A method presented for placement and anchorage of umbilical artery catheters utilizes the following formula: catheter length from the abdominal wall level = 0.33 × heel-crown length. An argument for positioning the catheter tip between T-6 and T-10 is also presented. It is believed that this formula will facilitate the uses of, and decrease the hazards of umbilical artery catheters when they are necessary for managing the critically ill neonate.
Weaver RL, Ahlgren EW. Umbilical Artery Catheterization in Neonates. Am J Dis Child. 1971;122(6):499-500. doi:10.1001/archpedi.1971.02110060069011