Key Point

Compared to late enteral feeding, early feeding significantly reduces ICU and hospital mortality among mechanically ventilated, critically ill medical patients.

DETROIT—Whether enteral feeding early in the course of illness is harmful or helpful to critically ill medical patients remains unclear. Most of the studies that could be viewed as favoring such a strategy were small and dealt mostly with critically ill surgical or trauma patients.

Artinian and coworkers have therefore evaluated the effect of early versus late enteral feeding on ICU and hospital mortality in a study of 4,049 critically ill medical patients requiring mechanical ventilation.¹ The investigators hypothesized that mortality would be lower among patients who received early enteral feeding, and that was indeed the case, although the observed mortality reductions were mainly in the sickest patients.

"Early enteral feeding improved ICU and hospital mortality at a magnitude not often seen with other ICU interventions," remarked Bruno DiGiovine, MD, one of the principal authors, in an interview with Pulmonary Reviews. The improvements occurred despite the fact that early feeding increased the risk of ventilator-associated pneumonia (VAP), pointed out Dr. DiGiovine, Medical Director of Medical Critical Care at the Henry Ford Hospital in Detroit.

The early enteral feeding group included the 2,537 patients who began such feeding within 48 hours of beginning mechanical ventilation. The remaining 1,512 patients made up the late enteral feeding group.

Because the study was not randomized, adjusting for confounders was unlikely to adequately control for the differences in age, illness severity, and other factors between the groups. Thus, the authors also used a logistic regression–based propensity score that minimized residual bias by controlling for the likelihood of receiving early or late feeding.

In an unadjusted analysis, overall ICU and hospital mortality was significantly lower in the early enteral feeding group than in the late enteral feeding group (18.1% and 28.7% vs 21.4% and 33.5%). These mortality reductions were largest among the patients in the top quartile of illness severity.

Adjusted comparative analysis of the early and late enteral feeding groups, by APACHE II, SAPS II, and mortality prediction model at time 0 score, associated early feeding with ICU and hospital mortality reductions of about 20% and 25%, respectively, in all three analyses. There were similar results when about 1,200 patients with matching propensity scores were compared.

In the unadjusted analysis, the difference in the rate of VAP between the early and late enteral feeding groups (11.2% vs 9.5%) was not significant. However, that difference was highly significant in the adjusted analyses, which showed VAP rates of about 13% and 9.5%, respectively, in the two groups; early feeding was an independent VAP risk factor in all adjusted analyses. The authors concluded that early enteral feeding is likely to benefit critically ill patients at high risk of death, although they suspected that it may be good for all critically patients.

—Timothy Begany

Reference
1. Artinian V, Krayem H, DiGiovine B. Effects of early enteral feeding on the outcome of critically ill mechanically ventilated medical patients. Chest. 2006;129:960-967.

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