Effects of Cardiopulmonary Bypass on Plasma Propofol Concentrations and Bis Values During Coronary Surgery

Cardiopulmonary bypass (CPB) is known to alter pharmacokinetics (PK) and brain sensitivity to several drugs, including propofol. Few studies, however, have tested if propofol pharmacokinetical alterations observed after CPB could contribute to the increased hypnotic effect of propofol after CPB. This study was designed to test the hypothesis that changes in the PK of propofol contribute to an increase in its hypnotic effects after CPB as evidenced by changes in bispectral index (BIS) values.

Twenty undergoing coronary artery bypass graft patients will be allocated in two groups: 1) CPB groups and 2) off-pump coronary artery bypass graft. Bispectral Index values and blood samples for plasma propofol concentration measurements will be collected along the surgery and up to 12 hours in the post-operative period. Plasma propofol concentrations, Bispectral index values and propofol PK will be compared between the groups.