critical care medicine
Acute Hypoxemic Respiratory Failure (AHRF, ARDS)
Prognosis for AHRF
Prognosis is highly variable and depends on a variety of factors, including etiology of respiratory failure, severity of disease, age, and chronic health status. Overall, mortality in ARDS was very high (40 to 60%) but has declined in recent years to 25 to 40%, probably because of improvements in mechanical ventilation and in treatment of sepsis. However, mortality remains very high (> 40%) for patients with severe ARDS (ie, those with a PaO2:FIO2 < 100 mm Hg). Most often, death is not caused by respiratory dysfunction but by sepsis and multiorgan failure. Persistence of neutrophils and high cytokine levels in bronchoalveolar lavage fluid predict a poor prognosis. Mortality otherwise increases with age, presence of sepsis, and severity of preexisting organ insufficiency or coexisting organ dysfunction. Pulmonary function returns to close to normal in 6 to 12 months in most ARDS patients who survive; however, patients with a protracted clinical course or severe disease may have residual pulmonary symptoms, and many have persistent neuromuscular weakness. 