Parenteral nutrition(PN) refers to the provision of nutrients by the intravenous route. In general, PN should only be used when it is not possible to supply nutrition using the GI tract ie when intestinal failure is present.
Total Parenteral Nutrition (TPN) implies that all macronutrient (carbohydrate, nuitrogen and lipid) and micronutrient (vitamins, trace elements and minerals) and fluid requirements are met by an intravenous nutrient solution and no significant nutrition is obtained from other sources. Some patients treated with PN can absorb some fluid and nutrition taken orally and in these patients PN is a supplement to their oral intake.
The European Society for Clinical Nutrition and Metabolism (ESPEN) has published a definition and classification of intestinal failure (Pironi,2015) is addition to guidelines for the management of both acute and chronic intestinal failure.
Intestinal failure occurs when there is “reduction of gut function below the minimum necessary for the absorption of macronutrients and/or water and electrolytes, such that intravenous supplementation (IVS) is required to maintain health and/or growth”.
Intestinal failure has been classified according to time scale, metabolic changes and outcome (Shaffer, 2002).
- Type I - an acute, short-term and usually self-limiting condition eg post-operative ileus
- Type II - a prolonged acute condition, often in metabolically unstable patients, requiring complex multi-disciplinary care and PN over periods of weeks or months.
- Type III - a chronic condition, in metabolically stable patients, who requirePN over months or years. It may be reversible or irreversible.
Pironi L, Arends J, Baxter J, Bozzetti F, Pelaez RB, Cuerda C, et al. ESPEN endorsed recommendations. Definition and classification of intestinal failure in adults. Clin Nutr 2015 Apr;34(2):171e80. http://dx.doi.org/10.1016/j.clnu. 2014.08.017. PubMed PMID: 25311444.
Shaffer J. Intestinal failure: definition and service development. Clin Nutr 2002;21(Suppl. 1):144-5.
Pironi L, Arends J, Bozzetti F, Cuerda C, Gillanders L, Jeppesen PB, Joly F, Kelly D, Lal S, Staun M, Szczepanek K, Van Gossum, Wanten G, Schneider SM, the Home Artificial Nutrition & Chronic Intestinal Failure Special Interest Group of ESPEN. ESPEN guidelines on chronic intestinal failure in adults. Clinical Nutrition 35 (2016) 247-307.
Thanks are due to many healthcare professionals who provided copy for this area of the BAPEN website. Among them are...
- Paula Murphy
- Kate Stoker
- Beth Thompson
- Kate Stoker
- Bernadette Tavner Allsopp
- Sean White
- Chris Mountford
- Ruth McKee
- Irina Grecu
- Ewan Forrest
With thanks also to the PENG committee of 2016 who reviewed content.