Enteral nutrition (EN) — feeding directly into the gastrointestinal tract via a nasogastric (NGT) or nasojejunal (NJT) tube, or via a PEG (percutaneous endoscopic gastrostomy) for longer-term use — is strongly preferred over parenteral nutrition whenever the gut is functional. The reasons are multiple and well-evidenced: EN preserves gut mucosal integrity (preventing villous atrophy and bacterial translocation from the gut lumen into the systemic circulation), stimulates gut motility, maintains the gut microbiome, supports gut-associated immune function, and is significantly less expensive and less associated with infectious complications (particularly line-related bacteraemia) than parenteral nutrition.

EN should be started early — within 24–48 hours of ICU admission — as soon as haemodynamic stability is achieved. There is no requirement for bowel sounds to be present before starting — peristalsis in the small intestine is preserved even during ileus of the large bowel, and early EN stimulates gut recovery. The initial rate is typically 20–30 mL/hour, titrated up over 24–48 hours to the target rate.

Gastric vs Post-Pyloric Feeding

Nasogastric feeding is the standard route and is appropriate for most ICU patients. Post-pyloric (nasojejunal or jejunal) feeding is used when there is significant gastric dysmotility — evidenced by high gastric residual volumes (>250–500 mL) — or in patients at high risk of aspiration (severe gastroparesis, repeated vomiting, prone positioning, recent upper GI surgery). Prokinetic agents (metoclopramide, erythromycin) should be tried before moving to post-pyloric feeding.