Indications: arterial blood gas; Blood pressure; Exchange transfusion (bleeding end); Infusion of liquid (not preferred, the maximum glucose concentration is 15%, if necessary, UAC can be used for antibiotics, but indomethacin and vasopressin such as adrenaline/dopamine/dobutamine are prohibited: UAC goes directly to the thoracic aorta, so it should not be too stimulating. Blood products can be used in emergencies).

　　Blood can be drawn for culture within 6 hours after catheterization.

　　Contraindications: omphalocele, umbilical cord inflammation, umbilical cord malformation, peritonitis, necrotizing enterocolitis, kidney, hip and lower limb vascular injury.