concentration-hour), desflurane causes 26.8 times the global warming of sevoflurane.[4]

Research[edit]

A recent clinical study found that desflurane has lower bispectral index and greater hypnotic effect than sevoflurane during the equipotent anesthesia. [5]

References[edit]

  1. ^ Fang, et al. (1995). "Carbon Monoxide Production from Degradation of Desflurane". Anesthesia and Analgesia. 
  2. ^ Sulbaek Andersen MP, Sander SP, Nielsen OJ, Wagner DS, Sanford Jr TJ, Wallington TJ (July 2010). "Inhalation anaesthetics and climate change". British Journal of Anaesthesia 105 (6): 760–766. doi:10.1093/bja/aeq259. 
  3. ^ Ryan, Susan M.; Nielsen, Claus J. (July 2010). "Global Warming Potential of Inhaled Anesthetics: Application to Clinical Use". Anesthesia & Analgesia (San Francisco, CA: International Anesthesia Research Society) 111 (1): 92–98. doi:10.1213/ane.0b013e3181e058d7. Retrieved 9 September 2011. 
  4. ^ Ryan SM, Nielsen CJ (July 2010). "Global Warming Potential of Inhaled Anesthetics: Application to Clinical Use". Anesthesia and Analgesia 111 (1): 92–98. doi:10.1213/ane.0b013e3181e058d7. 
  5. ^ Kim JK (Feb 2014). "Relationship of bispectral index to minimum alveolar concentration during isoflurane, sevoflurane or desflurane anaesthesia.". J Int Med Res 42 (1): 130–7. doi:10.1177/0300060513505525. PMID 24366495. 

Book references and Additional Reading[edit]

  • Eger, Eisenkraft, Weiskopf. The Pharmacology of Inhaled Anesthetics. 2003.
  • Rang, Dale, Ritter, Moore. Pharmacology 5th Edition. 2003.
  • Martin Bellgardt: Evaluation der Sedierungstiefe und der Aufwachzeiten frisch operierter Patienten mit neurophysiologischem Monitoring im Rahmen der Studie: Desfluran versus Propofol zur Sedierung beatmeter Patienten. Bochum, Dissertation, 2005 (pdf)
  • Susanne Lohmann: Verträglichkeit, Nebenwirkungen und Hämodynamik der inhalativen Sedierung mit Desfluran im Rahmen der Studie: Desfluran versus Propofol zur Sedierung beatmeter Patienten. Bochum, Dissertation, 2006 (pdf)
  • Patel SS, Goa KL. (1995) "Desflurane. A review of its pharmacodynamic and pharmacokinetic properties and its efficacy in general anaesthesia." Drugs Oct;50(4):742-67. PMID 8536556.