There are several types of lines and catheters that can be used for vascular access in a premature baby or ill newborn. The vascular devices are small catheters or tubes inserted into either a vein or an artery.
The need for vascular access
There are three reasons vascular access may be needed in a baby admitted to the Neonatal Intensive Care Unit (NICU):
- Nutrition: usually total parenteral nutrition (TPN), which contains fat, essential vitamins and nutrients. TPN is delivered directly into the bloodstream, bypassing the digestive system, either because it is immature and therefore unprepared to digest nutrition properly or because a baby’s condition prevents them from being fed.
- Drawing blood: for tests, of which there are many different types.
- Delivery of medicines directly to the bloodstream: such as fluids for hydration, antibiotics and transfusion of blood products (through peripheral venous lines and large-bore central lines).
Peripheral intravenous lines
The most familiar type of vascular access is a peripheral intravenous line (PIV). An IV is essentially a small hollow tube that is placed in a vein and attached to a long tube that goes into an IV pump. In newborns, PIVs are usually put into a vein in the hand, foot or scalp, allowing the health-care team to give medicine or other fluids. PIVs can be inserted and left in place for a few days and are generally used to deliver nutrition or medication and hydrating fluids. These lines are not threaded as deep into the body as other types of lines and usually last for hours to a few days. They are not the best option for babies who may need longer-term IV therapy. Some medications cannot be given in a PIV.
Umbilical venous catheters
An umbilical venous catheter (UVC) is placed into the cardiovascular system through the remaining “tail” of a cut umbilical cord in a newborn. Generally, they are the preferred method of venous access in the NICU; however, the catheter can only be inserted into a recently born baby. After about two weeks of age, the umbilical cord and the veins leading from it to the body naturally disappear. UVCs can be placed quickly and can remain in place for up to seven to 10 days if necessary, depending on the position of the catheter. The catheter is inserted in the umbilical cord, and the tip is positioned to just outside a chamber of the heart called the right atrium. The health-care team confirms the position of the tip by X-ray or point-of-care ultrasound.
Peripherally inserted central venous catheters
Peripherally inserted central venous catheters (PICC lines) are placed into a peripheral vein. Usually, the catheter is inserted in a vein in the arm, leg or scalp. The catheter is then advanced through veins until the tip of the catheter is in one of the major veins near the heart (either the superior or inferior vena cava, depending on which peripheral vein is used for inserting the PICC). For newborns having a PICC line inserted in the NICU, an X-ray is done to visually ensure correct placement of the tip. Sometimes, babies must go to the Image Guided Therapy (IGT) suite to have the PICC inserted. An IGT suite is a room with imaging devices that help interventional radiologists insert and thread the line to the right place. A PICC line can be left in place for several weeks or months. Depending on the size of the catheter, some may be used for blood draws. If a baby is expected to need an IV for an extended period, a PICC line may be used.
Central venous catheters
Central venous catheters are inserted into a vein in one part of the body, and the tube is then guided within the vein to a point near the heart. The choice of vascular access that is used depends on the baby’s gestational age and condition. Central venous catheters are used to deliver nutrition, fluids and medications, though they may also be used to take blood samples.
The catheters are fed through the vascular system to a point near the heart for several reasons:
- A premature baby or ill newborn’s veins can be fragile, so placing the tip near one of the larger veins means that it can last longer, is less likely to become dislodged and is less likely to cause damage.
- Blood flow is strongest near the heart, which means the flow of medicine, nutrition or fluids through the catheter will be stronger and more constant. If it is delivered at a point near the heart, medicine will diffuse throughout the body more quickly. This allows for higher concentrations of medicines to be delivered through the lines without irritating the veins. Depending on a baby’s condition, several lines may be needed at the same time. For example, one line might be used for nutrition while another separate line delivers medicine. Babies requiring several separate treatments are more likely to have more than one line. Some catheters have two or more separate tubes, or lumens, within one tube. This may allow separate treatments, such as delivery of two medications, to occur at the same time.
All methods of vascular access require regular maintenance and monitoring. For example, heparin, an agent that prevents blood clotting, is usually used to keep the lines of the catheter from clogging up. Additionally, all types of vascular access can cause complications, most of which are rare but can be serious. The NICU has a surveillance program in place to minimize these risks.