Umbilical catheters- sizes and depth of insertion

(Version 1.0 9/15/2006 to 5/29/2014)

UACs

Use a 2.5F catheter for all neonates <800g and for most <1000g.

A 3.5F catheter should be used in preterm infants >1000g.

You may use a 5F catheter in term infants.

If the diameter of the catheter is too large for the lumen of the aorta, there is an increased risk of vascular trauma, thromboembolism, and vasospasm.

At Vanderbilt, we traditionally use "low-lying" UACs, i.e. we position our UACs with the tip at the bifurcation of the aorta, below the renal and mesenteric vessels.

On X-ray, the tip of a low-lying UAC should be at the L3-L4 intervertebral space.

The depth of catheter insertion for the low-lying catheters should be approximately 60% of the distance from the shoulder to the umbilicus.

Although there are theoretical concerns about high-lying UACs contributing to renal arterial occlusion, NEC, etc., there is woefully little data to support this. Therefore, if an outborn infant arrives with a high-lying UAC (with the tip at T6 to T10), the line should not be pulled back. In some circumstances, a high-lying UAC may be preferred for its longevity and decreased incidence of "catheter toes." The surgeons often prefer a high-lying UAC in infants with CDH, and the cardiologists may use a high-lying line to identify a right-sided aortic arch.

For high UAC: (Weight in Kg x 3) + 9 = length of insertion of the UAC in cm.   Remember to add the length of the umbilical stump to the distance inserted. On CXR, the high position is at the level of thoracic vertebral bodies T6-T9.  This position is above the coeliac axis (T12), the superior mesenteric artery (T12-L1), and the renal arteries (L1).

The 2.5F catheter is only available as a single lumen catheter. Both the 3.5F and the 5F catheters come in both single and double lumen versions. Usually a double lumen catheter is preferable to provide a port for continuous iv fluid infusion as well as a uncontaminated line from which to draw blood gases and laboratory samples. However, cardiology may prefer a single lumen catheter as they tend to provide better arterial blood pressure tracings which may be invaluable in a baby being monitored for critical coarctation of the aorta, for instance.

A nice calculator can be found at the following site: NICU Tools

Reference:

Barrington KJ. Umbilical artery catheters in the newborn: effects of position of the catheter tip. http://www.nichd.nih.gov/cochrane/Barring/Barrington.htm

 

UVCs

A 3.5F single or double lumen catheter should be used in VLBW infants. A 5F single or double lumen catheter can usually be placed larger neonates.

A UVC should be passed through the ductus venosus so that its tip lies in the IVC or at the juncture of the IVC with the right atrium. The UVC tip should be above the diaphragm on X-ray. Beware advancing a UVC too far across the PFO and into the left atrium as any accidental air emboli may then proceed to the cerebral circulation. An important and life threatening complication can include cardiac tamponade from infiltration of fluid.  This can occur regardless of proper positioning of the UVC and must be recognized and treated promptly with pericardiocentesis.  

More information can be found here:

A depth of insertion of 66% of the distance from the shoulder to the umbilicus will usually appropriately place a UVC.  Alternative methods of measuring UVC insertion are either (length of high UAC/2) + 1 = length of UVC in cm, or (weight in Kg x 1.5) + 5.5.   On CXR, optimal position for UVC should have the tip of the catheter at the junction of the inferior vena cava and the right atrium. X-ray the catheter tip at T9-T10, approximately 1 cm above the diaphragm.

 More information:

A nice calculator can be found at the following site: NICU Tools

Until correct placement of the UVC is documented on X-ray, do not to use it to infuse any hypertonic solutions as direct intrahepatic administration of hypertonic IV fluids and medications can cause hepatic injury and necrosis.

An exception to the above may occur in the delivery room. Umbilical venous access may need to be obtained emergently to administer blood products or other volume expanders or medications during resuscitation. In the delivery room, an emergent UVC should be placed to a depth of about 5 cm just until free blood flow returns. Medications administered at this site will be well below the liver.

 

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