Study designs of evaluations included in the review
Randomised controlled trials (RCTs) were eligible for inclusion.
Specific interventions included in the review
Studies comparing the same drug delivered using two different inhaler devices were eligible for inclusion. Studies comparing devices of the same type were excluded, as were studies comparing oral or parenteral therapy with aerosol therapy. The delivery systems compared in the included studies were: MDI with DPI; nebuliser with MDI plus spacer or holding chamber; DPI with MDI plus spacer or holding chamber; DPI with nebuliser; MDI with nebuliser; and intermittent with continuous nebuliser. The medications delivered were mainly beta2-agonists, though there were some studies of corticosteroid and anticholinergic agents.
Participants included in the review
Inclusion criteria for the participants were not specified. The included studies were of adults and children with asthma and adults with chronic obstructive pulmonary disorder (COPD). The studies were conducted in acute care, out-patient and clinical laboratory settings.
Outcomes assessed in the review
Inclusion criteria for the outcomes were not specified. Studies were excluded if they did not have useable data or comparable outcomes (further details were not provided). The outcome of interest were forced expiratory volume in 1 second (FEV1), peak flow, mechanics, symptoms and physical findings, forced vital capacity, forced expiratory flow 25-75%, blood gas, adrenergic use, technique or preference, and heart rate, blood-pressure and electrocardiograph. A combined end point of FEV1, peak flow and specific airway conductance was also used for some of the comparisons. Details of the order of preference of measures used to evaluate these outcomes were reported.
How were decisions on the relevance of primary studies made?
Two investigators independently assessed studies for relevance.