Sevoflurane
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Sevoflurane (2,2,2-trifluoro-1-(trifluoromethyl) ethyl ether), also called fluoromethyl, is a sweet-smelling, non-flammable fully-fluorinated methyl isopropyl ether, used for induction and maintenance of general anesthesia. Together with desflurane, it is replacing isoflurane and halothane in modern anesthesiology. It is often administered in a mixture of nitrous oxide and oxygen. After desflurane it is the volatile anesthetic with the fastest onset and offset.
Though it vaporizes readily, it is a liquid at room temperature and is administered via a anesthetic vaporizer attached to an anesthetic machine.
It was introduced into clinical practice initially in Japan in 1990.
In contact with the soda lime in a rebreathing apparatus that serves as carbon dioxide absorber sevoflurane forms at least two degradation products, Compound A [fluoromethyl-2,2-difluoro-1-(trifluoromethyl)vinyl ether] and Compound B [1,1,1,3,3-pentafluoro-2-(fluoromethoxy)-3-methoxypropane], especially at higher temperatures and when the soda lime is desiccated. Compound A has been shown to cause renal necrosis in rats. In humans, direct histological evidence of renal toxicity has not been demonstrated, although there is dose-related proteinuria, glycosuria and enzymuria. During low-flow anaesthesia, when the lower fresh gas flow leads to decreased flushing of the circuit and increased temperature of the Soda Lime, Compound A may build up to clinically significant levels. As a result, sevoflurane is generally administered with a minimum fresh gas flow of 2 liters per minute, making it a relatively expensive choice for maintaining general anesthesia.
Physical properties
| Boiling point: | 58.6 °C | (at 101.325 kPa) |
| Density: | 1.517–1.522 g/cm³ | (at 20 °C) |
| MAC : | 2 vol % | |
| Molecular Weight: | 200 u | |
| Vapor pressure: | 157 mmHg (20.9 kPa) | (at 20 °C) |
| 197 mmHg (26.3 kPa) | (at 25 °C) | |
| 317 mmHg (42.3 kPa) | (at 36 °C)
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