Pharmacokinetics of ropivacaine during epidural block combined with general anesthesia

AIM:To study the pharmacokinetics characteristics of patients who used ropivacaine epidural block with general anesthesia. METHODS: Twelve patients scheduled for upper abdominal surgery were included in this study. 0.5% ropivacaine was injected into epidural space before general anesthesia. Blood samples were taken from left radial artery at 1,10,20,30,45,60,75,90,120,150 and 180 min after injecting ropivacaine. The plasma concentration of ropivacaine was determined by HPLC. The Compartment model was fitted by DAS statistics software, and the pharmacokinetic parameters were calculated. RESULTS: There were no adverse effects about ropivacaine during and after operation. The main pharmacokinetic parameters were as follow: tmax was 10 min;Cmax was 0.713 mg/L;t1/2α was 122 min;t1/2β was 190 min;AUC0→180 was (72±10) μg·mL-1·min-1. CONCLUSION: The concentration-time curves were fitted to two-compartment open pharmacokinetic model. 0.5% ropivacaine was proved to be safe, and it had good analgesia effect.