The Effect of Rapid Fluid Challenge Under Pulmonary Artery Catheter Monitoring on Physiological Indexes of Patients With Septic Shock

Fluid challenge is often carried out in septic shock patients. Its responsiveness usually requires invasive monitoring. The pulmonary artery catheter(PAC) is the most effective means of monitoring.To use non-invasive methods is very tempting. Investigators hypothesize that venous-to-arterial carbon dioxide difference,venous-to-arterial carbon oxygen difference, central venous-arterial carbon dioxide to arterial-venous oxygen content ratio and Central Venous SO2 variations provides feasible estimation on fluid responsiveness in septic shock patients.