RT Journal Article
SR Electronic
T1 On the effectiveness of steroids in acute lung injury: Experimental separation between inflammation and hypoxemia
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP 4317
VO 40
IS Suppl 56
A1 Lucy Kathleen Reiss
A1 Stefan Uhlig
YR 2012
UL http://erj.ersjournals.com/content/40/Suppl_56/4317.abstract
AB Acute lung injury (ALI) is defined by hypoxemia in the presence of excessive inflammation. Despite of a multitude of clinical trials the role of glucocorticoids in the treatment of ALI is under constant debate. The present study was designed to investigate the effectiveness of dexamethasone in dependence on the type and severity of lung injury and the fraction of inspired oxygen (FiO2).C57BL/6 mice were instilled intratracheally with 50 μL HCl at pH 1.5 or 1.8 and were then ventilated with recruitment manoeuvres (RM) and FiO2=0.3 or 1.0. Another group was ventilated without acid instillation and without RM to induce atelectasis. Dexamethasone [1mg/kg] was injected intravenously at the beginning of ventilation. Lung mechanics were followed by the forced oscillation technique. Cardiovascular parameters, oxygen saturation and body temperature were monitored. Blood gases, cytokines, neutrophil recruitment, microvascular permeability and lung histology were examined.Dexamethasone attenuated inflammation (neutrophil recruitment, edema formation, cytokine liberation) in all models. Hypoxemia and lung mechanics were improved in the groups instilled with acid pH 1.8 (moderate injury), but not in the groups instilled with acid pH 1.5 (severe injury) or in those with atelectasis. A high FiO2=1.0 augmented acid-induced lung injury, but did not affect the effectiveness of dexamethasone.In the present study steroids were highly effective in preventing inflammation under all conditions, whereas they improved the clinical outcome in moderate, but not in severe lung injury or in cases of derecruitment, suggesting that steroids are effective only in a subclass of patients with ALI.