Basics in clinical nutrition: Enteral nutrition

      Keywords

      Learning objectives

      • To appreciate the different routes by which enteral nutrition can be delivered
      • To understand the indications for and contraindications to enteral nutrition
      • To identify the indications and benefits of enteral tube feeding
      • To select an appropriate enteral feeding solution
      • To recognize key characteristics associated with the delivery of enteral tube feeds
      • To characterize complications associated with enteral nutrition

      1. Indications for enteral nutrition

      If a patient has a functioning gut but is unable or unwilling to eat sufficient to meet his/her nutritional needs, various options of enteral feeding can be considered.
      In principle, feeding solutions should be introduced to the gastrointestinal (GI) tract at the point where it is possible to absorb them. It is also possible to use modified feeds e.g. peptide based formulae to overcome gastrointestinal incapacity thereby avoiding the need for parenteral nutrition.

      2. Contraindications to enteral nutrition

      Although the enteral route should always be the first option, there may be occasions when it is contraindicated. These include:
      • absence of intestinal function due to failure, severe inflammation or, in some instances, post operative stasis
      • complete intestinal obstruction
      • inability to access the gut e.g. severe burns, multiple trauma
      • high loss intestinal fistulaea
      • relative contraindication to tube feeding is also increased likelihood of opportunistic infection e.g. maxillo-facial surgery or oncology treatments
      • ethical considerations e.g. terminal care.
      Note: In cases of doubt a time limited trial may be considered.

      3. Routes for enteral tube feeding

      The gut can be accessed in a range of places and the choice of feeding route will depend on the underlying pathology, the anticipated duration of tube feeding and the preference of the patient (see Fig. 1).
      Figure thumbnail gr1
      Fig. 1Routes for enteral feeding.

      4. Choice of feeding solution

      Local practice, preference and availability will help determine the most appropriate solutions for the majority of patients (see Fig. 2). With help of this diagram and structured approach to choice for a correct enteral diet a proper nutritional system can be selected.
      Figure thumbnail gr2
      Fig. 2Types of solutions available for enteral tube feeding.
      A structured approach will enable the correct choice to be made:
      • 1)
        Is gastrointestinal function normal?
        • Yes – Choose a whole protein feed
        • No – Consider a semi-elemental/elemental product
      • 2)
        Is the fluid volume restricted and/or is a higher energy containing feed needed?
        • Yes – Choose a high energy feed and consider whether a disease specific formula might be needed
        • No – Choose a standard feed
      • 3)
        Is the patient constipated?
        • Yes – Choose a feed containing insoluble fibre
        • No – Consider a standard feed or a feed containing soluble fibre
      Note: Feeds containing soluble fibre could be given instead of a standard feed due to the other benefits they confer e.g. glycaemic control.
      • 4)
        Is there a specific dietary restriction or other nutritional need?
        • Yes – Consider a disease specific or a paediatric formulation
        • No – Choose a standard feed

      5. Summary

      A selection of commercially produced enteral feeding solutions is widely available. The most suitable solution should be selected on an individual basis and it should be delivered as high up the GI tract as possible while ensuring maximum absorption.

      Conflict of interest

      There is no conflict of interest.