## Distinguishing Isoflurane from Sevoflurane ### Key Structural Difference **Key Point:** Isoflurane's **airway irritability** is the most clinically relevant discriminator. It causes dose-dependent airway irritation, laryngospasm, and coughing, making it unsuitable for inhalational induction — especially in pediatric patients. ### Comparative Properties | Property | Isoflurane | Sevoflurane | | --- | --- | --- | | **Airway irritation** | Marked (contraindicated for inhalational induction) | Minimal (ideal for inhalational induction) | | **Blood–gas coefficient** | 1.15 | 0.65 | | **MAC** | 1.15% | 2.0% | | **Hepatic metabolism** | ~0.2% | ~3–5% | | **Emergence time** | Slower (higher blood solubility) | Faster (lower blood solubility) | | **Cardiovascular effects** | Dose-dependent hypotension, reflex tachycardia | Dose-dependent hypotension, less tachycardia | ### Clinical Pearl **Clinical Pearl:** Sevoflurane's **non-irritant airway profile** and **rapid emergence** made it the agent of choice for pediatric inhalational induction, displacing isoflurane in modern practice. Isoflurane remains useful for maintenance in adults but cannot be used for gas induction. ### High-Yield Mnemonic **Mnemonic:** **SEVO = Smooth induction** (sevoflurane's non-irritant nature); **ISO = Irritant** (isoflurane's airway irritability). [cite:Stoelting's Pharmacology in Anesthesia Ch 4]
Sign up free to access AI-powered MCQ practice with detailed explanations and adaptive learning.