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

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.

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Key information

Conditions

Intubated ICU Patients Infections Inflammation Pathologic Processes Pathological Conditions, Signs and Symptoms Sepsis Sepsis and Septic Shock Shock Shock, Septic Systemic Inflammatory Response Syndrome

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Gaziosmanpasa Training and Research Hospital

Istanbul, Gaziosmanpasa, 34255, Turkey (Türkiye)

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Primary outcomes

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

Time frame: from march 2025 to january 2026

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

Secondary outcomes

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

Time frame: february 2025 to january 2026

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.

Sponsors and collaborators

Lead sponsor

Gaziosmanpasa Research and Education Hospital

Other Gov

Registry information

Important dates

Study start: 2025
Primary completion: 2025
Study completion: 2026
First posted: Jul 17, 2026
Registry last updated: Jul 17, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

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This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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Completed