Chapter 56. Umbilical Vessel Catheterization

Umbilical vessel catheterization was first described by Diamond in 1947 for an exchange transfusion in a neonate.1 Umbilical vessel catheterization serves many important functions in the ill neonate. Umbilical vessel catheterization can be used as a reliable method of obtaining rapid vascular access in the neonate. Umbilical vessel catheters may be used for fluid resuscitation, blood transfusion, medication administration, frequent blood sampling, and cardiovascular monitoring.2–5 However, the use of these catheters also carries significant risk of permanent morbidity and even death. Either the umbilical artery or vein may be used for vascular access. The artery can usually be accessed within the first 24 hours of life. It is occasionally possible to use the umbilical artery up to 7 days after birth.2 The umbilical vein can be accessed for up to 2 weeks of age.2,6

Umbilical artery catheterization is more desirable than umbilical vein catheterization because it allows frequent arterial blood gas sampling and continuous blood pressure monitoring, in addition to fluid, blood, and medication administration. Unfortunately, umbilical artery catheterization is more difficult and time consuming to perform, especially in unskilled hands. Therefore, umbilical vein catheterization is the preferred procedure for the infant in shock and in need of rapid resuscitation. Arterial access can be obtained later in a more controlled environment, such as in the neonatal intensive care unit. Umbilical vessel catheterization can lead to serious complications and should be reserved for the patient in whom peripheral venous access attempts have been unsuccessful.5,7

The fetal circulatory system is quite different from that of the neonate or infant (Figure 56-1). Oxygenated blood from the placenta travels via the umbilical vein, through the ductus venosus in the liver, to the inferior vena cava (IVC), and into the right atrium. Oxygenated blood from the IVC preferentially enters the left atrium through the foramen ovale. It then enters the left ventricle, then the aorta. This oxygen-rich blood supplies the brain prior to mixing with the oxygen-poor blood coming through the ductus arteriosus. Deoxygenated blood from the superior vena cava (SVC) enters the right ventricle and is pumped to the pulmonary artery. It then passes through the ductus arteriosus to meet the oxygenated blood in the aorta.

Pulmonary vascular resistance decreases dramatically as the infant takes its first breaths. The systemic vascular resistance increases when the umbilical cord is clamped. The foramen ovale closes with the combination of decreased pulmonary artery pressure and increased systemic resistance. The ductus arteriosus closes within 24 to 48 hours due to the release of prostaglandins and increased blood oxygen tension. The ductus venosus closes when the umbilical cord is clamped.

The umbilical vein and arteries can easily be differentiated by examination of a cross section of the umbilical cord (Figure 56-2). The umbilical vein is a single vessel with thin walls and a large lumen. It is usually flattened in one direction. There are two thick-walled umbilical arteries that are significantly smaller in diameter than the umbilical vein. Occasionally, only a single umbilical artery is present.

Umbilical artery catheterization is indicated when frequent arterial blood gas determinations and continuous monitoring of blood pressure are required in the first few days of life in critically ill neonates.4 Umbilical artery catheters can be used for delivering blood, fluids, total parenteral nutrition, medications, and for exchange transfusions.2,3 It reduces the need for multiple venipunctures and heel prick capillary blood sampling in the critically ill neonate.8 Neonates under 24 hours of age can usually be catheterized without much difficulty. Skilled Emergency Physicians can sometimes perform this in neonates up to 7 days of age.2

Umbilical vein catheterization is easier to perform than umbilical artery catheterization. It is the preferred procedure for the neonate in shock needing rapid administration of intravenous fluids, blood, or medications.1 In critically ill neonates, the umbilical vein can be used to monitor central venous pressure. This procedure is possible in neonates up to 2 weeks of age.2 Recently, the umbilical vein has been used to perform invasive cardiac procedures.9

Umbilical vessel catheterization in the Emergency Department should be performed only on severely ill neonates in whom peripheral vascular access attempts have failed. The contraindications are similar for the umbilical vein and umbilical artery catheterization. These include gastroschisis, an omphalocele, omphalitis, and peritonitis.2,10 Never insert an umbilical catheter if there are any signs of infection on or around the remnant of the umbilical cord. Umbilical vessel catheterization is contraindicated if a neonate is older than the previously stated ages. An alternate route of vascular access is required if the possibility of an abdominal abnormality exists, as manifested by a distended abdomen or visible defects.2 Relative contraindications for placement of an umbilical artery catheter include decrease perfusion to the lower extremities or buttock and suspicion of necrotizing enterocolitis.

• Umbilical vein catheters, 5.0 French and 3.5 French
• Umbilical artery catheters, 5.0 French and 3.5 French
• Umbilical tape
• Povidone iodine or chlorhexidine solution
• Sterile gauze
• Sterile drapes
• Sterile gown and gloves
• Cap and face mask
• Adhesive tape
• Radiant warmer with a light
• Cardiac monitor
• Pulse oximeter
• 3-0 or 4-0 silk suture with a needle
• Needle driver
• Smooth-curved iris forceps
• Iris scissors
• Two small, smooth-curved hemostats
• Straight Crile forceps
• #10 or #11 scalpel blade on a handle
• Three-way stopcock
• 10 mL syringe filled with normal saline
• Heparinized sterile saline solution, 1 unit of heparin/1 mL of saline

Umbilical artery and vein catheters are available in a variety of sizes. Umbilical vein catheters are available as a single-lumen or double-lumen catheter. They should not have side holes unless it is to be used specifically for an exchange transfusion. Use a 5.0 French umbilical venous catheter in neonates weighing >1200 g and a 3.5 French catheter in neonates weighing <1200 g. Use a 5.0 French umbilical artery catheter in neonates weighing >3500 g and a 3.5 French catheter in neonates weighing <3500 g.

Umbilical vessel catheterization kits are commercially available from several manufacturers. One example is the Argyle Neo-Sert™ Umbilical Vessel Catheter Insertion Tray (Tyco Healthcare, Mansfield, MA). The kits are sterile, disposable, and intended for single patient use. They contain all the equipment required including the instruments and catheters.

Attempts at peripheral venous access should have failed in a sick neonate prior to attempting umbilical vessel catheterization. All equipment should be readily available on a pre-prepared sterile tray. Place the tray with the instruments on a Mayo stand next to the neonate's bed. Place the neonate under a radiant warmer with a light source. Place the neonate on a cardiac monitor, continuous pulse oximeter, and supplemental oxygenation if needed. Place the neonate supine with the lower extremities in the frog-leg position (Figure 56-3). Their arms and legs may need to be restrained to prevent contamination of the sterile field.

This procedure requires strict sterile technique. The Emergency Physician performing the procedure should wear a cap, mask, sterile gloves, and sterile gown. Scrub the umbilical cord, umbilical cord clamp, and the neonate's abdomen with povidone iodine or chlorhexidine solution and allow it to dry. Place sterile drapes to form a sterile field around the umbilical area, ensuring the neonate's head is exposed for observation.

Sterile technique must be maintained throughout the entire procedure. Loosely tie a piece of umbilical tape around the base of the umbilical cord (Figure 56-4). Place a 3-0 or 4-0 silk purse-string suture through the base of the umbilical cord and just above the umbilical tape (Figure 56-4). Avoid piercing the umbilical vessels and the skin of the abdominal wall. Leave the suture untied and the ends uncut. This will be used later to secure the umbilical vessel catheter. Gently grasp the umbilical cord clamp. Use an #10 or #11 scalpel blade to cut the umbilical cord just beneath the clamp to expose a smooth, clean surface of the umbilical cord (Figure 56-4). Do not cut the cord too close to the base in case it needs to be re-cut for a repeat attempt. Tighten the umbilical tape if blood is oozing from the cut umbilical cord. Blot the blood with gauze squares. Do not rub the gauze against the umbilical cord to prevent damaging the fragile umbilical cord. Grasp the umbilical cord with forceps or fingers and identify the three vessels, two arteries, and one vein. The arteries are smaller, round, and have thick muscular walls. The vein is larger, has thinner walls, and is less round than the arteries. The umbilical artery or vein may now be catheterized as described in the following sections.

Umbilical Artery Catheterization

Determine the desired position of the catheter tip (Figure 56-5). There are two possible positions for the umbilical artery catheter tip, the high or low position. In the low position, the catheter tip is placed between the third and fifth lumbar vertebrae, a level corresponding to just above the aortic bifurcation.2,11 In the high position, the catheter tip is placed between the sixth and ninth or tenth thoracic vertebrae, a level corresponding to just above the diaphragm, between the ductus arteriosus and the origins of the mesenteric arteries.2,11–13 Controversy exists over which position is the preferred site for the catheter tip.14 A recent Cochrane Database review of six controlled trials demonstrated that the high position was associated with a lower occurrence of clinical vascular complications, removal, and adverse sequelae.4,5,21

A variety of methods have been used to determine the insertional length of umbilical arterial catheters. Some of these include electrocardiographic changes during placement, echocardiography-guided insertion, and ultrasound-guided insertion.15–19 However, these are hard to perform in clinical practice. Other methods for determining the appropriate depth of catheter insertion are based on the shoulder-to-umbilicus length and the neonate's birth weight. There are also standardized graphs for determining the appropriate catheter insertion depth.

Most centers use a calculation derived by Dunn on post-mortem infants where the length of insertion to the high position is measured from the external shoulder to the umbilicus (Figure 56-3).20 Measure the shoulder to umbilicus length by measuring the distance between the top of the shoulder to the level perpendicular to the umbilicus (Figure 56-3). Using the shoulder-umbilical length and the desired position of the catheter tip, determine the umbilical catheter length to be inserted into the artery (Figure 56-6). Add the length of the umbilical stump to the umbilical artery catheter length found on the y-axis of the graph to determine the corrected length of catheter to be inserted.

Another popular way to measure the length of insertion is the formula derived by Shulka and Ferrara.21 The insertion length (cm) at the high position = (3 × body weight [kg]) + 9 + the length (cm) of the umbilical cord stump. To place it in the low position, use this value divided by 2. For neonates <1000 g body weight, another formula seems to be more accurate.22 The insertion length (cm) at the high position = (4 × body weight [kg]) + 7 + the length (cm) of the umbilical cord stump.

Flush the catheter with the heparinized saline solution, if there are no contraindications to heparin. Attach the three-way stopcock, in the closed position, to the hub of the catheter. Identify the arteries and choose one for catheterization. Grasp the distal portion of the umbilical cord with the two smooth-curved hemostats to stabilize the end of the umbilical cord (Figure 56-7). Instruct an assistant to hold the hemostats. Do not apply traction to the hemostats to prevent injury to the umbilical cord. Insert the tips of the smooth-curved iris forceps approximately 0.5 cm into the lumen of the artery and gently allow the jaws of the forceps to open (Figure 56-7). This will dilate the arterial lumen. Repeatedly insert and open the tips of the curved iris forceps within the arterial lumen to a depth of 0.5 to 1.0 cm.2

Grasp the umbilical catheter approximately 1.0 cm from the tip. Gently insert the tip of the catheter into the artery (Figure 56-8). Apply gentle pressure for about 30 seconds. The muscles of the artery may spasm and prevent the catheter from advancing. If the spasm persists, remove the catheter. Place 0.1 mL of a 2% lidocaine solution into the catheter tip.2 Reinsert the catheter and flush the lidocaine into the artery at the level of the spasm. If the catheter still will not advance, a gentle twisting motion may allow it to advance. Catheterize the other umbilical artery if this fails. Advance the catheter to the predetermined length. Increased resistance will be felt as the catheter goes through the base of the umbilical cord and navigates the curve of the umbilical artery entering into the femoral artery. Tighten the umbilical tape to temporarily secure the catheter.

Obtain fluoroscopic, plain radiographic, or ultrasonic confirmation of placement prior to using the catheter. The single lumen catheter may not be properly positioned. The catheter may pass into the aorta but curve distally into the iliac or femoral artery. This can result in cyanosis, blanching, or necrosis of the extremity and/or buttock.23,24 This occurs more frequently when a 3.5 French catheter is inserted in a large neonate. Using a larger catheter (i.e., 5 French) will usually allow the catheter to go cephalad in the aorta. If the catheter goes distally, it can be partially withdrawn, twisted 90°, and re-inserted only if done during the procedure with real-time fluoroscopy or ultrasound during the procedure. Never advance a catheter that has been previously placed as it can introduce an infection. The catheter may also enter the aorta, turn 180° to reverse itself, and enter the iliac or femoral artery. This also occurs more often when a smaller (i.e., 3.5 French) catheter is used in a large neonate. The catheter must be removed if it is placed correctly but there is persistent lower extremity cyanosis, blanching, or decreased distal perfusion.

Umbilical Vein Catheterization

Catheterizing the umbilical vein is much easier than the umbilical artery. The lumen is larger and easier to negotiate. This quality makes the umbilical vein more desirable for vascular access in emergency situations.7,25

First determine the desired position of the catheter tip. Ideally, it should be located at the junction of the IVC and the right atrium (Figures 56-9 & 56-10). Measure the shoulder-umbilical length (Figure 56-3). Using the shoulder-umbilical length and the desired position of the catheter tip, determine the umbilical catheter length to be inserted into the vein (Figure 56-10). Add the length of the umbilical stump to the umbilical vein catheter length found on the y-axis of the graph to determine the corrected length of catheter to be inserted. Another method to calculate the depth of insertion is length (cm) = (3 × body weight [kg]) + 9, divided by 2, then add 1 cm.

Umbilical vein catheterization is similar to that of the artery with three exceptions. Any visible clots must be removed from the lumen of the vein prior to inserting the catheter. The vein requires no dilating. In an emergency, when awaiting radiographic confirmation is not feasible, the umbilical vein catheter should only be inserted 3 to 5 cm until there is free flow of blood. It is imperative that the catheter not be inserted too deeply in order to prevent entry into the hepatic vessels via the ductus venosus, since medications could potentially cause hepatocellular damage.2,5–7,26 The catheter can be replaced with a more permanent line once the patient has been stabilized.25 The nonemergent umbilical venous catheter should be placed with the tip above the diaphragm, at the junction of the IVC and right atrium as determined previously. Tighten the umbilical tape to temporarily secure the catheter. Obtain fluoroscopic, plain radiographic, or ultrasonic confirmation of placement prior to using the catheter.18

Umblical Multiple-Lumen Catheters

Reliable vascular access can be problematic in the sick neonate.27 Insertion of a double-lumen or triple-lumen catheter into the umbilical vein can provide additional venous access for the administration of incompatible drugs such as vasopressor agents, calcium, or sodium bicarbonate solutions.28 It is also useful for drugs requiring continuous infusions, leaving other ports for blood sampling, central venous pressure measurements, maintenance fluids, or medication administration. Infuse all these solutions into the proximal lumen(s), allowing measurements of central venous pressures from the distal port. Multi-lumen catheters can be placed directly by the same methods as a single-lumen catheter or using the Seldinger technique similar to inserting a central venous line (Chapter 49). The increased pliability of the multi-lumen catheter makes passage into the hepatic veins more likely.

A wire exchange technique may be used to place a multiple-lumen catheter in neonates with an indwelling single-lumen catheter. This method decreases the probability of loss of vascular access during the exchange. It has the risk of the guidewire entering the heart and causing a cardiac dysrhythmia and/or myocardial perforation. This technique should only be performed by those familiar with the Seldinger technique.

The catheter exchange over a guidewire requires strict sterile technique. Insert a guidewire through the catheter. Firmly hold the guidewire. Withdraw the catheter over the guidewire. The guidewire must always remain within the vein. Advance the multi-lumen catheter over the guidewire and into the vein while securely holding the guidewire. Remove the guidewire while maintaining the catheter in the umbilical vessel. Advance the multi-lumen catheter to the predetermined length. Tighten the umbilical tape to temporarily secure the catheter. Obtain fluoroscopic, plain radiographic, or ultrasonic confirmation of placement prior to using the catheter.

Confirm the proper placement of the catheter tip. The umbilical tape has been tightened to temporarily secure the catheter within the umbilical cord. Do not infuse anything through the line until proper placement is confirmed. This can be accomplished with fluoroscopy, plain radiographs, or ultrasonography. If the catheter is in too far, withdraw it and reevaluate the new catheter tip position. If the catheter is not in far enough, do not advance the catheter. Withdraw the catheter and restart the procedure with a new catheter.

Secure the catheter more permanently after confirming that the catheter tip is in the desired location (Figure 56-11). Tighten and tie a knot in the previously placed purse-string suture. Wrap the loose ends of the suture around the catheter as it enters the umbilical vessel, then secure it with several square knots (Figure 56-11). Loosen and remove the umbilical tape to avoid umbilical cord necrosis.4 Secure the catheter to the abdominal wall with adhesive tape. Antibiotic ointment may be applied at the junction of the umbilical cord and the catheter.

Significant morbidity can be associated with umbilical artery and vein catheterization.29 Prevention of complications requires strict adherence to sterile technique, flushing of the catheter prior to insertion, gentle catheter manipulation during insertion, and accurate positioning of the catheter. It is essential that no air be allowed to enter the catheter. An air bubble can enter the central circulation, pass through the foramen ovale, and lodge in an end artery. This air embolism can cause a stroke if it ends up in a central nervous system artery, a myocardial infarction if it ends up in a coronary artery, and it may lead to death.30,31

Even if all precautions are observed, complications are still unavoidable.5 Complication rates as high as 20% for venous catheters and 10% for arterial catheters have been reported.32 A venous catheter placed in the portal system may lead to hepatic necrosis, hemorrhage, and thrombus formation, which may lead to a pulmonary embolus or portal hypertension.3–6 Neonates are at higher risk for thromboembolic events because of their underdeveloped clotting mechanisms, small vessel diameters, and critical underlying diseases when compared with older children and adults.29 Phlebitis or nosocomial sepsis can ensue if strict aseptic technique is not followed.32 Rarely, the catheter can be transected or form a knot intravascularly.33,34 Vessel and bowel perforation from forceful manipulation of the catheter, an air embolus from an unflushed catheter prior to insertion, false track formation, cardiac arrhythmias, damage to cardiac valves, and myocardial perforation have all been reported.3,6,7,32,58 Necrotizing enterocolitis, biliary venous fistula, pericardial effusion, hypoglycemia from high positioning of an umbilical artery catheter, bladder rupture, congestive heart failure, hypertension, transection of an omphalocele, transection of the catheter, intravascular knots in the catheter, and Wharton's jelly embolus have also been reported.58–65 Occasionally, a persistent urachus in the umbilical cord stump may be mistaken for an umbilical vein. Catheterization of the urachus will result in the flow of urine, and not blood, from the catheter. This is easily identified and corrected.

Malpositioning of the umbilical vein catheter has resulted in rare complications such as pneumopericardium, cardiac tamponade, pleural effusion, pulmonary hemorrhage, pulmonary edema, pulmonary infarction, pulmonary abscess, cardiac thrombosis, endocarditis, myocardial perforation, atrial flutter, hyponatremia, perforation of the peritoneum, perforation of a Meckel's diverticulum, perforated urachal remnant, ascites from intraperitoneal extravasation of total parenteral nutrition (TPN), esophageal varices, hepatic laceration, hepatic necrosis, hepatic abscess, hepatic calcifications or bladder calcifications with infusion of calcium gluconate, biliary fistula, perforation of the IVC, gastric outlet obstruction, or bladder rupture.8,34–54

Malpositioning of the umbilical artery catheter has rarely resulted in sciatic nerve damage, refractory hypoglycemia from infusion into the celiac axis, or spinal cord injury with paraplegia from infusion into the artery of Adamkiewicz.2,23,32,56,57 Umbilical artery catheterization may be complicated by vasospasm, thrombosis or embolism, causing ischemia of the lower extremities or intraabdominal organs.2,5,6,32,55 Vasospasm can occur within moments of catheter insertion or up to several hours following placement. The signs include progressive ischemia resulting in discoloration or mottling of the lower extremities and/or buttocks. Embolization of clots can cause loss of digits, hematuria, kidney failure, hypertension, necrotizing enterocolitis, bowel infarction, cyanosis or blanching of the skin (of the back, buttocks or legs), or skin ulceration.

Umbilical vessel catheterization is a readily available method of obtaining vascular access in the sick newborn. These vessels can be used for fluid resuscitation, blood transfusion, medication administration, frequent blood sampling, and cardiovascular monitoring. Because serious complications may result from using this route, it should be reserved for infants in whom peripheral vascular access is unsuccessful.