Safe practices in epidural catheter tunneling.

Sir,

To avoid inward or the outward migration of epidural catheters, different catheter fixation techniques are reported with variable success, e.g., coiling the catheter under a transparent dressing, different types of dressing, adhesive foam, catheter clamp, or using medication port of intravenous bags.[1] The subcutaneous tunneling of epidural catheter has also been described to secure epidural catheter in easy steps and without added cost of device or apparatus.[2] However, a possibility of needle sticks to clinician and also the shearing of the epidural catheter are apprehended while needle is passed subcutaneously.[3] We would like to emphasize on points from our article that the epidural needle should be placed subcutaneously in paraspinous space by keeping needle tip approximately 1.5–2 cm away from the entry of epidural catheter [Figure 1a,b]. The subcutaneous passage of Touhy needle can also be facilitated by giving slight curvature to needle [Figure 1, inset]. It helps in controlling its subcutaneous placement and brings it out of skin. The use of needle guard, as shown in [Figure 1a], is another method to improve the safe practices in subcutaneous tunneling technique.[3] The use of needle guard at exit point of the needle tip from skin prevents needle stick injury and/or catheter shearing. It also provides counterpressure on skin to take out the needle tip in controlled manner. These simple practices improve the safety of the epidural catheter fixation by subcutaneous tunneling method for long term use.

Figure 1

(a) Image showing the use of needle guard to protect needle tip from any injury to catheter; showing the direction of needle movement in subcutaneous plane. (b) showing the direction of epidural catheter being thread into the needle to pulled back in subcutaneous tunnel. Inset showing the slight curve given to Touhy needle for its easy placement.

Epidural catheter contributing to epidural abscess is uncommon (incidence of 0.01–0.1%).[4] The safety from infection can be ensured by restricting the duration of epidural catheter in situ to 4 days.[5] There can be few indications for an extended period of epidural block, and reassessment of the risk/benefit ratio would certainly be wise after 4 days, if not sooner. It has been suggested that the administration set and filter should be changed after 3 days and that the anesthetist who placed the catheter must take full part in any decision to leave it for longer.[4] It would be interesting to have a randomized controlled trial comparing different fixation methods.