Introduction Delirium is characterised by acute onset of fluctuating confusion and altered conscious level. It is common in palliative patients and associated with worse outcomes. Recognition and management of delirium is poorly supported in palliative care units. I aimed to produce sustainable improvement in delirium care in an in-patient hospice unit.

Methods This service improvement project used a behaviour change Theoretical Domain Framework and Normalisation Process Theory based approach comprising one intervention stage and two evaluation stages, and co-design of a refined intervention. I used a mixed-methods evaluation to gather data from: case-note review, staff surveys and interviews.

The first intervention modified existing delirium guidelines, replacing the screening test with the 4AT and simplifying the symptom severity assessment. I integrated the guidelines into the electronic patient record system and appointed ‘delirium champions’ for sustainability. The second intervention was co-designed using a theory-led approach targeting barriers and facilitators to guideline implementation and focussing on sustainability. Feasibility was evaluated using the APEASE criteria (Acceptability, Practicability, Effectiveness, Affordability, Side-effects, Equity).

Results The first intervention delivered an improvement in delirium episodes diagnosed (19% to 39%), receiving systematic assessment of reversible causes (33% to 52%) and managed appropriately with non-pharmacological interventions (17% to 59%). Where risk assessment was conducted, 89% of patients were at high-risk. The co-design developed an intervention focussing on a hospice-wide ‘delirium-friendly’ environment, and the importance of 4AT screening as the pathway to guideline-adherent delirium care. Many elements are applicable to other palliative care inpatient settings.

Conclusion A theory-driven approach to complex intervention design and implementation is feasible in a hospice setting. Given the high-risk for delirium in hospice in-patients, focussing on applying delirium risk reduction strategies to all seems appropriate. Delirium screening appears to be a ‘gateway’ component of delirium care, facilitating delirium recognition and guideline-adherent delirium management.