Patients with acute lung injury (ALI) who were given a supplement of omega-3 fatty acids and antioxidants did not fare better, and in some cases fared worse, than those who did not receive the supplement, according to a study appearing in the Journal of the American Medical Association this week.
Todd Rice, Arthur Wheeler and colleagues in the NHLBI ARDS Network reported that patients who received omega-3 fatty acid and antioxidant supplementation to their enteral (tube) nutrition experienced longer stays in the intensive care unit, more days on the ventilator and a slight increase in mortality than patients in the control group who received omega-6 fatty acids and carbohydrates.
Previous studies suggested omega-3 fatty acids (fish oil) and antioxidants would improve outcomes in patients with ALI, which is a disease process that occurs in patients who develop sepsis, trauma, aspiration and other conditions. ALI causes the lungs to leak fluid, leading to breathing difficulty that usually results in the patient being placed on a ventilator.
“Your body puts fatty acids in the cell layer and then uses them to form inflammatory mediators. The mediators formed from omega-3 are much less inflammatory than omega-6 fatty acids; many think they are anti-inflammatory,” said Rice, assistant professor of medicine.
“We thought if we gave omega-3 fatty acids to patients with ALI they would make non-inflammatory, or less inflammatory, mediators that could decrease inflammation and possibly improve outcomes in these patients.”
The OMEGA study was a randomized, placebo-controlled, multicenter trial conducted at 44 hospitals in the National Heart, Lung, and Blood Institute ARDS Clinical Trials Network from January 2008 through February 2009. Participants were 272 adults within 48 hours of developing ALI requiring mechanical ventilation whose physicians intended to start enteral nutrition
Contrary to previous reports, the study didn’t find any benefit, and in fact there was some suggestion the patients who got the dietary supplement may have been worse off. The trial was stopped early because of futility.
Ventilator-dependent ICU patients are fed through a tube in the stomach continuously, but it’s never been fully understood what the best form of nutrition is or how often patients should receive it.
“[rquote]This study helps us to know that feeding fish oil isn’t beneficial and may be harmful[/rquote]. We still have questions of whether to provide formulations of feed that are less fat and more sugar or carbohydrates. There is work to be done there,” Rice said.
Vanderbilt is one of 12 centers in the NIH/NHILBI Acute Respiratory Distress Syndrome (ARDS) network, which performs studies in patients with ALI, a condition that affects approximately 190,000 Americans annually with a mortality rate near 25 percent. The NIH has funded a multi-year project to test treatments for ALI.
