Desflurane

Desflurane (2-(difluoromethoxy)-1,1,1,2-tetrafluoro-ethane) is a highly fluorinated methyl ethyl ether used for maintenance of general anaesthesia. 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 anaesthetic drugs used for general anaesthesia due to its low solubility in blood.

The major 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 that 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 absorbant in anesthesia circuits to produce detectable levels of carbon monoxide through degradation of the anesthetic agent. Baralyme appears less prone to cause this degradation than soda lime. Dry conditions in the carbon dioxide absorbant are conducive to this phenomenon, such as those resulting from high fresh gas flows.

Book references

 * Eger, Eisenkraft, Weiskopf. The Pharmacology of Inhaled Anesthetics. 2003.
 * Rang, Dale, Ritter, Moore. Pharmacology 5th Edition. 2003.

Desfluran Desflurane Desflurano Desfluraan Desfluran