Parenteral nutrition

Parenteral nutrition is a way of providing food in a liquid form into your body using the veins rather than the gut. All the nutrients you require go into your bloodstream thus bypassing the gut.

In order to provide parenteral nutrition, a small tube (catheter) will be inserted into one of your veins. This may be into one of the veins in your arm. This type of catheter is called a Peripherally Inserted Central Catheter (PICC).

Alternatively, a line is inserted into one of the larger veins in your neck or chest. This type of line may have already been inserted if you have had an operation. If not, then the line may be inserted using local anaesthetic or in some cases general anaesthetic.

The person who inserts this line will be able to discuss this procedure with you. Following catheter insertion, you may have a chest X-ray to make sure that the tip of the catheter is in the correct place before parenteral nutrition is started.

A PICC placed only for parenteral nutrition will usually have one access end (lumen). This is known as a ‘dedicated PN lumen’. A dedicated lumen for parenteral nutrition helps to reduce the risk of infection as it should only be used to administer parenteral nutrition. If other infusions are needed, then a PICC with more lumens may be required. 

Parenteral nutrition contains all of the nutrients you need for your body to function and replaces the food you would normally eat. It contains amino acids (the building blocks of protein) for growth and maintenance of tissues; glucose and fat for energy and to supply essential fatty acids, electrolytes such as sodium, potassium and calcium (for bones); and vitamins and trace elements which are essential for growth and health. This complex mixture of nutrients is delivered in approximately 500ml to 2500ml of water depending on the individual’s requirements. It comes in a large plastic container similar to a ‘drip’ which is placed into a protective bag.

The mixture is made in the Pharmacy department in a special clean room facility under extremely high standards of cleanliness and hygiene. The liquid from the bag is delivered into your veins in a controlled way using a pump that moves the liquid from the bag via the catheter and into your body at a set rate.

The majority of patients require parenteral nutrition for only a short period (days to weeks) whereas others may require it for a longer period of time (months to years). If you are having parenteral nutrition in hospital, then you will usually receive it initially over 24 hours (throughout the day and night).

The feeding time may then be reduced so that you receive the parenteral nutrition over a shorter time period (for example just overnight) so that you are then ‘free’ of the drip during the day (unless other infusions are required). Some patients have parenteral nutrition in this way at home after they have been trained to administer it to themselves.

Initially we will require relatively frequent blood tests (at least every other day) to check that we are giving you the correct amounts of everything in the bag. We can adjust what we give to you in the parenteral nutrition according to these blood tests. We will also need to check your weight at least once a week.

The parenteral nutrition provides water so that you do not need to worry if you are not allowed to or not able to drink any fluid. Parenteral nutrition can sometimes take away the feeling of hunger. At some point the doctors looking after you may allow you to start taking liquids and then food as and when your gut starts to work. We will change the amount of parenteral nutrition you receive accordingly and the dietitian will be able to advise you on drinking and eating. You may be allowed to eat and receive parenteral nutrition at the same time.

The majority of patients only require parenteral nutrition for a few days or weeks and make an uneventful recovery. The main risk of this type of treatment is an infection of the catheter which may then result in an infection in your blood. For this reason, great care is taken when handling the catheter (in particular when the bag of parenteral nutrition is connected or disconnected) to ensure that it does not become infected.

It is important that anyone touching the PICC line washes their hands, wears gloves and cleans the end of the catheter correctly. Disconnection is only allowed when the bag is empty (or infusion finished) by a trained professional.

Signs that a line may be infected include your temperature going up or a redness or swelling around the insertion site of the catheter. As this can have other causes, we will take blood samples from the catheter to check if there is an infection. If we think there is an infection in your catheter, we may remove it and/or treat you with antibiotics.