Figure 5-8 Dogs given constant ventilation demonstrate different rates of rise of the alveolar concentration of anesthetic/concentration of inspired anesthetic (FA/FI ratio). The rates of rise depend on the inspired halothane concentration. The two higher concentrations accelerated the rate of rise by depressing cardiac output and thereby decreasing uptake. (Adapted from Gibbons RT, Steffey EP, Eger EI II: The effect of spontaneous versus controlled ventilation on the rate of rise of alveolar halothane concentration in dogs. Anesth Analg 56:32–34, 1977.)