Abolition of the extradural sieve by addition of fentanyl to extradural bupivacaine

Abstract

A patient is described in whom breakthrough of pain occurred from uterine rupture during effective extradural analgesia, demonstrating the hypothesis of the "extradural sieve ". Subsequent abolition of this pain by addition of fentanyl to bupivacaine 0.25% raises the question whether or not this combination should be avoided in women with a scarred uterus undergoing "trial of labour". (Br. J. Anaesth. 1992;69:520-521). © 1992 British Journal of Anaesthesia.