Cerebral Protection, Eeg End-point

Administration of the various anesthetic agents including barbiturates results in a dose-related reduction in CMRO2 and cerebral blood flow. The maximum reduction occurs with the dose that results in electrocerebral silence. At this point, energy utilization associated with EEG activity has been reduced to zero, but energy utilization for cellular homeostasis persists unchanged. Additional barbiturate administration causes no further decrease in CBF or CMRO2. CMR decreases by 7% per Celsius degree of temperature reduction causing complete suppression of the EEG at about 20 degree C. However, in contrast to anesthetic agents, temperature reduction beyond that at which EEG suppression first occurs does produce a further decrease in CMR.