The PvCO2-PaCO2/CaO2-CvO2 Ratio in Septic Shock

Prognostic Value and Kinetics of the PvCO2-PaCO2/CaO2-CvO2 Ratio Compared to Arterial Lactate in the Initial Phase of Septic Shock

The ratio of the venous-arterial carbon dioxide partial pressure difference to the arteriovenous oxygen content difference (Pv-aCO₂/Ca-vO₂) may be a marker of anaerobic metabolism in patients with acute circulatory failure. This study aims to assess the prognostic value of the PvCO2-PaCO2/CaO2-CvO2 in the early phase of septic shock.

The ratio of the venous-arterial carbon dioxide partial pressure difference to the arteriovenous oxygen content difference (Pv-aCO₂/Ca-vO₂) may be a marker of anaerobic metabolism in patients with acute circulatory failure. This study aims to compare the kinetics of the PvCO2-PaCO2/CaO2-CvO2 ratio with a classic marker of anaerobic metabolism (arterial lactate) in the early phase of septic shock.

Inclusion Criteria:

Patients aged over 18 years presenting with septic shock, defined as sepsis with persistent hypotension requiring vasopressors to maintain a mean arterial pressure (MAP) ≥ 65 mmHg and lactatemia > 2 mmol/L despite adequate fluid resuscitation. Sepsis is defined by the presence of a suspected or confirmed infectious source associated with organ dysfunction (neurological, respiratory, renal, hepatic, or hematological). [Sepsis 3 criteria]

Exclusion Criteria:

• Absence of central venous access.
• Central venous access not positioned in the superior vena cava (e.g., femoral access).