Objectives

This clinical trial was designed to test the hypothesis that an aerosolized beta-2-agonist, albuterol, would improve clinical outcomes in patients with acute lung injury (ALI) and acute respiratory distress syndrome (ARDS).

Background

In patients with acute lung injury and acute respiratory distress syndrome (ALI/ARDS), inflammation of the pulmonary circulation increases vascular permeability. Fluid leaks from blood vessels into the pulmonary interstitium and alveoli. Recovery from this form of acute respiratory failure requires that the pulmonary edema resolve. The resolution of alveolar edema is driven by active transport of sodium and chloride ions from the luminal space across both type I and type II alveolar epithelial cells, creating an osmotic gradient for the reabsorption of water. In the ex vivo human lung, the rate of alveolar fluid clearance can be doubled by treatment with a cyclic AMP beta-2 adrenergic receptor agonist.

On the basis of the preclinical observations that treatment with beta-2-agonists could reduce pulmonary edema and accelerate the rate of alveolar fluid clearance, the ALTA study was designed and undertaken with the hypothesis that treatment of patients with ALI/ARDS with beta-agonist therapy would accelerate the resolution of alveolar edema and improve clinical outcomes.

Participants

282 ALI/ARDS patients that were intubated and receiving mechanical ventilation, had bilateral pulmonary infiltrates consistent with edema on frontal chest radiograph, had a ratio of PaO2 to FiO2 (fraction of inspired oxygen) of 300 or less (adjusted for altitude as appropriate), and did not have clinical evidence of left atrial hypertension.

Design

Study staff conducted a multicenter, randomized, placebo-controlled clinical trial in which subjects were randomized to receive aerosolized albuterol (5 mg) or saline placebo every 4 hours for up to 10 days. The primary outcome variable for the trial was ventilator-free days.

Conclusions

Ventilator-free days were not significantly different between the albuterol and placebo groups. The results suggest that aerosolized albuterol does not improve clinical outcomes in patients with ALI. Routine use of beta-2 agonist therapy in mechanically ventilated patients with ALI cannot be recommended (Am J Respir Crit Care Med. 2011; 184(5): 561-8).

Additional Details

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