Pathophysiology of acute respiratory distress syndrome. Glucocorticoid receptor-mediated regulation of inflammation and response to prolonged glucocorticoid treatment

SummaryBased on molecular mechanisms and physiologic data, a strong association has been established between dysregulated systemic inflammation and progression of ARDS. In ARDS patients, glucocorticoid receptor-mediated down-regulation of systemic inflammation is essential to restore homeostasis, decrease morbidity and improve survival and can be significantly enhanced with prolonged low-to-moderate dose glucocorticoid treatment. A large body of evidence supports a strong association between prolonged glucocorticoid treatment-induced down-regulation of the inflammatory response and improvement in pulmonary and extrapulmonary physiology. The balance of the available data from controlled trials provides consistent strong level of evidence (grade 1B) for improving patient-centered outcomes. The sizable increase in mechanical ventilation-free days (weighted mean difference, 6.58 days; 95% CI, 2.93 –10.23; P < 0.001) and ICU-free days (weighted mean difference, 7.02 days; 95% CI, 3.20–10.85; P < 0.001) by day 28 is superior to any investigated intervention in ARDS. The largest meta-analysis on the subject concluded that treatment was associated with a significant risk reduction (RR = 0.62, 95% CI: 0.43–0.91; P = 0.01) in mortality and that the in-hospital number needed to treat to save one life was 4 (95% CI 2.4–10). The balance of the available data, however, originates from small controlled trials with a moderate degree of heterogeneity and provides weak evidence (grade 2B) for a survival benefit. Treatment decisions involve a tradeoff between benefits and risks, as well as costs. This low cost highly effective therapy is familiar to every physician and has a low risk profile when secondary prevention measures are implemented.In this issueDoes my patient really have ARDS?L. Brochard, Geneva, Switzerland.Mechanical ventilation during acute lung injury: current recommendations and new conceptsL. Del Sorbo et al., Torino, ItalyProne positioning in acute respiratory distress syndrome: When and How?F. Roche-Campo et al., Barcelona, SpainPathophysiology of acute respiratory distress syndrome. Glucocorticoid receptor-mediated regulation of inflammation and response to prolonged glucocorticoid treatmentG. Umberto Meduri et al., Memphis, USAVirus-induced acute respiratory distress syndrome: epidemiology, management and outcomeC.-E. Luyt et al., Paris, FranceLung function and quality of life in survivors of the acute respiratory distress syndrome (ARDS)M. Elizabeth Wilcox and Margaret S. Herridge, Toronto, Canada