Iowa Neonatology Handbook: Procedures

Insertion of Umbilical Vessel Catheters

Iowa Neonatology Fellows
Peer Review Status: Internally Peer Reviewed

I. Umbilical artery catheters (UAC), are used primarily for monitoring blood pressure and obtaining samples for blood gases. In order to maintain the patency of the catheter, a saline and dextrose solution is infused through the line. Drugs and other solutions, including parenteral nutrition solutions, should be given through a venous line (peripheral or central), unless discussed with the staff physician.

II. Umbilical vein catheters (UVC), are used for exchange transfusions, monitoring of central venous pressure, and infusion of fluids (when passed through the ductus venosus and near the right atrium); and for emergency vascular access for infusions of fluid, blood products or medications.

III. Before the procedure is begun, the correct depth of the umbilical artery catheter insertion should be estimated (see #7 below). Gloves and goggles (or eyeglasses) should be worn. A sterilized umbilical catheterization tray with the necessary instruments and drapes is available in the nursery. After opening the tray, alcohol and sterile syringes, stopcocks, catheters and saline will be placed on it. Sterile technique must be observed; the use of goggles (or eyeglasses) is recommended.

IV. An umbilical catheter with a single end hole may be used for the catheterization of either umbilical artery or vein. On certain occasions, it may be advantageous to place a multi-port UVC. Infants with a birth weight of less than 1.5 kg will usually require a 3.5-Fr catheter for arterial catheterization. 5-Fr catheters are used for arterial placement in larger infants or umbilical venous placement regardless of infant size.

V. Catheters (4 and 5-Fr) with PaO2 monitoring capability (Neocath) are also available for umbilical artery catheterization . This device allows continuous monitoring of PaO2. Additionally, multiple-lumen catheters and catheters with oxygen saturation measurement capabilities for determination of SVO2 are available for umbilical vein catheterization where clinically indicated.

VI. If a luer-lock adapter is not present on the catheter end, approximately 9 cm of the wide end of the catheter can be cut off and a blunt end needle inserted. The 3.5-Fr catheter requires a 20-gauge and the 5-Fr catheter an 18-gauge blunt needle. A sterile stopcock is then attached and the system flushed with saline.

VII. External measurements are made to determine how far the catheter should be inserted. In a high setting, the arterial catheter tip should be positioned between the sixth and tenth thoracic vertebrae on chest x-ray. This can be achieved by inserting the catheter 1 cm more than the infant's umbilical-to-shoulder length. A low-lying catheter should have the tip at the third to fourth lumbar vertebra.

VIII. The infant's abdomen and cord are cleaned with alcohol. The alcohol should be sparingly applied to prevent pooling under the infant's back and buttocks. The area is then draped so that only the cord is exposed.

IX. Tie a piece of umbilical tape around the base of the umbilical cord tightly enough to minimize blood loss but loosely enough so that the catheter can be passed easily through the vessel.

X. Using a surgical blade, the cord is cut cleanly 1.0 to 2.0 cm from the skin.

XI. The cord is stabilized with a forceps or hemostat, and the vessels identified. The single, large, thin walled oval vein can readily be distinguished from the two smaller, thick-walled round arteries (see diagram).

XII. The arteries are usually constricted, so that the lumens appear pinpoint in size. By gently inserting the closed tips of the curved iris forceps into the lumen of the artery until the cut end of the artery is at the bend in the forceps, and then allowing the spring of the forceps to gently spread the tips, the artery can be dilated.

XIII. Grasping the catheter between the thumb and forefinger or with a forceps, the catheter can be inserted into the lumen of the dilated artery. Supporting the stump is usually necessary. Once the catheter has ben inserted, it may encounter resistance at the level of the anterior abdominal wall or at the bladder. This resistance can usually be overcome by application of gentle steady pressure. Repeated probing movements or excessive pressure must be avoided. If unsuccessful, wait 2-3 minutes until the vasospasm ceases, or attempt the other umbilical artery.

XIV. After the catheter is advanced the appropriate distance, the position of the catheter should be confirmed by x-ray. If, after sterile technique has been broken, the catheter is found to be in the wrong position, it can only be pulled back--IT MUST NEVER BE ADVANCED.

XV. Observe both legs for evidence of blanching, cyanosis or mottling. If a "blue leg" develops (presumably from vasospasm), the catheter should be removed or carefully observed for a short period of time to allow for resolution of the impaired circulation.

XVI. After placement of the catheter, a purse-string suture is placed around the umbilicus taking care not to puncture the catheter.

XVII. The procedure for catheterization of the umbilical vein is similar; differences are as follows:

A. Remove any visible clots from the lumen of the vein with forceps.

B. Never leave the catheter open to atmospheric pressure. The abdominal venous system is under negative pressure; with a deep inspiration air can enter the catheter with resultant air embolism.

C. For administration of fluid, the venous catheter must be in the inferior vena cava, just below the right atrium.Inserting the catheter two-thirds of the shoulder-to-umbilicus distance is a good estimate. A catheter in the portal venous system must not be used for the administration of fluids or medications and should be removed.

D. For the purpose of an exchange transfusion, the catheter should be advanced only until there is a free flow of blood, but never more the 8 cm in the full term infant. This catheter should be used only for withdrawal of blood (see section on Exchange Transfusion).

E. If code medications and/or fluid need to be given in the delivery room, a UVC should be placed and advanced only until there is a free flow of blood as in "D" above.

XVIII. To sample blood from an umbilical catheter, withdraw 1 ml of blood into a sterile syringe, keeping the syringe perpendicular to the infant. this will cause the blood to settle near the tip of the syringe. The tip of the syringe should be kept sterile, and not placed in the infant's incubator or bed.

XIX. The blood sample is then withdrawn into a second syringe and the initially withdrawn blood reinfused and the system flushed with a small amount of saline until free of blood.

XX. The alcohol should be washed off with sterile water after the procedure is completed. This is important to prevent clinical burns, especially in very small infants.

XXI. Heparin is not routinely added to the IV solution, except with the use of the Neocath. Whether the use of heparin decreases the incidence of thrombolitic complications has not been well studied.

XXII. The umbilical artery catheter is removed slowly when it is no longer needed. With proper care, the catheter need not be changed for the duration of its use.

Section Top | Title Page