Effect of age on MAC in humans: a meta-analysis.
It is well known that MAC, the minimum alveolar concentration required to prevent movement in response to surgical incision in 50% of patients, decreases with age. Regression analysis showed that data for humans derived from a comprehensive literature survey were consistent, for age > 1 yr, with log10 MAC decreasing with increasing age at the same rate for all inhaled anaesthetics; approximately equivalent to 6% change per decade of age. With some slight reservation on differences between data from different institutions, the present data for humans are consistent (for age > 1 yr), with the equation MAC = a x 10bx where x = difference in age (in years) from 40, b = -0.00269 (95% confidence limits (CL) -0.0030, -0.0024) and a = MAC at age 40 yr, which, for anaesthetics currently in use clinically, is given by: halothane, 0.75%; isoflurane, 1.17%; enflurane, 1.63%; sevoflurane, 1.80%; desflurane 6.6%; nitrous oxide, 104%; with 95% CL of approximately +/- 7% (+/- 10% for desflurane, +/- 17% for enflurane).
Mapleson
W W
WW
Department of Anaesthetics and Intensive Care Medicine, University of Wales College of Medicine, Cardiff.
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism*; D018685:Anesthetics, Inhalation / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000494:pharmacology; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D008875:Middle Aged; D008956:Models, Chemical; D009068:Movement / Q000187:drug effects*; D011650:Pulmonary Alveoli / Q000378:metabolism*
D018685:Anesthetics, Inhalation