Nutrition Support

Feeding a Baby Through an Intravenous (IV) Line

Not many premature or low birth weight babies can be fed during the first few hours in the NICU, and many sick babies are unable to take anything by mouth for a number of days. To make sure your baby is getting adequate nutrition, the NICU staff starts an IV to administer fluids containing water, glucose, sodium, potassium, chloride, calcium, magnesium, and phosphorus. This kind of nutrition is called total parenteral nutrition or TPN.

At first, the staff places the IV in a vein in the baby's head, hand, or lower leg. These IV lines often last for less than a day, so a baby may have several IVs placed in the first few days. After a few days, however, most babies need more nutrition than these small IV lines can supply. The staff then inserts a catheter into one of your baby's larger veins so that larger amounts of nutrients can be given

If a baby is very small or sick, catheters (long IV lines) may be placed in both the umbilical artery and vein. Fluids and medications can be given through the catheter and blood can be drawn for laboratory tests. More concentrated IV fluids can be given through an umbilical line so babies can get better nutrition. Umbilical lines last longer that smaller IV's, often for a week or more. Umbilical arterial lines can also be connected to a machine that continuously measures a baby's blood pressure.

If a baby is going to need TPN for more than a week to 10 days, doctors often insert another type of line, called a central line, that can remain in place for several weeks, until the baby no longer needs TPN.

Feeding a Baby By Mouth

Feeding by mouth (also called ?enteral nutrition?) should be started as soon as possible because it helps a baby's gastrointestinal (GI) tract grow and begin functioning. A very small baby may first need to be fed through a small plastic tube that goes through the mouth or nose and into the stomach. A small amount of breast milk or formula is given through this tube. Often the baby is given a combination of parenteral and enteral feedings at first, because it can take awhile for the GI tract to become accustomed to enteral feedings.

A baby needs approximately 120 calories per day for every 2.2 pounds (one kilogram) of weight. Regular formula and breast milk contain 20 calories per ounce. A baby of extremely low birth weight should receive special formula or fortified breast milk containing at least 24 calories per ounce to ensure adequate growth. The fortified breast milk and formula has more protein, calcium, and phosphorus, as well as carbohydrates and fats that are more easily digested by a very small baby.

It can take some time before all of a baby's nutritional needs can be met through enteral nutrition. The intestines of a small baby are not able to tolerate rapid increases in the amount of milk or formula, so increases in feedings must be done cautiously and gradually.

Other Common NICU Procedures


X-rays are one of the most commonly performed procedures in the NICU. The most common reason for an x-ray is to examine the baby's chest to see if the condition of the lungs is improving. X-rays are often taken of the baby's abdomen if he is not tolerating his enteral feedings.


Premature babies are also routinely evaluated by ultrasound. Ultrasound may be used to check for hemorrhage in the brain or for damage to the white matter surrounding the ventricles of the brain (a condition called periventricular leukomalacia ).

Blood and Urine Tests

Your baby's doctor may order blood work to test for the following:

  • blood gases (the amount of oxygen, carbon dioxide, and acid in the blood)-Blood gas levels can help the staff assess how well a baby's lungs are functioning and how much respiratory assistance may be needed. This test is usually performed on arterial blood. If your baby does not have an arterial catheter in place, a nurse can obtain a blood sample by pricking the baby's heel (a capillary blood gas );
  • hematocrit and hemoglobin -These tests provide information about how well a baby is able to carry oxygen through the body;
  • blood urea nitrogen (BUN) and creatinine -These substances indicate how well the kidneys are functioning; and
  • chemical salts, like sodium, glucose, potassium, chloride, calcium, phosphorus, and magnesium -Levels of these salts provide information about different aspects of a baby's medical condition.

The nurses also collect a few drops of urine every few hours. The urine is checked for pH level, and for sugar, protein, and blood content. These tests provide information about kidney function and metabolism.

Procedures to Measure Fluids

Nurses measure all the fluids your baby takes in (for example, by IV and by mouth) and all the fluids that leave the baby's body (for example, urine output and amount of blood taken for testing). This helps determine if the fluids are in balance-that is, if the baby takes in about the same amount of fluid as leaves his body. The nurses also weigh a baby frequently to help determine how much fluid he needs.

Blood Transfusions

Babies in the NICU often require blood transfusions because (1) their blood-forming organs are immature and are not producing enough red blood cells, and (2) they may be losing a lot of blood for various tests.