Performance and validation of two ICU delirium assessment and severity tools; a prospective observational study.

BACKGROUND

The clinical statistical performance of the Confusion Assessment Method Intensive Care Unit (CAM-ICU, including CAM-ICU-7) and Intensive Care Delirium Screening Checklist (ICDSC) have rarely been studied. Additionally, delirium severity is often not measured due to a lack of validation of delirium assessment tools.

OBJECTIVE

The aim was to determine the statistical performance of both delirium assessment tools in daily practice, and the correlation with the gold standard Delirium Rating Scale (DRS)-R98, for delirium severity.

RESEARCH METHOD: CAM-ICU-7 and ICDSC, performed by nurses were compared with the DRS-R98 assessed by delirium experts, twice weekly. Within a time-window of one hour all assessments were independently performed.

DESIGN

A prospective observational study performed between October and December 2020.

MAIN OUTCOME MEASURES: Sensitivity, specificity, positive and negative predictive value of both tools was determined. The correlation between DRS-R98 and CAM-ICU-7 and ICDSC was used for validation of delirium severity.

RESULTS

In total, 104 CAM-ICU-7 and 105 ICDSC assessments in 86 patients were compared with the DRS-R98. For the CAM-ICU-7 and ICDSC, respectively, the sensitivity was 90% and 95%, the specificity was 92.4% and 92.3%. The positive predictive value was 0.76 and 0.80, and negative predictive value was 0.77 and 0.97. Correlation of the CAM-ICU-7 score and ICDSC score with the DRS-R98 score was 0.74 (95% CI 0.64-0.81) and 0.70 (95%CI 0.59-0.79; both p < 0.001), respectively.

CONCLUSION

Both CAM-ICU-7 and ICDSC demonstrated good statistical performance and correlated well with the delirium severity tool DRS-R98.

IMPLICATIONS FOR CLINICAL PRACTICE: Nurses can either use the CAM-ICU(-7) or the ICDSC in their practice, both are accurate in delirium diagnosis. Total CAM-ICU-7 and ICDSC score reflects delirium severity well; the higher the score, the more severe the delirium. This enables nurses to gauge the impact of their interventions and enhance the well-being of patients experiencing delirium by minimizing distressing occurrences.