Detection of delirium in palliative care unit patients: a prospective descriptive study of the Delirium Observation Screening Scale administered by bedside nurses.

Background: The Delirium Observation Screening Scale (DOS) is designed to detect delirium by nurses' observations and has shown good psychometric properties. Its use in palliative care unit patients has not been studied.

Aim: To determine diagnostic and concurrent validity, internal consistency, and user-friendliness of the Delirium Observation Screening Scale administered by bedside nurses in palliative care unit patients.

Design: In this descriptive study, psychometric properties of the Delirium Observation Screening Scale were tested by comparing the performance on the Delirium Observation Screening Scale (bedside nurses) to the algorithm of the Confusion Assessment Method and the Delirium Index (DI) (researchers). Paired observations were collected on three time points. Afterward, the user-friendliness of the Delirium Observation Screening Scale was determined by bedside nurses using a questionnaire.

Setting/participants: In total, 48 patients were recruited from one palliative care unit (PCU) of a university hospital. Of the 14 eligible bedside nurses of the palliative care unit, 10 participated in the study.

Results: Delirium was present in 22.9% of patients. Diagnostic validity of the Delirium Observation Screening Scale was very good (area under the curve = 0.933), with 81.8% sensitivity, 96.1% specificity, 69.2% positive, and 98% negative predictive value. Concurrent validity of the Delirium Observation Screening Scale with the Delirium Index was moderate (rSpearman = 0.53, p = 0.001). The Cronbach's alpha for all Delirium Observation Screening Scale shift scores was 0.772. Generally, bedside nurses experienced the Delirium Observation Screening Scale as user-friendly. However, most Delirium Observation Screening Scale items (n = 11/13 items) need verbally active patients to perform the observations correctly.

Conclusion: The Delirium Observation Screening Scale can be used for delirium screening in verbally active palliative care unit patients. The scale was rated as easy to use and relevant. Further validation studies in this population are required.