Generalised oedema monitoring utilising a NIR hyperspectral camera in critically ill neonates: A feasibility study

Generalised oedema is common in neonatal intensive care units (NICUs), particularly in preterm and low-birth-weight infants. Characterised by tissue swelling from excess water accumulation, it can reflect systematic illness such as congestive heart failure, hepatic cirrhosis, nephrotic syndrome, sepsis, and acute kidney injury. Current clinical assessment methods, including formulas based on weight and fluid input/output and visual skin observation, lack accuracy and sensitivity, especially in critically ill infants. Techniques such as bioimpedance and ultrasound have been explored but are unsuitable for neonates and do not provide direct water content measurements. Spectroscopy, a non-invasive optical method, offers a promising solution by measuring tissue water content through light interactions in the Near Infrared (NIR) spectrum. This study investigates oedema in neonates using an NIR hyperspectral system in the NICU. Data was collected from 20 neonates, both with and without oedema over the course of three consecutive days. Spectral analysis revealed significant differences, notably at water absorption peaks around 1200 nm (p = 0.012). A Partial Least Squares Discriminant Analysis (PLS-DA) model effectively differentiated between oedematous and non-oedematous infants using spectral and standard clinical features, achieving 85.56 % recall and 100 % precision in testing. These findings suggest NIR spectroscopy combined with PLS-DA offers a reliable, non-contact method for early oedema detection in neonates, potentially enhancing monitoring and outcomes in the NICU.