Efficacy of augmentation of epidural analgesia for Caesarean section.

BACKGROUND Extension of a labour epidural for Caesarean delivery is thought to be successful in most cases and avoids the use of general anaesthesia. However, most previous studies that have estimated the failure rate of pre-existing epidural catheters were performed in small numbers of patients. METHODS Therefore, we undertook to retrospectively measure the failure rate of indwelling epidural catheters in a large number of patients. RESULTS The anaesthetic team was available at all times and was permanently led by a senior anaesthetist specialized in obstetrics. Extension was performed using lidocaine 2% with epinephrine (mean 18 (SD 6) ml), combined in most patients with sufentanil (9 (2.2) microg) and/or clonidine (75 microg). Among 194 consecutive extensions performed in a 1-yr period, general anaesthesia was required in five patients (2.6%) while sedation and/or i.v. analgesia were used in 27 patients (13.9%). In three cases where general anaesthesia was required, the interval between decision to incision was <10 min. No factor associated with failure could be identified. Addition of a lipophilic opioid or of clonidine did not modify the efficacy of the block (i.e. general anaesthesia or supplementation were required in a similar proportion). CONCLUSIONS The augmentation of labour epidurals for Caesarean section using lidocaine 2% plus epinephrine is a reliable and effective technique. No factor associated with failure could be identified.