Abstract

This systematic review aimed to compare the effectiveness of spinal anesthesia versus extending an existing labor epidural for urgent intrapartum cesarean deliveries. A systematic review of nine studies (one randomized trial, eight observational) was conducted including Europe, Asia, and North America. Primary outcomes were conversion to general anesthesia (GA) and analgesic failure. Secondary outcomes included timing metrics, maternal hemodynamics, and neonatal indices. It was found that GA conversion after attempted epidural activation ranged from 3.4% to 21%, varying by urgency and catheter quality. The single randomized trial found that spinal anesthesia provided a safer surgical block than epidural activation (block failure 2.5% vs 15.3%) and required fewer analgesic rescue interventions (1.3% vs 12.9%), with similar Apgar scores. While one cohort found switching to spinal shortened the anesthesia to incision interval, other studies noted that epidural activation or immediate GA achieved shorter decision to delivery intervals (DDI) than a new spinal. Spinal anesthesia produced more hypotension without an associated neonatal disadvantage. A recent epidural top-up increased the risk of a failed or high spinal. Removing a suboptimal epidural to perform a new neuraxial block improved success compared with attempting to activate the existing catheter. GA was fastest for category 1 deliveries, but was linked to worse neonatal condition and greater maternal blood loss. The evidence suggested extending a well-functioning epidural is a rapid option. For a poorly functioning catheter, a new spinal block is more reliable. Streamlined neuraxial pathways reduce avoidable GA conversions without compromising neonatal outcomes.

Key words: Effectiveness, spinal anesthesia, epidural anesthesia, obstetric surgery, emergency setting, systematic review