Figure 5-15 The rate at which the inspired anesthetic concentration (FINS) rises toward the inflowing concentration (FINF) is determined by the inflow rate and circuit volume. In the case illustrated, the circuit volume is 7 L. (Adapted from Eger EI II: Effect of anesthetic circuit on alveolar rate of rise. In Eger EI II [ed]: Anesthetic Uptake and Action. Baltimore, Williams & Wilkins, 1974, pp 192–205.)