Figure 21-1
The interdependency[21]
of cerebral electrophysiologic function and cerebral metabolic rate (CMR). Administration
of various anesthetics,[21]
[22]
[26]
including barbiturates, results in a dose-related
reduction in the cerebral metabolic rate of oxygen (CMRO2
) and cerebral
blood flow (CBF). The maximum reduction occurs with the dose that results in electrophysiologic
silence. At this point, energy utilization associated with electrophysiologic activity
has been reduced to zero, but energy utilization for cellular homeostasis persists
unchanged. Additional barbiturate causes no further decrease in CBF or CMRO2
.
EEG, electroencephalogram.
