Umbilical Catheters UVC UAC

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Diagram 1: Foetal circulation

Contents


This article provides a useful reference when Umbilical Venous Catheter (UVC) and Umbilical Arterial Catheter (UAC) placement.

  • Always follow your local guidelines, protocols and the clinical need of your patient.


Relative Contraindications


Catheter Choice

Single or double lumen catheters are available, depending on the likely requirements of the neonate.

  • UVCs allow central access for fluid and drug administration
  • UACs should be considered where there is considerable respiratory distress or regular blood sampling / blood gas analysis may be required.


Weight UVC Gauge x Weight UAC Gauge
< 1.5 kg 3.5 F x < 1.2 kg 3.5 F
1.5 - 3.5 kg 5 F x > 1.2 kg 5 F


All lines should be removed early as soon as they are no longer required or can be replaced with peripheral or long lines.

  • Aseptic technique at insertion and on handling these central lines is essential.


UVC

See Diagram 1 above re. foetal circulatory anatomy.

  • The umbilical vein is 2-3 cm long, 4-5 mm diameter and joins the left portal vein. It also gives off intra-hepatic branches, which the UVC can end up in.


Insertion Length Measurement

This can either be calculated from birthweight or determined by measuring Shoulder - Umbilicus Length and comparing with a graph.

  • see below for formulae and graphs


Techniques to pass a difficult catheter

Passage into and through the ductus venosus may be difficult. Do not force a catheter against resistance.

  • Pull back then advance while rotating it
  • Pass a second catheter alongside one which will not advance.


UAC

See Diagram 1 above re. foetal circulatory anatomy.

  • occasionally the catheter will pass into the femoral or gluteal artery - not suitable for blood pressure measurement or samping


Tip Positions - 2 positions are commonly used:

  1. High position: T6-9 ("above the diaphragm")
    • this ensures the tip is above the coeliac and mesenteric roots and the renal arteries.
  1. Low position: L3-4 ("above the bifurcation of the aorta")
    • the tip lies below most of the vessel roots, though the inferior mesenteric artery arises from L3-4


A high position is favoured by many units since it has been suggested that there are fewer vascular complications and the catheter life is longer (Cochrane Review, Ref 4).

  • if the high position is then not achieved, the catheter can be withdrawn slightly to the low position.


UVC + UAC Lengths - Formulae

Remember to add on the length of the stump of umbilical cord that remains. (Ref 3)




Calculator







  • DISCLAIMER: All calculations must be confirmed before use. The authors make no claims of the accuracy of the information contained herein; and these suggested values are not a substitute for clinical judgement. Neither Paeds.co.uk nor any other party involved in the preparation or publication of this site shall be liable for any special, consequential, or exemplary damages resulting in whole or part from any user's use of or reliance upon this material.


UVC + UAC Lengths - measurement charts

Diagram 2: UVC insertion length based on shoulder-umbilicus length. [Ref. 2] Click to enlarge


Diagram 3: UAC and UVC insertion length from weight. [Ref. 3] Click to enlarge


Imaging: Position Checks

Diagram 4: UVC and UAC: correct positions (UAC slightly high).
Diagram 5: UVC and UAC inserted to incorrect positions. Click to enlarge.


Potential Complications

The neonate should be monitored closely following insertion of central lines, including lower body perfusion.


UVC

  • Infection
  • Arrhythmias
  • Endocarditis
  • Pulmonary infarction
  • Abdominal perforation
  • Necrotising enterocolitis
  • hepatic necrosis


UAC

  • Infection
  • Vessel perforation
  • Abdominal perforation
  • Vasospasm
  • Thrombosis
  • Embolism
  • Loss of extremities
  • Haemorhage
  • Necrotising enterocolitis


References

  1. ADHB New Zealand
  2. Dunn PM. Arch Dis Child 1966;41:71
  3. Shukla H, Ferrar A. Rapid estimation of insertional length of umbilical catheters in newborns. Am J Dis Child 1986; 140:786
  4. Barrington KJ. Umbilical artery catheters: catheter position (Cochrane Review). In: The Cochrane Library, Issue 4, 2000: Update Software.
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