Different Types of Clinical Nutrition
An Introduction to Enteral and Parenteral Nutrition
When addressing disease-related malnutrition, the choice of nutrition support depends on the patient’s clinical state. The rule of thumb is: “if the gut works, use it.” The majority of patients with, or at risk of malnutrition may be managed using simple tools to increase nutritional intake, including dietary counselling or food fortification. Additional strategies include the use of oral nutritional supplements (ONS). When oral support is not sufficient, tube feeding/enteral or parenteral nutrition may be required alone or in combination. A formal nutrition assessment can determine the correct support therapy based on the patient’s disease-related malnutrition status.1,2,3,4,5,6
The following are the major types of clinical nutrition support:
Enteral Nutrition (EN)
According to the European Society for Clinical Nutrition and Metabolism (ESPEN) Enteral Feeding Guidelines, the term “enteral nutrition” is used to describe all forms of nutritional support that involve the use of ‘‘dietary foods for special medical purposes’’ independent of the route of administration. EN includes ONS and enteral tube feeding.7
Oral Nutritional Supplements (ONS)
ONS is a non-invasive approach to tackle malnutrition. Used as an integral part of an overall patient management strategy, ONS is an effective solution for a wide variety of patient groups. Current evidence suggests that appropriate use of ONS results in nutritional, functional, clinical and economic benefits.8
EN tube feeding is introduced via nasogastric, nasoenteral or percutaneous tubes,7 providing nutrients and energy to the mucosal cells, increasing mucosal blood flow, stimulating epithelial cell metabolism, bile flow and pancreatic secretions as well as the release of enterotrophic gastrointestinal (GI) hormones.9
Parenteral Nutrition (PN)
PN is the intravenous infusion of nutrients directly into the systemic circulation, bypassing the gastrointestinal (GI) tract.10 Generally, PN is indicated in patients who cannot be fed adequately and/or safely via the oral/enteral route and/or have a non-functional, inaccessible or perforated gastrointestinal (GI) tract.10,11 Additionally PN can help to improve patient outcomes12,13,14,15 and is safe when indicated and used appropriately.12,15
Supplemental Parenteral Nutrition
In cases where enteral intake cannot sufficiently meet the patient’s daily minimum food and fluid requirements, supplemental PN can be administered in conjunction with EN and can help reduce the risk of EN associated diarrhea in the critical care setting.15,16
Total Parenteral Nutrition
Total PN supplies the patients with all of their daily nutritional requirements in cases where EN is not feasible. Total PN delivers all the nutritional needs of the body intravenously, bypassing the digestive system.
A combination of the mentioned nutritional strategies may be used to manage disease-related malnutrition in an optimal way following a formal nutrition assessment.
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- 14. Heidegger CP, Berger MM, Graf S et al. Optimisation of energy provision with supplemental parenteral nutrition in critically ill patients: a randomised controlled clinical trial. Lancet 2013;381(9864):385-393.
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