Catheterization of Umbilical Vein
The umbilical cord stump and the surrounding abdomen are sterilized with a bactericidal solution. Sterile drapes are placed.
A purse-string suture or umbilical tape is tied around the base of the stump to provide hemostasis and to anchor the line after the procedure.
The cord is cut horizontally with the scalpel, approximately 1.5-2 cm from the abdominal wall. Two thick-walled small arteries and one thin-walled larger vein should be identified (see the images below). When identifying vessels, remember that the vein is usually located in the 12-o’clock position. The umbilical vein may continue to ooze blood. Hemostasis is achieved by tightening the umbilical tape or suture. The arteries do not usually bleed secondary to vasospasm.
Forceps are then used to clear any thrombi and dilate the vein (see the image below).
A 3.5-French catheter is used for preterm newborns, and a 5-French catheter is used for full-term newborns. The catheter is flushed with preheparinized solution and attached to a closed stopcock. The stopcock is left closed until the catheter is in the vein.
The catheter is then grasped 1 cm from its distal tip with the iris forceps and gently inserted, with the tip aimed toward the right shoulder (see the image and the video below). The catheter should be advanced only 1-2 cm beyond the point at which good blood return is obtained; this is approximately 4-5 cm in a full-term neonate. If resistance is initially met, the umbilical tape or suture should be loosened and the angle of approach manipulated. Advancement must not be forced.
The catheter is secured with a suture through the cord, marker tape, and a tape bridge. The position of the catheter must be confirmed radiographically. [7] A properly placed umbilical vein catheter appears to travel cephalad until it passes through the ductus venosus. [8] A firm understanding of the anatomy of the umbilical vein and its further course is crucial for correct catheter placement. [9]
Umbilical vein catheters may be placed in the inferior vena cava above the level of the ductus venosus and below the level of the right atrium (10-12 cm). This acts as central venous access, allowing central venous pressure (CVP) monitoring, medication infusions, and the administration of hyperalimentation solutions.
Standardized graphs estimate the length of catheter insertion on the basis of shoulder-to-umbilicus length. Alternatively, the shoulder-to-umbilicus length may be multiplied by 0.6 to determine a length that leaves the tip of the catheter above the diaphragm but below the right atrium. The use of birth weight rather than surface measurements to estimate insertion depth in newborns has been studied, but it does not appear to improve positioning of umbilical vein catheters (though it may improve positioning of umbilical artery catheters). [10]
In an emergency, it is best to advance the catheter only 1-2 cm beyond the point at which good blood return is obtained so as to avoid injecting hyperosmolar fluids into the portal vessels and causing liver necrosis.
The catheter may be pulled back, but not advanced, once the sterile field is down.
To prevent air embolism as the catheter is removed, tighten the purse-string suture or tape, and apply pressure to the umbilicus.
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Umbilical vein catheterization. Technique for umbilical vein dilation and insertion of catheter.
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Illustration of umbilical vein and arteries.
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Umbilical catheter (5 French). Note proximal attachment for stopcock.
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Close-up of umbilical catheter.
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Umbilical vein catheterization. Dilating umbilical vein and clearing thrombus.
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Umbilical vein catheterization. Insertion of umbilical vein catheter.
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Umbilical stump, with two arteries and one vein visible.
