Partial anomalous pulmonary venous connection as incidental finding Explanation for apparently paradoxical central venous blood gas analysis results

A partial anomalous pulmonary venous connection (PAPVC) is a congenital abnormality of the great thoracic vessels the incidence of which is underestimated and is associated with a left-right shunt. It rarely develops into a right-sided cardiac insufficiency. Because of the mostly low left-right shunt volume, a PAPVC is often asymptomatic and mostly incidentally detected in advanced age. Incorrect positioning of a central venous catheter or paradoxical blood gas parameters can serve to indicate the presence of a PAPVC. This article presents the case a 50-year-old patient with a PAPVC of the left upper lobe pulmonary vein draining into the left innominate vein without prior clinical symptoms. Blood gas analyses from the superior vena cava, where the catheter placement was confirmed by computed tomography angiography, showed unexplainable arterial values. The anatomical abnormality was confirmed by computed tomography.