Non-invasive assessment of the microvascular health remains a major challenge in critical care. A commonly used approach relies solely on tissue oxygenation measurements combined with a VOT on the patient’s arm. However, the lack of standardization in this method has made it difficult to integrate into routine monitoring of microvascular health in the ICU.
For the first time, data from over 300 patients were utilized to characterize the microvascular and endothelial health in the diverse and heterogeneous population admitted to the ICU by means of optical data combined with VOT using a unique optical platform developed in the hosting group.
These data have been utilized to perform a comprehensive characterization of both healthy and general ICU population. The tissue oxygenation, perfusion as well as the local baseline metabolism have been characterized at rest and in the response to VOT. The patient displayed an impaired microvascular reactivity in all the parameters, in particular, to the ones related to endothelial function, with generally lower baseline metabolism and slower reoxygenation and reperfusion during the cuff deflation.
The initial analysis utilized basic statistical methods to explore the relationships between optical data and VOT-derived parameters, correlations with demographic variables and potential confounding factors.
Within this framework, the project focused on standardizing measurement protocols. Notably, measurements at rest were shown to provide valuable parameters, such as the oxygen metabolism, which correlate with VOT-derived metabolic data. Shortened VOTs and machine learning were also explored as a potential method for predicting VOT-derived endothelial parameters.
The project also explored various non-machine learning techniques to identify patterns and outliers in this heterogeneous ICU population, such as principal component analysis (PCA) using optics and VOT-derived parameters. A preliminary attempt was also made to analyse whole time-series data without extracting specific parameters, furthermore, providing quantitative analysis methods for standardization and to identify subjects whose behaviour deviated from the general ICU population.
This work represents a step forward in standardizing patient monitoring in the ICU, utilizing optics for more efficient and non-invasive assessments.
