LOW LYING UVC

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A low-lying umbilical venous catheter (UVC) in neonatology refers to a UVC that has not been advanced far enough into the inferior vena cava (IVC) and instead remains positioned within the portal venous system or hepatic circulation.

Ideal vs. Low-Lying UVC Placement

• Correct UVC position:
  • Tip in the inferior vena cava (IVC), just above the diaphragm (T6–T9 on X-ray).
• Low-lying UVC:
  • Tip remains in the liver/portal circulation rather than reaching the IVC.

Why is Low-Lying UVC Placement a Concern?

• Risk of liver injury (hepatic necrosis, perforation, thrombosis).
• Ineffective delivery of medications, especially inotropes (metabolized by the liver before reaching systemic circulation).
• Increased risk of extravasation and thrombosis.

When Can a Low-Lying UVC Be Used?

✅ Safe for:

• Clear fluids (e.g., dextrose).
• First dose of antibiotics if no alternative access.

🚫 Should NOT be used for:

• Inotropes (dopamine, dobutamine, adrenaline, noradrenaline).
• Hypertonic solutions (e.g., concentrated glucose >12.5%).
• Parenteral nutrition (PN) with calcium/phosphates.

Management of a Low-Lying UVC

• Confirm tip position on X-ray.
• If low-lying, avoid using it for critical medications.
• Consider replacing with a properly positioned UVC or alternative access (PICC, peripheral IV, or long line).
• If inotropes are needed, switch to a central line or peripheral route.

Would you like a visual guide on this? 🚼📸

 DV, ductus venosus; HV, hepatic vein; iLPV, inferior left portal vein; PS, portal sinus; RPV, right portal vein; SDV, subdiaphragmatic vestibulum; sLPV, superior left portal vein; UV, umbilical vein.

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Inserting a UVC can be a technical challenge, with problems encountered including: creating a false passage so that the catheter lies outside the umbilical vein, snagging of the catheter as it passes the umbilical ring into the abdomen, entering one of the veins other than the ductus venosus exiting the portal sinus or the tip impinging on the wall of the portal sinus. In this last case, the UVC advances a few centimetres into the baby but then will not advance further and blood cannot be aspirated. Withdrawing the catheter a minimal amount brings the tip into the portal sinus which is relatively large and filled with blood, allowing blood to be aspirated freely. Turning the line in a clockwise direction as the catheter is inserted sometimes helps it to enter the ductus venosus.

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1 and 6 are probably in the sub-diaphragmatic vestibulum and are safe for use. 2 and 7 are long. 2 has most likely passed through the foramen ovale into the left atrium, possibly even into the left superior pulmonary vein. 7 probably enters into the right atrium and should be pulled back before use. 3 and 8 end slightly low but point towards the right atrium and are therefore most likely in the portal sinus or ductus venosus. 4 ends at the lower border of T10, deviating to the right. The x-ray is reasonable well-centered so the deviation is unlikely to be due to rotation. The catheter is likely to have penetrated a small vein leaving the portal sinus. 5 is likely to end in the portal sinus. The rotation of the x-ray creates the impression the UVC turns right when in fact it is likely travelling in a posterior direction. This film highlights the importance of knowledge of the 3 dimensional vascular anatomy.

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