"hDOS": an automated hybrid diffuse optical device for real-time noninvasive tissue monitoring: precision and in vivo validation

Significance: The hybrid diffuse optical system (hDOS) is a fully automated platform designed to bring advanced optical monitoring closer to clinical practice. Many existing systems lack automation, multiparametric output, and operator independence, limiting their use in demanding environments such as intensive care. hDOS integrates time-domain near-infrared spectroscopy, diffuse correlation spectroscopy, and pulse oximetry to assess both tissue oxygenation and perfusion. Although initially developed in the context of vascular occlusion tests, its modular design makes it suitable for broader applications, including trauma, surgery, anesthesia, and studies in healthy subjects. Aim: It aims to design and validate hDOS, focusing on precision, repeatability, and usability for peripheral microvascular monitoring in both clinical and research settings. Approach: Validation included test-retest measurements, a 7-month clinical deployment in the critical care, and a comparison with a commercial continuous wave NIRS device (INVOS 5100C). Results: The device underwent extensive validation, accumulating over 200 h of usage across ∼150 measurement sessions. The system showed high precision (test-retest CV <1.2% for oxygenation, <13% for perfusion), stable long-term performance, and lower variability than INVOS. It has also detected statistically significant differences during VOTs and detected hemodynamic impairment in ICU patients (n = 100) compared with healthy volunteers (n = 37). Conclusions: hDOS performed well in both bench and clinical settings, offering a unique combination of parameters in a fully automated, self-contained platform.