The dose of inhaled anaesthetic required to maintain immobility (MAC) is reduced in all of the following conditions EXCEPT:

• A Hypothermia
• B Chronic alcohol abuse (acute intoxication)
• C Increasing age
• D Hyperthyroidism ✓

Explanation

MAC decreases with hypothermia (approximately 5% per degree Celsius), acute alcohol intoxication (CNS depression), and increasing age (7% per decade after age 40). Hyperthyroidism has no consistent effect on MAC because MAC is primarily determined by spinal cord rather than metabolic rate; it is a common misconception that elevated metabolism raises MAC. Chronic alcohol abuse without acute intoxication may actually increase MAC due to tolerance.

Reference: Morgan & Mikhail's Clinical Anesthesiology, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.