This study evaluated the correlation and agreement between the Bispectral Index 
(BIS) or A-line Autoregressive Index (AAI) and a clinical scoring system, the 
Ramsay Sedation Scale (RSS), in 40 patients after elective cardiac surgery and 
admission to the intensive care unit. All patients received sedation with 
propofol according to the study protocol. BIS, AAI and RSS were documented at 
two different levels of sedation: deep sedation RSS 4 - 6; and slight 
sedation/extubation RSS 2 - 3. Both the BIS and AAI agreed well with the RSS 
(eta-coefficients of 0.902 and 0.836, respectively, for mean overall RSS 
stages). The systems agreed well among each other (overall intra-class 
correlations of 0.670 for consistency and 0.676 for absolute agreement). There 
was significant discrimination between RSS 2 - 3 and RSS 4 - 6 with BIS and AAI 
(BIS mean difference of 24.73, 95% confidence intervals [CI] 21.08 - 28.37; AAI 
mean difference of 20.90, 95% CI 14.64 - 27.16). In conclusion, BIS and AAI 
correlated well with RSS overall and also at different levels of sedation.