An umbilical venous catheter is used for vascular access in a neonate. The umbilical vein is found with the two umbilical arteries and travels to the inferior vena cava (IVC) via the left portal vein and ductus venosus. The ductus venosus begins at the left portal vein and enters the IVC closely related to the hepatic veins. The correct position of the tip of the UVC is at or close to the inferior cavo-atrial junction. Misplacement can occur amongst other places, in normal anatomy, at the level of the left portal vein and at the level of the hepatic veins.
The umbilical vein closes soon after birth (<7 days) and becomes the round ligament of the liver. This lies in the free edge of the falciform ligament and is also continuous with the ligamentum venosum (the remnant of the ductus venosus).
An umbilical artery catheter (UAC) is passed through either one of the umbilical arteries and descends to the iliac artery before ascending to the aorta. Appropriate placement of the tip is in either a low (L3-L4) or high (T6-T10) position. This avoids the tip being associated with the origin of major aortic vessels.
The first radiograph above demonstrates several lines present. The ET tube (A) is appropriately sited. An oesophageal temperature probe (B) is present with its tip close to the gastro-oesophageal junction. An NG tube lies with its tip beyond the limits of the radiograph in the stomach. The UAC (D) lies slightly too low at T11 and the UVC (E) lies slightly too high in the right atrium.
The second radiograph demonstrates an NG tube, but also an umbilical venous catheter with its tip within the right portal vein.
The third radiograph demonstrates a UAC (short arrows) which can be identified by its dip into the pelvis (lower short arrow). The tip lies at T4, which is too high. It is less easy to determine the tip of the UVC (arrowhead). This may still lie in the IVC, but appears too far to the right. It may lie in a portal venous branch, but, extravascular, intrahepatic misplacement should be considered.