Formulation of enteral diets for use in jejunal enteral feeding

Nasogastric enteral feeding is not tolerated in patients with gastric atony and in many critically-ill patients in whom gastric emptying may be delayed and in whom gastro-oesophageal regurgitation may lead to pulmonary aspiration of enteral feed and the development of pneumonia. Initial attempts to overcome these problems led to the development of post pyloric enteral feeding techniques with the infusion port of the tubes positioned in the duodenum. In many centres this technique is still the most practised post-pyloric enteral feeding technique. Nasoduodenal feeding tubes often retroperistalse into the stomach. The technique of choice, therefore, in these difficult patients is to position the infusion port of the feeding tube well distal to the ligament of trietz (post ligament of trietz nasojejunal enteral tube feeding). While nasogastric and nasoduodenal enteral feeding techniques have been shown to elicit a stimulatory exocrine pancreatic response, distal jejunal enteral feeding does not. During this mode of feeding the ileal brake is activated and pancreatic exocrine pancreatic secretion inhibited by the action of the released peptide YY and glucagon-like peptide-1 hormones, in turn the inhibition of pancreatic secretion being the result of inhibition of trypsin secretion. In the light of the findings showing the absence of a stimulatory pancreatic exocrine response to nasojejunal enteral feeding these patients should receive a predigested rather than a polymeric enteral diet.