RESUMO
OBJECTIVE: To study the effects of maternal epidural anaesthesia on the maternal uterine circulation and the fetal umbilical placental circulation by using Doppler ultrasound techniques. STUDY DESIGN: Twenty-seven patients delivered by elective caesarean section under lumbar epidural anaesthesia were studied. All had a normal pregnancy with no indication of fetal compromise and no indication of maternal disease. Each patient received a 1 litre intravenous crystalloid infusion over 20~30 minutes before an epidural bupivacaine injection. The uterine and fetal umbilical artery velocity waveforms were recorded. And then intravenous cannula and an epidural catheter were inserted. The local anaesthetic agent were injected through the epidural catheter(0.5% bupivacaine 10ml, 20% lidocaine 10 ml). At achieve sensory blockade to the T-4 level after the injection of the anaesthetic agent, the uterine and fetal placental circulation flow velocity-time waveforms were again recorded by using Doppler ultrasound(Multigon 500A, 4 MHz). Significance was tested by means of the paired student t-test. RESULTS: 1. Significant differences were observed between the two groups(Before anaesthesia, S/D ratio of fetal umbilical artery was 2.48+/-0.50. Following anaesthesia, S/D ratio of fetal unbilical artery was 2.24+/-0.40, p < 0.005). 2. Significant differences were observed between the two groups(Before anaesthesia, S/D ratio of maternal uterine artery was 2.29+/-0.41. Following anaesthesia, S/D ratio of maternal uterine artery was 1.95+/-0.25, p < 0.001). CONCLUSION: This study suggests a beneficial fetal effect from the improved maternal uterine perfusion after epidural anesthesia.