Optimizing clinical O2 saturation mapping using hyperspectral imaging and diffuse reflectance spectroscopy in the context of epinephrine injection

Summary, in English

Clinical determination of oxygen saturation (sO2) in patients is commonly performed via non-invasive optical techniques. However, reliance on a few wavelengths and some form of pre-determined calibration introduces limits to how these methods can be used. One example involves the assessment of sO2 after injection of local anesthetic using epinephrine, where some controversy exists around the time it takes for the epinephrine to have an effect. This is likely caused by a change in the tissue environment not accounted for by standard calibrated instruments and conventional analysis techniques. The present study aims to account for this changing environment by acquiring absorption spectra using hyperspectral imaging (HSI) and diffuse reflectance spectroscopy (DRS) before, during, and after the injection of local anesthesia containing epinephrine in human volunteers. We demonstrate the need to account for multiple absorbing species when applying linear spectral unmixing in order to obtain more clinically relevant sO2 values. In particular, we demonstrate how the inclusion of water absorption greatly affects the rate at which sO2 seemingly drops, which in turn sheds light on the current debate regarding the time required for local anesthesia with epinephrine to have an effect. In general, this work provides important insight into how spectral analysis methods need to be adapted to specific clinical scenarios to more accurately assess sO2.

• Author: Nils Gustafsson; Josefine Bunke; Ludvig Magnusson; John Albinsson; Julio Hérnandez-Palacios; Rafi Sheikh; Malin Malmsjö; Aboma Merdasa
• Department/s: LTH Profile Area: Nanoscience and Semiconductor Technology; NanoLund: Centre for Nanoscience; LU Profile Area: Light and Materials; Ophthalmology Imaging Research Group; LTH Profile Area: Photon Science and Technology; Clinical and experimental lung transplantation; NPWT technology
• Publishing year: 2024-03-01
• Language: English
• Pages: 1995-2013
• Publication/Series: Biomed. Opt. Express
• Volume: 15
• Issue: 3
• Links: http://dx.doi.org/10.1364/BOE.506492
• Document type: Journal article
• Publisher: Optical Society of America
• Topic: Medical Laboratory and Measurements Technologies
• Keywords: Absorption spectroscopy; Clinical applications; Diffuse optical spectroscopy; Diffuse reflectance; Hyperspectral imaging; Spectral linewidth
• Status: Published
• Research group: Ophthalmology Imaging Research Group; Clinical and experimental lung transplantation; NPWT technology
• ISBN/ISSN/Other: ISSN: 2156-7085