In acute asthma inhaled beta-2-agonists are often administered to relieve bronchospasm by wet nebulisation, but some have argued that metered-dose inhalers with a holding chamber (spacer) can be equally effective. In the community setting nebulisers are more expensive, require a power source and need regular maintenance.To assess the effects of holding chambers compared to nebulisers for the delivery of beta-2-agonists for acute asthma.We last searched the Cochrane Airways Group trials register in November 2002 and the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 3, 2002).Randomised trials in adults and children (from two years of age) with asthma, where holding chamber beta-2-agonist delivery was compared with wet nebulisation.Two reviewers independently applied study inclusion criteria (one reviewer for the first version of the review), extracted the data and assessed trial quality. Missing data were obtained from the authors or estimated. Results are reported with 95% confidence intervals (CI).This review has been updated in 2003 and has now analysed 1076 children and 444 adults included in 22 trials from emergency room and community settings. In addition, five trials on in-patients with acute asthma (184 children and 28 adults) have been added to the review. Method of delivery of beta-2-agonist did not appear to affect hospital admission rates. In adults, the relative risk of admission for holding chamber versus nebuliser was 0.88 (95% CI 0.56 to 1.38). The relative risk for children was 0.65 (95% CI 0.4 to 1.06). In children, length of stay in the emergency department was significantly shorter when the holding chamber was used, with a weighted mean difference of -0.47 hours, (95% CI -0.58 to -0.37 hours). Length of stay in the emergency department for adults was similar for the two delivery methods. Peak flow and forced expiratory volume were also similar for the two delivery methods. Pulse rate was lower for holding chamber in children, weighted mean difference -7.6% baseline (95% CI -9.9 to -5.3% baseline).Metered-dose inhalers with holding chamber produced outcomes that were at least equivalent to nebuliser delivery. Holding chambers may have some advantages compared to nebulisers for children with acute asthma.
Background Helium and oxygen mixtures (heliox), have been used sporadically in respiratory medicine for decades. Their use in acute respiratory emergencies such as asthma has been the subject of considerable debate. Despite the lapse of more than 60 years since it was first proposed, the role of heliox in treating patients with acute severe asthma remains unclear. Objectives To determine the effect of the addition of heliox to standard medical care on the course of acute asthma, as measured by pulmonary function testing and clinical endpoints. Search methods Randomised controlled trials were identified from the Cochrane Airways Review Group Asthma Register which is a compilation of systematic searches of CINAHL, EMBASE, MEDLINE, and CENTRAL and hand searching of the 20 most productive respiratory care journals. In addition, primary authors and experts were contacted to identify eligible studies. References from included studies, known reviews and texts were also searched. Selection criteria Studies were selected for inclusion in the review if they met the following inclusion criteria: 1) randomised, single or double blind, controlled trials; 2) children or adults with a clinical diagnosis of acute asthma seen in emergency departments or equivalent acute care settings; and 3) compared treatment with inhaled heliox to placebo (oxygen or air). Two reviewers independently assessed the studies for inclusion and quality assessment; disagreement was resolved by a third reviewer and consensus. Data collection and analysis Data from all included trials were combined using the Review Manager (Version 4.1) using random effects weighted mean (WMD) and standardised mean differences (SMD), with 95% confidence intervals (95% CI). Homogeneity of effect sizes were tested with the Dersimonian and Laird method with p<0.1 as the cut point for significance. Sensitivity analyses were performed on age (adults vs. children), different helium‐oxygen mixtures (80/20, vs. 70/30 or 60/40), methodological quality (Jadad score >2 vs. <3) and method of heliox use (studies designed to washout air in the lungs and replace it with heliox versus studies that used heliox to deliver nebulized therapy). Main results This review has been updated in 2002 to include two new trials. A total of six randomised controlled trials were selected for inclusion with a total of 369 acute asthma patients. Five studies involved adults and one study dealt solely with children. Two were assessed as high quality (Jadad score >3). The main outcome variable was spirometric measurements (PEF % predicted, PEF L/min, FEV1 % of predicted, FEV1L). Heliox use did not improve pulmonary functions compared to standard care (SMD = 0.13; 95% CI: ‐0.09 to 0.34). All pulmonary function tests were recorded during heliox administration (15 to 60 min). The test of homogeneity was not significant (p=0.25). There were no significant differences between groups when adults vs. children, high vs. low quality, and high vs. low heliox dose studies were compared. Authors' conclusions The existing evidence does not provide support for the administration of helium‐oxygen mixtures to ED patients with moderate to severe acute asthma. At this time, heliox treatment does not have a role to play in the initial treatment of patients with acute asthma. Since these conclusions are based upon between‐group comparisons and small studies, they should be interpreted with caution. Additional research in this setting is needed.
Asthma exacerbations can be frequent and range in severity from relatively mild to status asthmaticus. The use of magnesium sulfate (MgSO4) is one of numerous treatment options available during acute exacerbations. While the efficacy of intravenous MgSO4 has been demonstrated, little is known about inhaled MgSO4.To examine the efficacy of inhaled MgSO4 in the treatment asthma exacerbations.Randomised controlled trials were identified from the Cochrane Airways Group "Asthma and Wheez*" register. These trials were supplemented with trials found in the reference list of published studies, studies found using extensive electronic search techniques, as well as a review of the gray literature and conference proceedings.Randomised (or pseudo-randomised) controlled trials were eligible for inclusion. Studies were included if patients were treated with nebulised MgSO4 alone or in combination with beta(2)-agonist and where compared to beta2-agonist alone or inactive control.Trial selection, data extraction and methodological quality were assessed by two independent reviewers. Efforts were made to collect missing data from authors. Results from fixed effects models are presented as standardized mean differences (SMD) for pulmonary functions and relative risks (RR) for hospital admission; both are displayed with their 95% confidence intervals (95% CI).Six trials involving 296 patients were included. Four studies compared nebulised MgSO4 with beta2-agonist to beta2-agonist and two studies compared MgSO4 to beta2-agonist alone. Three studies enrolled only adults and 2 enrolled exclusively pediatric patients; three of the studies enrolled severe asthmatics. Overall, there was a significant difference in pulmonary function between patients whose treatments included nebulised MgSO4 in addition to beta2-agonist (SMD: 0.30; 95% CI: 0.03 to 0.56; 4 studies); however, hospitalizations were similar between the groups (RR: 0.69; 95% CI: 0.42 to 1.12; 3 studies). Subgroup analyses did not demonstrate significant differences in lung function improvement between adults and children, but were significantly different between severe and mild to moderate asthmatics (SMD: 0.69; 95% CI 0.13 to 1.25). Conclusions regarding treatment with nebulised MgSO4 alone are difficult to draw due to lack of studies in this area.Nebulised inhaled magnesium sulfate in addition to beta2-agonist in the treatment of an acute asthma exacerbation, appears to have benefits with respect to improved pulmonary function and there is a trend towards benefit in hospital admission. The benefit is significantly greater in more severe asthma exacerbations. Heterogeneity between trials included in this review precludes a more definitive conclusion.
Acute exacerbations are common occurrences for asthmatics. Contact with airway irritants ( e.g. viral upper respiratory tract infections, aero-allergens) and nonadherence to controller medications, along with the natural history of the disease can result in deterioration in lung function, increased symptoms and an increased need for reliever medication. It is estimated that nearly 2 million emergency department (ED) asthma visits occur annually in the USA alone 1. Since the frequency of exacerbations is related to asthma severity on the one hand, and increasing degrees of airway eosinophilia are associated with increased disease severity on the other 2, understanding the pathophysiology of exacerbations is critically important to disease control.
The medical consequences of these events can range from minor life interruptions to severe illness. These severe exacerbations often result in ED presentation or unscheduled visits to health professionals for urgent care, and may require hospital admission. While rare, death from exacerbations does occur. The economic consequences of asthma have been well documented 3, 4 and the acute attack has been estimated to represent ∼25% of overall asthma costs 5. The control of chronic asthma with the use of inhaled corticosteroids (ICS), with or without the use of additional agents ( e.g. long-acting β-agonists or leukotriene receptor antagonists), anticholinergics and in some cases newer biological agents, have proven effective in reducing the frequency and severity of these exacerbations. In addition, nonpharmacological approaches (regular follow-up, action plans, immunisation, asthma education) have also proven to be effective but adherence to these can be low 6, 7.
Despite these advances, a gap between what is known and what is practiced hampers efforts to improve the quality of life of patients with asthma. This gap may be the result of poor access to care and resources, failure of physicians to treat the disease …
