Mapleson W W
Department of Anaesthetics and Intensive Care Medicine, University of Wales College of Medicine, Cardiff.
Br J Anaesth. 1996 Feb;76(2):179-85. doi: 10.1093/bja/76.2.179.
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).
众所周知，MAC（即50%的患者对手术切口无反应所需的最低肺泡浓度）会随着年龄的增长而降低。回归分析表明，从全面的文献调查中得出的人类数据在年龄大于1岁时是一致的，即对于所有吸入麻醉剂而言，log10 MAC随着年龄的增长以相同的速率下降；大约每十岁变化6%。尽管对不同机构的数据差异略有保留，但目前的人类数据（年龄大于1岁）与方程MAC = a x 10bx一致，其中x = 与40岁的年龄差（以年为单位），b = -0.00269（95%置信区间（CL）为-0.0030，-0.0024），a = 40岁时的MAC，对于目前临床使用的麻醉剂，其值如下：氟烷，0.75%；异氟烷，1.17%；恩氟烷，1.63%；七氟烷，1.80%；地氟烷，6.6%；氧化亚氮，104%；95%置信区间约为±7%（地氟烷为±10%，恩氟烷为±17%）。
