Desflurane (1,2,2,2-tetrafluoroethyl difluoromethyl ether) is a highly fluorinated methyl ethyl ether used for maintenance of

general anesthesia General anaesthesia (UK) or general anesthesia (US) is medically induced loss of consciousness that renders a patient unarousable even by painful stimuli. It is achieved through medications, which can be injected or inhaled, often with an analgesi ...

. Like

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 ...

, enflurane, and isoflurane, it is a racemic mixture of (''R'') and (''S'') optical isomers (

enantiomer In chemistry, an enantiomer (Help:IPA/English, /ɪˈnænti.əmər, ɛ-, -oʊ-/ Help:Pronunciation respelling key, ''ih-NAN-tee-ə-mər''), also known as an optical isomer, antipode, or optical antipode, is one of a pair of molecular entities whi ...

s). 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

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% by volume. Due to this airway irritability, desflurane is infrequently used to induce anesthesia via inhalation techniques. Though it vaporizes 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 Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...

absorbent in anesthesia circuits to produce detectable levels of

carbon monoxide Carbon monoxide (chemical formula CO) is a poisonous, flammable gas that is colorless, odorless, tasteless, and slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the si ...

through degradation of the anesthetic agent. The absorbent Baralyme, when dried, is most culpable for the production of carbon monoxide from desflurane degradation, although it is also seen with

soda lime Soda lime, a mixture of sodium hydroxide (NaOH) and calcium oxide (CaO), is used in granular form within recirculating breathing environments like general anesthesia and its breathing circuit, submarines, rebreathers, and hyperbaric chambers and u ...

absorbent as well. Dry conditions in the carbon dioxide absorbent are conducive to this phenomenon, such as those resulting from high fresh gas flows.

Pharmacology

the exact mechanism of the action of general anaesthetics has not been delineated. Desflurane is known to act as a positive allosteric modulator of the GABA_A and glycine receptors, and as a negative allosteric modulator of the nicotinic acetylcholine receptor, as well as affecting other

ligand-gated ion channel Ligand-gated ion channels (LICs, LGIC), also commonly referred to as ionotropic receptors, are a group of transmembrane ion-channel proteins which open to allow ions such as sodium, Na+, potassium, K+, calcium, Ca2+, and/or chloride, Cl− to ...

Stereochemistry

Desflurane medications are a racemate of two enantiomers.Rote Liste Service GmbH (Hrsg.): ''Rote Liste 2017 - Arzneimittelverzeichnis für Deutschland (einschließlich EU-Zulassungen und bestimmter Medizinprodukte)''. Rote Liste Service GmbH, Frankfurt/Main, 2017, Aufl. 57, , S. 175.

Physical properties

Physiologic effects

Desflurane induces a dose dependent reduction in blood pressure due to reduced systemic vascular resistance. However, rapid increases in desflurane may induce a transient sympathetic response secondary to catecholamine release. Even though it is highly pungent, it is still a bronchodilator. It reduces the ventilatory response to hypoxia and hypercapnia. Like sevoflurane, desflurane vasodilatory properties also cause it to increase intracranial pressure and cerebral blood flow. However, it reduces cerebral metabolic rate. It also promotes muscle relaxation and potentiate neuromuscular blockade at a greater level than sevoflurane.

Contraindications

It is contraindicated for induction of general anesthesia in the non-intubated pediatric population due to the high risk of laryngospasm. It should not be used in patients with known or suspected susceptibility to malignant hyperthermia. It is also contraindicated in patients with elevated intracranial pressure.

Global-warming potential

Desflurane is a

greenhouse gas Greenhouse gases (GHGs) are the gases in the atmosphere that raise the surface temperature of planets such as the Earth. Unlike other gases, greenhouse gases absorb the radiations that a planet emits, resulting in the greenhouse effect. T ...

. The twenty-year global-warming potential, GWP(20), for desflurane is 3714, meaning that one tonne of desflurane emitted is equivalent to 3714 tonnes of

in the atmosphere, much higher than sevoflurane or isoflurane. In addition to

global warming potential Global warming potential (GWP) is a measure of how much heat a greenhouse gas traps in the atmosphere over a specific time period, relative to carbon dioxide (). It is expressed as a multiple of warming caused by the same mass of carbon dioxide ( ...

s, drug potency and fresh gas flow rates must be considered for meaningful comparisons between anesthetic gases. When a steady state hourly amount of anesthetic necessary for 1 minimum alveolar concentration (MAC) at 2 liters per minute (LPM) for Sevoflurane, and 1 LPM for Desflurane and Isoflurane is weighted by the GWP, the clinically relevant quantities of each anesthetic can then be compared. On a per-MAC-hour basis, the total life cycle GHG impact of desflurane is more than 20 times higher than Isoflurane and Sevoflurane (1 minimal alveolar concentration-hour). One paper finds anesthesia gases used globally contribute the equivalent of 1 million cars to

global warming Present-day climate change includes both global warming—the ongoing increase in global average temperature—and its wider effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes ...

. This estimate is commonly cited as a reason to neglect pollution prevention by anesthesiologists. However, this is problematic. This estimate is extrapolated from only one U.S. institution's anesthetic practices, and this institution uses virtually no Desflurane. Researchers neglected to include

nitrous oxide Nitrous oxide (dinitrogen oxide or dinitrogen monoxide), commonly known as laughing gas, nitrous, or factitious air, among others, is a chemical compound, an Nitrogen oxide, oxide of nitrogen with the Chemical formula, formula . At room te ...

in their calculations, and reported an erroneous average of 17 kg CO2e per anesthetic. However, institutions that utilize some Desflurane and account for nitrous oxide have reported an average of 175–220 kg CO2e per anesthetic. Sulbaek-Anderson's group therefore likely underestimated the total worldwide contribution of inhaled anesthetics, and yet still advocates for inhaled anesthetic emissions prevention. In March 2023, Scotland became the first country to ban its use due to its environmental impact.