A thiopentone infusion titrated to EEG burst suppression is used as salvage therapy for refractory intracranial hypertension. The therapeutic rationale is BEST described as follows:

• A Barbiturates suppress basal cellular metabolism throughout the brain uniformly
• B Deeper EEG suppression below burst suppression level yields proportionally greater metabolic protection
• C Burst suppression uncouples cerebral blood flow from metabolism, maximally lowering flow
• D CMRO2 falls in proportion to the suppression of neuronal electrical activity, and no further reduction occurs once burst suppression is reached ✓

Explanation

Barbiturates reduce cerebral metabolic rate only insofar as it is devoted to neuronal electrical activity; once the EEG shows burst suppression, that component is essentially abolished and deeper dosing produces no additional metabolic saving, because basal cellular metabolism continues unchanged. Flow falls passively in parallel with metabolism since coupling is preserved, not uncoupled. This ceiling effect explains why titration targets burst suppression and why outcome benefit remains unproven.

Reference: Miller's Anesthesia, 9th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.