Acute respiratory distress syndrome (ARDS) is the sudden failure of the respiratory (breathing) system. It can develop in anyone over the age of 1 who is critically ill. A person with ARDS has rapid breathing, difficulty getting enough air into the lungs and low blood oxygen levels. ARDS usually develops in people who are already very ill with another disease or who have major injuries. They are usually already in the hospital when they develop the ARDS. ARDS can be life-threatening because your body's organs need oxygen-rich blood to function well. The good news is that because of improved treatment in recent years, more people are surviving ARDS. If you have ARDS your lung function is likely to return to normal or near normal within several months. But some people with ARDS have lasting damage to their lungs or to areas outside the lungs.