Early enteral nutrition: a challenge in the ICU?

Introduction

In modern intensive care medicine there is a strive for enteral nutrition (EN) since it has been shown to protect gut mucosal function, to reduce infective morbidity, to hasten recovery from illness and to contribute to a lower mortality rate. EN requires a functioning, intact gastrointestinal tract, may cause diarrhoea and has an attendant risk of pulmonary aspiration. Further, data indicate that discrepancies between prescription and delivery of EN carry a risk of undernutrition. We therefore designed this study, with the aim to identify discrepancies between prescribed and delivered nutrition and to evaluate benefits and problems associated with EN and parenteral nutrition (PN). We also compared the actual amounts of fat, glucose and nitrogen delivered with calculated requirements.

Methods

Data on nutritional supply (energy intake, amount glucose, fat and nitrogen) and gut function (diarrhoea, gastric retention and vomiting) were registered daily for all patients admitted to the ICU during 6 weeks. Patients treated for less than 3 days were excluded. Energy requirements were calculated according to the Harris–Benedict equation and the nitrogen (N) demand was set as 0.15 g/N/kg. Data are based on 267 treatment days, and are presented as mean ± SEM.

Results

Twenty-six out of 74 patients stayed in the ICU for >3 days, and were thus included in the study. On average, patients received adequate amounts of energy (around 1500 kcal/day) from the third day, and throughout the study period. Of the energy delivered, fat accounted for 20–30%. The daily N supply was approximately 14 g. There was a good correlation between prescribed and administered amounts of enteral nutrition (R² = 0.90). Of the total amount of energy delivered 53% was administered enterally. Bowel function was considering normal for 151/241 days (63%). Daily registrations of gut function demonstrated diarrhoea (11%), gastric retention (29%) and vomiting (2.5%).

Conclusions

EN was gradually increased, according to our nutrition guidelines, and predominated after the first 7 days. The energy input was usually adequate within 3 days after admission. EN was generally well tolerated with few complications. Diarrhoea was most frequent in the enterally fed patients and gastric retention was common among patients given PN. The correlation between prescribed and received amounts of enteral feed was high.