title: The effect of epidural anaesthesia for caesarean section on maternal uterine and fetal umbilical artery blood flow velocity waveforms.
abstract: The blood flow resistance in the maternal uteroplacental and fetal umbilical artery circulation was studied in eight otherwise normal patients undergoing elective lower segment caesarean section. The systolic/diastolic A/B ratio (the ratio of peak systolic to least diastolic flow velocity) for the uteroplacental and fetal umbilical circulation was determined from the artery blood flow velocity-time waveform and used as an index of blood flow resistance. Each patient received a 1 litre intravenous crystalloid infusion before an epidural bupivicaine injection. Both crystalloid infusion and epidural anaesthesia resulted in a significant decrease in the maternal uteroplacental systolic/diastolic (A/B) ratios, associated with a decrease in fetal umbilical artery A/B ratio. This study suggests a beneficial fetal effect from the improved maternal uterine perfusion after epidural anaesthesia.
mesh_terms: D000767:Anesthesia, Epidural; D000773:Anesthesia, Obstetrical; D001783:Blood Flow Velocity; D002585:Cesarean Section; D005260:Female; D005312:Fetal Blood / Q000502:physiology*; D006801:Humans; D011247:Pregnancy; D014469:Umbilical Arteries; D014599:Uterus / Q000098:blood supply*