The minimum alveolar concentration of an anesthetic at 1 atmosphere that will result in immobilization of 50% of patients exposed to a noxious stimulus is called the MAC. Mapleson developed an equation to adjust the MAC for age. The authors is from the University of Wales.



(1) MAC for the anesthetic of a 40 year old adult, in percent

(2) age of the patient


MAC for an anesthetic in a patient in percent =

= (MAC for a person at 40 years)*(10^(-0.00269 * ((age)-40)))


MAC at age 40 for various anesthetics:

(1) halothane: 0.75%

(2) isoflurane: 1.17%

(3) enflurane: 1.63%

(4) sevoflurane: 1.80%

(5) desflurane: 6.6%

(6) nitrous oxide: 104%


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