Figure 4-3 Plot of the halothane minimum alveolar concentration (MAC) in dogs versus temperature. When measured as a function of the gas-phase partial pressure, MAC decreases with decreasing temperature. When measured as a function of calculated aqueous concentrations, MAC remains relatively constant with changes in temperature from 28°C to 43°C. (From Franks NP, Lieb WR: Temperature dependence of the potency of volatile general anesthetics. Anesthesiology 84:716, 1996.)