Review of gut-specific strategies to reduce intensive care unit-acquired infections:

Optimizing the benefits and minimizing the risks of enteral nutrition in the critically ill: role of small bowel feeding

BACKGROUND

Strategies that maximize the delivery of enteral nutrition while minimizing the associated risks have the potential to improve the outcomes of critically ill patients. By delivering enteral feeds in the small bowel, beyond the pylorus, the frequency of regurgitation and the risk of aspiration is thought to be decreased while at the same time, nutrient delivery is maximized. The purpose of this paper is to systematically review those studies that compare gastric with small bowel feeding.

METHODS

We searched computerized bibliographic databases, personal files, and relevant reference lists to identify eligible studies. Only randomized, clinical trials of critically ill patients that compared small bowel and gastric feedings were included in this review. In an independent fashion, relevant data on the methodology and outcomes of primary studies were abstracted in duplicate.

RESULTS

There were 10 studies that met the inclusion criteria for this review. In 1 study, small bowel feeding was associated with a reduction in gastroesophageal regurgitation and a trend toward reduced pulmonary aspiration. Several studies document that small bowel feeding was associated with an increase in protein and calories delivered and a shorter time to target dose of nutrition. Compared with gastric feeding, when the results of 7 randomized trials were aggregated statistically, small bowel feeding was associated with a reduction in pneumonia (relative risk, 0.76; 95% confidence intervals, 0.59, 0.99). There was no difference in mortality rates between the 2 groups.

CONCLUSIONS

Small bowel feeding may be associated with a reduction in gastroesophageal regurgitation, an increase in nutrient delivery, a shorter time to achieve desired target nutrition, and a lower rate of ventilator-associated pneumonia.

Gastrointestinal promotility drugs in the critical care setting: a systematic review of the evidence

CONTEXT

Gastrointestinal promotility agents may improve tolerance to enteral nutrition, reduce gastroesophageal reflux and pulmonary aspiration, and therefore have the potential to improve outcomes of critically ill patients.

OBJECTIVE

To systematically review and critically appraise studies of promotility agents in the critical care setting.

DATA SOURCES

Computerized bibliographic search of published research (1980-2001), citation review of relevant articles, and contact with primary investigators.

STUDY SELECTION

Randomized trials of critically ill adult patients that evaluated the effect of promotility agents on measures of gastrointestinal motility were included.

DATA EXTRACTION

Relevant methods and outcome data were abstracted in duplicate by independent investigators.

DATA SYNTHESIS

We reviewed 60 citations; 18 articles met the inclusion criteria (six studies of feeding tube placement, 11 studies evaluating gastrointestinal function, and one study of clinical outcomes). The heterogeneity of study methods and outcomes measured precluded a quantitative synthesis of the data. Although there are conflicting studies, the larger and more methodologically robust studies suggest that metoclopramide has no effect on feeding tube placement. Erythromycin has been shown to increase success rates with small-bowel tube placement in two studies. Eight of ten studies evaluating the effect of cisapride, metoclopramide, or erythromycin on measures of gastrointestinal transit demonstrated positive effects; the two studies that did not were relatively small (n = 27 and 10) and likely had inadequate power to detect a difference in treatment effect. No study demonstrated a positive effect on clinical outcomes.

CONCLUSIONS

As a class of drugs, promotility agents appear to have a beneficial effect on gastrointestinal motility in critically ill patients. A one-time dose of erythromycin may facilitate small-bowel feeding tube insertion. Administration of metoclopramide appears to increase physiologic indexes of gastrointestinal transit and feeding tolerance. Concerns about safety and lack of effect on clinically important outcomes preclude strong treatment recommendations.