Delirium screening for patients in the Intensive Care Unit: A prospective validation study of the iCAM-ICU by nurse researchers and bedside nurses in routine practice

Abstract Background Daily delirium assessment using the Confusion Assessment Method for the Intensive Care Unit was recommended for patients in the intensive care unit, yet implementation may be difficult because of lack of simple and standardized data collection schemes which may result in low sensitivities when used by bedside nurses. Objective This study was to validate the diagnostic accuracy of the i ntelligent C onfusion A ssessment M ethod for the I ntensive C are U nit (iCAM-ICU) used by both nurse investigators and bedside nurses in Chinese patients in the intensive care unit. Design Prospective cohort study. Setting A university affiliated tertiary hospital in China. Participants A total of 373 hospitalized patients (181 in phase I and 192 in phase II) in the intensive care units met the inclusion criteria and participated in the study. There were two nursing researchers (phase I) and 24 bedside nurses (phase II) used the iCAM-ICU to assess delirium among patients. Methods Two prospective cohort studies were conducted to validate the diagnostic accuracy of iCAM-ICU on delirium screening when it was used by nurse investigators and bedside nurses in the intensive care unit. Using the Diagnostic and Statistical Manual of Mental Disorders as the gold standard, the sensitivity, specificity, predictive values along with the likelihood ratios were determined to estimate the performance of the iCAM-ICU in patients in the intensive care setting. The Kappa consistency test was examined to determine the inter-rater consistency. Subgroup analysis in terms of different age, level of education, severity of illness and cognitive status were also conducted to evaluate potential variations of the iCAM-ICU performance in different patient groups. Results A total of 373 patients were included in the validation studies. In comparing with the gold standard, the sensitivities of the iCAM-ICU demonstrated by the two nurse investigators were 95.2 % and 93.7%, while the specificities of the iCAM-ICU were 93.3% and 93.2%. The Kappa consistency between two nurse investigators was 0.96. The sensitivity and specificity of the iCAM-ICU demonstrated by bedside nurses in intensive care patients were 86.7% and 97.7%, respectively. Subgroup analysis also revealed that the sensitivities and specificities in those different subgroups were acceptable, with all statistics being above 80%. Conclusions The iCAM-ICU, an information technology enabled delirium screening tool, showed highly acceptable accuracy in detecting delirium in the intensive care units. It can assist bedside nurses to detect delirium reliably and identify potential patients with delirium accurately. Registration number ChiCTR-OCH-13003050.