Annals of Emergency Medicine
Volume 36, Issue 3 , Pages 236-238, September 2000

Easier Breathing?☆

Department of Emergency Medicine, MetroHealth Medical Center, Case Western Reserve University, Cleveland, OH

Article Outline

Abstract 

[Cydulka RK. Easier breathing? Ann Emerg Med. September 2000;36:236-238.]

 

See related article, p. 198.

Asthma affects 4% to 5% of the population in the United States and accounts for approximately 2 million visits to the nation’s emergency departments.1, 2 Although asthma is a chronic illness that is usually easily managed with proper ongoing, comprehensive ambulatory care, much of its economic impact is associated with asthma exacerbation, ED use, and hospitalization, which is likely a result of a failure of our medical system to provide the aforementioned ongoing care.2 As a result of the increasing prevalence and impact of asthma on both the adult and pediatric population, much time and energy has been devoted to its study. A quick computerized literature search of PubMed yielded 1,311 articles related to “asthma AND emergency treatment” since 1990.3 The proliferation of asthma-related research and literature has helped promote and publicize the understanding that asthma is largely a chronic inflammatory disorder (or group of disorders) rather than an episodic bronchospastic event and has served to formulate the guidelines that direct our current treatment of asthma.4, 5, 6, 7, 8, 9 Despite the recognition of asthma as an inflammatory disorder and the ongoing quest to determine the optimal method of reducing inflammation in asthmatic patients, bronchodilation with β2-agonists remains an essential ingredient in the therapeutic armamentarium for emergency physicians, who primarily treat asthmatic patients with acute exacerbation, rather than managing chronic disease.

Many questions still remain regarding the use of β-agonists in the treatment of acute exacerbation. For example, researchers have not determined whether a single β-agonist agent is superior to the others; nor have they resolved whether isomers of β-agonists are superior to the racemic versions of the drug. Also unresolved are the problems of optimal dosing, optimal methods of delivery, timing of delivery, as well as a myriad of other issues regarding both treatment efficacy and effectiveness. The result is that treatment choices recommended by current guidelines are left somewhat open-ended.6, 7, 8, 9 In 1997, the National Institutes of Health National Asthma Education and Prevention Program revised its guidelines based on several well-conducted clinical trials to suggest that asthmatic patients experiencing a severe exacerbation can be treated with inhaled high-dose β-agonists by either nebulization every 20 minutes or continuously for 1 hour.6, 10, 11

The use of continuous albuterol nebulization was first reported in 14 children in 1987, where high-dose continuous nebulization was shown to produce a greater improvement in FEV1 than intermittent-dose albuterol or bolus-dose albuterol followed by a lower continuous dose.12 Although 2 early reports indicated that improvement in pulmonary function tests persisted longer in patients treated with continuous nebulization than in those treated with intermittent treatment,13, 14 the study by Scalabrin et al15 of 21 children with acute asthma did not support these findings. Papo et al16 later found that children with severe asthma unresponsive to conventional treatment who were subsequently treated with continuous nebulization demonstrated a more rapid clinical improvement in asthma and had shorter hospital stays than those treated with intermittent β-agonist therapy.

The option of continuous nebulization of albuterol was first described in adults as a case report in 1990.17 Unlike the pediatric clinical trials, which were conducted primarily in an intensive care setting, the subsequent trials in adults focused on the treatment of acute asthma exacerbation in the ED. Early trials revealed no difference in pulmonary function at the end of a 2-hour observation period among patients treated with continuous nebulization or intermittent albuterol.18 Two later trials also reported no differences in response between adults treated with continuous nebulization or intermittent albuterol, although—based on post hoc analyses—they reported that patients with severe obstruction responded more favorably with continuous nebulization and required fewer hospital admissions.10, 11 The conclusions of Rudnitsky et al10 were based on statistically significant, but clinically insignificant, differences in peak expiratory flow rate (PEFR) between groups after completion of treatment. Lin et al’s11 conclusions were determined by the rate of improvement of percent predicted FEV1 rather than differences in improvement of pulmonary function after treatment was completed.

In this issue of Annals , Besbes-Ouanes et al19 present the first study comparing continuous versus intermittent nebulized β-agonist agents in patients with severe exacerbation (PEFR <50% predicted). Their study design differed from the others in several ways: (1) the dosing scheme and duration of continuous albuterol called for 27.4 mg of salbutamol over 6 hours rather than lower doses over a shorter period; (2) they used a standard ED small-reservoir nebulizer for both the continuous and the intermittent groups rather than a small-reservoir nebulizer for the intermittent group and a large-reservoir nebulizer for the continuous group; and (3) they included clinical severity, time to improvement, spirometric values, failure to improve rate, and side effects as their outcome measures rather than simply comparing pulmonary function values. Unlike the investigators who preceded them, Besbes-Ouanes et al reported that continuous β-agonist therapy performed no better than did intermittent nebulization treatments for patients with severe asthma with regard to clinical symptoms and scores, pulmonary function, side effects, and need for hospitalization. Unfortunately, as the authors noted, the study was insufficiently powered to detect differences in treatment failure and hospitalization rates.

Does this study close the door on this issue? Au contraire, it opens the door to further investigation. First, would Besbes-Ouanes et al19 have found important clinical differences between the 2 modalities if their study had been sufficiently powered? Second, are the size and kind of reservoir and nebulizer used for continuous therapy important? Might their results have differed if they had used a standard large-chambered reservoir for the continuous therapy group? Only a large, 3-armed trial of patients with severe obstructive asthma that compares intermittent nebulization using a small reservoir with continuous nebulization using a small reservoir and continuous nebulization using large reservoir will provide the information that we seek. Despite these unanswered questions, Besbes-Ouanes et al have provided the reassurance that continuous-dose β-agonist therapy is as effective as intermittent-dose therapy, which is a relief for emergency physicians treating asthmatic patients in busy EDs, where only one size reservoir may be available, and respiratory therapists may not be available for the care of “routine” asthmatic patients, and nurses are so busy that providing a fresh dose of β-agonist every 20 minutes may be an unrealistic expectation.

Although the goal of this study and the thousands of other studies routinely performed on patients with acute asthma exacerbation was to determine how to optimize emergency treatment of acute asthma, it, and most others, failed to address a more urgent issue: that is, the recognition that asthma is a chronic problem whose long-term control and consequences must be addressed in the ED. Although it is certainly crucial to provide optimal care in the ED, it makes little difference whether continuous β-agonist therapy is better than intermittent β-agonist therapy if we fail to provide asthmatic patients with proper discharge medications, are unable to arrange prompt follow-up for all asthmatic patients discharged from the ED, and we do not teach asthmatic patients with acute exacerbation how to care for themselves on a daily basis.20, 21, 22, 23 The goal of our research should be multifaceted: improve emergency therapy, bridge the gap between emergency therapy and primary care, and instruct our patients about the possibility of effectively managing their disease so that they rarely require a visit to the ED for an acute attack. It is in these areas that we should now strive to advance the care of asthma in the ED. It’s time we recognize that an asthma exacerbation represents an opportunity to make a significant intervention in the care of a patient with a chronic disease and a chance to work in concert with our colleagues in internal medicine, family practice, pulmonary medicine, and allergy and immunology who provide the long-term ambulatory care for asthmatic patients.

In the meantime, however, Besbes-Ouanes et al19 have elegantly demonstrated that the simpler decision of whether to use continuous or intermittent β-agonist therapy in the ED treatment of patients with severe obstructive asthma will remain one of preference, convenience, and availability of equipment and staffing.

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References 

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☆ Reprints not available from the author. Address for correspondence: Rita K. Cydulka, MD, Department of Emergency Medicine, MetroHealth Medical Center, Room S1-203, Cleveland, OH 44109; 216-778-5088; E-mail: rcydulka@metrohealth.org.

PII: S0196-0644(00)46285-2

doi:10.1067/mem.2000.109687

Refers to article:

  • Continuous Versus Intermittent Nebulization of Salbutamol in Acute Severe Asthma: A Randomized, Controlled Trial

    Lamia Besbes-Ouanes, Semir Nouira, Souhail Elatrous, Jalel Knani, Mohamed Boussarsar, Fekri Abroug
    Annals of Emergency Medicine September 2000 (Vol. 36, Issue 3, Pages 198-203)

Annals of Emergency Medicine
Volume 36, Issue 3 , Pages 236-238, September 2000

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