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Created: 24/11/2004


Uses: Induction and maintenance of general anaesthesia

Chemical: Halogenated ether

Presentation: Clear colourless liquid, non-flammable

Mode of action: Mechanism of general anaesthesia remains unclear

Routes: Inhalation, via a calibrated vaporiser. Induction dose 5-8%, maintenance 0.5-3%


Cardiovascular system: Causes a decrease in myocardial contractility and mean arterial pressure. Has little effect on the heart rate and does not sensitise the myocardium to circulating catecholamines. Does not cause ‘coronary steal’

Respiratory system: Causes an increase in respiratory rate; minute volume remains unchanged. Decreased response to hypoxia and hypercapnia. Has a pleasant, non-irritant odour. Relaxes bronchial smooth muscle

Central nervous system: Principal effect is general anaesthesia; little analgesic effect. Decreases cerebral vascular resistance and cerebral metabolic rate. Increases intracranial pressure in a dose-related manner. Does not cause epileptiform EEG activity

Genitourinary system: Decreases renal blood flow

Toxicity: Trigger agent for malignant hyperthermia

Absorption: Coefficients - blood/gas: 0.6; oil/gas: 47; minimum alveolar concentration: 2.05

Sevoflurane is exceptionally insoluble in blood; alveolar concentration therefore reaches inspired concentration very rapidly, resulting in a rapid induction of anaesthesia

Distribution: Initially to areas of high blood flow (brain, heart, liver and kidney). Later to less well-perfused organs

Metabolism: By hepatic cytochrome P450IIEI to yield hexafluoroisopropanol, which is further conjugated to its glucoronide. 3% of the absorbed dose is metabolised

Excretion: Via the lungs, predominantly unchanged. Elimination is rapid due to its low solubility

Special points: Sevoflurane is unstable in the presence of moist soda lime, producing small amounts of a sevo-olefin called ‘Compound A’. Potentiates action of depolarising and non-depolarising muscle relaxants to a greater extent than either halothane or enflurane

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