Evaluation of Microcirculation With Photoplethysmography (Pulse Oximetry) in Healthy Volunteers and Ventilated Patients

The objective of this observational study is to explore microcirculation in healthy volunteers and in ventilated patients in the operating room and in critical care. The general objective of this study is to evaluate microcirculation with photoplethysmography (PPG) in different pathophysiological situations and to compare PPG with available standard methods. Specifically, evaluate the correlation between the determinations of AC-DC waves obtained by Photoplethysmography (PPG) and those obtained in different dynamic tests in healthy volunteers. To compare microcirculation assessments \[capillary refill time (CRT), perfusion index (PI), perfusion index variability (PIV)\] with measurements obtained by PPG in the context of critically ill patients. To compare microcirculation assessments (CRT, PI PVI) with measurements obtained by PPG in the context of patients on invasive mechanical ventilation (IMV) in the operating room and in critical care.