Figure 5-20 The differential suggested by Figure 5-19 extends to measures of more subtle degrees of awakening, such as the digit symbol substitution test (DSST), a measure of judgment and cognition. Notice that there appears to be a greater spread between the results after 2 versus 8 hours of anesthesia. MAC is the minimum alveolar concentration. (Adapted from Eger EI II, Gong D, Koblin DD, et al: Effect of anesthetic duration on kinetic and recovery characteristics of desflurane vs. sevoflurane (plus compound A) in volunteers. Anesth Analg 86:414–421, 1998.)