BACKGROUND: Effects of cardiopulmonary bypass (CPB) on pharmacokinetics of propofol have been investigated based on the analysis using arterial blood concentration (CA). However, it has been indicated that the usual pharmacokinetic analysis may fail to precisely estimate propofol concentrations in the brain and the depth of anesthesia. We have investigated pharmacokinetics of propofol in the brain using internal jugular venous bulb blood (CJ). In the present study, we measured propofol concentrations in the mixed venous blood (CV) as well as CA and CJ to investigate pharmacokinetics of propofol in the brain and other organs. METHODS: Six adult patients undergoing elective coronary artery bypass graft surgery were studied. Blood samples were taken to measure propofol concentrations before, during and after CPB. CPB was performed by nonpulsatile flow at 37 degrees C. RESULTS: CA and CJ decreased significantly immediately after the start of CPB, but soon recovered to the baseline value. On the other hand, CV remained unchanged at a lower level during the study period. Arterio-jugular concentration gradient (CA-CJ) did not change significantly, while arterio-mixed venous concentration gradient (CA-CV) increased significantly during CPB. CONCLUSIONS: Pharmacokinetics of propofol might be different in the brain compared in other organs.
BACKGROUND: Effects of cardiopulmonary bypass (CPB) on pharmacokinetics of propofol have been investigated based on the analysis using arterial blood concentration (CA). However, it has been indicated that the usual pharmacokinetic analysis may fail to precisely estimate propofol concentrations in the brain and the depth of anesthesia. We have investigated pharmacokinetics of propofol in the brain using internal jugular venous bulb blood (CJ). In the present study, we measured propofol concentrations in the mixed venous blood (CV) as well as CA and CJ to investigate pharmacokinetics of propofol in the brain and other organs. METHODS: Six adult patients undergoing elective coronary artery bypass graft surgery were studied. Blood samples were taken to measure propofol concentrations before, during and after CPB. CPB was performed by nonpulsatile flow at 37 degrees C. RESULTS: CA and CJ decreased significantly immediately after the start of CPB, but soon recovered to the baseline value. On the other hand, CV remained unchanged at a lower level during the study period. Arterio-jugular concentration gradient (CA-CJ) did not change significantly, while arterio-mixed venous concentration gradient (CA-CV) increased significantly during CPB. CONCLUSIONS: Pharmacokinetics of propofol might be different in the brain compared in other organs.