It is recognised from research done in the aged care population that environmental aspects of hospitals contribute to delirium, and environmental alterations can prevent delirium.  It has been suggested that rates of delirium are potentially relevant as proxy measures of the quality of in-patient care.
A number of studies in aged care settings use multicomponent interventions to attempt to prevent delirium in patients at high risk. Provision of specialist geriatric medical / nursing interventions have been studied. Environmental interventions have focused on normalising sleep patterns, regular activities to maintain cognitive stimulation, limiting the use of catheters and restraints, encouraging mobilisation, regularly reorienting patients, maintaining hydration, and providing and using vision and hearing aids. These interventions involve changes in the organisation of care, and institutionalising these changes is a significant challenge. [2-4]
A similar approach has not been studied in the palliative care setting. Questions about how settings of care affect the mental state of cognitively vulnerable palliative care patients, which aspects of the organisation of care may contribute to the incidence of delirium in palliative care patients, and how delirium impacts on patients’ ability to be cared for in different settings (including at home) have not yet been studied.
What is known
A Cochrane review of interventions to prevent delirium identified only one study which was adequately powered to give a clinically useful result.  This study showed that there was a reduction in incidence and severity of delirium in patients undergoing surgery for hip fracture when a proactive geriatric consultation was provided, with a number needed to treat of 5.6. However further well planned studies are needed to understand the role of preventive strategies for delirium.  There are no studies of preventive approaches in a palliative care population.
What it means in practice
- There is evidence for the impact of environmental factors on cognitively vulnerable patients.  It is important to consider clinical practices and features of the palliative care environment which may increase the risk or severity of delirium, or worsen disorientation, and to minimise these (eg, room and staff changes, day / night disruption, avoidable immobilisation and catheterisation, making sure patients have their hearing aids and glasses, and so on).
- This includes minimising the medication burden wherever possible, with special attention to psychoactive drugs.  A careful assessment of benefit and burden of any medications given to treat palliative care symptoms is necessary.
- Educating and counselling caregivers is an important aspect of managing patients at risk for delirium, or when delirium is diagnosed.