Changes in blood oxygen metabolism indices and their clinical significance in children with septic shock

The key to the treatment of septic shock is to provide adequate oxygen supply and improve tissue perfusion. Lactate and central venous oxygen saturation (ScvO2) are commonly used as the indices of oxygen metabolism, but tissue hypoxia may still exist even when lactate and ScvO2 are within the normal range. Arteriovenous difference in carbon dioxide partial pressure (CO2 gap) can accurately reflect oxygen delivery when ScvO2 is in the normal range. This article reviews the advantages and shortages of lactate, lactate clearance rate, ScvO2, and CO2 gap in evaluating tissue hypoxia, in order to provide a reference for treatment and severity evaluation of septic shock.