Background
Epidural extension for caesarean section (CS) is anaesthetic technique used at Royal Brisbane and Women’s Hospital (RBWH). We aimed to review the success rate of epidural extension for emergency CS and compare the results with a cohort audited in 2013, prior to implementation of an institutional guideline.
Methods
Ethics exemption was obtained. Data was obtained from the Anaesthesia Benchmarking System Database and the electronic medical record. Information collected included: patient characteristics, mode of delivery, urgency of the CS, epidural drugs and volumes, requirement for general anaesthesia (GA) and reasons for conversion to GA. Successful epidural extension was defined as completion of caesarean section under epidural anaesthesia with no intraoperative conversion to GA. Chi-square test was used to compare success before and after the guideline.
Results
One hundred and seventy-eight women had an epidural and proceeded to Category 1 or 2 CS between July and December 2020. Their mean (SD) age was 31 (4.9) years and 154 (87%) were nulliparous. Successful epidural extension was achieved in 165 patients (92.6%). Epidural extension failed in 4 of 14 Category 1 (29%) and 9 of 164 Category 2 cases (6%). Lignocaine was the most commonly-used local anaesthetic (156, 87% ), followed by ropivacaine (14, 7%). The median (IQR) volume of local anaesthetic for top-up was 20ml (16.5-22.0). In the 2013 cohort, 132 women had an epidural inserted and 122 (92%) had successful epidural extension for CS. The median (IQR) volume of local anaesthetic used in 2013 was 15ml (10-20). There was no significant difference between epidural extension before and after guideline implementation. (p = 0.93).
Conclusion
Epidural extension success at RBWH has changed following introduction of an institutional guideline, however the median volume of local anaesthetic used has increased. Extension failure was more common in Category 1 CS.