Effects of continuous versus bolus infusion of enteral nutrition in critical patients

Abstract

PURPOSE: Enteral alimentation is the preferred modality of support in critical patients who have acceptable digestive function and are unable to eat orally, but the advantages of continuous versus intermittent administration are surrounded by controversy. With the purpose of identifying the benefits and complications of each technique, a prospective controlled study with matched subjects was conducted. PATIENTS AND METHODS: Twenty-eight consecutive candidates for enteral feeding were divided into 2 groups (n = 14 each) that were matched for diagnosis and APACHE II score. A commercial immune-stimulating polymeric diet was administered via nasogastric tube by electronic pump in the proportion of 25 kcal/kg/day, either as a 1-hour bolus every 3 hours (Group I), or continuously for 24 hours (Group II), over a 3-day period. Anthropometrics, biochemical measurements, recording of administered drugs and other therapies, thorax X-ray, measurement of abdominal circumference, monitoring of gastric residue, and clinical and nutritional assessments were performed at least once daily. The principal measured outcomes of this protocol were frequency of abdominal distention and pulmonary aspiration, and efficacy in supplying the desired amount of nutrients. RESULTS: Nearly half of the total population (46.4%) exhibited high gastric residues on at least 1 occasion, but only 1 confirmed episode of pulmonary aspiration occurred (3.6%). Both groups displayed a moderate number of complications, without differences. Food input during the first day was greater in Group II (approximately 20% difference), but by the third day, both groups displayed similarly small deficits in total furnished volume of about 10%, when compared with the prescribed diet. CONCLUSIONS: Both administration modalities permitted practical and effective administration of the diet with frequent registered abnormalities but few clinically significant problems. The two groups were similar in this regard, without statistical differences, probably because of meticulous technique, careful monitoring, strict patient matching, and conservative amounts of diet employed in both situations. Further studies with additional populations, diagnostic groups, and dietetic prescriptions should be performed in order to elucidate the differences between these commonly used feeding modalities.