Abstract: Objective  To evaluate the guidance value of venousarterial carbon dioxide difference  (PcvaCO2)  in fluid resuscitation towards patients with septic shock. Methods  A total of 105 patients with septic shock admitted to ICU of  the hospital  from January 2016 to December 2018 were collected. All  patients underwent initial resuscitation on the basis of the early goal directed therapy principle. The blood gases analysis of radial artery and superior vena cava were carried out  simultaneously 6 hours before resuscitation and 6 hours after resuscitation,  PcvaCO2 was also calculated.  The patients were divided into four groups on the basis of lactic acid(lac)  level and PcvaCO2 6 hours  after  fluid  resuscitation:group A,  lac＞2 mmol/L, PcvaCO2＜6 mmHg; group B,  lac＞2 mmol/L,  PcvaCO2≥6 mmHg;  group C,  lac＜2  mmol/L, PcvaCO2＜6 mmHg;  group D,  lac＜2  mmol/L,  PcvaCO2≥6 mmHg. Sequential Organ Failure Assessment（SOFA）  scores at day1 and day3,  length of ICU stay and 28day motality of all four groups were recorded. Results  After resuscitation, the heart rate(HR) of the patients of all four groups was lower than that before resuscitation, while mean arterial pressure,  central venous pressure and central venous oxygen saturation were higher than those before resuscitation(P<0.05). The lac level of group C and D were lower than that of group A and B after resuscitation；PcvaCO2 of group A and C were lower than that of group B and D(P<0.05). Moreover,  SOFA score at day3, 28day motality of group C were lower than that of the rest three groups(P<0.05). Conclusion  During the initial resuscitation towards spetic shock patients,  those whose PcvaCO2 and lac level reach the criterion will have a better prognosis. Also,  PcvaCO2 combined with lac level can guide the initial resuscitation towards patients with septic shock.

Key words: shock, septic, venousarterial carbon dioxide difference, lactic acid