Longnecker's Anesthesiology > Part 4. Managing Anesthesia Care > Section E. Specialty Areas of Anesthetic Practice > Chapter 50. Neuroanesthesia Michael M. Todd, MD, David S. Warner, MD, PhD, Mazen A. Maktabi, MD, and Kamila Vagnerova, MD

Key Points

"1. Most of the physiologic parameters neuroanesthesiologists want to measure are not easy to record in the clinical setting, such as the effect of drugs on cerebral blood flow, cerebral metabolic rate, or intracranial pressure (ICP).

2. To understand ICP, the anesthesiologist should remember the analogy of the brain as a "closed box," out of which something must leave if something else goes in.

3. Although blood is the smallest of the four kinds of tissues located in the brain, its importance lies in the fact that the cerebral blood volume—and hence ICP—can be changed very rapidly.

4. The five factors that control cerebral flow, cerebral blood volume, and intracranial pressure are PaCO₂, PaO₂ plus arterial content, autoregulation, cerebral flow-metabolism coupling, and autonomic nervous system control.

5. While the mechanism(s) controlling flow-metabolism coupling are unknown, it is important to recognize that anesthetics do not "uncouple" flow and metabolism.

6. Different anesthetics (e.g., barbiturates, propofol, etomidate, the volatile agents, and narcotics) all have somewhat different effects on cerebral blood flow (CBF) and cerebral metabolic rate (CMR). In general, intravenous drugs reduce CBF, whereas..."