Delirium in a Medical Intensive Care Unit: Prevalence, Risk Factors and Outcomes

Abstract

Objective: Delirium is a common problem in critical care. Its prevalence in the unit varies, depending upon the severity of the illness and the diagnostic methods. Currently, the CAM-ICU is a diagnostic tool with good diagnostic accuracy. Our study aimed to determine the prevalence, associated factors, and outcomes of delirium in our unit by using the CAM-ICU. Methods: Our prospective cohort study included all patients admitted to the hospital’s medical ICU from August to December, 2013. Patients with psychosis and/or in a coma (RAAS<-3) were excluded. We assessed delirium by using the CAM-ICU within the first 24 hours of admission and then serially, every 48 hours until discharge. Factors associated with this condition and patients’ outcomes were also explored. Results: A total of 74 patients were included. Of these, 43% were male, 40% had sepsis, and 81% were mechanically ventilated. Twenty-eight patients (38%) had delirium upon admission. The delirium patients were older and had a higher percentage of dementia. Univariate analysis revealed that dementia, anemia, acute metabolic acidosis, and the use of mechanical ventilation were associated with the occurrence of delirium, and, for age > 70 years, anemia and metabolic acidosis remained significant on multivariate analysis. Delirium was significantly associated with prolonged hospitalization (>30 days), with OR = 4.84 (p=0.009), and with increased mortality, with OR = 25.0 (p=0.001). Conclusion: This study confirmed that delirium was common in the medical ICU and was associated with poor outcomes. Importantly, associated factors with delirium in our study appeared to be modifiable. Further study on early management and prevention of those risk factors is crucial.