Blood Management
May 3, 2021

An Intro to Vascular Access in NICU Patients — UAC

Drawing blood from NICU patients requires taking certain precautions to ensure patient safety and the success of the procedure.
Drawing blood from NICU patients requires taking certain precautions to ensure patient safety and the success of the procedure.

Given the delicate health of NICU patients, collecting blood samples for labs and health monitoring requires more care than it would when drawing blood from a healthy, full-grown adult. Health care providers often use umbilical artery catheters (UACs) — thin, pliant tubes that are placed in one of the two arteries found at the end of the newborn’s umbilical cord — to take samples, monitor blood pressure, and do blood gas sampling.

Umbilical artery catheters are staples in NICUs, but they’re not without risk. Learn more about how the Hummi Micro-Draw Blood Transfer Device offers a better, safer way to draw blood from neonates.

How Umbilical Artery Catheters Work

UACs must be properly prepared before they can be placed. First, the infant needs to be kept warm during the procedure in order to prevent hypothermia, so radiant warmers and exothermic mattresses may be necessary.

Before placement, the three-way stopcock that will be used during the procedure must be connected to the catheter and flushed with saline. 0.45% normal saline is recommended to avoid introducing too much sodium into the infant’s system, causing hypernatremia. The syringe used to flush the catheter must remain attached to the three-way stopcock with the switch turned off.

The insertion length also needs to be determined before placement — one formula recommended by researchers, even for use in emergency situations is: [infant birth weight (in kg) x 3) + 9] cm. Likewise, the ideal position for the catheter tip should also be determined before proceeding. The descending aorta above the origin of the celiac, mesenteric, and renal arteries is preferred in order to prevent these critical vascular routes from becoming occluded. A higher position for the UAC tip — thoracic vertebra level T6-T9, above the renal arteries — is also recommended to reduce the risk of developing complications of thrombosis.

Before placing the UAC tip, the neonate should be restrained to prevent any potentially disruptive movement and their umbilical cord cleaned with an antiseptic solution. Next, an umbilical tie should be placed around the cord, securely enough to keep blood loss to a minimum but not so tight that the catheter cannot be easily inserted into one of the umbilical arteries. These can be distinguished by thick walls and smaller lumen. After the artery has been gently dilated using iris forceps, the UAC tip can be inserted into the artery with gentle, steady pressure. From there it can be guided toward the aorta.

It’s important to remember that repeated probing of the umbilical or excessive pressure with the UAC tip can lead to perforating the blood vessel. If this occurs, the other artery must be catheterized.

While UACs are incredibly useful devices, they aren’t without risks, which can include reduced blood flow to organs and limbs, blood clots, infections, or artery spasms around the catheter. However, these umbilical artery catheter complications can be mitigated with the right tools — such as the Hummi Micro-Draw Blood Transfer Device from Kentec Medical. Here’s what procurement managers and NICU units should know about how to use these tools for vascular access.

Avoiding Umbilical Artery Catheter Risks and Complications

Kentec Medical’s Micro-Draw Closed Blood Transfer Device improves on traditional UAC blood draw techniques in a number of ways. First, the Hummi blood transfer device functions like a closed system during vascular line access and can reduce blood clearance by 75% and flush volumes by up to 80% compared to current methods. This helps keep the baby’s sodium levels more stable.

The Hummi is also designed specifically to help reduce the known risk factors for intraventricular hemorrhage (IVH) and periventricular leukomalacia (PVL). The Hummi only requires a total of 1.3mL of blood — as compared to the 4-6mL required by other current sampling methods — which minimizes the amount of total fluid movement as compared to other current sampling methods. Reducing hemodynamic change is key to preventing neonates from developing IVH or PVL.

Furthermore, the Hummi streamlines your line set-ups and eliminates the need to draw blood samples into the arterial line. This means that there’s no residual blood inline after the draw, which further minimizes the risk of developing bacterial growth in the stopcock and line components and helps to keep the infant healthy.

The Hummi Micro-Draw Blood Transfer Device is able to offer these improvements thanks to its Y-hub design with two micro-bore tubing extensions. These tubing extensions are marked with different color clamps for easy visual identification — blue for waste clearance blood and red for the sample itself.

When preparing to collect a sample, the Hummi Micro-Draw Blood Transfer Device can be inserted into the micro-T split-septum T-connector attached to the UAC hub. The blunt stainless steel tube of the Hummi should then come to rest within 1-2mm of the catheter opening. Next, a clearance waste volume of 0.5mL can be drawn with a self-venting syringe or with an aspirating syringe from the Hummi blood transfer device’s blue waste line, which clears the UAC dead space. The sample can then be easily drawn from the red line.

Improve Patient Outcomes with Safer Technologies

Hummingbird medical devices are a breakthrough in neonatal blood sampling technology. They can help you more efficiently monitor an infant's blood pressure, collect successful samples, and reduce the risk of potentially serious health conditions like IVH and PVL — all without falling prey to the health risks associated with umbilical artery catheters.  

The Kentec Medical team believes that providing superior customer service from the ground up is what makes modern healthcare solutions effective and accessible. We’re standing by to help you learn more about the Hummi blood transfer device, our other products, and how we can help you get them into your NICU units. Contact us today to learn more.

Works Cited

Barrington, K. J. (1999). Umbilical artery catheters in the newborn: effects of position of the catheter tip. Cochrane Database of Systematic Reviews.

Perlman, J. M., Goodman, S., Kreusser, K. L., & Volpe, J. J. (1985). Reduction in Intraventricular Hemorrhage by Elimination of Fluctuating Cerebral Blood-Flow Velocity in Preterm Infants with Respiratory Distress Syndrome. New England Journal of Medicine, 312(21), 1353–1357.

Shukla, H. (1986). Rapid Estimation of Insertional Length of Umbilical Catheters in Newborns. Archives of Pediatrics & Adolescent Medicine, 140(8), 786.