We searched for studies using the MEDLINE (1966 to 2001), EMBASE (1980 to 2001), and CINAHL (1982 to 2001) databases. The following MeSH terms were used in the search: Emerg* or acute or status and continuous or intermittent or multi-dose or dosage or nebuli* and P-agonist or bronchodilat*. Also, a search of the Cochrane Controlled Trials Register was completed using the above terms. Finally, we checked bibliographies of all trials and review articles that had been identified from the databases and medical journals to determine potentially relevant citations. Criteria for considering trials included the following: (1) randomized controlled trials conducted in an ED setting; (2) studies with adult patients (ie, > 18 years old) with acute asthma; (3) patients who had been randomized to receive either continuous or intermittent P-agonists early in the ED treatment (continuous P-agonist administration included frequent refOiing of the nebulizer, use of a nebulizer and infusion pump, or use of a large-volume nebulizer with high-output extended aerosol respiratory therapy [HEART]); and (4) change in pulmonary function test results as the primary outcome (absolute or percent predicted of peak expiratory flow [PEF] and absolute or percent predicted FEV1), and side effects/adverse effects and admissions to the hospital as secondary outcomes. Assessments included up to 3 h of treatment. Asthma medications inhalers Click Here Because the peak bronchodilator effect after the administration of multiple doses of salbutamol/albuterol occurs within 1 to 2 h, and because approximately two thirds of adults with acute asthma require 90 min of treatment with inhaled P-agonists to have their conditions improve sufficiently to be discharged from the hospital, it is reasonable to expect significant improvement at this time.