Final answer:
Umbilical artery catheters are used for continuous blood pressure monitoring, repeated blood sampling, and administering certain medications and fluids in neonatal intensive care units.
Step-by-step explanation:
An umbilical catheter placed in an artery (UAC) is generally used in neonatal medicine for several critical purposes. It allows for the continuous monitoring of blood pressure in critically ill or premature infants. This is vital as these infants cannot tolerate much blood loss, and arterial access enables repeated blood sampling without additional trauma. Moreover, the catheter can deliver medications that require arterial distribution or can't be given via veins. In some cases, it supports the infusion of fluids that help maintain adequate blood pressure and perfusion in vital organs. The procedure for inserting an umbilical catheter is invasive and is therefore usually reserved for intensive care situations, often during surgery or in neonatal intensive care units, reflecting the delicate balance of risks and benefits in the care of vulnerable neonatal patients.