Color your epidural: color flow Doppler to confirm labor epidural needle position

Abstract

Background: Labor epidural analgesia success depends on precise needle position placement within the epidural space, with reported failure rates to be as high as 32%. In this study, we describe a novel technique employing color Doppler to aid in the confirmation of the correct position of the epidural needle tip.

Methods: Retrospective evaluation of 35 patients who received labor combined spinal-epidural (CSE) with confirmation of epidural needle position with color flow Doppler (CFD) ultrasonography. Demographic data, intervertebral level of insertion and dermatome sensory level were extracted. Video and image evaluation of CFD patterns were used to confirm epidural needle tip and catheter position. CFD was used to visualize intrathecal injection of local anesthetic in two patients.

Results: Three different color flow patterns were visualized after the loss of resistance technique: visualization of a red and blue mosaic adjacent to the posterior complex, a mosaic pattern enveloping the trajectory of the epidural needle, and a linear deeper mosaic color pattern during spinal injection in relation to the posterior complex. Identification of epidural needle tip and epidural catheter tip occurred in 77% and 37.1% of patients, respectively.

Conclusions: CFD is a novel and useful technique to confirm the precise position of the epidural needle tip in the context of labor analgesia. Identification of the epidural catheter with CFD is difficult despite an adequate CSE technique.