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. Pharmacology
As of 2005 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 GABAA and glycine receptors, and as a negative allosteric modulator of the nicotinic acetylcholine receptor, as well as affecting other ligand-gated ion channels. Stereochemistry
Desflurane medications are a racemate of two enantiomers. Physical properties
Global-warming potential
Desflurane is a greenhouse gas. 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 carbon dioxide in the atmosphere, much higher than sevoflurane or isoflurane. In addition to global warming potentials, 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).
Freys syndrome (also known as Baillargers syndrome, Dupuys syndrome, auriculotemporal syndrome, or Frey-Baillarger syndrome) is a rare neurological disorder resulting from damage to or near the parotid glands responsible for making saliva, and from damage to the auriculotemporal nerve often from surgery.The symptoms of Freys syndrome are redness and sweating on the cheek area adjacent to the ear (see focal hyperhidrosis). They can appear when the affected person eats, sees, dreams, thinks about or talks about certain kinds of food which produce strong salivation. Observing sweating in the region after eating a lemon wedge may be diagnostic. Signs and symptoms
Signs and symptoms include erythema (redness or flushing) and sweating in the cutaneous distribution of the auriculotemporal nerve, usually in response to gustatory stimuli. There is sometimes pain in the same area, often burning in nature. Between attacks of pain there may be numbness or other altered sensations (anesthesia or paresthesia). This is sometimes termed "gustatory neuralgia". Causes
Freys syndrome often results as a complication of surgeries of or near the parotid gland or due to injury to the auriculotemporal nerve, which passes through the parotid gland in the early part of its course. The auriculotemporal branch of the mandibular branch (V3) of the trigeminal nerve carries parasympathetic fibers to the parotid salivary gland and sympathetic fibers to the sweat glands of the scalp.