Background and Objectives: Epidural analgesia is an established method for pain management. The failure rate is 8% to 12% due to technical difficulties (catheter dislocation and/or disconnection; partial or total catheter occlusion) and management. The mechanical properties of the catheters, like tensile strength and flow rate, may also be affected by the analgesic solution and/or the tissue environment.
Methods: We investigated the tensile strength and perfusion pressure of new (n = 20), perioperatively (n = 30), and postoperatively (n = 73) used epidural catheters (20-gauge, polyamide, closed tip, 3 side holes; Perifix [B. Braun]). To prevent dislocation, epidural catheters were taped (n = 5) or fixed by suture (n = 68) to the skin. After removal, mechanical properties were assessed by a tensile-testing machine (INSTRON 4500), and perfusion pressure was measured at flow rates of 10, 20, and 40 mL/h.
Results: All catheters demonstrated a 2-step force transmission. Initially, a minimal increase of length could be observed at 15 N followed by an elongation of several cm at additional forces (7 N). Breakage occurred in the control group at 23.5 ± 1.5 N compared with 22.4 ± 1.6 N in perioperative and 22.4 ± 1.7 N in postoperative catheters (P < 0.05). Duration of catheter use had no effect on tensile strength, whereas perfusion pressure at clinically used flow rates (10 mL/h) increased significantly from 19 ± 1.3 to 44 ± 72 mm Hg during long-term (≥7 days) epidural analgesia (P < 0.05, analysis of variance). Fixation by suture had no influence on tensile strength or perfusion pressure.
Conclusions: Epidural catheter use significantly increases the perfusion pressure and decreases the tensile strength.
Statistics from Altmetric.com
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.
Drs. Kim and Meyer equally contributed to this work.
Dr. Meyer is professor emeritus for Textile Machinery, ETH Zurich, Switzerland.