[Incidence of intensive care unit delirium]

Abstract

Introduction: Intensive care unit (ICU)-delirium is defined by an acute, fluctuating course. Hallucinations and anxiety are frequent. This patient group experiences increased morbidity and mortality. The incidence of ICU-delirium is reported to range from 16% to 87% in international studies, but until now the incidence in Denmark has remained unknown. Many studies focus on the risk in elderly patients. The aim of this study was to elucidate the incidence of ICU-delirium in Denmark and to describe relations to medication and age.

Material and methods: At three ICUs, a total of 139 adult patients were screened for delirium by the Confusion Assessment Method for the ICU (CAM-ICU) from 48 hours after admission and until they were transferred to another ward or died. The CAM-ICU takes into account the sedation level of the patient and is applicable even if patients are in a respirator.

Results: A total of 41 patients (29.5%) had at least one positive score for delirium, 61 (43.9%) never had a positive score and 37 (26.6%) were too sedated throughout their stay at the ICU to be scored. Thus, the incidence for ICU-delirium was 40.2% among patients eligible for scoring by the CAM-ICU. Lightly sedated patients (with or without medication) had a 10-fold increased risk of ICU-delirium. Age was not associated with any difference in incidence. Patients were mostly unsedated when scored to have delirium; no sedation medication significantly increased ICU-delirium. Fentanyl used as analgesic showed an increased relative risk of 4.79.

Conclusion: ICU-delirium is common and occurred in all age groups in the present study.