Which drug shown to protect the brain from CPB ischemia?

• A. Halothane
• B. Nifedipine
• C. Chlorpromazine
• D. Pentothal

Answer: (D)

The brain protection strategy during CPB ischemia centers on lowering the brain’s metabolic demands so neurons can tolerate reduced blood flow longer. Thiopental (Pentothal) is a potent barbiturate that strongly enhances GABAergic inhibition, which massively depresses CNS activity and reduces cerebral metabolic rate for oxygen. This metabolic suppression also lowers cerebral blood flow and helps limit excitotoxic injury and edema during periods of ischemia. Because of this profound reduction in neuronal energy use, thiopental has been used to provide neuroprotection during CPB. The other options don’t offer the same reliable reduction in cerebral metabolic demand or can even raise intracranial pressure or have unclear protective effects in this setting.