Gas in scattering media absorption spectroscopy as a potential tool in neonatal respiratory care

Abstract

Gas in scattering media absorption spectroscopy (GASMAS) is a novel optical technology employing near-infrared light. It has a potential use in the medical setting as a monitoring and diagnostic tool by detecting molecular oxygen within gas pockets and thus may be a useful adjunct in respiratory monitoring. GASMAS has potential advantages over other monitoring devices currently used in clinical practice. It is a non-invasive, continuous, non-ionising technology and provides unique information about molecular oxygen content inside the lungs. GASMAS may have a future role in optimising respiratory management of neonates in different clinical scenarios such as monitoring cardiorespiratory transition in the delivery room, assessing surfactant deficiency, and optimising endotracheal tube positioning. This article aims to summarise current evidence exploring GASMAS application in a neonate, discuss possible clinical benefits, and compare with other devices that are currently used in neonatal care. IMPACT: This article presents a novel optical technique to measure lung oxygen concentrations that may have important clinical uses. This review summarises the current literature investigating the concept of optical lung oxygen measurement. Information from this review can guide researchers in future studies.

Fig. 1. Schematic drawing of the GASMAS-based lung analyser system.

1 – Dual laser source; 2 – Data acquisition and laser control module; 3 – PC; 4 – Signal pre-amplifier; 5 – Reference measurement cube; 6 – Fibre interference eliminator; 7 – Optical fibre; 8 – Light source probe (emitter); 9 – Diffuse light passing through the lung tissue; 10 – Photosensitive detector probe; 11 – Electric cable; 12 – Neonatal lung.

Fig. 2. GASMAS clinical application for neonatal lung oxygen detection and monitoring.

a, b Skin placement of the probes overlying lung area. LS - light source probe, DP - detector probe. c, d Illustration of light distribution using thoracic CT images of a full-term 4-week-old newborn as an example. Parental consent to use images obtained. Pink-coloured areas represent the approximate extent of near-infrared light illumination used for GASMAS. Given the difficulties in predicting photon migration, the areas of light illumination are not necessarily the same as the areas of light detection.