Objective To investigate the
pharmacokinetic profile of propofol with single bolus intravenous
injection in elderly patients.
Methods In 7 elderly patients aged 67 81 undergoing selective surgical procedures,ASA grade Ⅰ Ⅱ,a single bolus dose of propofol 1 mg/kg was injected via a forearm vein. From right internal jugular vein,3 ml blood sample was taken for whole blood propofol estimation before
injection,and after the end of the propofol injection at the following timepoints: 1,2,4,6,10,15,30,45,60,75,90,120,150,180,240,300 and 360 min. Each sample was thoroughly mixed in tubes containing liquaemin sodium,then centrifuged,the plasma was removed and stored in refrigerator at 4 ℃. Propofol concentrations of plasma were determined by high performance liquid chromatography with fluorescence detection.
Pharmacokinetic analysis was performed using 3P87 programe. Results Pharmacokintics of propofol in 7 elderly patients were best described by a three compartment pharmacokinetic model. The pharmacokinetic parameters including T 1/2 pi (1 5 min,Vc (0 1076 L/kg),K 12 (0 2085 min 1 ),K 13 (0 0866 min 1 ),K 10 (0 1368 min 1 ),CL (0 0142 L·kg 1 ·min 1 ) were similar to those described by the other authors,but T 1/2 α (15 8 min) and T 1/2 β (148 3 min) were shorter. Vc and CL were lower in the elderly compared with those in adult patients reported by the others. Conclusions Propofol has the characteristics of fast onset and short duration of action and rapid recovery when used for anesthesia induction in elderly patients. Because Vc and CL were decreased, the propofol requirements must be reduced in the elderly in order to relieve the side effects and to prevent accumulations.