What is the rationale/evidence to support doing 4 puffs of albuterol vs. 2 puffs for a reversibility study?  

The rationale per ATS in 2005 is that 4 puffs of albuterol is higher on the dose-response curve and thus would potentially avoid getting a suboptimal (< 12%, < 200 mL) response from 2 puffs. Having said that, there was a study of this issue in 240 pediatric patients showing non-inferiority of ...