Management of delirium at the end of life - developing an evidence base

Author: Meera Agar

Agar, Meera, 2013 Management of delirium at the end of life - developing an evidence base, Flinders University, School of Medicine

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Abstract

Aim: Delirium in the palliative care population is a prevalent and distressing problem. To improve delirium recognition and management understanding of how clinical decisions are made for patients with a palliative diagnosis and delirium is crucial. Cholinergic mechanisms are considered important in the pathophysiology of delirium but has not been explored in the palliative population. This thesis aims to explore clinical decision-making in the management of delirium from medical and nursing perspectives, to understand the contribution of anticholinergic mechanisms in delirium pathophysiology and how these impact on outcomes, and to develop clinical trial designs which can assess net clinical benefit of delirium therapies in the palliative setting. Methods: The thesis presents four distinct studies, and a clinical trial protocol with results to date. The first study utilises survey methodology to determine medical specialists' views on care location, investigations, and management of delirium in advanced cancer. In the second study, qualitative methods explored nurses' views on delirium symptoms, management choices, and their views on what caused distress for the person with delirium and their family. Anticholinergic medication use was mapped longitudinally to death, and associations with symptoms, quality of life, functional status and health-service utilisation were explored. The third study comprised serum anticholinergic activity on admission to an inpatient palliative care unit and its association with prevalent and incident delirium in palliative care patients with advanced cancer, after consideration of other demographic and aetiological factors. In the final study, a clinical trial compared the efficacy of risperidone, haloperidol and placebo in delirium in palliative care, discussing robust trial design to determine net clinical benefit of therapies for delirium. Results: Significant variability in delirium care from both medical and nursing perspectives exists. Anticholinergic medication is predominantly symptom control medication associated with reduced function, dry mouth and difficulty concentrating, but not health-service utilisation nor survival. Delirium occurrence was not associated with anticholinergic medication or serum anticholinergic activity. Comorbid illness severity, benzodiazepine dose and presence of cerebral metastases on admission predicts delirium. Implications: Some of the variability seen in clinical practice relates to an evidence practice gap with implications for translation of the delirium evidence base into practice; equally, there are some aspects of delirium care unique to the palliative population. Anticholinergic prescribing in palliative care has potential impacts on function, symptoms and quality of life; however, not on delirium occurrence. Vigilance is needed for the palliative patient with comorbid illness and cerebral metastases, as their chance of developing delirium is high. Well-designed and feasible randomised controlled trials can be conducted to evaluate delirium therapies, and this can also be achieved in the palliative population. Statistical methods need to adequately power the study, and account for delirium fluctuation and other factors influencing delirium outcomes. Standardised treatment algorithms and a contingency for participants whose symptoms escalate and safety or distress is an issue are important. Legislative frameworks can ensure balance of protection of those who lack decision-making capacity, with ethical proxy consent and advancement of the evidence base to improve delirium care.

Keywords: delirium,palliative care
Subject: Medicine thesis, Palliative Care thesis

Thesis type: Doctor of Philosophy
Completed: 2013
School: School of Medicine
Supervisor: Professor David Currow