1. Same as described earlier for conventional technique.

2. If possible, leave catheter from previously attempted standard procedure in place to aid in vessel identification.

3. Ensure that abdominal incision is on abdominal wall

and not too close to umbilical stump.

4. Identify landmarks carefully to avoid cutting or catheterizing urachus.

5. When incising mesenchymal sheath, take care to avoid

transecting vessel.

6. Secure the catheter with an internal ligature that is just

tight enough to prevent accidental removal but loose

enough for elective removal or reinsertion, in case

the catheter becomes occluded by thrombus or precipitate.

Technique (28)

See Fig. 29.13.

1. Insert an orogastric tube to keep the bowel as decompressed as possible.

2. Prepare infant and drape as for umbilical artery catheterization (see earlier in chapter).

3. If catheter has been left in place after previous attempt,

include vessel and catheter in the preparation, leaving

the catheter accessible for removal.

164 Section V ■ Vascular Access

4. Anesthetize area of skin immediately below umbilicus,

at umbilical stump–abdominal wall junction, with

0.5 mL of lidocaine.

5. Prepare UAC as for standard procedure, leaving catheter filled with flush solution. Estimate length for insertion based on patient size. Subtract 1 to 2 cm from that

recommended for standard insertion, as cutdown catheter will enter vessel farther along course.

6. Make a smile-shaped incision from 4 to 8 o’clock

through the skin of the abdominal wall at the junction

with the umbilical stump.

7. Place self-retaining retractor to maintain exposure.

8. Using blunt dissection through the subcutaneous tissue

with mosquito forceps, identify the fascia overlying the

urachus and umbilical vessels.

The mesenchymal sheath is composed of three layers of fascia and is from 1 to 3 mm thick. Although it is

barely perceptible in extremely premature infants, in

term infants it may be thick enough to require making

an incision through the sheath prior to blunt dissection.

9. While elevating the fascia with two forceps, make a

small incision between their tips. Enlarge incision with

scissors to the same size as skin incision. In very immature infants, simple dissection should suffice.

10. With curved mosquito forceps, dissect in the midline

and identify the urachus (Fig. 29.13).

The urachus is a white, glistening, cordlike structure

in the midline. Its position may be confirmed by traction cephalad, pulling the dome of the bladder into

view. The umbilical arteries lie posterolaterally on

either side but not touching the urachus.

11. Identify the umbilical arteries lying to either side of the

urachus.