Delirium and delirium severity screening in the intensive care-correspondence of screenings tools

Abstract

Background: Delirium severity scores are gaining acceptance for measuring delirium in the intensive care unit (ICU).

Objective: The aim of this study was to evaluate the concordance between the Confusion Assessment Method for the intensive care unit (CAM-ICU)-7 and the Intensive Care Delirium Screening Checklist (ICDSC) as delirium severity measurement tools.

Methods: This was a prospective, comparative, observational multicentre study. This study was conducted in 18 Danish ICUs. Delirium was assessed in adult critically ill patients admitted to an ICU with a Richmond Agitation and Sedation Score (RASS) of -2 or above. ICU nurses assessed delirium with randomised paired delirium screening instruments, using the CAM-ICU, the ICDSC, and the CAM-ICU-7. The correlation between the CAM-ICU-7 and the ICDSC severity scores was evaluated for all predefined patient subgroups.

Results: A total of 1126 paired screenings were conducted by 127 ICU nurses in 850 patients. The patients' median age was 70 years (interquartile range: 61-77), 40% (339/850) were female, and 54% (457/850) had at least one positive delirium score. Delirium severity ranges (CAM-ICU-7: 0-7; and ICDSC: 0-8) were positively correlated (Pearson's correlation coefficient, r = 0.83; p < 0.0001). The overall agreement between the CAM-ICU-7 and the ICDSC for delirium measurement (CAM-ICU-7: >2, and ICDSC: >3) was substantial (kappa = 0.74), but the agreement decreased to fair (kappa = 0.38) if a patient had a RASS less than 0.

Conclusions: The agreement between the CAM-ICU-7 and the ICDSC for delirium severity measurement was substantial but might be affected by the patient's sedation and agitation level at the time of assessment.

Implications for practice: Both CAM-ICU-7 and ICDSC can be implemented for delirium severity measurement. Attention is warranted in both scores if a patient has a RASS of -2.

Keywords: Critically ill; Delirium; Delirium severity; Intensive care unit; Screening method.