[Proceedings: The evaluation of the mixed venous O2-saturation in the oxymetric determination of heart minute volume and shunt size].

An investigation has been conducted into three groups of patients without intracardiac shunt (A: 59 adults without anesthesia, B: 58 children in anesthesia, C: 53 children without anesthesia). Oxygen saturation in the pulmonary artery was plotted against saturation in both venae cavae or against saturation in only one of them. The resulting 9 equations can be used as formulas to calculate the saturation of mixed venous blood in patients with an intracardiac shunt. Furthermore, mixed venous saturation can be estimated from "subclavian catheter" blood samples in patients without shunt.