Palliative sedation (PS) is imperative for relieving untreatable and intractable symptoms in terminally ill patients. Refractory symptoms include distress, anxiety, delirium, and pain for which palliative care (PC) is adjusted accordingly. Terminally ill patients at the end of life (EOL) may require continuous sedation until death (CSD) to manage refractory suffering with appropriate sedation and analgesia. An optimal evaluation of consciousness and comfort to guide medication adjustments is indispensable for optimizing PC and patient well-being in CSD [1].

Traditionally, behavioral observational scales have been used in CSD to adjust sedative medication and analgesics, aiming to prevent over- and under-medication. These observational scales primarily assess the motor responses of sedated patients to stimuli. In PS, a lack of response is generally interpreted as a sign of comfort, absence of pain, lack of distress due to physiological changes in dying patients, and lack of awareness. However, unresponsiveness does not automatically indicate unconsciousness or unawareness [2]. Therefore, the clinical observation of terminally ill patients undergoing PS, especially CSD, when relying solely on motor unresponsiveness, can fail to detect or underestimate consciousness, awareness, discomfort, or pain. This may result in unrecognized and undertreated discomfort and awareness, potentially leading to uncomfortable death during PS 3, 4.

Advanced technological modalities have been developed to assess distress, pain, awareness, and consciousness in anesthetically sedated patients independent of an observational motor response. Neurophysiological monitoring of consciousness using processed electroencephalography (pEEG) monitoring (such as bispectral index [BIS] or Wavelet Anesthetic Value [WAVcns]) and analgesia nociception index (ANI) monitoring for pain and distress are well established in anesthetic and critical care settings 5•, 6, 7. Incorporating similar neurophysiological monitoring into CSD is not common practice and has been relatively infrequently studied. This narrative review discusses the potential improvements in quality care through neurophysiological monitoring in CSD and its implementation.