How Do You Place an Umbilical Artery Catheter? Position, Uses, Procedure

Umbilical artery catheterization requires a highly skilled technique and thorough practice of catheterizing.

Umbilical artery catheterization (UAC) is a standard-of-care (commonly performed) procedure in neonatal intensive care units for arterial access in neonates.

UAC is relatively easy to perform, but it is challenging and requires a highly skilled technique and thorough practice of catheterizing.

Before the procedure is initiated, the insertion depth of the catheter is determined based on the neonate’s height and weight.

• The catheter is passed through the umbilicus of the neonate, from where it travels inferiorly through the umbilical artery to an anterior division of the internal iliac artery, then into the common iliac artery, and finally reaches the aorta.
• It is extremely necessary to ensure that the tip of the catheter is in the aorta itself and not in a branch of the aorta because being there it can block the vessel or instill a highly concentrated solution directly into an organ vessel, such as the renal artery.

The tip of the catheter can be placed in two locations based on the thoracic and lumbar vertebrae levels:

1. High position: At T6 to T10 level
   • The insertion depth can be calculated by using the following formulas:
     • Shukla formula:
       • Umbilical artery catheter depth (cm) = (birth weight [kg] × 3) + 9 
     • Wright formula:
       • Umbilical artery catheter depth (cm) = (birth weight [kg] × 4) + 7 
     • Gupta formula: Used more often in low-birth-weight infants
       • (UN – 1 cm) + 2USp
         • UN is the distance from the umbilicus to the nipple, and USp is the distance from the umbilicus to the symphysis pubis.
2. Low position: At L3 to L5 level
   • The high position is preferred due to a low incidence of vascular complications and without an increase in adverse sequelae.
   • The desired position is ensured by an X-ray. Once the catheter is in the right position, it is held up in a place with a thread or taped to the belly area of the newborn.

What is the purpose of UAC?

The umbilical cord consists of two arteries and a vein to carry the blood back and forth between the mother and fetus.

An umbilical line consists of a catheter that is inserted in any of the two arteries or veins of the umbilical cord.

When the catheter is inserted into the artery, it is known as umbilical artery catheterization (UAC), and when it is inserted into the vein, it is known as umbilical vein catheterization.

UAC is preferred in extremely premature or critically ill neonates because it provides quick access to the central circulation for continuous blood pressure monitoring, frequent measurement of arterial blood gases, and blood sampling.

What is an umbilical artery catheter used for?

When a newborn is ill right after birth, an umbilical catheter (long, soft, and hollow tube) is primarily indicated in the following conditions:

• Continuous arterial blood pressure monitoring
• Infusion of fluids for maintenance purposes (parenteral nutrition) when other routes are inaccessible
• Strong medications are required to control blood pressure in a neonate
• Blood sampling for laboratory tests
• Blood sampling for measuring arterial blood gases
• Exchange transfusion
• Angiography

How long can umbilical artery catheters stay in?

The umbilical artery is used for arterial access during the first five to seven days of life, whereas it is rarely used beyond 7 to 10 days.

Umbilical artery catheterization is contraindicated in the following conditions:

• Cord anomalies
• Peritonitis (inflammation of the peritoneum or covering of the abdominal wall)
• Omphalocele (a birth defect of the abdominal wall)
• Omphalitis (an infection of the umbilical stump)
• Necrotizing enterocolitis (a serious intestinal disease in premature infants)

What are the risks of umbilical catheters?

Umbilical artery catheterization may cause complications such as:

• Blood-borne catheter-related infection (sepsis)
• Air embolism
• Thromboembolic complications
• Heart tamponade
• Heart rhythm disorders (cardiac arrhythmias)
• Substantial blood loss
• Vascular compromise (interrupted blood flow) to the kidneys, buttocks, or lower limbs
• Hepatic necrosis
• Portal hypertension