Compared with BIS, both RASS and PCS appear to be relatively blunt instruments at the lower end of their respective scales. Due caution should be taken interpreting and making clinical decisions based solely on the RASS and PCS and, by extension, other observational measures of patient comfort and sedation.

Background: Terminal delirium, specifically the hyperactive delirium subtype at the end of life, is common in palliative care patients. Standard care often involves sedation to alleviate distress. The alpha2-adrenoreceptor agonist dexmedetomidine may have promise in terminal delirium, due to its properties of decreasing delirium and permitting rousable sedation. Aim: This study aimed to describe the effect of dexmedetomidine on delirium and sedation, when delivered via continuous subcutaneous infusion (CSCI) in patients with terminal delirium. Design: The trial was prospectively registered in the ANZCTR database (ACTRN12618000658213) and conducted in accordance with CONSORT (pilot study extension). Twenty-two adult patients were treated with a CSCI of dexmedetomidine with a two-tier dose schedule, low and high dose. Delirium severity was measured by the Memorial Delirium Assessment Scale (MDAS, target <13), and sedation by the Richmond Agitation-Sedation Scale, Palliative Version (RASS-PAL, target −1 to −3). Results: All patients had a response to dexmedetomidine as measured by decrease in MDAS after initiation; 59% required escalation to high dose to maintain control of delirium. All responses to high dose were sustained. RASS-PAL scores showed significant variability, however mean scores remained within target range on both doses, and the majority of patients were rousable. Fifty percent of patients treated crossed over to standard care; no patients who crossed over were experiencing moderate-severe delirium. Predominant reason for crossover was family request for deeper sedation. Conclusion: Dexmedetomidine shows potential for the management of terminal delirium with improved interactivity. Further research is needed to determine efficacy compared to current standard care.

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