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

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.