Age-adjusted MAC

MAC at a given age: MAC = MAC₄₀ × 10^(−0.00269 × (age − 40))

Agent

Age (years)

Result

2.05 %

Aim for ~1.0–1.3 MAC for surgical anesthesia (combine with opioids/N₂O to reduce volatile load).

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Age-adjusted MAC = MAC₄₀ × 10^(−0.00269 × (age − 40))
= 2.05 × 10^(−0.00269 × (40 − 40))
= 2.05%

Clinical note: MAC drops ~6% per decade past 40. Other reducers: opioids, α2-agonists, hypothermia, hypoxia, hyponatremia, pregnancy. Increasers: chronic alcohol, hyperthermia, hypernatremia, infants (peak at 6 mo). Education only.