Central venous-arterial carbon dioxide difference as an indicator of cardiac index

The mixed venous-arterial (v-a) pCO(2) difference has been shown to be inversely correlated with the cardiac index (CI). A central venous pCO(2), which is easier to obtain, may provide similar information. The purpose of this study was to examine the correlation between the central venous-arterial pCO(2) difference and CI. Prospective, cohort study. Intensive care unit of an urban tertiary care hospital. Eighty-three consecutive intensive care unit patients. Simultaneous blood gases from the arterial, pulmonary artery (PA), and central venous (CV) catheters were obtained. At the same time point, cardiac indices were measured by the thermodilution technique (an average of three measurements). The cardiac indices obtained by the venous-arterial differences were compared with those determined by thermodilution. The correlation (R(2)) between the mixed venous-arterial pCO(2) difference and cardiac index was 0.903 (p