Mortality Within 2 Years After Surgery in Relation to Low Intraoperative Bispectral Index Values and Preexisting Malignant Disease

Abstract

Using a similar set of co-variates as in previous work, we confirmed the statistical relation between 1-yr mortality and T(BIS <45), and we extended this observation to 2-yr mortality. However, this relation is sensitive to the selection of co-variates in the statistical model, and a randomized study is required to demonstrate that there really is a causal impact from and T(BIS <45) on postoperative mortality and, if it does, the effect is probably very weak in comparison with co-morbidity as assessed by ASA physical score, the preexisting malignancy status at surgery and age.