A controlled trial of nebulized isoetharine in the prehospital treatment of acute asthma. Acute asthma is a potentially life-threatening disorder, recognizable to the prehospital care provider. While therapies are available to the prehospital care provider for treating acute asthma, no previous controlled studies have been performed demonstrating the treatment in the field is efficacious and safe. The authors conducted a controlled trial of the prehospital use of nebulized isoetharine in an urban emergency medical services system. Fifty-two patients with acute asthma were studied. Patients were initially evaluated with a peak flow meter. Half of the patients received isoetharine, while the control group received basic life support only. There was no difference in baseline values. Peak expiratory flow increased from 138 L/min to 148 L/min in the control group, while it increased from 149 L/min to 218 L/min in the treatment group (P less than .001). The authors conclude that paramedic treatment of acute asthma with nebulized isoetharine is effective in improving pulmonary function and clinical status during transport. 