UTERINE AND UMBILICAL BLOOD-FLOW VELOCITY DURING EPIDURAL-ANESTHESIA FOR CESAREAN-SECTION

The purpose of this study was to use colour Doppler to determine the e ffect of epidural anaesthesia on the uterine and umbilical blood flow velocities. After determining the precision of the technique, Doppler insonation of the uterine and umbilical arteries was performed in cons enting non-labouring patients requesting epidural anaesthesia for Caes arean section. Patients in Group I were normal and those in Group II w ere at high risk for uteroplacental blood flow abnormalities. The puls atility indexes (PI) of both uterine and umbilical arteries were compa red at the following times: control, after fluid and after anaesthesia using repeated measure analysis of variance. In Group I (n = 30) the PI increased from 0.72 to 0.82 in the left uterine artery and from 0.7 1 to 0.85 in the right uterine artery (P < 0.05). In Group II (n = 10) the PI increased from 0.67 to 0.85 in the left uterine artery (NS) an d from 0.98 to 1.38 in the right uterine artery (P < 0.05). There was no change in the PI in the umbilical artery. We conclude that the PI o f the uterine arteries increases after epidural anaesthesia with lidoc aine, epinephrine and fentanyl but there is no change in the umbilical PI. While these changes do not appear to be clinically important in t he low-risk population, further studies are required to determine the impact of fetuses at high risk for in utero hypoxaemia.