Chapter 28: Arterial Access: Umbilical Artery Catheterization

I. INDICATIONS

1. Frequent or continuous measurements of arterial blood gases.

2. Continuous arterial blood pressure monitoring.

3. Access for exchange transfusion (to withdraw blood).

4. Angiography.

5. Infusion of maintenance solutions.

6. Administration of emergency resuscitation medications and emergency infusion of volume expanders and fluids. (Note: Umbilical vein preferred.)

7. Short-term infusions, parenteral nutrition, and/or medications (controversial). Parenteral nutrition can be given through an umbilical artery catheter (UAC) and has been used in some centers, especially in very low birthweight (VLBW) infants; however, the umbilical artery is not preferred and should be used with caution. The maximum dextrose concentration that can be administered using this method is 15%. Antibiotics can be given via UAC, but this also is not preferred. Indomethacin, vasopressor medications (epinephrine, dopamine, dobutamine), calcium boluses, and anticonvulsants should not be given via the UAC.

8. Blood products (controversial, emergency only) Blood products can be given via a UAC (less preferred, as this may enhance risk of thrombosis).

II. EQUIPMENT

1. Basic. Prepackaged UAC trays (usually include sterile drapes, tape measure, a needle holder, suture scissors, hemostat, forceps, scalpel, 3-way stopcock), umbilical tape, 2–0 to 4–0 silk suture, gauze pads, antiseptic solution, sterile gown, gloves, mask, hat, 10-mL syringe, 0.5% normal saline (NS) flush solution (0.25% NS for very small infants to reduce hypernatremia risk), and NS with heparin (0.25–1.0 U/mL) in continuous infusion calibrated pressure transducer for pressure monitoring; point-of-care ultrasound (if available) to guide catheter insertion and verify location of the catheter.

2. Umbilical artery catheter (sizes 3.5 and 5F). Size recommendations vary based on institutional guidelines. Some general guidelines:

   1. UAC size: infant <1.5 kg, use 3.5F; infant >1.5 kg, use 5F.

   2. Perinatal Continuing Education Program recommendations: <1000 g, use 3.5F; >1000 g, use 5F. Recommend use of single-lumen UAC.

   3. End-hole catheters are preferred and are associated with a decreased risk of aortic thrombosis when compared with side-hole catheters based on a Cochrane review.

   4. Feeding tubes used as umbilical artery catheters are associated with increased thrombosis risk and should be avoided.

   5. Cochrane review notes that there is no benefit of using a heparin-bonded polyurethane catheter versus the standard polyvinyl chloride catheter. A catheter made of Silastic (silicone) is more difficult to use because it is softer but may reduce aortic thrombosis compared with polyvinyl chloride (PVC) tubing. Teflon or polyurethane catheters have been associated with fewer infections and thrombogenicity than PVC or polyethylene catheters.

III. PROCEDURE

1. Umbilical artery catheterization practical tips

   1. The 2 umbilical arteries (1 umbilical artery in ~1% of births) are muscular walled vessels (2–3 mm) that carry deoxygenated blood from the fetus to the placenta. The umbilical arteries are the direct continuation of the internal iliac arteries. The catheter enters the umbilical artery at the umbilicus; it courses downward into the internal iliac artery and then superiorly into the common iliac and then the aorta.

   2. The umbilical arteries usually constrict within seconds after birth ...