nonthrombogenic umbilical catheter, 3.5, Fr (premature babies) or, 5Fr (fullterm); infusion solution, often normal saline, containing heparin (1 U/mL) Procedure During the catheterization, monitor heart rate and pulse oximetry, and keep the infant under a radiant warmer to maintain normothermia Figure 130.8A shows the pertinent anatomy Historically, there has been debate regarding optimal catheter tip location to prevent complications, but emerging evidence suggests that placement of the catheter in the “high” (T6–T9) rather than “low” (L3–L4) position may be preferred Place the infant supine in the frog-leg position and restrain him/her as necessary Gauze pads may be wrapped around the ankles and wrists and either pinned or taped securely to the bed/sheet Wearing mask, gown, and gloves, hold the sterile umbilical catheter over the infant to measure the vertical distance from the lateral aspect of the clavicle to the umbilicus The catheter will be advanced into the artery 60% of this distance, beginning at the skin surface, so its tip will reach the bifurcation of the aorta, the subdiaphragmatic (i.e., “low”) position For catheters to be placed in the “high” position, use the nomogram ( Fig 130.8A ) to establish the appropriate insertion length Recommended insertion lengths not account for the length of catheter that is within the umbilical stump from the abdominal wall Mark the catheter appropriately and attach it to the T-connector, stopcock, and syringe Flush it, leaving it full of fluid While lifting the umbilical cord with gauze in one hand, scrub the lower umbilical cord and abdomen from the xiphoid process to the symphysis pubis with povidone-iodine solution Drape the infant on both sides by folding two drapes into triangles or use an aperture drape; cover the area below the umbilicus with a third square drape At the base of the umbilical stump, suture a 3-0 or 4-0 silk tie around the cord to make a purse string, but leave the knot untied While holding the gauze on the nonsterile distal umbilicus, sever the cord 1.5 to cm above the abdominal wall with the scalpel as shown in Figure 130.8B , part A Remove the cut umbilicus and gauze from the sterile area Bleeding is usually minimal, stopping with gentle pressure or wiping; rarely, the purse string must be tightened Locate the umbilical vessels, usually two thick, white-walled arteries on one side, and a larger, thinner-walled vein on the other If the arteries in the stump are tortuous, cut it closer to the abdominal wall to facilitate cannulation Attach two clamps on opposite sides of the umbilicus, being careful to grasp a fibrous portion of the cord and not just Wharton jelly or an artery Evert the clamps to immobilize and expose the cord, and use the small curved forceps, as in Figure 130.8B , part B, to enter and then stretch the lumen of the artery Gentle,