SN3 SHORT NOTE 5M

Describe Sevoflurane in detail.

General Surgery · Final Professional

Properties

Sevoflurane is a fluorinated volatile agent that is non-irritant and pleasant to breathe, with a low blood–gas solubility (0.65) giving rapid onset and offset and a MAC of ~2%. These properties make it the agent of choice for inhalational (gaseous) induction, particularly in children and in patients where intravenous access is difficult or a difficult airway is anticipated.

Uses & Effects

It is used for both induction and maintenance. It causes dose-dependent cardiovascular and respiratory depression but little arrhythmia and is generally well tolerated. It undergoes some metabolism, and it can react with dry CO₂ absorbent to form ‘compound A’ (of theoretical nephrotoxic concern, minimised by adequate fresh gas flows and moist absorbent).

CLINICAL PEARL

Sevoflurane = the inhalational-induction agent: non-irritant, sweet-smelling and of low solubility, giving a smooth, rapid gaseous induction where an intravenous technique is unsuitable.

Comparison & Role

Compared with the older agents, sevoflurane offers the smooth, non-pungent induction that halothane once provided but with far less arrhythmogenicity and a lower solubility that gives quicker control and recovery, and without halothane’s hepatotoxic reputation. Its main practical niches are therefore inhalational induction — where its lack of airway irritation is decisive — and everyday maintenance, and its chief theoretical drawback, the formation of compound A with dry absorbent, is readily managed by avoiding very low flows through desiccated soda lime.

CLINICAL PEARL

In one line: sevoflurane is the agent you can safely ask a frightened child to breathe — sweet-smelling and non-irritant, with a low solubility that lets you deepen and lighten anaesthesia quickly.

DANGER / REMEMBER

Its low solubility gives another practical benefit — depth can be changed quickly during the case and recovery is prompt — so sevoflurane suits day-case surgery as well as inhalational induction.

In Brief

That combination of safety in induction and speed in recovery is why it has become the default volatile agent in much of everyday practice.

Agent of choice for gas induction in children.

KEY POINT

Key points TO remember

Sevoflurane: non-irritant, low solubility (fast), MAC ~2%.
Agent of choice for inhalational induction (children, difficult access/airway) and for maintenance.
Dose-dependent CVS/RS depression, little arrhythmia.
Can form ‘compound A’ with dry absorbent — use adequate flows/moist soda lime.

EXAM TIP

Sources: Morgan & Mikhail’s Clinical Anesthesiology; Miller’s Anesthesia; Ajay Yadav’s Short Textbook of Anaesthesia.

All questions in Inhalational Anaesthetic Agents

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