Pathophysiology
Clinical meaning
Palliative sedation is the monitored use of sedative medications to reduce consciousness in a terminally ill patient with refractory symptoms โ symptoms that cannot be adequately controlled despite aggressive conventional treatments trialed at adequate doses within an acceptable time frame. The pharmacological basis involves enhancing inhibitory neurotransmission through GABA-A receptor potentiation. Benzodiazepines (midazolam) bind the benzodiazepine site on GABA-A receptors, increasing the frequency of chloride channel opening and producing dose-dependent anxiolysis, sedation, and amnesia. Barbiturates (phenobarbital) bind a separate site on GABA-A receptors and at high doses directly open chloride channels independent of GABA, producing deeper and more sustained sedation. Propofol enhances GABA-A activity through yet another mechanism, providing rapid-onset, easily titratable sedation in ICU settings. The depth of sedation is measured using the Richmond Agitation-Sedation Scale (RASS), targeting -3 to -5 depending on whether proportional (lightest effective level) or continuous deep sedation is indicated. A critical distinction separates palliative sedation from euthanasia: in palliative sedation, the intent is symptom relief (not death), the dose is proportionally titrated to the minimum needed for comfort, and death results from the underlying...