Delirium incidents in three Danish intensive care units

Delirium as a result of hospitalization in an intensive care unit (ICU) is defined by a mental state different from the patients' normal state and an acute fluctuating course. Both morbidity and mortality are increased in relation to delirium. The incidence of delirium has been reported from 16% to 87% in international studies primarily in elderly patients.

The purpose of this study was to evaluate the incidence of delirium in adult intensive care patients in Denmark and to identify correlations between delirium, sedatives, opioid analgesics and age.

In a prospective follow-up study, 139 adult patients were screened for delirium using the confusion assessment method for the ICU (CAM-ICU) from 48 h after admission to ICU, twice a day until discharged.

A total of 41 patients had at least one positive score for delirium, 61 had only negative scores and 37 were too heavily sedated to be scored during the study period. Thus, the incidence of delirium was 40% among patients who were able to be CAM-ICU scored. Patients who were lightly sedated had a 10-fold increased risk of delirium. There was no difference in incidence by age. Patients who received Fentanyl were more at risk of developing delirium compared with patients who received other or no analgesics. Sedative drugs did not influence the incidence.

In this study delirium occurred in 40% of adult ICU patients of all ages.