A New Continuous Catheter Delivery System

Abstract

To the Editor: The use of continuous peripheral nerve blockade (CPNB) is an effective technique for providing surgical, perioperative, and chronic anesthesia and analgesia [1-3]. Despite these benefits, the lack of a simple, consistent method of catheter insertion makes this technique difficult and cumbersome. Because of these difficulties, CPNB is reserved for select cases and hence is inconsistently applied. Current catheter delivery systems require multiple manipulations before final catheter placement. Each maneuver adds to the risk of contamination or malintroduction of the catheter [4]. Further, present systems do not allow concomitant nerve stimulation, aspiration for blood, or injection of local anesthetics. These systems also rely on placing a modified IV catheter sheath to deliver local anesthetics. The short length of these systems precludes their use on sites other than the upper extremity. The ideal system would be self-contained and applicable to multiple anatomic sites. It should allow placement of a long, separate catheter. In addition, it should require only one operator to manipulate the needle and catheter. The device should be simple to use, based on conventional single-injection block techniques. It should also consist of a blunt needle, allow peripheral nerve stimulation, continuous aspiration for blood, and injection of local anesthetics. In particular, there should be no need to attach or remove connection tubing while the needle is in close proximity to a neural structure. In an attempt to achieve these goals, we assembled a system from readily available components Figure 1. The system consisted of an 18-gauge Touhy epidural needle, which was covered by a 16-gauge Teflon angiocatheter to provide insulation for nerve stimulation. The catheter covered the entire needle, except at the distal end and a segment of the proximal end. Attached to the proximal end was an alligator clip connected to a nerve stimulator. Connected to the proximal lumen, we secured extension tubing, which allowed for continuous aspiration. By disconnecting this tubing, a 20-gauge epidural catheter could be advanced. This system was useful, but it was time-consuming to assemble, awkward to maneuver, and difficult to maintain sterility. Our regional anesthesia team has devised the following system to improve on this initial set up Figure 2. The system is based on a modified 18-gauge Touhy epidural needle. The needle has been entirely insulated with a Teflon coating, except for the very distal 2 mm. A connector for a nerve stimulator is permanently attached to the needle. At the most proximal end of the needle is an adapter consisting of a luer-lock head with central diaphragm and side arm connector (identical to that found on a central line cordis introducer). This allows continuous aspiration for blood and passage of a catheter through different ports without disconnections. The present system accommodates a standard 20-gauge epidural catheter. The catheter delivery system is simple and self-contained, and it incorporates many safety features that we believe are important for CPNB. By using this type of system, we hope to facilitate CPNB and make it easier to perform. Susan M. Steele, MD Stephen M. Klein, MD Francine J. D'Ercole, MD Roy A. Greengrass, MD, FRCP David Gleason, CRNA Section of Regional Anesthesia; Department of Anesthesiology; Duke University Medical Center; Durham, NC 27710