Color Flow Doppler in Spinal Ultrasound: A Novel Technique for Assessment of Catheter Position in Labor Epidurals

( Reg Anesth Pain Med 2022;47:775–779) Epidural analgesia is one of the most common pain relief treatments during labor and delivery and is usually very effective. In a small percentage of epidurals, misplacement of the epidural catheter can cause inadequate anesthetic effects. To reduce instances of insufficient pain relief, it would be beneficial to be able to assess the position and flow of the catheter before administering medication. This study was designed to visualize flow in the epidural space using a structured color flow Doppler assessment, and to describe the location of the flow relative to the catheter insertion site. The primary outcome was the visualization of flow in the epidural space by color flow Doppler ultrasound. Secondary outcomes were visualization of catheter flow at the interspace of insertion, and at the interspaces above and below insertion, as well as visibility from unilateral or bilateral view, and visibility of flow on injection of saline only or an injection of a saline and air mixture.