Acute respiratory distress syndrome medical therapy

Overview
The possibilities of non-invasive ventilation are limited to the very early period of the disease or, better, to prevention in individuals at risk for the development of the disease (atypical pneumonias, pulmonary contusion, major surgery patients).

Treatment of the underlying cause is imperative, as it tends to maintain the ARDS picture.

Appropriate antibiotic therapy must be administered as soon as microbiological culture results are available. Empirical therapy may be appropriate if local microbiological surveillance is efficient. More than 60% ARDS patients experience a (nosocomial) pulmonary infection either before or after the onset of lung injury.

Fluid management
Several studies have shown that pulmonary function and outcome are better in patients that lost weight or wedge pressure was lowered by diuresis or fluid restriction.

Corticosteroids
Patients with ARDS do not benefit from high-dose corticosteroids. Meduri et al however did find significant improvement using modest doses. This is probably because of a suppression of ongoing inflammation during the fibroproliferative phase of ARDS. The initial regimen consists of methylprednisolone 2 mg/kg daily. After 3-5 days a response must be apparent. In 1-2 weeks the dose can be tapered to methylprednisolone 0.5-1.0 mg daily. In the absence of results steroids can be discontinued.

The recent NIH-sponsored ARDSnet LAZARUS study of corticosteroids for ARDS demonstrated that they are not efficacious in ARDS.

Nitric oxide
Inhaled nitric oxide (NO) potentially acts as selective pulmonary vasodilator. Rapid binding to hemoglobin prevents systemic effects. It should increase perfusion of better ventilated areas. There are no large studies demonstrating positive results. Therefore its use must be considered individually.

Almitrine bismesylate stimulates chemoreceptors in carotic and aortic bodies. It has been used to potentiate the effect of NO, presumably by potentiating hypoxia-induced pulmonary vasoconstriction. In case of ARDS it is not known whether this combination is useful.

Surfactant therapy
To date no prospective controlled clinical trial has shown a significant mortality benefit of exogenous surfactant in ARDS.