The correlation between actual blood concentration of propofol and the difference of estimated lean body mass with actual lean body mass in target controlled infusion

Abstract

Background: We evaluated the correlation between the difference of estimated lean body mass (LBME) with actual lean body mass (LBMA) and actual blood concentration of propofol, hemodynamic variables and Bispectral index (BIS) during target controlled infusion (TCI) of propofol in Korean female patients who would take total intravenous anesthesia (TIVA) using propofol-remifentanil combination. Methods: Eighty Korean women participated in this trial. Demographic data were collected and LBMA was measured using body mass analyzer. Target concentration of propofol was set at 6μg/ml during induction and 3μg/ml during maintenance. Hemodynamic variables and BIS were measured at 60 minutes after anesthetic induction. Peripheral blood sample was collected from a large forearm vein on the contralateral side of infusion for measurement of whole blood concentration of propofol at 60 minutes after anesthetic induction. Delta lean body mass (ΔLBM) was obtained by subtracting LBMA from LBME. Correlation analyses were done between ΔLBM and plasma propofol concentration, blood pressure, and BIS, respectively. Results: Blood concentrations of propofol were 1.9−6.9μg/ml. Mean plasma concentration of propofol was higher than target concentration. ΔLBM had a positive correlation with actual plasma propofol concentration. ΔLBM was not correlated with hemodynamic variables and BIS. Conclusions: TCI of propofol resulted in large variation in measured plasma concentration. We thought ΔLBM was one of interpatient variation factors of propofol plasma concentration during TCI. We found that TCI of propofol using Schnider model would result in higher blood concentration than target concentration in Korean women.