Assessing the effects of racemic and single-enantiomer albuterol on airway secretions in long-term intubated patients

Objective: In vitro data suggest that the S-enantiomer of albuterol can induce mucociliary dysfunction. This clinical study assesses the clinical significance of standard doses of the S-enantiomer on airway secretions in long-term intubated patients by comparing a racemic formulation of albuterol, an B-enantiomer formulation, and normal saline solution. Design: A placebo-controlled crossover study. Patients: Fourteen stable intubated patients with a median duration of intubation of 21 months and a median age of 72 years. Setting: Long-term ventilator unit in skilled nursing faculty. Interventions: Following a 2-week washout period during which regularly scheduled β₂-agonists were discontinued, tracheal aspirates were collected for 4 h/d for a 5-day period to establish baseline values, and the patients were then randomized in crossover manner to each of three nebulized treatments: normal saline solution, racemic albuterol, and R-albuterol. Each treatment was administered three times daily for 5 days, followed by a 2-day washout. Measurements: Tracheal aspirates were analyzed for volume, sodium, chloride, bicarbonate, interleukin (IL)-8, IL-1β, soluble intercellular adhesion molecule, and tumor necrosis factor-α. Results: There were no consistent significant differences among the three treatment periods either in terms of volume of secretions or in the concentrations of the electrolytes or the inflammatory indexes. However, all three treatments, including saline solution, were associated with increased secretion volume after the first dose, but this effect was not apparent on subsequent doses. Conclusion: There were no significant differences between racemic albuterol and R-albuterol observed in this study for any of the parameters studied, suggesting that the S-enantiomer does not adversely affect airway secretions at recommended doses. In addition, the routine administration of nebulized β₂-sympathomimetic agonists to stable patients undergoing prolonged intubation, for the sole purpose of changing the volume and composition of secretions of airway secretions, is not supported by the results of this study.