Nutrition For Critically Ill Patients

Feb 6, 2012
Although some data have suggested that reduced caloric nourishment via a feeding tube may provide benefit to critically ill patients who require mechanical ventilation, patients with acute lung injury who received a decreased amount of nourishment did not have an improvement in ventilator-free days, risk of death at 60 days, or infectious complications, compared to patients who received full caloric nourishment, according to a study appearing in JAMA.1

The study is being posted online early to coincide with its presentation at the 41st Critical Care Congress.

Data have been conflicting regarding the beneficial effects of providing nutritional support meeting a higher percentage of caloric needs vs. providing nutrition with reduced volume and caloric amounts (trophic nutrition) via a feeding tube for patients who require mechanical ventilation, according to background information in the article.

Todd W. Rice, M.D., M.Sc., of the Vanderbilt University School of Medicine, Nashville, Tenn., and colleagues with the National Heart, Lung, and Blood Institute Acute Respiratory Distress Syndrome (ARDS) Clinical Trials Network Writing Committee, conducted a trial to compare the effect of trophic enteral (via gastrointestinal tract) feeding vs. full enteral feeding on clinical outcomes, including ventilator-free days (VFDs) and survival for patients on mechanical ventilation.

The study, conducted from Jan. 2008 through April 2011, included 1,000 adults with acute lung injury who required mechanical ventilation and whose physicians intended to start enteral nutrition. The participants were randomized to receive either trophic feeding or full enteral feeding for the first 6 days. After day 6, the care of all patients who were still receiving mechanical ventilation was managed according to the full feeding protocol.

The researchers found that initial trophic feeding did not increase the number of ventilation-free days through day 28 (14.9 vs. 15.0) or reduce 60-day mortality (23.2 percent vs. 22.2 percent) compared with full enteral feeding. There were also no differences between groups regarding organ failure-free days, intensive care unit-free days, or the incidence of infections.

Despite receiving more prokinetic agents (used to treat certain gastrointestinal symptoms), the full-feeding group experienced more vomiting (2.2 percent vs. 1.7 percent of patient feeding days) and constipation (3.1 percent vs. 2.1 percent of feeding days). Average plasma glucose values and average hourly insulin administration were both higher in the full-feeding group over the first 6 days.

“This study demonstrated no statistically significant difference in clinical outcomes, including VFDs, among patients with acute lung injury initially provided trophic vs. full enteral feeding for the first 6 days of mechanical ventilation.

Contrary to previous reports in critically ill adults, hypocaloric [less than normal] nutrition did not significantly reduce mortality, decrease infectious complications, or reduce lengths of stay,” the authors write.

Richard D. Griffiths, B.Sc., M.B.B.S., M.D., F.R.C.P., F.F.I.C.M., of the University of Liverpool, United Kingdom, comments on the findings of this study in an accompanying editorial2.

“Providing effective nutritional support for critically ill patients represents a difficult aspect of the overall management of complex patients. The current study by Rice et al, taken together with existing data from other recent rigorous studies, highlights the need to challenge commonly used nutritional support practices and to achieve an individualized, evidence-based approach for optimal nutritional therapy in patients with acute lung injury.”

1. (JAMA. 2012;307[8]:doi:10.1001/jama.2012.137.
2. (doi:10.1001/jama.2012.168.