Objective: Experimental studies demonstrate that beta-adrenergic agonists markedly stimulate alveolar fluid clearance if concentrations of 10(-6) M are achieved in alveolar fluid. However, no studies have determined whether aerosolized beta-adrenergic agonists are delivered to the distal air spaces of the lung in therapeutic concentrations in patients with pulmonary edema.
Design and setting: This retrospective study measured albuterol levels in the pulmonary edema fluid and plasma from mechanically ventilated patients with pulmonary edema from a hydrostatic mechanism ( n=10) or from acute lung injury ( n=12).
Measurements and results: After a total aerosolized albuterol dose of 4.2+/-3.2 mg in the prior 6 h the median pulmonary edema fluid albuterol level was 1,250 ng/ml (10(-6) M) in patients with hydrostatic pulmonary edema; after 3.5+/-2.6 mg the figure was 1,240 ng/ml (10(-6) M) in patients with pulmonary edema from acute lung injury. Plasma albuterol levels were much lower, with a median of 5.2 ng/ml (0.01 x 10(-6) M) in patients with hydrostatic pulmonary edema and 3.1 ng/ml (0.01 x 10(-6) M) in patients with pulmonary edema from acute lung injury.
Conclusions: These results provide the first evidence that levels of beta-adrenergic agonists that are physiologically efficacious in experimental models can be achieved with conventional delivery systems in ventilated, critically ill patients with acute respiratory failure from pulmonary edema.