Clinical factors predicting a rapid response to short-acting beta2 agonists in mild and moderate asthma exacerbations

The need for establishing criteria that facilitate decision-making has lead to search for factors that could predict prognosis and response to treatment for asthma exacerbations.

To assess which clinical factors are associated with a rapid response to short-acting beta2 agonists during asthma exacerbations.

Two hundred and twenty consecutive adults with mild to moderate asthma crisis were included. Their medical history and physical examinations were completed and closely monitored: heart rate, respiratory rate, SO2, and FEV-1. They were initially treated with O2 and micronebulized albuterol (2.5 mg every 20' x 4). A FEV-1 > or = 80% of predicted and an improvement at 90' were considered as good response.

One hundred and forty-four (65.5%) patients had a good response to micronebulized albuterol, while 76 (34.5%) required steroids and hospitalization. Early relapse rate (72 hours) in this study was low (3.4%) and it was associated to other factors, such as: upper airway infection (40%) and history of oral steroids usage in the previous year (80%). The variables associated to a good response were: < 6 hours since crisis started, no hospitalization or steroid use during a crisis in the last year, initial SO2 > or = 90% and initial FEV-1 > or = 60%.

These variables are easily measured and predict a therapeutic response in asthma patients when first seen in the emergency room.