Total parenteral nutrition

Total parenteral nutrition

Fewer hospitals are now preparing TPN solutions from scratch. Standard-isation of regimens for adults, paediatrics and neonates has enabled com-mercial manufacturers with specials licences to take a significant part of the TPN market. However, the greatest impact has been the introduction of technologies such as multicompartmental TPN bags, which enable manu-facturers to provide macronutrients in standard quantities as terminally ster-ilised solutions in individual compartments of the bag. These presentations have long shelf-lives, often at room temperature, and are activated to permit mixing of components immediately before use. Many of the hospitals where TPN is still compounded prepare or purchase batches of ‘base TPN’ bags in which macronutrients (glucose, amino acids, lipid and water) are present in standard amounts. Standard TPN formulations are available with standard electrolyte concentrations or as electrolyte-free solutions to which patient-specific electrolytes can be added before administration. In all cases, it is necessary to add unstable components such as vitamins and trace elements prior to use.

Standard formulae are satisfactory for the majority of patients requiring TPN and there is no scientific or clinical evidence to support some of the very complex individualised preparations that have been used in the past. It must be recognised, however, that some patients (for example, renal patients) have specific needs and the NHS must retain the expertise and capacity to com-pound individualised TPN feeds in cases of genuine clinical need. The 2010 National Confidential Enquiry report A Mixed Bag addresses many of the clinical aspects of decision-making and use of TPN.