Assessment of Venous-to-arterial Carbon Dioxide Difference as a Marker of Global Perfusion in Sepsis Syndromes

Abstract

epsis is one of the oldest and most elusive syndromes in medicine. Sepsis is a clinical syndrome characterized by systemic inflammation due to infection. There is a variation of severity ranging from sepsis to severe sepsis and septic shock. Over 1,665,000 cases of sepsis occur in the United States each year, with a mortality rate up to 50 percent. A shock is a form of acute circulatory failure associated with an inequality between systemic oxygen delivery (DO2) and oxygen consumption (VO2), which result in tissue hypoxia. Early recognition and adequate resuscitation of tissue hypoperfusion are of particular importance in the management of septic shock to avoid the development of tissue hypoxia and multiorgan failure. Assessment of mixed venous oxygen saturation (SvO2) from a pulmonary artery catheter has been proposed as an indirect marker of global tissue oxygenation. SvO2 reflects the balance between oxygen demand and supply. The mixed venous-to-arterial carbon dioxide (CO2) tension difference [P (v-a) CO2] is the difference between carbon dioxide tension (PCO2) in mixed venous blood (sampled from a pulmonary artery catheter) and the PCO2 in arterial blood. P (v-a) CO2 depends on the cardiac output and