Desflurane

Trifluoroethanol is also the starting material for the anesthetic Isoflurane (l-chloro-2,2,2-trifluoroethyl difluoromethyl ether [26675-46-7]) (55,56) and Desflurane (2-difluoromethoxy-l,l,l,2-tetrafluoroethane [57041-67-5]) (57). 

Desflurane is less potent than the other fluorinated anesthetics having MAC values of 5.7 to 8.9% in animals (76,85), and 6% to 7.25% in surgical patients. The respiratory effects are similar to isoflurane. Heart rate is somewhat increased and blood pressure decreased with increasing concentrations. Cardiac output remains fairly stable. Desflurane does not sensitize the myocardium to epinephrine relative to isoflurane (86). EEG effects are similar to isoflurane and muscle relaxation is satisfactory (87). Desflurane is not metabolized to any significant extent (88,89) as levels of fluoride ion in the semm and urine are not increased even after prolonged exposure. Desflurane appears to offer advantages over sevoflurane and other inhaled anesthetics because of its limited solubiHty in blood and other tissues. It is the least metabolized of current agents. 

The anesthesiologist selects the anesthetic drug that will produce safe anesthesia, analgesia (absence of pain), and in some surgeries, effective skeletal muscle relaxation. General anesthesia is most commonly achieved when the anesthetic vapors are inhaled or administered intravenously (IV). Volatile liquid anesthetics produce anesthesia when their vapors are inhaled. Volatile liquids are liquids that evaporate on exposure to air. Examples of volatile liquids include halothane, desflurane, and enflurane. Gas anesthetics are combined with oxygen and administered by inhalation. Examples of gas anesthetics are nitrous oxide and cyclopropane. 

Desflurane (Suprane), a volatile liquid, is used for induction and maintenance of anesthesia A special vaporizer is used to deliver this anesthetic because delivery by mask results in irritation of the respiratory tract. 

Hypnotics. Common hypnotics are thiopental, propofol, midazolam, etomidate, ketamine and inhaled anesthetics. The incidence of hypersensitivity reactions with thiopental is rare. Recently, thiopental was involved in less than 1% of allergic reactions in France [9]. Ever since Cremophor EL, used as a solvent for some non-barbiturate hypnotics, has been avoided, many previously reported hypersensitivity reactions have disappeared. In the last French surveys, reactions to propofol accounted for less than 2.5% of allergic reactions, and reactions to midazolam, etomidate or ketamine appear to be really rare [9]. Finally, no immune-mediated immediate hypersensitivity reaction involving isoflurane, desflurane or sevoflurane has been reported despite their wide use. 

The commercial anesthetic desflurane is a prime example of a bioactive compound containing a 1,2,2,2-tetrafluoroethyl group. In general, this group is not commonly encountered, and when it is seen, it is usually as an ether or a sulfide (Scheme 6.6). 

The distribution of anesthetic throughout the entire body may be viewed as an equilibration process (Fig. 7.1.13), with tissues characterized by high blood flows reaching equilibration faster than muscle and fatJ4 Nevertheless, an anesthetic that is excessively soluble in blood will not partition substantially into brain and other tissues. The anesthetic properties of nitrous oxide and diethyl ether have been known since the 1840s. Zeneca Pharmaceuticals introduced the first modem inhalation anesthetic fluothane in 1957. Methoxyfluorane followed in 1960, enflurane 1973, isoflurane 1981, desflurane by Anaquest (Liberty Comer, NJ) in 1992, and sevoflurane by Abbott Laboratories in 1995J6 ... 

Figure 7.1.12 The molecular structure of desflurane (suprane or 1,2,2,2-tetrafluoroethyl difluoromethyl ether).

Economic Value of Desflurane in Comparison to Isoflurane in Low Flow Anesthesia. I. Kuhn, MD, H. Wissing, MD, Department of Anesthesiology, University Hospital Frank-furt/Main, Germany, Theodor Stem Kai, D-60590 Frankfurt/Main, Germany, http //gasnet.med.yale.edu/esia/1998/may/economic.html... 

After drawing and labelling the axis draw a series of build-up negative exponential curves with different gradients as shown. The order of the curves is according to the blood gas partition coefficients. The more insoluble the agent, the steeper the curve and the faster the rate of onset. The exceptions to this are the N20 and desflurane curves, which are the opposite way round. This is because of the concentration effect when N20 is administered at... 

Halothane Isoflurane Enflurane Sevoflurane Desflurane Nitrous oxide... 

Q73 Desflurane is preferred to isoflurane for induction of anaesthesia because it is rapid acting. Desflurane is a liquid at room temperature. 

Desflurane is a rapid-acting, volatile, liquid anaesthetic. Hov/ever, compared v/ith isoflurane, it has a lower potency. Desflurane is not used for the induction of anaesthesia, as it is irritant to the upper respiratory tract leading to cough, apnoea, laryngospasm and increased secretions. 

Desflurane is a close structural relative of isoflurane, but has low lipophilicity that permits rapid induction and recovery as well as good control of anesthetic depth. 

In addition to the medicines mentioned above, a number of opiate- and non-opiate-based analgesics, including COX-2 inhibitors, anaesthetics (e.g. propofol, desflurane, sevoflurane, ropivacaine, levobupivacaine and remifentanil), neuromuscular blockers (e.g. rocuronium bromid, zemuron, cisatracuiium, doxacurium. 

Desflurane 3-5 Yes Some Some Decrease Decrease Bad odor airway irritation, t... 

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