160 Section V ■ Vascular Access

a. Tighten only enough to prevent bleeding and, if

possible, place around Wharton jelly rather than

skin.

b. It may be necessary to loosen the tie when inserting

the catheter.

9. Cut cord horizontally with scalpel (Fig. 29.8).

a. Approximately 1 to 1.5 cm from skin

b. Avoid tangential slice.

Bloom et al. (25) described an alternative

approach to the artery with lateral arteriotomy. To

perform this method, 3 to 4 cm of cord must be preserved because the cord must be rolled over a Kelly

clamp 180 degrees (25,26).

(1) Clamp across end of cord with a mosquito

hemostat in the nondominant hand and pull

firmly toward the infant’s head.

(2) Roll cord 180 degrees over hemostat toward

abdominal wall.

(3) Identify arteries in superior right and left lateral

aspects of cord.

(4) Approximately 1 cm from abdominal wall,

incise Wharton jelly down to arterial wall, using

a no. 11 scalpel blade.

(5) Incise artery through half of circumference. If

necessary, dilate lumen with iris forceps.

(6) Insert catheter into lumen of artery, directed in a

caudad direction, for predetermined distance.

10. Control bleeding by gentle tension on umbilical tape.

11. Blot surface of cord stump with gauze swab. Avoid rubbing, as this damages tissue and obscures anatomy.

12. Identify cord vessels (Fig. 29.9).

a. Vein is easiest to identify as large, thin-walled, sometimes gaping vessel. It is most frequently situated at

the 12-o’clock position at the base of the umbilical

stump.

b. Arteries are smaller, thick-walled, and white and

may protrude slightly from cut surface.

c. Omphalomesenteric duct is rarely present.

Fig. 29.8. Traction is being placed on cord in direction of the

arrow. Operator is about to make a horizontal cut across cord.

A B

Fig. 29.7. Anteroposterior (A) and lateral (B) radiographs showing satisfactory low position of a UAC.

Catheter tip is at the level of the superior margin of the fourth lumbar vertebral body, which in newborns

usually corresponds to the aortic bifurcation.