title: Central venous-to-arterial carbon dioxide difference: an additional target for goal-directed therapy in septic shock?
abstract: OBJECTIVE
  To test the hypothesis that, in resuscitated septic shock patients, central venous-to-arterial carbon dioxide difference [P(cv-a)CO(2)] may serve as a global index of tissue perfusion when the central venous oxygen saturation (ScvO(2)) goal value has already been reached.
  
  
  METHODS
  Prospective observational study.
  
  
  METHODS
  A 22-bed intensive care unit (ICU).
  
  
  METHODS
  After early resuscitation in the emergency unit, 50 consecutive septic shock patients with ScvO(2) > 70% were included immediately after their admission into the ICU (T0). Patients were separated in Low P(cv-a)CO(2) group (Low gap; n = 26) and High P(cv-a)CO(2) group (High gap; n = 24) according to a threshold of 6 mmHg at T0.
  
  
  METHODS
  Measurements were performed every 6 h over 12 h (T0, T6, T12).
  
  
  RESULTS
  At T0, there was a significant difference between Low gap patients and High gap patients for cardiac index (CI) (4.3 +/- 1.6 vs. 2.7 +/- 0.8 l/min/m(2), P < 0.0001) but not for ScvO(2) values (78 +/- 5 vs. 75 +/- 5%, P = 0.07). From T0 to T12, the clearance of lactate was significantly larger for the Low gap group than for the High gap group (P < 0.05) as well as the decrease of SOFA score at T24 (P < 0.01). At T0, T6 and T12, CI and P(cv-a)CO(2) values were inversely correlated (P < 0.0001).
  
  
  CONCLUSIONS
  In ICU-resuscitated patients, targeting only ScvO(2) may not be sufficient to guide therapy. When the 70% ScvO(2) goal-value is reached, the presence of a P(cv-a)CO(2) larger than 6 mmHg might be a useful tool to identify patients who still remain inadequately resuscitated.
authors.affiliation: Pôle d'Anesthésie et Réanimation, Unité de Réanimation Polyvalente de Purpan, GRCB 48, Université Paul Sabatier, CHU de Toulouse, France. vallee.f@chu-toulouse.fr
authors.forename: Fabrice
authors.initials: F
authors.lastname: Vallée
authors.forename: Benoit
authors.initials: B
authors.lastname: Vallet
authors.forename: Olivier
authors.initials: O
authors.lastname: Mathe
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Parraguette
authors.forename: Arnaud
authors.initials: A
authors.lastname: Mari
authors.forename: Stein
authors.initials: S
authors.lastname: Silva
authors.forename: Kamran
authors.initials: K
authors.lastname: Samii
authors.forename: Olivier
authors.initials: O
authors.lastname: Fourcade
authors.forename: Michèle
authors.initials: M
authors.lastname: Genestal
mesh_terms: D018806:APACHE; D000136:Acid-Base Equilibrium; D000328:Adult; D000368:Aged; D001784:Blood Gas Analysis; D002245:Carbon Dioxide / Q000097:blood*; D005260:Female; D005440:Fluid Therapy; D006801:Humans; D007362:Intensive Care Units; D019344:Lactic Acid / Q000097:blood; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012720:Severity of Illness Index; D012772:Shock, Septic / Q000097:blood* / Q000503:physiopathology* / Q000628:therapy
chemical_list: D002245:Carbon Dioxide; D019344:Lactic Acid