CVP central venous pressure monitoring is a more important technical means in critical care medicine, central venous pressure mainly reflects the return blood volume, right ventricular filling pressure and cardiac function, reflecting the systemic effective circulation volume, the normal central venous pressure is 5-12cmH2O, the reasons for the increase of central venous pressure are as follows: 1, the systemic effective circulation volume is too heavy, which will lead to central venous pressure > 12cmH2O, at this time, the return blood When the right heart function decreases, the return blood volume cannot return to the left heart through the right heart and pulmonary circulation, then it is necessary to increase the myocardial contraction and reduce the cardiac preload. When the right heart function decreases, the cardiac blood can not return to the left heart through the right heart and pulmonary circulation, then it is necessary to increase the myocardial contraction and reduce the preload of the heart, which can avoid the aggravation of the right heart function by appropriate diuresis and reducing the rehydration. 3.