PROSPECTIVE, RANDOMIZED TRIAL OF EPINEPHRINE, METAPROTERENOL, AND BOTH IN THE PREHOSPITAL TREATMENT OF ASTHMA IN THE ADULT PATIENT

Study objective: To compare the effectiveness and incidence of adverse reactions with three treatment regimens for asthma in adults in the p rehospital setting. Design: Prospective, randomized clinical study. Se tting: inner-city emergency medical service system providing basic and advanced life support and transport to 14 urban area hospital emergen cy departments. Participants: One hundred fifty-four adult asthmatic p atients, 18 to 50 years old, who presented to paramedics with shortnes s of breath and wheezing. Results: Eligible patients were randomly ass igned by the base station physician to one of three treatment groups: subcutaneous epinephrine, nebulized metaproterenol, or subcutaneous ep inephrine and nebulized metaproterenol. Peak expiratory flow rate (PEF R), blood pressure, heart rate, and respiratory rate were measured bef ore and after treatment in each patient. During a 9-month period (Octo ber 1992 through June 1993), 154 patients were enrolled in the study; 53 (34%) received epinephrine, 49 (32%) received metaproterenol, and 5 2 (34%) received both. There were no significant differences in patien t demographics, initial vital signs, or pretreatment PEFR among the th ree groups. The mean difference between pretreatment and posttreatment PEFR was 73 L/min and did not significantly differ among the treatmen t groups. Significant changes in vital signs were seen in no treatment group. Conclusion: Nebulized metaproterenol is as effective as subcut aneous epinephrine in the prehospital treatment of adult patients with acute asthma. The combination of these two treatments offered no addi tional clinical benefit in the patients we studied.