TPN AND CENTRAL LINE
Information on Total Parental Nutition (TPN) and Care of the Central Line or Catheter.
Total parenteral nutrition (TPN) or (PN) is a way of supplying all the nutritional needs of the body by bypassing the digestive system and dripping nutrient solution directly into a vein.
TPN is used when individuals cannot get their nutrition through eating. For example when the intestines are obstructed, or when the small intestine is not absorbing nutrients properly due to a gastrointestinal fistula (abnormal connection). It is also used when the bowels need to rest and not have any food passing through them such as following surgery to remove a blockage of the bowel. It may also be use long term to treat children with Short Bowel Syndrome.
Concentration of TPN, needs to be administered into one of the larger veins through a tube called a catheter or central line. Parenteral nutrition(PN) is a way of giving nutrition intravenously when oral or enteral feeds are unable to provide adequate nutrition for the baby or child. However, oral feeding is essential and it is important to encourage oral feeding for intestinal adaptation. The behavioural aspect of oral feeding are also important rather than just as a means of providing nutrition.
TPN given to your child will be an individualised solution containing salts, glucose, vitamins and minerals and fats that is given directly into your child’s bloodstream.
The contents of the TPN solution are determined based on the age, weight, height, and the medical condition of the individual. All solutions contain sugar (dextrose) for energy and protein (amino acids). Fats (lipids) may also be added to the solution. Electrolytes such as potassium, sodium, calcium, magnesium, chloride, and phosphate are also included, as these are essential to the normal functioning of the body. Trace elements such as zinc, copper, manganese and chromium are also needed. Vitamins can be included in the TPN solution, and insulin, a hormone that helps the body use sugar, may need to be added.
Who can administer TPN?
Normally TPN is administered in a hospital, but under certain conditions and with proper patient and caregiver education, it may also be used at home for long-term therapy. TPN solution is mixed daily under sterile conditions. Maintaining sterility is essential for preventing infection. For this reason, the outside tubing leading from the bag of solution to the catheter is changed daily, and special dressings covering the catheter are changed every other day.
What is a central line?
A central line (central venous catheter) is a thin, flexible hollow tube that is be placed under your babies skin into a vein in their chest close to their heart. The other end of the line sits outside their body.
The line that hangs outside has a clamp on it which enables the control of fluids entering or leaving the line.
The central line also enables blood to be obtained painlessly, as your child will also require regular blood tests to ensure they are receiving the proper nutrition specific to their needs.
CARE OF THE CENTRAL LINE
Dressing and safety loop.
Initially after the insertion of a central line, a transparent dressing is in place which needs to stay on for 10 days, it will then be changed by 2 of the nurses. The nursing staff will then teach the parents how to change the dressing, ensuring that there is always a safety loop in it in case the line gets accidentally pulled.
Ensure end of line is capped off
When the line is not in use, it is very important that this clamp remains shut. It will also have a bung on the end of the tube, this will be removed when the line is needed to be used and either a syringe or drip can be attached. The line must remain capped whenever its not in use as this will help prevent any bugs going into the line.
Central lines can easily be hidden under clothing and in babies and small children it is advised that a vest be worn so they can’t be pulled at.
Parents will be supplied with a pair of blue plastic clamps which they must have with them at all times in case a problem occurs with the clamp on the line, or if a small hole should appear in the line (If you notice a hole, contact the ward area you were discharged from or community specialist nurse and the line will be repaired).
Nursing staff will explain and demonstrate all of the above procedures prior to being discharged from the hospital.
Successful TPN requires frequent, monitoring of the individual's weight, glucose (blood sugar) level, blood count, blood gasses, fluid balance, urine output, waste products in the blood (plasma urea) and electrolytes. Liver and kidney function tests may also be performed. The contents of the TPN solution prescribed are individualized for each child and are based on the results of these tests.
Complications of a central line
The 3 main complications of a central line are:
INFECTION – Despite being looked after carefully, some lines can become infected. Sepsis - or infection of the blood can be introduced through contamination of the line or from bacterial overgrowth in the gut. In both cases immediate action and treatment is extremely important. Children with central lines are monitored closely for signs of infection as sepsis is extremely dangerous. Signs can include:
Redness or swelling at the line site
Lethargy and decreased feeding
Unexplained increase in stool output
If a child with a central line has a high temperature, parents should immediately contact the hospital for the child to be admitted in order for blood samples be taken. Blood cultures are then used to confirm whether or not, the line is causing the infection. Intravenous antibiotics (IV) will be given and if antibiotics do not clear up the infection then the line may have to be removed and replaced with a new one.
MOVED POSITION OR FALLING OUT – If the line was to move position or fall out you must contact your local hospital immediately. If you’re worried the line has moved position then a lineogram (special scan) can be done to check the position of the line.
BLOCKAGE - Occasionally lines may seem to be blocked. This can be caused by the line lying at an odd angle against the wall of the vein. It can also be caused by the line becoming clogged up, despite being flushed with fluid regularly. If this happens, drugs can be used to try to dissolve the blockage so the line can be used again.