Prospective, Randomized Trial of Epinephrine, Metaproterenol, and Both in the Prehospital Treatment of Asthma in the Adult Patient,☆☆,

Presented at the National Association of Emergency Medical Service Physicians annual meeting, Portland, Oregon, August 1994.
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Abstract

Study objective: To compare the effectiveness and incidence of adverse reactions with three treatment regimens for asthma in adults in the prehospital setting. Design: Prospective, randomized clinical study. Setting: Inner-city emergency medical service system providing basic and advanced life support and transport to 14 urban area hospital emergency departments. Participants: One hundred fifty-four adult asthmatic patients, 18 to 50 years old, who presented to paramedics with shortness of breath and wheezing. Results: Eligible patients were randomly assigned by the base station physician to one of three treatment groups: subcutaneous epinephrine, nebulized metaproterenol, or subcutaneous epinephrine and nebulized metaproterenol. Peak expiratory flow rate (PEFR), blood pressure, heart rate, and respiratory rate were measured before and after treatment in each patient. During a 9-month period (October 1992 through June 1993), 154 patients were enrolled in the study; 53 (34%) received epinephrine, 49 (32%) received metaproterenol, and 52 (34%) received both. There were no significant differences in patient demographics, initial vital signs, or pretreatment PEFR among the three groups. The mean difference between pretreatment and posttreatment PEFR was 73 L/min and did not significantly differ among the treatment groups. Significant changes in vital signs were seen in no treatment group. Conclusion: Nebulized metaproterenol is as effective as subcutaneous epinephrine in the prehospital treatment of adult patients with acute asthma. The combination of these two treatments offered no additional clinical benefit in the patients we studied. [Quadrel M, Lavery RF, Jaker M, Atkin S, Tortella BJ, Cody RP: Prospective, randomized trial of epinephrine, metaproterenol, and both in the prehospital treatment of asthma in the adult patient. Ann Emerg Med October 1995;26:469-473.]

Section snippets

INTRODUCTION

Acute bronchospasm in the asthmatic patient is a potentially life-threatening condition that is commonly evaluated and treated by prehospital personnel.1 Although subcutaneous epinephrine was previously considered the treatment of choice for these patients, inhaled β 2-agonists have come to be preferred in many treatment protocols during the last 10 to 15 years.2, 3, 4 In the emergency department setting, β 2-agonists have been shown to be as effective as subcutaneous epinephrine5 and to have

MATERIALS AND METHODS

The study was conducted from October 1992 through June 1993. Our emergency medical service (EMS) provides basic and advanced life support to a largely inner-city population of 400,000, with more than 45,000 patients transported yearly. The EMS has a two-tiered priority response system with paired paramedic crews. There are approximately 14,000 advanced life support calls per year, resulting in 6,000 patient transports. Paramedics treat patients in the field with standing orders for cardiac

RESULTS

During a 9-month period, 197 patients were enrolled in the study, with 154 (78%) patients evaluable. Forty-three patients were considered not evaluable for the following reasons: documentation error (n=18), medication error or protocol not followed (n=11), data incomplete (n=11), patient removed from protocol and intubated (n=2), and unable to treat before arrival at hospital (n=1). Fifty-three (34%) of the evaluable patients were treated with epinephrine, 49 (32%) with metaproterenol, and 52

DISCUSSION

Inhaled β 2-agonist therapy has become first-line treatment for moderate to severe exacerbation of asthma in the ED.3 Epinephrine, however, is still frequently used.4, 10 Paramedics have used subcutaneous epinephrine for the prehospital treatment of acute asthma for many years. Although inhaled β 2-agonists have been added to many prehospital treatment regimens, a recent survey reported that fewer than 50% of urban advanced life support services carry β 2-agonists for inhalation.11 Prospective

CONCLUSION

In this prospective, randomized study of the treatment of moderate to severe exacerbation of asthma in adult patients in the prehospital setting, we found no significant differences in efficacy, as measured by increase in PEFR, among epinephrine, metaproterenol, or both treatments. There appears to be little justification for the simultaneous administration of epinephrine and metaproterenol in the patients we studied. There is a need for critical examination of prehospital treatment of asthma

Acknowledgements

The authors thank the paramedics of the Emergency Medical Services of University Hospital, New Jersey Medical School/University of Medicine and Dentistry of New Jersey, without whose assistance this study would not have been possible.

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From the University of Medicine and Dentistry of New Jersey*, the Department of Emergency Medicine, University Hospital, The New Jersey Medical School, Newark, New Jersey; Section of Trauma and EMS, Department of Surgery, the New Jersey Trauma Center, Newark, New Jersey§; and the Department of Environmental and Community Medicine, The Robert Wood Johnson Medical School, Piscataway, New Jersey

☆☆

Address for reprints: Mark Quadrel, MD, UMDNJ-University Hospital, Emergency Department-C384, 150 Bergen Street, Newark, New Jersey 07103, 201-982-5129, Fax 201-982-6646

Reprint no. 47/1/67141

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