Comparison of loss of resistance technique between Epidrum® and conventional method for identifying the epidural space

Abstract

Background: Epidrum® is a recently developed, air operated, loss of resistance (LOR) device for identifying the epidural space. We investigated the usefulness of Epidrum® by comparing it with the conventional LOR technique for identifying the epidural space.

Methods: One hundred eight American Society of Anesthesiologists (ASA) physical status I or II patients between the ages of 17 and 68 years old and who were scheduled for elective surgery under combined spinal-epidural anesthesia were enrolled in this study. The patients were randomized into two groups: one group received epidural anesthesia by the conventional LOR technique (C group) and the second group received epidural anesthesia using Epidrum® (ED group). While performing epidural anesthesia, the values of variables were recorded, including the number of failures, more than 2 attempts, the incidence of dural puncture, the time needed to locate the epidural space, the distance from the skin to the epidural space and ease of performance, and the satisfaction scores.

Results: The ED group showed a lower failure rate, fewer cases of more than 2 attempts, a lesser time to identify the epidural space, and better ease and satisfaction scores of procedure than the C group, with statistical significance.

Conclusions: Using Epidrum® compared to the conventional LOR technique is an easy, rapid, and reliable method for identifying the epidural space.

Keywords: Epidrum®; Epidural anesthesia; Loss of resistance.

Figures

Fig. 1

The Epidrum® is 2.5 × 2 cm in size and consists of a hard plastic body chamber, an injection port with a one way valve (right side), an outlet port to connect to the epidural needle (left side), and a soft, thin silicon membrane diaphragm on top of the device.

Fig. 2

The injection port connected to the syringe has a one way valve. When air is injected by the connected syringe, the silicon membrane diaphragm assumes the inflated position if the epidural needle end through the outlet port on either end is plugged.

Fig. 3

When the epidural needle tip penetrates the ligamentum flavum into the epidural space, the diaphragm assumes the deflated position because of decreased intra-chamber pressure through the epidural space.