StO2

StO2, or tissue oxygen saturation, is a non-invasive measurement that reflects the oxygen saturation of hemoglobin in the microcirculation of tissues. It is distinct from SaO2, which measures arterial oxygen saturation. StO2 provides insight into the balance between oxygen delivery and oxygen consumption at the cellular level. This measurement is typically obtained using near-infrared spectroscopy (NIRS). NIRS devices emit light at specific wavelengths that can penetrate tissue and measure the differential absorption by oxygenated and deoxygenated hemoglobin.

Changes in StO2 can indicate various physiological states. A decrease in StO2 suggests increased oxygen extraction by tissues, potentially due to increased metabolic demand or reduced oxygen supply. Conversely, an increase in StO2 might signify improved oxygen delivery or decreased oxygen consumption. StO2 monitoring has applications in critical care, surgery, and sports medicine, where it can aid in assessing tissue perfusion and identifying potential ischemia. For instance, it can be used to monitor the effectiveness of resuscitation efforts, evaluate muscle oxygenation during exercise, or detect compromised blood flow to organs. While a valuable tool, StO2 interpretation requires consideration of the specific clinical context and potential confounding factors.