A study published early in JAMA , to coincide with the presentation at the 41st Critical Care Congress, reveals that even though some data indicated that lower caloric nourishment via a feeding tube may be beneficial for critically ill patients in need of mechanical ventilation, those with acute lung injury who received a smaller amount of nourishment displayed no improvement in terms of infectious complications, ventilator-free days, or mortality risk at 60 days, compared with those who received full caloric nourishment.

According to background information in the article, there has been a conflict of data as to what is more beneficial for patients; i.e. providing a higher percentage of caloric needs in nutritional support, or providing lower amounts of nutrition with reduced caloric amounts (trophic nutrition) via a feeding tube for patients who require mechanical ventilation.

To compare the efficacy of trophic feeding via gastrointestinal tract (trophic enteral feeding) and full enteral feeding on clinical results, including ventilator-free days (VFDs) and survival for patients on mechanical ventilation, Dr. Todd W. Rice of the Vanderbilt University School of Medicine in Nashville, Tenn. and his team from the National Heart, Lung, and Blood Institute Acute Respiratory Distress Syndrome (ARDS) Clinical Trials Network Writing Committee, conducted a trial involving 1,000 adults with acute lung injury who required mechanical ventilation and whose physicians intended to start enteral nutrition.

The trial took place from Jan. 2008 to April 2011, with researchers randomizing participants to receive either trophic feeding or full enteral feeding for the first 6 days, after which all those who were still ventilated mechanically received the full feeding protocol.

The findings revealed no increase in the number of ventilation-free days until day 28 in the trophic group (14.9%), compared with the full enteral group (15.0%), or reduction in 60-day mortality with 23.2% compared with 22.2% respectively between both groups. The researchers did not observe any differences between both groups in terms of incidence of infections, organ failure-free days or intensive care unit-free days.

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.

The researchers conclude:

"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."

Editorial: Nutrition For Critically Ill Patients - How Much is Enough?

In an accompanying editorial 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 in the UK, writes:

"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."

Written by Petra Rattue