The use of epidural waveform analysis in the perioperative care and obstetrics: a narrative review

Abstract

Background: Epidural anesthesia is widely utilized for postoperative analgesia and intraoperative anesthesia in both surgical and obstetric settings. Despite advancements, conventional techniques still have a significant failure rate, often due to incorrect catheter placement using the LOR method alone. EWA offers a more objective method for confirming epidural space by using a pressure system that detects oscillations synchronized with the pulsatile epidural arterial circulation.

Study objective: The objective of this narrative review is to describe the reliability of EWA as well as its added value in different situations.

Methods: We included articles sourced from databases MEDLINE, EMBASE, Cochrane Library, and Google Scholar. Screening and eligibility analysis were performed by one reviewer (V.P.). The primary inclusion criterium was the utilization of EWA and its reliability in the operative setting, in pain management as well as in the obstetrical use. We selected 4 prospective trials, 6 observational trials, 1 randomized control trial and 2 systematic reviews.

Results: The studies demonstrate the reliability of EWA for epidural needle and catheter placements at cervical to lumbar levels across various surgeries and in laboring patients. Excluding two outliers, sensitivity ranges from 81% to 100%, and specificity from 42% to 100%. One study reported 0% sensitivity due to no pulsatility observed, while another showed 0% specificity due to a single false positive.

Conclusion: This review highlights the reliability of EWA for guiding anesthetists during epidural needle and catheter insertion, as well as post-insertion evaluation. EWA is effective across various patient conditions, but further high-quality studies are required to assess its effectiveness in challenging cases, such as patients with higher BMI or anatomical variations, to ensure its broader clinical applicability.