Cephalad origin of the superior vena cava and the level of the central venous catheter tip on chest radiographs

Background: There are suggested radiographic landmarks for the lower margin of the superior vena cava (SVC), but none for the cephalad origin of the SVC in children. Therefore, we determined the cephalad origin of the SVC in relation to the level of thoracic vertebrae in children. Methods: Sixty-five patients (2-96 months) scheduled for routine diagnostic cardiac catheterization were the subjects of the study. Vena cavogram was obtained. The crossing point between the SVC and the innominate vein was considered as the cephalad origin of the SVC, then this point was related to the level of the thoracic vertebra as a radiographic landmark. Results: In approximately 90% of the patients studied the proximal origin of the SVC was situated above the level of Th4/5 interspace. Conclusion: We would like to suggest that the position of the tip of central venous line, when inserted via the right internal jugular vein, should optimally be at the level of Th4/5 interspace on the postoperative chest radiograph.