Background:
The purpose of this retrospective study was to analyse the occurrence of gastrointestinal side effects in enterally fed ITU patients.

Methods:
We analysed the records of 195 ITU patients fed enterally, over at least five days, with commercial mixtures administered as 20-h infusions. Gastric retention, the number of defecations, and incidents requiring discontinuation of enteral feeding, were noted during the first 3 days of nutrition.

Results:
Enteral nutrition was usually started during the first week of treatment (median 4, range: 1–33). In 118 patients receiving parenteral nutrition, the median day of implementing enteral feeding was day 5; some received enteral mixtures much earlier (day 2). The mean infusion rates of enteral mixtures were: 33 mL h–1 on day 1, 58 mL h–1 on day 2, and 68 mL h–1 on day 3. Gastric retention was observed in 49 (25.1%) patients during the first day, in 37 (19.0%) on day 2, and in 25 (12.8%) on day 3. Discontinuation of enteral nutrition was necessary in 6 patients due to: surgery (1), high gastric retention (4), gastrointestinal bleeding (1). A statistically significant correlation was found between the occurrence of gastric retention, infusion rates and CRP, and between the number of defecations and infusion rates.

Conclusions:
Enteral feeding with commercial diets is well tolerated when implemented gradually. Intolerance and the need for the discontinuation of enteral feeding were usually associated with a worsening of the patient’s general condition and progression of the underlying disease.