Objective: To evaluate the effect of routine use of the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) on the diagnosis rate of delirium in elderly Emergency Department (ED) patients and the validity of the CAM-ICU in the ED setting.
Methods: This was a prospective observational study in a tertiary care academic ED. We compared the diagnosis rate of delirium before implementation of the CAM-ICU, without routine use of a screening tool, with the diagnosis rate after implementation of the CAM-ICU. All consecutive patients aged 70 years or older were enrolled. The diagnosis rate before implementation was based on chart review and after implementation on a positive CAM-ICU score. In a subsample, the presence of delirium was evaluated independently according to the Diagnostic and Statistical Manual of Mental Disorders, 4th ed., text revision (DSM-IV-TR) criteria to assess the validity of the CAM-ICU.
Results: The total study population included 968 patients: 490 before and 478 after implementation of the CAM-ICU. The two groups were not significantly different in patient characteristics. Before implementation of the CAM-ICU, delirium was diagnosed in 14 patients (3%) and after implementation in 48 patients (10%) (P<0.001). The sensitivity of the CAM-ICU for delirium in the ED setting was 100%, specificity was 98%, positive predictive value was 92%, and negative predictive value was 100%.
Conclusion: The diagnosis rate of delirium after implementation of the CAM-ICU was three-fold higher than before. The CAM-ICU is a reliable screening tool in the ED, with high sensitivity, specificity, and positive and negative predictive value.