Acute respiratory distress syndrome (ARDS) and acute lung injury (ALI) are medical conditions that occur when there is severe inflammation and increased fluids in both lungs, making it difficult for the lungs to function properly. Hospital treatment for a person with ALI/ARDS often includes the use of a breathing machine, or ventilator, until the person is able to breathe without assistance. Initiating proper nutrition through a feeding tube early in a person's hospital stay may help to improve recovery, but the optimal timing, composition, and amount of feeding treatments remain unknown. This study will evaluate whether early or delayed full-calorie feeding through a feeding tube is more effective in reducing recovery time and increasing survival rates in people with ALI/ARDS.

ALI/ARDS involves extensive inflammation in the lungs that can lead to rapid respiratory failure. These conditions are most commonly caused by pneumonia, generalized infection, or severe trauma to the lungs, but can also be less commonly caused by smoke or salt water inhalation, drug overdose, or shock.

For some people, ALI/ARDS resolves without treatment, but many severe cases result in hospitalization in the intensive care unit (ICU), where 30% to 40% of cases end in mortality. Current treatments for ALI/ARDS include assisted breathing with a ventilator, supportive care, and management of the underlying causes. Enteral feeding, in which patients receive nutrition through a feeding tube, plays an important role in treatment, too. Some recent studies have shown that enteral feeding initiated soon after a patient begins assisted breathing is associated with a shorter hospital stay and a better chance of survival than delayed enteral feeding. However, other studies have shown the opposite, and studies on optimal feeding volume and composition have shown conflicting results. This study will evaluate the effects of early versus delayed full-calorie enteral feeding on mortality, ventilator-free days, ICU-free days, and organ failure in people with ALI/ARDS.

Upon admission to the ICU, a dietary evaluation will be done on each participant to determine goal, or full-calorie, feeding rates, which will be based on body weight and daily energy consumption. Participants will also undergo baseline assessments and procedures, which will include vital sign measurements, blood draws, a frontal chest radiograph, ventilator settings, and placement of a feeding tube. Participants will be randomly assigned to receive initial enteral feedings that are either minimal (trophic) or full-calorie. All participants will begin enteral feeding within 6 hours of treatment assignment.

Participants assigned to initial minimal enteral feedings will receive feedings at 10 cubic centimeters (cc) per hour, to be continued at this rate for 144 hours, provided that the participant remains on the ventilator. After the 144 hours, the feeding rate will be advanced to full-calorie rates.

Participants assigned to initial full-calorie enteral feedings will receive feedings at 25 cc per hour, and the feeding rate will be increased by 25 cc per hour every 6 hours until the goal rate is reached. During enteral feedings, gastric residual volumes (GRVs) will be checked every 6 to 12 hours to assure acceptable levels. Participants will complete enteral feedings upon hospital discharge, Day 28 of treatment, death, or ability to achieve 48 hours of unassisted breathing.

Blood pressure, heart rate, ventilation settings, and various blood factors will be measured during treatment. Phone-based follow-up assessments will occur at Months 6 and 12 after ICU discharge and will include measurements of health-related quality of life; psychological, neurocognitive, and physical activity outcomes; healthcare utilization; and mortality.

Inclusion Criteria:

• Must meet the following three criteria within a 24-hour period of study entry: 1) PaO2/FiO2 less than or equal to 300 (if altitude is more than 1000 meters, then PaO2/FiO2 less than or equal to 300 x [barometric pressure/760]), 2) bilateral infiltrates (patchy, diffuse, homogeneous, or asymmetric) consistent with pulmonary edema on frontal chest radiograph, and 3) requirement for positive pressure ventilation via endotracheal tube
• No clinical evidence of left-sided cardiac failure to account for bilateral pulmonary infiltrates
• Intention of primary medical team to enterally feed the patient
• Undergoes enteral feeding within 48 hours of meeting other inclusion criteria

Exclusion Criteria:

• Neuromuscular disease that impairs ability to breathe without assistance, such as cervical spinal cord injury at level C5 or higher, amyotrophic lateral sclerosis, Guillain-Barré syndrome, or myasthenia gravis
• Pregnant or breastfeeding
• Severe chronic respiratory disease (more information about this criterion can be found in the protocol)
• Burns on greater than 40% total body surface area
• Cancer or other irreversible disease or condition for which 6-month mortality is estimated to be greater than 50% (more information about this criterion can be found in the protocol)
• Allogeneic bone marrow transplant in the 5 years before study entry
• Patient, surrogate, or physician not committed to full support (exception: a patient will not be excluded if he/she would receive all supportive care except for attempts at resuscitation from cardiac arrest)
• Severe long-term liver disease (Child-Pugh score of 11 to 15)
• Diffuse alveolar hemorrhage from vasculitis
• Morbid obesity, defined as 1 kg/cm body weight
• Unwilling or unable to use the ARDS network 6 mL/kg PBW ventilation protocol
• Moribund patient not expected to survive 24 hours after study entry
• No intent to obtain central venous access for monitoring intravascular pressures
• More than 72 hours since mechanical ventilation initiated
• Refractory shock (more information about this criterion can be found in the protocol)
• Unable to obtain enteral access
• Presence of partial or complete mechanical bowel obstruction
• Presence of ischemia or infarction
• Current total parenteral nutrition (TPN) use or intent to use TPN within 7 days of study entry
• Severe malnutrition with body mass index less than 18.5 or loss of more than 30% total body weight in the 6 months before study entry
• Laparotomy expected within 7 days of study entry
• Unable to raise head of bed 30 to 45 degrees
• Short-bowel syndrome or absence of gastrointestinal tract
• Presence of high-output (greater than 500 cc/day) enterocutaneous fistula
• International normalized ratio greater than 5.0, platelet count less than 30,000/mm3, or history of bleeding disorder
• Intracranial hemorrhage in the 1 month before study entry
• Allergy to enteral formula
• Requirement for, or physician insistence on, enteral formula supplemented with omega-3 fatty acids (e.g., Oxepa®, Impact®) or treatment with omega-3 fatty acid, gamma-linolenic acid (GLA), or antioxidant supplementation