Central venous oxygen saturation and central venous-to-arterial carbon dioxide difference in guiding fluid resuscitation of surgical septic shock

doi:10.3969/j.issn.1002-1949.2015.10.021

Abstract：Objective To determine whether central venous -to -arterial carbon dioxide P(cv-aCO2) and central venous oxygen saturation (ScvO2) could be sufficient guides early during fluid resuscitation in surgical septic shock patients .Methods Forty six postoperative septic shock patients were surveyed in this study .According to artery and superior vena cava blood gas , during both the beginning of resuscitation (T0) and in the 6th hour of resuscitation (T6), the correlation of cardiac output between ScvO 2 , Pcv -aCO2 and lactic acid, Base excess could be determined .Patients were divided into survival group and terminal group by the prognosis .Then, ScvO2 and Pcv -aCO2 levels were determine and compared between groups .Then they were divided into groups according to ScvO 2 and Pcv-aCO2 , and compared lactate clearance rate , mechanical ventilation time , ICU stay and 28-day mortality.Results There was a moderate correlation among ScvO 2, Pcv-aCO2 and lactic acid, Base excess , and there was a strong correlation between ScvO 2 , Pcv-aCO2 and cardiac output .Patients were divided into survival group and terminal group by the prognosis . After continuous 6 hour resuscitation, there was significant differences in the amount Pcv -aCO2 between the two groups , but there was no significant difference in the amount ScvO 2 .All enrolled patients who had ScvO 2 were greater than 70%after 6 hour resuscitation , they were divided into two groups , based on whether the patients'T6 Pcv-aCO2 was less than 6 mm Hg ( low gap group ) or greater than or equal to 6 mmHg ( high gap group ) .There was significant difference in the clearance of lactate and 28 d mortality ( P=0.018,P=0.001).All enrolled patients who had Pcv -aCO2 less than 6 mm Hg after 6 hour resuscitation were divided into two groups , based on whether the patients'T6 ScvO2 was less than 70%(low gap group) or greater than or equal to 70%(high gap group).There were significant differences in the clearance of lactate ( P =0.024 ).T6 Pcv -aCO2 concentration also helped prognostic ability (AUROC=0.758).All enrolled patients were divided into lower ScvO 2 group ( <70%), middle ScvO2 group (70%to 80%), and higher ScvO2 group ( >80%) after 6 hour resuscitation, there was no significant difference in 28 d mortality (χ2 Value =5.319, P =0.070 ).Conclusion The combination of ScvO2 and Pcv-aCO2 may guide the shock resuscitation .The clearance of lactate was the highest in the group of patients achieving the goals of both ScvO 2 >70% and Pcv-aCO2 <6 mm Hg. Septic patients targeting only ScvO 2 may still have inappropriate tissue perfusion , especially when Pcv-aCO2≥6 mm Hg, which indicates insufficient resuscitation .Combined ScvO 2 and Pcv-aCO2 to guide resuscitation of septic shock could be better affect the patient's prognosis .