Serial administration of a modified Richmond Agitation and Sedation Scale for delirium screening

Abstract

Objectives: Because delirium is a common yet frequently unrecognized condition, this study sought to design a brief screening tool for a core feature of mental status and to validate the instrument as a serial assessment for delirium.

Design: Prospective cohort study.

Setting: Tertiary VA Hospital in New England.

Participants: A total of 95 veterans admitted to the medical service.

Methods: A consensus panel developed a modified version of the Richmond Agitation and Sedation Scale (RASS) to capture alterations in consciousness. Upon admission, and daily thereafter, patients were screened with a modified RASS (mRASS) and independently underwent a comprehensive mental status interview by a geriatric expert, who determined whether the criteria for delirium were met. The sensitivity, specificity, and positive likelihood ratio (LR) of the mRASS for delirium are reported.

Results: As a single assessment, the mRASS had a sensitivity of 64% and a specificity of 93% for delirium (LR, 9.4). When used to detect change, serial mRASS assessments had a sensitivity of 74% and a specificity of 92% (LR, 8.9) in both prevalent and incident delirium. When prevalent cases were excluded, any change in the mRASS had a sensitivity of 85% and a specificity of 92% for incident delirium (LR, 10.2)

Conclusion: When administered daily, the mRASS has good sensitivity and specificity for incident delirium. Given the brevity of the instrument (<30 seconds), consideration should be given to incorporating the modified RASS as a daily screening measure for consciousness and delirium.