SummaryEpidural mixtures containing lidocaine with or without additives are commonly used to convert epidural analgesia in labour to anaesthesia for emergency Caesarean section, but direct comparisons with alternative, single agents in this situation are few. In a prospective double-blinded trial, we compared a freshly prepared lidocaine-bicarbonate-adrenaline mixture (final concentrations 1.8%, 0.76% and 1 : 200,000, respectively) with our standard agent, levobupivacaine 0.5%, for extending epidural blockade for emergency Caesarean section. Using a sequential analysis technique, with data analysed in blocks of 40, women receiving epidural analgesia in labour who required top-up for Caesarean section were randomly assigned to receive 20 ml of epidural solution over 3 min. The first analysis (n = 40) indicated that the study should be stopped, as significant differences were found in our primary outcome data. Median (IQR [range]) times to reach a block to touch to T5 and cold to T4 were, respectively, 7 (6-9 [5-17]) min and 7 (5-8 [4-17]) min for lidocainebicarbonate-adrenaline, and 14 (10 )17 [9-31]) min and 11 (9-14 [6-30]) min for levobupivacaine (p = 0.00004 and 0.001, respectively). Pre-and intra-operative supplementation ⁄ pain, maternal side-effects and neonatal outcomes (excluding five women who underwent instrumental delivery) were similar between the groups. Intra-operative maternal sedation (scored by the mother on a 10-point scale) was greater with lidocaine-bicarbonate-adrenaline (4.5 (3-8 [1-9])) than with levobupivacaine (3 (1-4 [1-7])), but not significantly so (p = 0.07). We conclude that epidural lidocaine-bicarbonate-adrenaline halves the onset time when extending epidural analgesia for Caesarean section although there is a possibility of increased maternal sedation. When extending epidural analgesia in labour for emergency Caesarean section, the most appropriate choice of local anaesthetic for achieving rapid and reliable epidural anaesthesia remains unclear. A recent survey of leading UK obstetric anaesthetists [1] found that 13 combinations of local anaesthetics and adjuncts are used in this situation, with 2% lidocaine (alone or in combination) used by 40% of respondents and 0.5% levobupivacaine or bupivacaine used by 72% of respondents (some respondents using more than one in their practice). In our unit, levobupivacaine is the standard agent used in this situation and was adopted as a result of previous studies that showed no consistent advantage of alternatives [2][3][4], and because of the superior safety profile of levobupivacaine compared with bupivacaine [5,6]. Use of levobupivacaine has recently been recommended as best practice when extending epidural analgesia for emergency Caesarean section [7].We have found that trainees rotating to our unit often report the use of a lidocaine-bicarbonate-adrenaline mixture in other units when a faster onset of block is required, for example when there is fetal compromise.