Use of cyclopropane to test generality of anesthetic requirement in the elderly.

The minimum alveolar concentration (MAC) of cyclopropane was determined in young (mean age, 32 yr; n = 16) and older (mean age, 81 yr; n = 12) surgical patients. Cyclopropane requirement was 23% lower in the elderly (P less than 0.01). This reduction in anesthetic requirement with age is similar to that reported previously for halothane and isoflurane and supports the thesis of a general effect of age on anesthetic requirement.