devices for accurate placement of epidural tuohy needle for anaesthesia administration
;N. Vaughan;V. N. Dubey;M. Y. K. Wee;R. Isaacs
advances in medical education and practice2014Vol. 5pp. 1-6
98
vaughan2014mechanicaldevices
Abstract
The aim of this project is to design two sterile devices for epidural needle
insertion which can measure in real time (i) the depth of needle tip during
insertion and (ii) interspinous pressure changes through a pressure
measurement device as the epidural needle is advanced through the tissue
layers. The length measurement device uses a small wireless camera with
video processing computer algorithms which can detect and measure the moving
needle. The pressure measurement device uses entirely sterile componenets
including a pressure transducer to accurately measure syringe saline in
mm Hg. The data from these two devices accurately describe a needle insertion
allowing comparison or review of insertions. The data was then
cross-referenced to pre-measured data from MRI or ultrasound scan to
identify how ligemant thickness correlates to our measured depth and
pressure data. The developed devices have been tested on a porcine specimen
during insertions performed by experienced anaesthetists. We have obtained
epidural pressures for each ligament and demonstrated functionality of our
devices to measure pressure and depth of epidural needle during insertion.
This has not previously been possible to monitor in real-time. The benefits
of these devices are (i) to provide an alternative method to identify
correct needle placement during the procedure on real patients. (ii) The
data describing the speed, depth and pressure during insertion can be used
to configure an epidural simulator, simulating the needle insertion
procedure. (iii) Our pressure and depth data can be compared to pre-measured
MRI and ultrasound to identify previously unknown links between epidural
pressure and depth with BMI, obesity and body shapes.