A Negative Pressure Method Using a CVP Manometer for the Ascertainment of the Epidural Space

Cheun, Jae Kyu; Jee, Dae Lim

Abstract

To identify the epidural space various methods have been recommended and the methods are divided into two major categories, either loss of resistance or negative pressure technics. A s#yringe technic to feel loss-of-resistanse is now widely used clinically due to its reliability and simplicity. However, in some instances, it is very difficult to recognize the epidural space despite using the above methods so that the need for a more safe and easier one is required. After the patient is placed in a sitting flexed position, an 18 gauge Tuohy needles is inserted epidurally at the lumbar area with a saline filled CVP manometer connected via a 3-way stopcock, then a sudden drop of pressure is usually observed and a fluctuation of the pressure can be observed in the water column of the manometer according to the changes in positions, respiration and heart beat. Although this method can be criticized because the technique is somewhat cumbersome and is difficult for retrial when the dura has been punctured, the authors appreciate the experimental values of the technic and suggest its aduantanges as follows: 1) it is a visual thchnic. 2) the measurement of epidural pressure is possible. 3) it prevents back-drip of local anesthetic solution with a 3-way stopcock. 4) it is useful as an index for determination of local anesthetic volume to be injected.