The learning curve associated with the epidural technique using the Episure™ AutoDetect™ versus conventional glass syringe: an open-label, randomized, controlled, crossover trial of experienced anesthesiologists in obstetric patients.

Abstract

The Episure™ AutoDetect™ (spring-loaded) syringe has been observed to successfully identify the epidural space in 2 pilot studies. In this study we evaluated the impact of the spring-loaded syringe on the establishment of successful epidural labor analgesia (primary outcome), elapsed time for catheter placement, and learning curve (cumulative summary analysis, i.e., Cusum) of experienced anesthesiologists. Fourteen attending and fellow anesthesiologists were randomized to perform 50 consecutive epidural technique attempts using a spring-loaded or conventional glass syringe. Ten participants completed an additional 50 attempts with the alternate syringe in a crossover design. A total of 1200 epidural placement attempts were performed. Use of the spring-loaded syringe was associated with a nonsignificant difference of estimated success rate in obtaining analgesia success (absolute difference of 1.0% 95% confidence interval, CI: -8.9% to 10.8%), shorter elapsed mean time to epidural catheter placement (ratio of 0.92 95% CI, 0.89-0.96); P = 0.003) and similar Cusum curves when compared with a conventional glass syringe. Analgesia success was more common with attending versus fellow anesthesiologists (absolute difference of 34.6% 95% CI, 14.9% to 54.3%; P < 0.001), and when the initial preferred technique was loss-of-resistance to continuous saline versus intermittent air (absolute difference of 33.8% 95% CI, 12.6% to 55.0%; P < 0.001). Shorter elapsed mean times were also observed in the group exposed to the spring-loaded syringe first (ratio of 0.65 95% CI, 0.62-0.67; P = 0.02). When used by experienced obstetric anesthesiologists, the spring-loaded syringe was associated with a similar overall rate for establishing successful epidural labor analgesia, a shorter elapsed time to epidural catheter insertion, particularly when the anesthesiologist was randomized to use the novel syringe first, and a similar Cusum curve when compared with a conventional glass syringe. Attending versus fellow anesthesiologists and an initial technique preference for loss-of-resistance to continuous saline were associated with greater analgesia success with the novel syringe.