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

Abstract

BackgroundDelirium severity scores are gaining acceptance for measuring delirium in the intensive care unit (ICU). ObjectiveThe 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. MethodsThis 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. ResultsA 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. ConclusionsThe 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 practiceBoth 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.