The tissue perfusion marker (lactate, ScVO2) has limitations. Therefore, the PvaCO2 gap is described as a parameter reflecting tissue hypoperfusion. Since occult regional ischemia, ie undetected at the systemic level, is considered a major contributor to morbidity and mortality after major trauma and in other critically ill patients, early detection of regional hypoxia is necessary. Traditionally, oxygenation is measured with invasive devices. NIRS is further used as a noninvasive monitoring technique that assesses regional brain oxygen saturation.

Keywords : PvaCO2 gap, NIRS, StO2, Sepsis.