[Brain uptake of propofol during target-controlled infusion when effect compartment concentration is targeted]

To study the correlation between the effect compartment concentration (ECC) and the brain uptake of propofol during sedation by target-controlled infusion (TCI).

Twelve ASA physical status I to II patients with neither cardiac nor intracranial diseases were scheduled for elective abdominal operation. Computer-assisted target-controlled infusion of propofol was performed for general anesthesia in all patients with the target ECC set at 4.0 microgram/ml. The plasma propofol concentrations were measured simultaneously from the radial artery and the jugular bulb at different time points by high performance liquid chromatography (HPLC), and the area under time-concentration curve (AUC(a-jv)) was calculated.

Before reaching the target propofol concentration of 4.0 microgram/ml (4.7+/-0.16 min), EEC was positively correlated with AUC(a-jv) (r(ECC-AUC)=0.977, P<0.001), but neither the arterial (Ca) nor jugular bulb propofol concentrations (Cjbv) showed such relation to AUC(a-jv) (r(Ca-AUC)= 0.054, P=0.92; r(Cjbv-AUC)=0.335, P=0.516). When ECC was controlled at 4.00 microgram/ml by TCI, Ca was comparable with Cjbv (P=0.512). Positive correlation was noted between AUCa-jv and ECC (r(ECC-AUC)=0.942, P<0.005) after the termination of infusion till the consciousness recovery of the patients, and Ca and Cjbv showed similar correlation with AUC(a-jv) (r(Ca-AUC)=0.986, P<0.001; r(Cjbv-AUC)=0.974, P<0.001).

During TCI of propofol with ECC as the target concentration, ECC is significantly correlated with AUC(a-jv) to reflect the dynamic changes in cerebral propofol uptake.