 The investigators led a prospective observational study in pregnant women undergoing elective C-section under spinal anesthesia SA using 10 mg of hyperbaric BPV. After surgery, they received bilateral ultrasound-guided TAP block with 50 mg of BPV in each side. Venous blood samples were collected immediately before and at 10, 30, 45, 60, 90, 120, 180, 240, 720 and 1440 minutes after both TAP blocks. The investigators used high performance liquid chromatography HPLC to measure BPV total plasma concentrations. Mean BPV area under the curve AUC was calculated from 0 to 24 hours according to the linear trapezoidal rule. Mean peak of total BPV plasma concentration Cmax and time to reach the peak Tmax were recorded. Electrocardiographic ECG recordings were also repeated at 1, 2, 3 and 4 hours to investigate the effect of BPV on corrected QT QTc intervals. Data were computed using SPSS 20. Quantitative data were expressed as means SD. Qualitative data were expressed as percentages. 