Chapter 29 ■ Umbilical Artery Catheterization 159

a. High position (14,19): Level of thoracic vertebrae

T6–T9 (Fig. 29.6); catheter tip above origin of celiac

axis

b. Low position (14,19): Level of lumbar vertebrae L3–

L4 (Fig. 29.7)

(1) Catheter tip is below major aortic branches such

as renal mesenteric arteries.

(2) In most newborns, this position coincides with

the aortic bifurcation at the upper end of the

fourth vertebra.

2. Make external measurements as necessary to estimate

length of catheter to be inserted (see Figs. 29.1–29.3)

(20–23).

3. Prepare as for major procedure (see Chapter 5).

4. Attach stopcock to hub of catheter and fill system with

flush solution. Turn stopcock to catheter “off.”

5. Place sterile gauze around umbilical stump and elevate

out of sterile field or have an ungloved assistant grasp

the cord by the cord clamp or forceps and pull the cord

vertically out of the sterile field.

6. Prepare cord and surrounding skin with antiseptic solution to radius of approximately 5 cm. The use of

chlorhexidine in infants <2 months of age is not recommended (24).

7. Drape area surrounding cord.

8. Place umbilical tie around umbilicus and tie loosely

with a single knot.

Fig. 29.5. The aorta and branches.

A B

Fig. 29.6. UAC in satisfactory high position at the level of the ninth thoracic vertebral body on anteroposterior (A) and lateral (B) projections.