Validity and reliability of an intuitive conscious sedation scoring tool: The nursing instrument for the communication of sedation*

Abstract

OBJECTIVE: To develop a symmetrical 7-level scale (+3, "dangerously agitated" to -3, "deeply sedated") that is both intuitive and easy to use, the Nursing Instrument for the Communication of Sedation (NICS). DESIGN: Prospective cohort study. SETTING: University medical center. PATIENTS: Mixed surgical, medical intensive care unit (ICU) population. INTERVENTIONS: Patient assessment. MEASUREMENTS AND MAIN RESULTS: Criterion, construct, face validity, and interrater reliability of NICS over time and comparison of ease of use and nursing preference between NICS and four common intensive care unit sedation scales. A total of 395 observations were performed in 104 patients (20 intubated [INT], 84 non intubated) by 59 intensive care unit providers. Criterion validity was tested comparing NICS WITH the 8-point level of arousal scale, demonstrating excellent correlation (rs = .96 overall, .95 non intubated, 0.85 intubated, all p < .001). Construct validity was confirmed by comparing NICS with the Richmond Agitation-Sedation Scale, demonstrating excellent correlation (rs = .98, p < .001). Face validity was determined in a blinded survey of 53 intensive care unit nurses evaluating NICS and four other sedation scales. NICS was highly rated as easy to score, intuitive, and a clinically relevant measure of sedation, and agitation and was preferred overall (74% NICS, 17% Richmond Agitation-Sedation Scale, 11% Other, p < .001 NICS vs. Richmond Agitation-Sedation Scale). Interrater reliability was assessed, using the five scales at three timed intervals, during which 37% of patients received sedative medication. The mean NICS score consistently correlated with each of the other scales over time with an rs of >.9. Using the intraclass correlation coefficient as a measure of Interrater reliability, NICS scored as high, or higher than Richmond Agitation-Sedation Scale, Riker Sedation-Agitation Scale, Motor Activity Assessment Scale, or Ramsay over the three time periods. CONCLUSION: NICS is a valid and reliable sedation scale for use in a mixed population of intensive care unit patients. NICS ranked highest in nursing preference and ease of communication and may thus permit more effective and interactive management of sedation.