Which halogenated volatile agent produces the LEAST depression of cardiac output at equipotent doses, largely because it preserves baroreceptor reflex responsiveness?

• A Halothane
• B Enflurane
• C Nitrous oxide
• D Isoflurane ✓

Explanation

Isoflurane causes dose-dependent vasodilation with a modest fall in systemic vascular resistance, but cardiac output is well preserved because baroreceptor reflex tachycardia compensates. Halothane directly depresses myocardial contractility and blunts baroreflexes, producing the greatest fall in cardiac output among the halogenated agents. Enflurane causes intermediate depression. Nitrous oxide is a mild myocardial depressant but is not a halogenated volatile agent, so it fails the stem condition.

Reference: Stoelting's Pharmacology and Physiology in Anesthetic Practice, 5th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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