Higher doses of opioids in patients who need palliative sedation prior to death: cause or consequence?

BACKGROUND: Palliative sedation (PS) is necessary in a significant percentage of patients dying on an acute palliative care unit (PCU). Common indications are terminal restlessness, pain and dyspnoea. On our PCU, terminal restlessness was the main indication for PS but pain was the most prevalent symptom during admission. Because delirium is often drug induced in terminal cancer patients and opioids are amongst the most frequently implicated drugs, we hypothesised that the underlying pain problem and its treatment might have been related to the need for sedation. PATIENTS AND METHODS: To test this hypothesis, we did a retrospective analysis on the use of medication with potential cognitive side-effects, focusing on analgesics, in 68 patients who died on the PCU after PS and 89 patients who died without PS. RESULTS: Ultimately sedated patients used opioids in significantly higher doses; they were more often treated with a rotation to another opioid and with amitriptyline. The dose of opioids used at various time points between admission and death was strongly related to the probability of PS. CONCLUSIONS: Our findings support the hypothesis that, although pain was not the main indication for PS, pain and its treatment might have been primarily related to the need for palliative sedation in this patient cohort.