### Description

The length of catheter needed in neonates to reach specific intravascular locations from the umbilical artery or vein can be estimated from the horizontal distance between the shoulders and the umbilicus.

Measurements for the shoulder to umbilicus distance:

(1) an imaginary horizontal line connects both shoulders

(2) an imaginary horizontal line is placed through the umbilicus

(3) the distance in centimeters between these lines is measured

Umbilical Artery

 distance from shoulder to umbilicus in cm distance to aortic valve in cm distance to diaphragm in cm distance to aortic bifur-cation in cm 8 12.8 7.9 3.6 9 14.6 9.2 4.3 10 16.5 10.4 5.1 11 18.4 11.6 6 12 20.3 12.8 6.6 13 22.1 14 7.6 14 24 15.2 8.4 15 26 16.4 9.2 16 27.8 17.6 10 17 29.6 18.8 10.8

This data can be approximated by the following equations:

distance to the aortic valve in cm =

= (1.87697 * (distance from shoulder to umbilicus in cm)) - 2.252121

distance the level of the diaphragm in the aorta in cm =

= (1.205455 * (distance from shoulder to umbilicus in cm)) - 1.6782

distance to the aortic bifurcation in cm =

= (0.8085 * (distance from shoulder to umbilicus in cm)) - 2.9461

Umbilical Vein

 distance from shoulder to umbilicus in cm distance to diaphragm level of the inferior vena cava in cm distance to the left atrium in cm 8 4.5 5.7 9 5.2 6.5 10 5.8 7.3 11 6.4 8.1 12 7 9 13 7.6 9.7 14 8.4 10.5 15 8.9 11.3 16 9.6 12 17 10.2 12.8

This data can be approximated by the following equations:

distance to the level of the diaphragm in the inferior vena cava in cm =

= (0.63152 * (distance from shoulder to umbilicus in cm)) - 0.53394

distance to the left atrium in cm =

= (0.7897 * (distance from shoulder to umbilicus in cm)) - 0.5812

where:

• For an umbilical venous catheter tip to reach the left atrium would require passage through the foramen ovale.