saudigastro.com/patients/parenteral-nutrition
Results
Nutrition is delivered as soon as the line is checked and the first bag is started. Gains in weight, strength and healing take days to weeks, and your team tracks them through weight, blood tests and symptoms. How long PN is needed varies widely: days to weeks in acute illness, but months or years, even lifelong, in chronic intestinal failure. Your team will review regularly whether it can be reduced or stopped.
This article is educational and does not replace your doctor's advice. Seek urgent care for any red-flag symptoms.
What is it?
“Parenteral” means “outside the gut”. In parenteral nutrition (PN), a sterile liquid containing carbohydrate (sugar), amino acids (the building blocks of protein), fats, vitamins, minerals and trace elements is given through a thin tube (catheter) placed into a vein, bypassing the digestive system. It is made up by a specialised pharmacy or supplied as ready-made bags, according to the person’s needs. For short periods or smaller amounts it may be given through a vein in the arm (a peripheral line). For longer or fuller feeding it is given through a central line, a thin tube whose tip lies in a large vein near the heart, such as a PICC line (inserted in the arm), a tunnelled line (placed under the skin in the chest, for long-term use) or an implanted port. It is usually given with a pump, either continuously or over part of the day (for example overnight) once the person is stable.
Why is it done?
It is used when the gut cannot be used or cannot absorb enough nutrition, and tube feeding into the stomach or bowel is not possible or not enough. It keeps the body nourished, supports healing and prevents severe malnutrition. Examples include intestinal failure (for instance after major bowel surgery or short bowel syndrome, where much of the small bowel is missing or not working), complete blockage of the bowel, severe bowel fistulas, prolonged paralysis of the bowel, severe inflammatory bowel disease complications, or when the gut must rest. Because it has more risks than feeding through the gut, it is used only when needed and for as short a time as possible, unless the problem is long-term.
Who needs it?
- People with intestinal failure, such as short bowel syndrome, who cannot absorb enough food and fluid through the gut
- People whose bowel is blocked, paralysed or needs complete rest, for example after surgery or in severe complications of Crohn’s disease or pancreatitis
- Seriously ill or malnourished people who cannot be fed through the gut for several days or more
- People who need long-term feeding at home because of chronic intestinal failure, under a specialist team
Before the procedure
- The decision to start PN is made by a nutrition team (doctor, dietitian, pharmacist and nurse) after checking whether the gut can be used. You will have blood tests, a weight and a nutrition assessment.
- A vein access is needed. A peripheral cannula is quick. A central line (PICC, tunnelled line, or port) is put in by a trained team under local anaesthetic, sometimes with ultrasound or X-ray guidance, and its position is checked with an X-ray before use. You may need to fast for a few hours and have sedation for some lines; follow the instructions you are given.
- Tell the team about all your medicines, especially blood thinners (warfarin, apixaban, rivaroxaban, clopidogrel, aspirin), diabetes medicines and any allergies (including allergy to egg, soy, fish or peanut, since some fat solutions contain them), kidney or liver disease, and previous problems with lines or infections. Never stop medicines unless instructed.
- If PN will be given at home, you or a carer will be trained to connect and disconnect the bag, use the pump, keep the line sterile and wash hands properly, and you will be given supplies, a fridge plan for the bags and emergency contacts. Training can take days to weeks.
- If you fast for Ramadan, discuss with your team: people on PN for medical reasons are usually advised on an individual basis, and the schedule may be adjusted.
During the procedure
Placing a line: the skin is cleaned and numbed, the line is placed into the vein, and its tip position is confirmed; this is usually done in a procedure room and takes under an hour. Giving PN: a nurse (or you, once trained) connects the bag to the line using a strict clean technique. The bag runs through a pump over many hours, such as 10 to 24 hours depending on your needs. Your team checks blood sugar, blood salts and minerals, and liver tests often at the start, then less often. You can usually move around, wash and carry on normal activities as allowed, using a portable pump or bag where available. The line and dressing are looked after carefully to prevent infection.
After the procedure
You will be monitored with regular weight checks and blood tests, and the mix is adjusted as your needs change. Keep the dressing clean, dry and intact; do not get the line wet unless advised; wash hands and use the sterile technique for every connection. Report any problem with the line at once. Your team will also encourage eating or tube feeding when possible, to keep the gut working, and will wean PN when the gut can take over. Long-term users get regular reviews of nutrition, bone health, liver tests and the line. Keep contact numbers handy and know what to do out of hours.
Risks
- Line infection and bloodstream infection (the most important risk), which can be serious; strict hygiene and care of the line lowers the risk
- Blood clots in the vein around the line, line blockage, line moving or breaking, and problems at insertion such as bleeding, a collapsed lung (rare) or air entering the vein (rare)
- High or low blood sugar, and imbalances of salts and minerals, which are checked through blood tests
- Liver and gallbladder problems, such as fatty liver, cholestasis (reduced bile flow) and gallstones, particularly with long-term use; these are monitored and the mix adjusted
- Refeeding syndrome, a dangerous shift of salts and fluids when feeding starts after a long period of poor intake; the team starts slowly and monitors closely
- Bone thinning, vitamin or trace element problems, and the burden of daily routines, especially with long-term home PN
- Seek urgent help for fever, chills or shaking (especially during or after a connection), redness, swelling, pain or pus at the line site, a leaking, broken or displaced line, arm or neck swelling or pain, chest pain, shortness of breath, confusion, excessive thirst or passing a lot of urine, or severe weakness.
When you get results
Alternatives if you decline
When the gut works, enteral (tube) feeding into the stomach or bowel is preferred because it is safer. Other options include food fortification and nutrition drinks, treating the cause (for example medicines or surgery), and, for some people with short bowel, medicines that help absorption or surgery. Some people may choose not to have PN, for example in advanced illness, which is a valid decision to talk through with your doctors and family. Declining PN when the gut cannot be used may lead to severe malnutrition, dehydration and a risk to life.
Questions to ask your doctor
Save this list or print it before your appointment — doctors appreciate prepared patients.
- Why can’t I be fed through my gut, and could that change?
- Which type of line is best for me, and how long will I need PN?
- How do I prevent infections, and what should I do if I get a fever?
- Can I eat or drink while on PN, and can I travel or work?
- How often will my blood, liver tests and weight be checked?
Was this guide helpful?
Status: Approved for publication by SGA; individual clinician review is ongoing · Published 24/04/2026
For general education only; it does not replace your doctor’s advice. Individual clinician review of this guide is ongoing. SGA clinician? Review this guide