Figure 5-5 The alveolar concentration of anesthetic/concentration of inspired anesthetic (FA/FI ratio) rises more rapidly if ventilation is increased. Solubility modifies this impact of ventilation; the effect on the anesthetizing partial pressure is greatest with the most soluble anesthetic (ether) and least with the least soluble anesthetic (nitrous oxide). (Adapted from Eger EI II: Ventilation, circulation and uptake. In Eger EI II [ed]: Anesthetic Uptake and Action. Baltimore, Williams & Wilkins, 1974, pp 122–145.)