A Randomized Comparison of Loss of Resistance Versus Loss of Resistance Plus Electrical Stimulation: Effect On Success of Thoracic Epidural Placement

Abstract

Background: Loss of resistance (LOR) for epidural catheter placement has been utilized for almost a century. LOR is a subjective endpoint associated with a high failure rate. Nerve stimulation (NS) has been described as an objective method for confirming placement of an epidural catheter. We hypothesized that the addition of NS to LOR would improve the success of epidural catheter placement.Methods: One-hundred patients were randomized to thoracic epidural analgesia (TEA) utilizing LOR-alone or loss of resistance plus nerve stimulation (LOR+NS). The primary endpoint was rate of success, defined as loss of sensation following test dose. Secondary endpoints included performance time. An intention-to-treat analysis was planned, but a per-protocol analysis was performed to investigate the success rate when stimulation was achieved.Results: In the intention-to-treat analysis there was no difference in success rates (90% vs 82% [LOR+NS vs LOR-alone]; P = 0.39). The procedural time increased in the LOR+NS group (33.9 ± 12.8 vs 24.0 ± 8.0 min; P < 0.001). The per-protocol analysis found a statistically higher success rate for the LOR+NS group compared to the LOR-alone group (98% vs. 82%; P = 0.017) when only patients in whom stimulation was achieved were included.Conclusions: Addition of NS technique did not statistically improve the success rate for epidural placement when analyzed in an intention-to-treat format and was associated with a longer procedural time. In a per-protocol analysis a statistically higher success rate for patients in whom stimulation was obtained highlights the potential benefit of adding NS to LOR.Trial registration: ClinicalTrials.gov identifier NCT03087604 on 3/22/2017; Institutional Review Board Wake Forest School of Medicine IRB00039522, Food and Drug Administration Investigational Device Exemption: G160273.