Effect of persistent left superior vena cava on hemodynamic calculations.

When comparing means, there is no difference between right and left SVC saturations, and the difference does not affect cardiac output calculations. Because of the wide variability between right and left SVC saturations and their calculated cardiac output within patients, along with the higher correlation of left versus right SVC saturation with pulmonary artery saturation, the Fick-derived cardiac index calculation should be interpreted with caution when a left SVC is present. A prospective study with near-simultaneous sampling in all vessels should be undertaken.