Pharmacokinetics of propofol in women undergoing elective caesarean section

We have compared the pharmacokinetics of a bolus induction dose of propofol 2 mg kg-1 in 10 Chinese women undergoing elective Caesarean section with those in six non-pregnant Chinese women having laparoscopic sterilization. Blood propofol concentrations were measured using high pressure liquid chromatography with fluorimetric detection. Pharmacokinetic data were analysed by a model independent method based on statistical moment theory. Data from the laparoscopy group also underwent compartmental analysis, which produced similar kinetic results. Non-compartmental analysis estimated that the women undergoing Caesarean section had a similar elimination half-life (mean 81.27 (SD 18.87) min) and apparent volume of distribution at steady state (2.66 (0.63) litre kg-1) as non-obstetric patients (99.45 (29.40) min and 3.36 (1.87) litre kg-1). Clearance was more rapid in the Caesarean section group (39.32 (8.07) ml min-1 kg-1 vs 29.40 (8.72) ml min-1 kg-1) (P less than 0.05). The increased total body clearance may result from blood loss and delivery of the fetus and placenta at operation, although an increase in extrahepatic clearance is also possible.