Clinical meaning
Palliative sedation is the monitored use of sedative medications to reduce consciousness in a terminally ill patient with refractory symptoms — 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 disease process. This distinction is supported by the principle of double effect. Importantly, sedation does NOT equal analgesia — the sedated patient may still experience pain, and opioid infusions must be continued concurrently because benzodiazepines and barbiturates have no analgesic properties. Refractory symptoms warranting palliative sedation most commonly include intractable delirium with agitation (most frequent indication), refractory dyspnea, uncontrollable pain, refractory seizures, and hemorrhagic emergencies in patients with comfort-only goals.