A comparison of the hemodynamic effects of paracervical block and epiduralanesthesia for labor analgesia

Background: Both paracervical block (PCB) and epidural analgesia are someti mes associated with hemodynamic effects potentially harmful to the well-bei ng of the fetus. Our study was designed to test the hypothesis that PCB wou ld have a more profound effect on maternal and fetal blood flow than epidur al analgesia. Methods: Forty-four healthy primiparous parturients were randomized to rece ive either PCB (n=21) or epidural analgesia (n=23) with 25 or 30 mg of bupi vacaine, respectively for labor analgesia. Maternal blood pressure and feta l heart rate were recorded. Blood flow was measured using a color Doppler d evice. The blood flow measurements consisted of assessment of the pulsatili ty indices (PI) of the right maternal femoral artery and the main branch of the uterine artery (placental side), the umbilical artery and the fetal mi ddle cerebral artery. The measurements were performed before administration of analgesia and approximately 15-20 min later after the onset of analgesi a. Results: Both methods provided in general good analgesia, but rescue medica tion was required more often after PCB. Epidural analgesia decreased matern al blood pressure more than PCB and the PI of maternal femoral artery decre ased after onset of epidural analgesia, indicating epidural-induced vasodil ation. The PI of the uterine artery increased after the onset of PCB, indic ating vasoconstriction of this artery. No significant adverse effects or di fferences in the well-being of the newborn were observed, as indicated by s imilar Apgar scores and pH-status. Conclusion: There were small differences in the effects of PCB and epidural analgesia on uteroplacental circulation as well as on maternal hemodynamic s. PCB may have a vasoconstrictive effect on the uterine artery. This and t he fact that the parturients required rescue analgesia more frequently afte r PCB than after epidural block speaks for the feasibility of the latter in obstetrics. (C) Acta Anaesthesiologica Scandinavica 44 (2000).