ARDS affects approximately 150,000 people in the United States each year. Despite 20 years of research into the mechanisms that cause this syndrome and numerous developments in the technology of mechanical ventilation, the mortality has remained greater than 50 percent. Many of the patients are young, and to the tragic loss of human life can be added the cost to society because these patients spend an average of 2 weeks in intensive care units and require multiple high tech procedures. Because of the overwhelming nature of the lung injury once it is established, prevention would appear to be the most effective strategy for improving the outlook in this condition.