Sevoflurane. Features, Organ Effects and Contraindications.

    Sevoflurane used as an inhalational (volatile) anaesthetic for induction and maintenance of general anesthesia. Sevoflurane acts as a positive allosteric modulator of the GABAA receptor and an NMDA receptor antagonist.

    Rapid increases in alveolar anesthetic concentration provides fast induction, but low blood solubility results in a rapid fall in alveolar anesthetic concentration upon discontinuation and rapid emergence.

Toxicity:

• There has been no association with peak fluoride levels following sevoflurane and any renal concentrating abnormality. 

• Alkali such as barium hydroxide lime or soda lime (but not calcium hydroxide) can degrade      sevoflurane, producing another proven nephrotoxic end product (compound A). Accumulation of compound A increases with increased respiratory gas temperature, lowflow anesthesia, dry barium hydroxide absorbent, high sevoflurane concentrations, and anesthetics of long duration.

• some clinicians recommend that fresh gas flows be at least 2 L/min for anesthetics lasting more than a few hours and that sevoflurane not be used in patients with preexisting renal dysfunction.

• Sevoflurane can also be degraded into hydrogen fluoride (can produce an acid burn on contact with respiratory mucosa.)

• Sevoflurane may  sensitize the heart to catecholamine-induced arrhythmias.

Contraindications:

• severe hypovolemia
• susceptibility to malignant hyperthermia
• intracranial hypertension.