Nutrition in ICU
7. Types of feed and problems with enteral feeding
A number of different companies provide a variety of feed types and one should be found to suit the particular needs of each patient:
- Standard (1-1.2 kcal/ml) for patients with normal requirements
- High Energy (1.5-2 kcal/ml) for patients requiring low volume feed or extra calories
- High Energy and High Protein for catabolic patients requiring lower volume feed
- Low Sodium – for hypernatraemic patients,
- Low Electrolyte and High Energy for patients on haemofiltration
- Peptide/Elemental for pancreatic insufficiency or malabsorption
- Some feeds have extra fibre added which may be used for patients with diarrhoea.
- Feeds with added immunonutrients are available but at present are rarely used in Scotland.
Complications of enteral feeding
Ventilator-associated pneumonia (VAP)
This is thought to be due to reflux of gastric contents into the mouth which then trickle down beside the cuff of the endotracheal tube into the lungs. Aspiration of infected secretions will occur whether or not a patient is fed but the volume of aspiration may be higher if feed is poorly absorbed. Strategies to reduce aspiration include a head up tilt (30-45 degrees) and subglottic drainage of secretions via a port on a specially designed endotracheal tube. Selective decontamination of the digestive tract (SDD) using antibiotics is a controversial technique which may prevent VAP. Small bowel feeding compared to gastric feeding does not appear to reduce VAP rates.
- Kinked or clogged tubes lead to inadequate feeding.
- Tubes may cause nasal skin or mucosal damage.
- The NPSA Guidelines on correct tube placement should be followed – feeding into a lung may prove fatal.
Gastro-intestinal problems and treatment
- High gastric residuals and emesis: treat with metoclopramide and erythromycin
- Gastroparesis may be successfully circumvented by post-pyloric feeding
- Ileus: may be treated by the administration of either a bolus or infusion of neostigmine.
- Diarrhoea: May be due to bowel wall oedema, decreased absorption, bacterial overgrowth and drugs. Exclude infectious causes and stop offending drugs if possible. Loperamide may reduce stool volume and improve consistency.