Effect of Adrenaline on Extradural Anaesthesia and Plasma Bupivacaine Concentrations During Caesarean Section

Extending low‐dose epidural analgesia for emergency Caesarean sectionA comparison of three solutions

“…The alternatives would be a spinal or general anaesthetic, which many would consider as inappropriate in the presence of a functioning epidural. Previous work has shown that slow (3-5 min) injection of 20 ml of epidural bupivacaine 0.5% [1] or lignocaine 2% with adrenaline [2] was safe; although Price et al reported blocks up to C 7 , as in our series, there were no complications when this occurred. A high or total spinal requiring intubation and ventilation may result if the top-up is administered intrathecally.…”

“…Laishley et al [1] and Price et al [2] demonstrated nontoxic plasma levels of local anaesthetic when the epidural top-ups followed the use of higher concentrations of bupivacaine in labour than used in our study (0.25% bupivacaine vs. 0.1% bupivacaine) and it would follow that toxic plasma levels of local anaesthetic are very unlikely to occur after top-up of a pre-existing low-dose epidural for Caesarean section.…”

“…The addition of adrenaline to epidural bupivacaine 0.5% has been shown to improve quality of block for elective Caesarean section but not when an existing epidural is extended for emergency Caesarean section [1]. Howell et al did not demonstrate any reduction in onset time when adrenaline with bupivacaine was used for elective Caesarean section compared with using bupivacaine alone [3].…”

“…Howell et al did not demonstrate any reduction in onset time when adrenaline with bupivacaine was used for elective Caesarean section compared with using bupivacaine alone [3]. One of the reasons adrenaline is added to local anaesthetic solutions is the reduction in local anaesthetic plasma levels that it produces, and consequent increased safety margin; however, it has been demonstrated that epidural adrenaline does not usefully reduce systemic absorption of 0.5% bupivacine in emergency Caesarean section [1]. The aim of this study was to compare three commonly used Caesarean section top-up solutions and the combination of bupivacaine with adrenaline is not used in our institution.…”

“…Various solutions of local anaesthetic have been used for Caesarean section carried out under epidural anaesthesia. Pre-existing epidurals using 0.25-0.5% bupivacaine may be safely extended for Caesarean section with slow boluses of 20 ml 0.5% bupivacaine [1] or 20 ml 2% lignocaine with 1 : 200 000 adrenaline [2]. Because a 50 : 50 mixture of 0.5% bupivacaine and 2% lignocaine with 1 : 200 000 adrenaline may be superior to 2% lignocaine for elective Caesarean section [3], this mixture is often used to extend low-dose epidural analgesia for emergency Caesarean section.…”