The reliability and validity of a new and simple method to measure sedation levels in intensive care patients: a pilot study

BACKGROUND: Since more sophisticated ventilation techniques have enabled patients to comply with the ventilator with little or no sedation, deep sedation levels can easily be avoided. However, successful ventilation techniques also expanded the treatment possibilities for more severely ill patients who require deeper sedation levels. We developed a new sedation score to improve the prevention of oversedation and to simplify scoring practice in the intensive care unit (ICU). OBJECTIVE: The study's objective was to establish the validity and reliability of a new sedation score (Sedic score) for critically ill, sedated adult patients. METHODS: We prospectively evaluated the reliability and validity of the Sedic score. The study took place in a 30-bed ICU in a university teaching hospital. Forty-six consecutive mechanically ventilated and sedated ICU patients were included. The constructed scale consists of five levels of stimuli and five levels of responses. Sedation levels are defined by the sum of stimulus and response. The reliability of the Sedic score was assessed by simultaneous measurement by the research nurse and attending nurse (n=70). Validity was expressed as (1) the hierarchic relation between stimulus and response (n=443), (2) the prediction of wake-up time by the Sedic score (n=46), and (3) the association between the Sedic score and the Ramsay scale (n=88). RESULTS: The method showed excellent reliability. Validity: Weighted kappa between stimulus and response was .82. Multivariate analysis: (recovery time as independent variable) regression line (Y=-2.53+ 2.16 * beta; P <.001) (r2=42%). Correlation between the Sedic scores and the Ramsay scores was r(s) .74 (P=.01). Sixty-seven percent of the patients with a maximum Ramsay score of 6 had scores ranging between 6 and 10 on the Sedic scale, indicating that the Ramsay scale has a serious ceiling effect. CONCLUSION: The Sedic score demonstrates sufficient reliability and validity, and correlates well with wake-up time. It allows for frequent use by nurses to avoid oversedation in patients