Parenteral nutrition, often called PN or TPN, gives the body its nutrition straight into the blood, so the gut is not needed at all. It is used when the gut cannot absorb enough, or should not be used for a while. When the gut cannot absorb enough to keep you well, doctors call it intestinal failure.
Why people need it
Common reasons include a bowel that is too short after surgery, a bowel damaged by illness, a bowel that does not move food along properly, a blockage, or a leak from the bowel (a fistula). Some people on PN can still eat or drink a little, depending on their condition. Others, like me, cannot eat at all.
What is in the bag
The bag holds a mixture made up for your body: water, sugar (glucose), protein in the form of amino acids, fats, salts such as sodium and potassium, vitamins and trace elements. Your nutrition team and pharmacist decide exactly what goes in, based on your blood tests, and it can change over time.
How it gets in
The mixture is strong and would irritate small veins, so it goes into a large vein close to the heart through a central line. At home this is usually a tunnelled line such as a Hickman line, which comes out through the skin on the chest. Some people have a PICC line in the arm, or a port placed under the skin.
Because the end of the line sits so close to the heart, keeping germs out matters more than anything else. You are taught a careful clean routine for connecting and disconnecting, and you should never be rushed through it.
How long it runs
Most people at home run their feed through a pump overnight, often for 12 hours or more, so the day is free. How many nights a week depends on what your body needs: some people need it every night, others have a night or more off. Some, like me, have needed day feeds instead. Some people also need extra fluid bags.
Deliveries and storage
A homecare company delivers your bags, pump supplies and dressings. Many bags must be kept in a fridge, and you will be told how long to take them out before you connect. Keep to the storage instructions on your own bags.
Being looked after
You will have regular blood tests and clinic appointments so the team can check your salts, sugar, liver and kidneys, and adjust the bag.
Remember: if you feel unwell during or after a feed, or have a temperature or shivers, contact your nutrition team straight away. See the risks to know about.