Introduction

It is 03:00 and you are staring at the X-ray of an umbilical venous catheter (UVC) you inserted earlier in the shift. The nursing team want to know if they can start to use the line. Is it safe? Does it need adjustment? Can you start total parenteral nutrition (TPN)? What about inotropes? This article aims to equip you with the ability to answer these questions using an understanding of the relevant anatomy and which UVC positions on X-ray are most likely to cause harm.

UVCs are commonly used to administer: drugs, fluid and blood products, TPN, hypertonic fluid (concentrations of glucose solution above 12.5% in hypoglycaemic infants needing fluid restriction, for instance) or for exchange transfusion in the early neonatal period.

There are various formulae that are employed to determine how far UVCs should be inserted.1 2 The distance from the base of the umbilical stump to the xiphisternum, adding the length of the umbilical stump, works as an acceptable approximation for emergency insertion. UVCs can sometimes be inserted some days after birth when deemed essential, but as the umbilical stump dries the procedure becomes increasingly difficult.

As for any form of indwelling central vascular access, UVCs are subject to complications such as infection and thrombus formation. Butler-O’Hara et al’s prospective study in infants with birth weights below 1251 g found that the overall rate of UVC-related infection was 17% and thrombus formation was 11%.3 Again, in common with other forms of vascular access, the risk of line-related infection may be limited by strict adherence to insertion protocols and minimising the length of time that the UVC is left in place.3 4

Specific problems relating to different catheter tip positions are listed in table 1. Of particular note, if UVCs with tips in the liver …