Nutrition in ICU
Overfeeding the patient may occur, especially if parenteral nutrition is used.
- Excess carbohydrate administration leads to increased CO2 production and increased minute ventilation. This exacerbates respiratory failure in patients with limited pulmonary reserve.
- Hyperglycaemia causes hyper-insulinaemia with increased transport of potassium and phosphate into the cells.
- In the liver, if fat or carbohydrate load is greater than 150% of total energy expenditure, fatty deposition, transaminitis, cholestasis and hepatomegaly occur.
- Excess lipid administration leads to congestion of the reticulo-endothelial system and an increase in serum triglycerides.
- Excess protein administration leads to increased production of urea. Electrolyte imbalances also occur.
- Overfeeding was a particular problem in the early days of parenteral nutrition and may have contributed to the excess morbidity seen in some trials comparing parenteral with enteral nutrition. Opinions on the harmfulness of parenteral nutrition are now being revised. (see later under Methods of Feeding).