UAC / UVC Depth
Umbilical arterial and venous catheters are among the most commonly placed lines in the NICU. Correct tip positioning is critical: too deep risks cardiac arrhythmia or hepatic complications; too shallow risks malposition and medication errors. This calculator provides estimated insertion depths from both weight-based and anatomical measurement methods.
UAC target positions
High: T6–T9 (above diaphragm, descending aorta)
Low: L3–L4 (below renal/mesenteric arteries)
Avoid T10–L2 (renal/celiac/mesenteric level)
UVC target
IVC/right atrium junction: T8–T10
Just above the diaphragm on AP X-ray
Avoid intracardiac and intrahepatic positions
Measurement method
Add to catheter depth from cord surface to obtain insertion length from skin
Shukla H, Ferrara A. Rapid estimation of insertional length of umbilical catheters in newborns. Am J Dis Child. 1986;140(8):786-788.
Dunn PM. Localization of the umbilical catheter by post-mortem measurement. Arch Dis Child. 1966;41(215):69-75.
Verheij GH, et al. Incorrect positioning of umbilical vascular catheters. Arch Dis Child Fetal Neonatal Ed. 2013;98(6):F509-514.
Frequently asked questions
How is UAC depth estimated?
Common methods use birth weight (e.g., Shukla: 3 × weight in kg + 9 cm for a high UAC) or the shoulder–umbilicus measurement (Dunn). Always confirm tip position radiographically.
Where should the catheter tips sit?
A high UAC tip sits at roughly T6–T9, and a UVC tip at the inferior vena cava–right atrium junction (about T8–T9).
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