Continuous vs Intermittent β-Agonists in the Treatment of Acute Adult Asthma: A Systematic Review With Meta-analysis

doi:10.1378/chest.122.1.160

Chest

Volume 122, Issue 1, July 2002, Pages 160-165

https://doi.org/10.1378/chest.122.1.160 Get rights and content

Background

Since the late 1980s, there has been considerable clinical and academic interest in the use of continuous aerosolized bronchodilators for the treatment of patients with acute asthma. These studies have suggested that this therapy is safe, is at least as effective as intermittent nebulization, and may be superior to intermittent nebulization in patients with the most severely impaired pulmonary function.

Objectives

To determine whether continuous nebulization offered an advantage over intermittent nebulization for the treatment of adults with acute asthma in the emergency department (ED).

Design

Systematic review of randomized controlled trials of adults with acute asthma.

Outcomes

Change in pulmonary function tests as primary outcome, and admissions to the hospital and side effects as secondary outcomes.

Results

Six studies including 393 adults with acute asthma were selected. No significant differences were demonstrated between the two delivery methods in terms of pulmonary function measures obtained after 1 h of treatment (standardized mean difference [SMD], −0.15; 95% confidence interval [CI], −0.35 to 0.05) and after 2 to 3 h of treatment (SMD, −0.19; 95% CI, −0.39 to 0.01). No significant heterogeneity was demonstrated (p > 0.5). At the end of treatment, there was a significantly greater decrease in pulse rate when the continuous nebulizer was used (weighted mean difference [WMD], −6.82; 95% CI, −8.67 to −3.90 beats/min; χ², 2.55; degrees of freedom [df], 4; p = 0.6). Additionally, the analysis showed a significant decrease of serum potassium concentration with the use of intermittent nebulization (WMD, 0.12; 95% CI, 0.24 to 0.01 mmol/L; χ², 0.5; df, 2; p = 0.8). However, this finding was obtained on the analysis of only two trials. Finally, at the end of the study period, no significant differences were identified between patients treated with continuous or intermittent nebulization with respect to hospital admission (relative risk, 0.68; 95% CI, 0.33 to 1.38; χ², 2.06; df, 1; p = 0.2).

Conclusions

Overall, this review supports the equivalence of continuous and intermittent albuterol nebulization in the treatment of acute adult asthma.

Section snippets

Literature Search and Selection of Studies

A computerized search was conducted to identify literature on the topic of continuous vs intermittent nebulization with β-agonists in adult patients with acute asthma. We searched for studies using the MEDLINE (1966 to 2001), EMBASE (1980 to 2001), and CINAHL (1982 to 2001) databases. The following MeSH terms were used in the search: Emerg* or acute or status and continuous or intermittent or multi-dose or dosage or nebuli* and β-agonist or bronchodilat*. Also, a search of the Cochrane

Results

Sixty-two articles were identified in the initial search. Of these, reviewers found that 16 articles were potentially eligible. Most of the others were excluded because they were not clinical trials of patients with acute asthma. The reasons for subsequent exclusion were nonrandomized trials (n = 6),³⁵⁶²⁰²¹²² only a continuous nebulization group included in the study (n = 1),²³ only pediatric patients included in the study (n = 2),⁷⁸ and non-acute asthma patients included in the study (n = 1).⁴

Discussion

The purpose of this systematic review is to determine whether continuous nebulization offered an advantage over intermittent nebulization for the treatment of adults with acute asthma in the ED. Our analysis failed to demonstrate statistically significant differences between groups in terms of pulmonary function or hospital admission rates. The intensity of treatment (ie, the albuterol dose) and the severity of the exacerbation did not influence the effect of either method of albuterol

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Citation Excerpt :
While our patient received a very high dose of albuterol, tachycardia did not worsen and improved with stabilization of the underlying physiology. However, much debate remains regarding a preference between continuous versus intermittent B2 agonists [5–8]. While acute settings may prompt physicians to administer variable doses and frequencies of albuterol, the overall goal in the management of severe acute asthma is the fastest delivery of medication to the most distal regions of the bronchial tree.
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A 37 year-old African American woman presented to our Level 1 Trauma Center after a high-speed motor vehicle crash and was intubated on arrival for airway protection. The patient developed diffuse wheezing and persistent tachycardia, with elevated peak airway pressures and air trapping on mechanical ventilation. Her symptoms were refractory to inhaled steroids, systemic steroids, intravenous magnesium, continuous albuterol administration and ventilator optimization. Heliox, an admixture of 80:20 percent helium to oxygen, was initiated to assist with laminar flow. Throughout the next 24 h, the patient's air trapping improved, subsequently decreasing intrathoracic pressure, improving venous return and resolving her tachycardia. The patient's multiple orthopedic injuries were treated and she was eventually weaned off of Heliox, steroids, and continuous albuterol. She was extubated and endorsed a history of poorly controlled asthma requiring hospitalizations and multiple intubations.
Recognition of CAS can be challenging in the trauma patient with distracting injuries. This case illustrates the utility of a stepwise approach to a trauma patient suffering from CAS, and should encourage further research into novel therapies when conventional treatment fails. Given that the populations most affected by CAS are often also subject to a disproportionate burden of trauma, trauma surgeons should maintain both a vigilance for the syndrome as well as a working knowledge of the treatment modalities available.
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Chest

Clinical InvestigationsAsthmaContinuous vs Intermittent β-Agonists in the Treatment of Acute Adult Asthma: A Systematic Review With Meta-analysis

Background

Objectives

Design

Outcomes

Results

Conclusions

Section snippets

Literature Search and Selection of Studies

Results

Discussion

Am J Emerg Med

J Allergy Clin Immunol

Ann Emerg Med

Ann Emerg Med

Chest

Control Clin Trials

Clin Epidemiol

Control Clin Trials

Chest

Chest

Ann Emerg Med

Chest

Chest

National Asthma Education and Prevention Program. Expert panel report 2: guidelines for the diagnosis and management of asthma

British guidelines on asthma management: 1995 review and position statement

Thorax

Clinical Investigations
Asthma
Continuous vs Intermittent β-Agonists in the Treatment of Acute Adult Asthma: A Systematic Review With Meta-analysis