title: Epidural catheter with integrated light guides for spectroscopic tissue characterization.
abstract: Epidural catheters are used to deliver anesthetics and opioids for managing pain in many clinical scenarios. Currently, epidural catheter insertion is performed without information about the tissues that are directly ahead of the catheter. As a result, the catheter can be incorrectly positioned within a blood vessel, which can cause toxicity. Recent studies have shown that optical reflectance spectroscopy could be beneficial for guiding needles that are used to insert catheters. In this study, we investigate the whether this technique could benefit the placement of catheters within the epidural space. We present a novel optical epidural catheter with integrated polymer light guides that allows for optical spectra to be acquired from tissues at the distal tip. To obtain an initial indication of the information that could be obtained, reflectance values and photon penetration depth were estimated using Monte Carlo simulations, and optical reflectance spectra were acquired during a laminectomy of a swine ex vivo. Large differences between the spectra acquired from epidural adipose tissue and from venous blood were observed. The optical catheter has the potential to provide real-time detection of intravascular catheter placement that could reduce the risk of complications.
authors.affiliation: Department of Medical Physics and Bioengineering, University College London, London, UK.
authors.forename: R P
authors.initials: RP
authors.lastname: Soto-Astorga
authors.forename: S
authors.initials: S
authors.lastname: West
authors.forename: S
authors.initials: S
authors.lastname: Putnis
authors.forename: J C
authors.initials: JC
authors.lastname: Hebden
authors.forename: A E
authors.initials: AE
authors.lastname: Desjardins
keywords: (170.3890) Medical optics instrumentation; (170.6510) Spectroscopy, tissue diagnostics