Objectives: To determine the benefit of IV [[beta].

Objectives: To determine the benefit of IV [[beta].sub.2]-agonists for hard acute asthma treated in the difficulty department (ED).

Methods: Randomized controll trials were identified using EMBASE, MEDLINE, and CINAHL; the Cochrane Airways Review clump database; hand searching; bibliographies; pharmaceutical companies; and author contact. Studies where IV [[beta].sub.2]-agonists were compared to placebo and/or existing standards of care were considered. Where appropriate, trials were combined using unevens ratios (ORs) or weighted mean differences with 95% confidence intervals (CIs).

Results: From 746 identified allusions 55 potentially relevant articles were identified and 15 articles were included. All trials were performed outside North America and were published prior to 1997 Three main treatment strategies were reviewed: strategy 1 (three articles), IV [[beta].sub.2]-agonists with inhaled [[beta].sub.2]-agonists v inhaled [[beta].sub.2]-agonists; strategy 2 (six articles), IV [[beta].sub.2]-agonists alone v inhaled [[beta].sub.2]-agonists; and strategy 3 (six articles), IV [[beta].sub.2]-agonists v IV methylxanthines. Compared to all treatments, IV [[beta].sub.2]-agonist use did not lead to clinical or statistical significant differences in vital signs, pulmonary functions, laboratory measures, adverse powers or clinical success. Although statistically nonsignificant, seven methodologically sound studies demonstrated that peak expiratory melts and heart rates were unchanged following [[beta].sub.2]-agonist use compared to all other treatments at 60 min (83 L/min [95% CI, 176 to 342] and 365 beats/min [95% CI, 29 to 102] respectively), with an increased risk of adverse results (OR, 1.98; 95% CI, 05 to 82)

Conclusions: Evidence is lacking to support the use of IV [[beta].sub.2]-agonists in ed patients with severe acute asthma. Moreover, the clinical benefit appears questionable, while the potential clinical risks are obvious. The simply recommendations for IV [[beta].sub.2]-agonist use should be in those patients in whom inhaled therapy is not feasible, or in the words immediately preceding [i]or[/i] following of a controlled clinical trial comparing IV [[beta].sub.2]-agonists with standard care v standard care alone.

explanation words: asthma; [beta]-agonists; emergency department; IV; pulmonary function; side effects

Abbreviations: ABG = arterial vital fluid gas; CI = confidence interval; CPG = clinical practice guideline; df = steps of freedom; ED = unforeseen occasion department; OR = odds ratio; PEFR = peak expiratory grow rate; PFT = pulmonary function test; RCT = randomized controll trial; WMD = weighted mean difference

**********

The general approach to treating patients with acute asthma is to use inhaled [beta]-agonist bronchodilators and corticosteroids. For unrelenting acute asthma, penetration of inhaled [beta]-agonists to the affected small conducting airways may be impeded, and consequently answers may be a result of unsalable article reaching the receptors via the systemic circulation. In these circumstances, if bronchodilatation present itselfs predominantly in response to the systemic distribution of the remedy IV rather than inhaled administration of bronchodilators may provide an earlier clinical answer (1)

The research investigating the part of IV [beta]-agonists in the emergent treatment of asthma has spanned > 25 years. At at hand each of the clinical practice guidelines (CPGs) in Europe (British Thoracic Society), Canada (Canadian Association of conjuncture Physicians), and the United States (National Asthma Education and Prevention Program) praise inhaled [beta]-agonist therapy for all cases of asthma that not away to the emergency department (ED) (2-5) Each CPG refer tos IV and subcutaneous [beta]-agonists as second-line therapy for use in patients unresponsive to inhaled bronchodilator and systemic corticosteroid therapy, or if the inhaled path is not practical for the patient (ie, excessive coughing, too weak to inspire adequately, or moribund patient). (2-5) IV use is not approved in the National Asthma Education and Prevention Program guidelines. (5) Each CPG variously describe "near-death asthma" or "life-threatening asthma" as qualifying expressions for adult candidates for IV or subcutaneous administration. These are listed as alternative therapies paralleling inhalational anesthetics and IV methylxanthines.

However, principally of the CPG recommendations for IV or subcutaneous agents originate from low-grade and/or soft levels of evidence; as a arise debate regarding the IV way of treatment continues. This lack of consensus cogitates the fact that no systematic review of the IV or subcutaneous [beta]-agonist literature for the treatment of asthmatic exacerbations has been published to date. Consequently the objective of this review was to determine if the evidence from randomized trials supports the use of IV [beta]-agonists in the treatment of patients with exact acute asthma who present to the ED

MATERIALS AND METHODS

Inclusion Criteria

...