[Influence of processed EEG monitoring in the anesthetic management and its cost in off-pump coronary surgery: a research protocol].

Backgroud: Although in some studies intraoperative processed EEG monitoring has shown advantages such as less use of hypnotic drugs and decrease duration of both anesthetic emergency and recovery times, there is controversy on the incidence of awareness. It has not been demonstrated that this type of monitoring interferes with length of hospital stay, morbidity and mortality. Processed EEG monitoring, such as the bispectral index (BIS) has been widely accepted in assessing anesthetic depth, yet its usage is not part of the standard monitoring of the American Society of Anesthesiologiy (ASA). Other forms of monitoring anesthetic depth widely used are clinical monitoring associated with monitoring expiratory fraction of halogenated anesthetic agents.

Methodology: Prospective randomized study comparing two groups of patients undergoing coronary artery bypass surgery without cardiopulmonary bypass (CPB): group A - BIS visible (BIS value is shown throughout the procedure) and group B - BIS not visible (BIS is hidden and monitoring of anesthetic depth is based on clinical signs associated with the monitoring of expiratory fraction of halogenated anesthetic agent). The aim of this study is to verify the existence of differences in anesthetic depth and associated costs in the two group study's and also to add evidence to anesthetic depth monitoring in an area where few studies have been done - cardiac surgery.