Figure 5-10 The alveolar rate of rise of halothane concentration is more rapid in children (dashed lines) than in adults (solid lines). The difference probably results from the greater ventilation and perfusion per kilogram of tissue in children and the fact that a disproportionate amount of the increased perfusion is devoted to the vessel-rich tissues. FA/FI is the alveolar concentration of anesthetic/concentration of inspired anesthetic. (Data from references ^{[6] [49] [50]} and ^[51] .)