Association of Arterio-Venous Oxygen and Carbon Dioxide Gradients With Tissue Hypoperfusion and Mortality in Sepsis

Gaziosmanpasa Research and Education Hospital88 enrolled

Overview

In patients with sepsis who are treated in the intensive care unit under invasive mechanical ventilation, the combined evaluation of ScvO₂ and PcvCO₂ may provide a comprehensive insight into tissue oxygenation and metabolic stress, allowing a more precise hemodynamic assessment in critically ill patients. The aim of this study is to evaluate the monitoring of ScvO₂, PcvCO₂, and EtCO₂ in intensive care patients in order to predict hemodynamic instability, 28-day mortality, and length of ICU stay, as well as to investigate their effects on cardiac output, tissue oxygenation, and hypoperfusion.

In intubated patients admitted to the intensive care unit due to sepsis and receiving inotropic support, placement of a central venous catheter and blood gas analysis, as well as radial artery cannulation for invasive hemodynamic monitoring, are routinely performed. In these patients, ScvO₂ and ScvCO₂ measurements are obtained via the central venous catheter. End-tidal CO₂ (EtCO₂) is measured using capnography. Arterial blood gas analysis, including SaO₂ and PaCO₂, is performed through the radial arterial catheter. Data recorded at admission and at 6, 12, and 24 hours will be evaluated. Additional hemodynamic parameters, including heart rate, blood pressure, arterial blood gas values (pH, PaCO₂, HCO₃-), serum lactate levels, and cardiac output, will also be analyzed. Finger-tip perfusion index is measured using a pulse oximetry probe. Outcomes such as duration of mechanical ventilation, length of ICU stay, and 28-day mortality and morbidity will be assessed in conjunction with APACHE II and SOFA scores.

Study Type

OBSERVATIONAL

Enrollment

Conditions

Intubated ICU Patients Sepsis and Septic Shock

Medical Language ↔ Plain English

Inclusion Criteria: * Adult patients aged 18 years or older * Diagnosis of sepsis * Admission to the intensive care unit * Intubated and receiving invasive mechanical ventilation * Presence of a central venous catheter Exclusion Criteria: * Patients younger than 18 years * Patients in whom a central venous catheter cannot be placed * Patients receiving oxygen therapy via face mask or nasal cannula * Patients treated with non-invasive mechanical ventilation

Outcomes

Primary Outcomes

Correlation of the central venous-arterial carbon dioxide difference with 28-day mortality

The primary outcome of this study is to evaluate the correlation between the central venous-arterial carbon dioxide difference and mortality in patients with sepsis admitted to the intensive care unit. The central venous-arterial carbon dioxide difference will be calculated using paired central venous and arterial blood gas samples obtained at predefined time points (at admission and at 6, 12, and 24 hours). Mortality will be assessed as 28-day all-cause mortality. The correlation between the carbon dioxide difference and mortality will be analyzed to determine its potential value as an indicator of mortality

Time frame: from march 2025 to january 2026

Secondary Outcomes

Predictive accuracy of perfusion parameters and APACHE II score for 28-day mortality

The predictive accuracy of central venous-to-arterial carbon dioxide difference (Pcv-aCO₂), end-tidal carbon dioxide (EtCO₂), serum lactate concentration, and APACHE II score for 28-day all-cause mortality will be assessed using the area under the receiver operating characteristic curve (AUC-ROC) in patients with sepsis and septic shock. Each parameter will be evaluated separately for its discriminatory ability to predict mortality.

Time frame: february 2025 to january 2026