Monday January 12, 2009
Central venous-to-arterial carbon dioxide difference

Very interesting !!!

Objective: To test the hypothesis that, in resuscitated septic shock patients, central venous-to-arterial carbon dioxide difference

[P(cv-a)CO2]

may serve as a global index of tissue perfusion when the central venous oxygen saturation (ScvO2) goal value has already been reached.

It was a prospective observational study.

Patients: After early resuscitation in the emergency unit, 50 consecutive septic shock patients with ScvO2 > 70% were included immediately after their admission into the ICU (T0). Patients were separated according to a threshold of 6 mmHg at T0.

• Low P(cv-a)CO2 group (Low gap) - 26 patients and
• High P(cv-a)CO2 group (High gap) - 24 patients

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/m²,) but not for ScvO2 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 as well as the decrease of SOFA score at T24
• At T0, T6 and T12, Cardiac Index (CI) and P(cv-a)CO2 values were inversely correlated

Conclusion: In ICU-resuscitated patients, targeting only ScvO2 may not be sufficient to guide therapy. When the 70% ScvO2 goal-value is reached, the presence of a P(cv-a)CO2 larger than 6 mmHg might be a useful tool to identify patients who still remain inadequately resuscitated.



Reference: Click to get abstract

Central venous-to-arterial carbon dioxide difference: an additional target for goal-directed therapy in septic shock? - Intensive Care Medicine, Volume 34, Issue 12 / December , 2008- Pages 2218 - 2225