Statistical Analysis
Patient demographic and baseline clinical data were summarized with standard descriptive statistics. All continuous study outcome data were summarized using means (±SD). Post- vs pre-treatment measurements for each drug therapy were compared using paired t-tests. Linear mixed effects models were then used to compare outcome data between the albuterol dose levels and saline placebo. Each model included fixed effects indicator variables for the treatment period (1-3) and within period treatment dose (1-6) to account for any potential temporal effects on the outcome measurements. A random effect (random intercept) for the study participant, robust standard errors, and an unstructured covariance matrix were used in all models. Rates of occurrence for categorical tolerability outcomes were calculated. All statistical analyses were performed using STATA/SE 15.1 (StataCorp, College Station, TX).