Delirium in an intensive care unit: a study of risk factors

Objectives: (1) To establish risk factors for the development of delirium i n an intensive care unit (ICU) and (2) to determine the effect of delirium on morbidity, mortality and length of stay. Design: Prospective study. Setting: Sixteen-bed medical/surgical ICU in a university hospital. Patients: Two hundred and sixteen consecutive patients admitted to the ICU for more than 24 h during 5 months were included in the study. Interventions: Medical history, selected laboratory values, drugs received and factors that may influence patient psychological and emotional well-bei ng were noted. All patients were screened with a delirium scale. A psychiat rist confirmed the diagnosis of delirium. Major complications such as self- extubation and removal of catheters, as well as mortality and length of sta y were recorded. Results: Forty patients (19 %) developed delirium-, of these, one-third wer e not agitated. In the multivariate analysis hypertension, smoking history, abnormal bilirubin level. epidural use and morphine were statistically sig nificantly associated with delirium. Traditional factors associated with th e development of delirium on general ward patients were not significant in our study Morbidity (self-extubation and removal of catheters), but not mor tality, was clearly increased. Conclusion: Predictive risk factors for the development of delirium in stud ies outside the ICU may not be applicable to critically ill patients. Delir ium is associated with increased morbidity. Awareness of patients at risk m ay lead to better recognition and earlier intervention.