Delirium assessment in ICU patients: a comparison study

Introduction

Delirium is a frequent problem in the ICU and is associated with a poor prognosis. Delirium in the ICU seems to be underdiagnosed by nursing and medical staff. Several detection methods have been developed for use in ICU patients. The aim of this study was to compare the value of three detection methods (the Confusion Assessment Method for the ICU (CAM-ICU), the Intensive Care Delirium Screening Checklist (ICDSC) and the impression of the ICU physician) with the diagnosis of a psychiatrist, neurologist or geriatrician.

Methods

All patients were eligible for inclusion. We excluded deeply sedated patients (Ramsay score greater than 4), comatose patients (Glasgow coma score less than 8), patients in whom no informed consent was obtained, patients who did not speak or understand Dutch or English, or patients who were deaf. Delirium evaluations were performed by different investigators independently and blinded to each other assessments. The CAM-ICU was used by a trained ICU nurse, the ICDSC was administered by another ICU nurse, the ICU physician was asked whether a patient was delirious or not. Further, a psychiatrist, geriatrician, or neurologist serving as reference rater diagnosed delirium using DSM-IV criteria, based on all available information.

Results

During an 8-month period, 126 patients (mean age 62.4, SD 15.0; mean APACHE II score 20.9, SD 7.5) admitted to a 32-bed mixed medical and surgical ICU were studied. The CAM-ICU showed higher sensitivity and negative predictive value (64% and 83%) than the ICDSC (43% and 75%). The ICDSC showed better specificity and positive predictive value (95% and 82% vs. 88% and 72%). The sensitivity of the physicians view was only 29%, with 96% specificity, 75% positive predictive value and 74% negative predictive value.

Conclusion

The present study shows that the impression of intensive care physicians is not sensitive enough to identify delirium. In this investigation in a mixed ICU population, the CAM-ICU had a higher sensitivity than the ICDSC [1].