BJA Advance Access published online on January 27, 2009
British Journal of Anaesthesia, doi:10.1093/bja/aen402
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Antepartum continuous epidural ropivacaine therapy reduces uterine artery vascular resistance in pre-eclampsia: a randomized, dose-ranging, placebo-controlled study
1 Department of Anesthesiology and Critical Care Medicine
2 Department of Obstetrics and Gynecology, Hadassah Hebrew University Medical Center, PO Box 12000, Ein Kerem, Jerusalem 91120, Israel
3 School of Pharmacy, Hebrew University of Jerusalem, Jerusalem, Israel
4 School of Public Health, Tel Aviv University, Tel Aviv, Israel
* Corresponding author. E-mail: yginosar{at}netvision.net.il
Background: No therapy is currently available to improve the reduced uteroplacental blood flow (UPBF) that characterizes pre-eclampsia. We hypothesized that sympathectomy induced by epidural local anaesthesia reduces uterine vascular resistance (which is inversely correlated with UPBF) in pre-eclampsia.
Methods: Ten pregnant women between 24 and 32 weeks of gestation with pre-eclampsia and uterine artery flow abnormalities were randomized to antepartum continuous epidural therapy (ACET) or control. ACET was initiated by a 5 day dose-ranging trial (ACET-1) of 0.04, 0.06, 0.08, and 0.1% ropivacaine and saline placebo, each at 10 ml h–1 for 24 h. Doses were randomized and double-blind. Doppler ultrasound indices of vascular resistance were assessed at baseline and after each 24 h dosing period in both uterine arteries. Subsequently, these ACET patients were administered 0.1% ropivacaine until delivery (ACET-2), with one additional randomized double-blind placebo day.
Results: Five patients were randomized to ACET. In each patient, one uterine artery exhibited a dose-dependent reduction in vascular resistance (P=0.035), a response that returned to baseline following placebo (P<0.001). The contralateral uterine artery exhibited either increased vascular resistance or no change. In all cases, the uterine artery that responded to ACET had higher baseline resistance than its pair (P=0.043). Baseline right–left difference in resistance between paired uterine arteries was greatly diminished following ACET. Although ACET patients had a mean (SD) duration to delivery of 19 (9) days compared with control 2 (1) days (P=0.008), this should be interpreted with caution because of demographic differences between groups.
Conclusions: ACET reduces uterine artery resistance in pre-eclampsia <32 weeks. Uteroplacental re-distribution is a novel observation and warrants further investigation.
Keywords: anaesthetic techniques, epidural; anaesthetics local, ropivacaine; complications, pre-eclampsia; pregnancy
These data were presented in part at the 78th Annual Meeting of the International Anesthesia Research Society, Tampa, FL, USA, March 2004, and at the 36th Annual Meeting of the Society of Obstetric Anesthesia and Perinatology, Ft Myers, FL, USA, May 2004. The complete study was presented at the 21st International Conference of the Israel Society of Anesthesiologists, Tel Aviv, Israel, September 2008.