After giving consent to participate in the study, the subjects included in the study will undergo a 15-minute measurement of tissue oxygen saturation (StO2) measured non-invasively on the forearm by means of near-infrared spectroscopy (NIRS). Once a baseline stable StO2 value is obtained, a provocative test, consisting of a transient vascular occlusion, will be performed. The test will allow the obtention of a local metabolic rate, and a StO2 recovery rate after the ischemic stimulus. This StO2 recovery rate will be considered as a reflection of the endothelial health of the patient.~Patients will be studied as soon as possible after admission to the ICU, and followed-up until ICU discharge or death.
The purpose of this study is to characterize microvascular reactivity on the forearm muscle using non-invasive near-infrared spectroscopy in critically ill COVID-19 patients, and to correlate its alterations with 28-day mortality in ICU COVID-19 patients.