Parenteral Nutrition

Parenteral Nutrition

Parenteral nutrition refers to the infusion of nutrients via the veins, i.e. the provision of nutrition intravenously.  

Parenteral Nutrition (PN) is often referred to as Total Parental Nutrition (TPN) which implies that this is the sole source of nutrition; in some cases, patients on PN may receive a small amount of nutrition via the gastrointestinal tract.  

Parenteral nutrition is used when patients have an inaccessible or non-functioning gastrointestinal system. 

The National Institute for Clinical Excellence (NICE) recommends that healthcare professionals should consider parenteral nutrition for patients who are malnourished or at risk of malnutrition and have an inadequate or unsafe oral and/or enteral nutritional intake, or a non-functional, inaccessible or perforated (leaking) gastrointestinal tract.

Parenteral nutrition is delivered to the patient’s bloodstream through an intravenous catheter, which is ideally placed centrally into a large vein near the heart; this is usually called a central line or a peripherally inserted central catheter (PICC).  Less frequently, smaller veins further from the heart are used; this is called peripheral administration.  Safe intravenous access and catheter care is essential to minimise the risk of complications and infection. 

A multi-disciplinary team of clinicians, dietitians, nutrition nurse specialists and pharmacists are required to establish, monitor and manage patients on parenteral nutrition in the acute setting.

Some patients may require parenteral nutrition on a long term basis and may be discharged on home parenteral nutrition.  For those patients whose gastrointestinal function improves or recovers, parenteral nutrition may be gradually withdrawn, but only once adequate oral or enteral nutrition is tolerated and nutritional status is stable.

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Nutritional Regimens

Standardised ranges of compounded parenteral nutrition regimens are available for both adults and newborn children and are tolerated by a broad spectrum of patients. Parenteral nutrition may also be specifically tailored to a patient’s nutritional needs; an accurate assessment of a patient’s nutritional needs is required to ascertain the precise composition of the nutrition. For this reason, regular monitoring of the patient’s biochemistry and fluid balance is essential.

The stability of the PN bags is affected by volume and the proportion of the constituents, especially amino acids and fat, amino acid formulation, glucose and electrolytes.

Parenteral nutrition is governed by pharmaceutical law.  The Medicines and Healthcare Regulatory Authority (MHRA) is the UK body responsible for authorisation and regulation of products and associated devices.

A list of the courses available for healthcare professionals in the UK can be viewed here.




BSNA has produced a guide to parenteral nutrition, which can be downloaded here.

A Guide to Parenteral Nutrition

A Guide to Parenteral Nutrition