Figure 21-7 Estimated changes in cerebral blood flow (CBF) and the cerebral metabolic rate of oxygen (CMRO₂ ) caused by volatile anesthetics. The CBF data for halothane, enflurane, and isoflurane were obtained during 1.1 minimum alveolar concentration (MAC) anesthesia (with blood pressure support) in humans^[295] and are expressed as the percent change from awake control values. The CMRO₂ data for halothane, enflurane, and isoflurane were obtained from cats^{[285] [300]} and are expressed as the percent change from N₂ O-sedated control values. Data for sevoflurane were obtained during 1.1 MAC anesthesia in rabbits and are expressed as the percent change from a morphine/N₂ O-anesthetized control state.^[287] CBF values were obtained in patients who received 1 MAC sevoflurane anesthesia.^[301] Desflurane data were obtained in patients to whom 1 MAC desflurane was administered. ^[302]