Development of delirium: Association with old age, severe burns, and intensive care

Delirium is defined as a disturbance of attention and awareness that develops over a short period of time, is a change from the baseline, and typically fluctuates over time. Burn care involves a high prevalence of known risk factors for delirium such as sedation, inflammation, and prolonged stay in hospital. Our aim was to explore the extent of delirium and the impact of factors associated with it for adult patients who have been admitted to hospital with burns.

In this retrospective study, all adult patients who had been admitted with burns during a four-year period were studied, including both those who were treated with intensive care and intermediate care only (no intensive care). Daily records of the assessment of delirium using the Nursing Delirium Screening Scale (Nu-DESC) were analysed together with age, sex, the percentage of total body surface area burned, operations, and numbers of wound care procedures under anaesthesia, concentrations of plasma C-reactive protein, and other clinical variables. Logistic regression was used to analyse factors that were associated with delirium and its effect on mortality, and linear regression was used to analyse its effect on the duration of hospital stay.

Fifty-one patients (19%) of the total 262 showed signs of delirium (Nu-DESC score of 2 or more) at least once during their stay in hospital. Signs of delirium were recorded in 42/89 patients (47%) who received intensive care, and in 9/173 (5%) who had intermediate care. Independent factors for delirium in the multivariable regression were: age over 74 years; number of operations and wound care procedures under anaesthesia; and the provision of intensive care (area under the curve 0.940, 95% CI 0.899-0.981). Duration of hospital stay, adjusted for age and burn size, was 13.2 (95% CI 7.4-18.9, p < 0.001) days longer in the group who had delirium. We found no independent effects of delirium on mortality.

We found a strong association between delirium and older age, provision ofr intensive care, and number of interventions under anaesthesia. A further 5% of patients who did not receive intensive care also showed signs of delirium, which is a finding that deserves to be thoroughly investigated in the future.