Decreased venous blood oxygen saturation (SVO2)

Oxygen Saturation of Mixed Venose Blood (SvO2), reference value 68% to 77%, average 75% Clinical significance: Calculate arterial and venous blood oxygen content difference by measuring mixed venous oxygen saturation (SvO2), Can more accurately reflect cardiac output. Waller et al. Have pointed out that there is a high correlation between SvO2 and cardiac index, stroke index, and left ventricular stroke index. When SvO2 decreases and arterial blood oxygen saturation and oxygen consumption are still normal, it can be proved that the cardiac output is also low. Therefore, the oxygen saturation test of mixed venous blood is now considered to be of great value for the monitoring of severe heart and lung diseases. Mixed venous oxygen saturation (SvO2) refers to the oxygen saturation in the pulmonary arterial blood, which reflects the degree of oxygenation of the tissue, and is affected by the oxygen supply and oxygen consumption. Decreased oxygen supply and increased oxygen consumption can lead to a decrease in SvO2. The heart index is calculated from the stroke volume and body surface area. It is an important index for measuring circulation efficiency, cardiac contractility, and evaluating the function of the heart pump. It can objectively and specifically reflect changes in cardiac hemodynamics. Clinical reports indicate that SvO2 is highly correlated with cardiac output (CO) and cardiac index (CI). The decrease in SvO2 is caused by abnormal cardiovascular function that limits cardiac output and insufficient oxygen band capacity. Some scholars have found that there is a strong clinical correlation between the correlation between SvO2 and CI and patient survival. In the case of obvious venous hypoxemia, cardiac output cannot be increased, which can reduce survival rate.