Prevalence and associated factors for delirium in critically ill patients at a Japanese intensive care unit

ObjectiveTo investigate the prevalence and associated factors of delirium in critically ill patients during an intensive care unit (ICU) stay.MethodsWe investigated 103 of 172 patients admitted consecutively to a university-based 20-bed ICU in a 3-month period. Six ICU physicians, who were familiar with the Confusion Assessment Method for the ICU (CAM-ICU), assessed patient delirium daily. Patient demographics, diagnosis, Acute Physiology and Chronic Health Evaluation (APACHE) II score, mechanical ventilation and maximum serum C-reactive protein (max-CRP) level during the ICU stay (max-CRP) were compared between patients who developed delirium and those who did not.ResultsTwenty-one (20%) of 103 patients and 13 (76%) of 17 mechanically ventilated patients developed delirium. APACHE II scores and max-CRP were significantly higher in patients who experienced delirium than in those who did not (P<.001). Use of a mechanical ventilator (P=.002), max-CRP (P=.032) and length of ICU stay (P=.043) were identified as independent associations for delirium development.ConclusionsThe prevalence of delirium was 20% in ICU patients and 80% in ventilated patients in a Japanese ICU.