Objective: The objective of this study is to provide an expert review of delirium in the context of palliative care.
Methods: Based on a primary selection criterion, firstly, studies were included for review if the population studied either had a diagnosis of advanced cancer or was receiving palliative care; alternatively, in the absence of data derived from these populations, studies conducted in other populations were included. Secondly, from the studies meeting the primary selection criterion, we selected those that examined specific standard outcome measures. Thirdly, we selected studies and literature reviews that identified delirium research issues.
Results: Delirium occurs commonly in the context of palliative care where it is likely to cause heightened distress for patients, carers, and families alike, and make interpretation of pain and other symptoms extremely difficult. There is a profound dearth of rigorous studies on delirium in this setting. Ambiguous terminology, varying definitions in internationally recognized classification systems, and failure to use validated assessment tools lead to wide-ranging incidence and prevalence of delirium episodes in such populations. Episodes are usually multifactorial in origin and may portend poor prognosis by preceding death in many cases. Despite this, many are often at least partially reversible with relatively low-burden interventions. The patient's disease status, previous quality of life, and prior expressed wishes regarding goals of care should all be taken into account. Antipsychotics are the pharmacotherapeutic agents most commonly used to control symptoms despite limited evidence either supporting their efficacy or examining their adverse event profile. Often, symptomatic control alone is indicated. In cases with refractory symptoms, deeper or "palliative" sedation may be required.
Conclusion: Further research is needed regarding delirium recognition, phenomenology, the development of low-burden instruments for assessment, family education, predictive models for reversibility, and evidence-based guidelines on the appropriate use of palliative sedation.