Efficacy of augmentation of epidural analgesia for Caesarean section

Background. Extension of a labour epidural for Caesarean deliveryis thought to be successful in most cases and avoids the useof general anaesthesia. However, most previous studies thathave estimated the failure rate of pre-existing epidural catheterswere performed in small numbers of patients. Methods. Therefore, we undertook to retrospectively measurethe failure rate of indwelling epidural catheters in a largenumber of patients. Results. The anaesthetic team was available at all times andwas permanently led by a senior anaesthetist specialized inobstetrics. Extension was performed using lidocaine 2% withepinephrine (mean 18 (SD 6) ml), combined in most patients withsufentanil (9 (2.2) µg) and/or clonidine (75 µg).Among 194 consecutive extensions performed in a 1-yr period,general anaesthesia was required in five patients (2.6%) whilesedation and/or i.v. analgesia were used in 27 patients (13.9%).In three cases where general anaesthesia was required, the intervalbetween decision to incision was <10 min. No factorassociated with failure could be identified. Addition of a lipophilicopioid or of clonidine did not modify the efficacy of the block(i.e. general anaesthesia or supplementation were required ina similar proportion). Conclusions. The augmentation of labour epidurals for Caesareansection using lidocaine 2% plus epinephrine is a reliable andeffective technique. No factor associated with failure couldbe identified. Br J Anaesth 2003; 91: 532–5