Effects of Immune-Enhancing Enteral Nutrition on Mortality and Oxygenation in Acute Lung Injury and Acute Respiratory Distress Syndrome: A Meta-Analysis

Abstract

Purpose The contribution of the immune system to the pathogenesis of acute respiratory distress syndrome (ARDS) has led to a recent interest in the use of immune-enhancing enteral nutrition as a treatment modality. The purpose of this meta-analysis was to determine the effectiveness of immune-enhancing enteral nutrition as compared with standard enteral nutrition, with respect to mortality and change in oxygenation status, in patients with acute lung injury (ALI)/ARDS. Methods A systematic review was conducted of randomized controlled trials comparing immune-enhancing enteral nutrition with standard enteral nutrition in adult intensive care unit (ICU) patients with ALI/ARDS. Data were combined in a meta-analysis with STATA SE version 9.2 (StataCorp) using a random effects model. Results Three studies fulfilled inclusion criteria, totaling 411 patients. These studies demonstrated a statistically significant relative risk (RR) for in-hospital mortality, favoring patients who received immune-enhancing enteral nutrition (RR, 0.58; 95% confidence interval [CI], 0.42-0.79). With respect to change in oxygenation status, a statistically significant standardized mean difference (SMD) was observed at day 4 (SMD, 1.97; 95% CI, 0.27-3.67), favoring the immune-enhancing enteral nutrition group. At study day 7, the SMD did not reach statistical significance (SMD, 1.71; 95% CI, −0.13 to 3.56). Conclusions Oxygenation and mortality benefits of immune-enhancing enteral nutrition in adult ICU patients with ALI/ARDS have been shown in individual trials and meta-analyses. Subsequent clinical trials and meta-analyses are required to fully elucidate the role of immune-enhancing enteral nutrition in this patient population.