The article presents a study which assesses the association among cumulative duration of low processed electrogram-based bispectral index (BIS), anesthetic dose after cardiac surgery, and intermediate-term mortality. It relates that the researchers studied 460 patients who undertook cardiac surgery at the Washington University Medical Center in Saint Louis, Missouri between September 2005 and October 2006. It states that perioperative factors were evaluated using multivariable Cox regression analysis to identify its potential relation with intermediate-term all-cause mortality. The results show that there was no statistically substantial difference in the relationship between concentrations of the end-tidal anesthetic gas during the BIS and anesthetic maintenance phase.