Value of Central Venous to Arterial CO(2) Difference after Early Goal-directed Therapy in Septic Shock Patients

BACKGROUND AND AIMS: Venous to arterial difference of carbon dioxide (Pv–aCO(2)) tracks tissue blood flow. We aimed to evaluate if Pv–aCO(2) measured from a superior central vein sample is a prognostic index (ICU length of stay, SOFA score, 28th mortality rate) just after early goal-directed therapy (EGDT)comparing its ICU admission values between patients with normal and abnormal (>6 mm Hg) Pv–aCO(2). As secondary objectives, we evaluated the relationship of Pv–aCO(2) with other variables of perfusion during the 24 hours that followed EGDT. MATERIALS AND METHODS: Prospective observational study conducted in an academic ICU adult septic shock patients after a 6-hour complete EGTD. Hemodynamic measurements, arterial/central venous blood gases, and arterial lactate were obtained on ICU admission and after 6, 18 and 24 hours. RESULTS: Sixty patients were included. Admission Pv–aCO(2) values showed no prognostic value. Admission Pv–aCO(2) (ROC curve 0.527 [CI 95% 0.394 to 0.658]) values showed low specificity and sensitivity as predictors of mortality. There was a difference observed in the mean Pv–aCO(2) between nonsurvivors (NS) and survivors (S) after 6 hours. Central venous oxygen saturation (ScvO(2)) and Pv–aCO(2) showed significant correlation (R2 = –0.41, P < 0.0001). Patients with normal ScvO(2) (>70%) and abnormal Pv–aCO(2) (>6 mm Hg) showed higher SOFA scores. Normal Pv–aCO(2) group cleared their lactate levels in comparison to the abnormal Pv–aCO(2) group. CONCLUSION: In septic shock, admission Pv–aCO(2) after EGDT is not related to worse outcomes. An abnormal Pv–aCO(2) along with a normal ScvO(2) is related to organ dysfunction. HOW TO CITE THIS ARTICLE: Araujo DT, Felice VB, Meregalli AF, Friedman G. Value of Central Venous to Arterial CO(2) Difference after Early Goal-directed Therapy in Septic Shock Patients. Indian J Crit Care Med 2019;23(10):449–453.