Best evidence topic reports. Delivery of bronchodilators in acute asthma in children

Interventions for escalation of therapy for acute exacerbations of asthma in children: an overview of Cochrane Reviews

BACKGROUND

Asthma is an illness that commonly affects adults and children, and it serves as a common reason for children to attend emergency departments. An asthma exacerbation is characterised by acute or subacute worsening of shortness of breath, cough, wheezing, and chest tightness and may be triggered by viral respiratory infection, poor compliance with usual medication, a change in the weather, or exposure to allergens or irritants. Most children with asthma have mild or moderate exacerbations and respond well to first-line therapy (inhaled short-acting beta-agonists and systemic corticosteroids). However, the best treatment for the small proportion of seriously ill children who do not respond to first-line therapy is not well understood. Currently, a large number of treatment options are available and there is wide variation in management.

OBJECTIVES

Main objective - To summarise Cochrane Reviews with or without meta-analyses of randomised controlled trials on the efficacy and safety of second-line treatment for children with acute exacerbations of asthma (i.e. after first-line treatments, titrated oxygen delivery, and administration of intermittent inhaled short-acting beta₂-agonists and oral corticosteroids have been tried and have failed) Secondary objectives - To identify gaps in the current evidence base that will inform recommendations for future research and subsequent Cochrane Reviews - To categorise information on reported outcome measures used in trials of escalation of treatment for acute exacerbations of asthma in children, and to make recommendations for development and reporting of standard outcomes in future trials and reviews - To identify relevant randomised controlled trials that have been published since the date of publication of each included review METHODS: We included Cochrane Reviews assessing interventions for children with acute exacerbations of asthma. We searched the Cochrane Database of Systematic Reviews. The search is current to 28 December 2019. We also identified trials that were potentially eligible for, but were not currently included in, published reviews. We assessed the quality of included reviews using the ROBIS criteria (tool used to assess risk of bias in systematic reviews). We presented an evidence synthesis of data from reviews alongside an evidence map of clinical trials. Primary outcomes were length of stay, hospital admission, intensive care unit admission, and adverse effects. We summarised all findings in the text and reported data for each outcome in 'Additional tables'.

MAIN RESULTS

We identified 17 potentially eligible Cochrane Reviews but extracted data from, and rated the quality of, 13 reviews that reported results for children alone. We excluded four reviews as one did not include any randomised controlled trials (RCTs), one did not provide subgroup data for children, and the last two had been updated and replaced by subsequent reviews. The 13 reviews included 67 trials; the number of trials in each review ranged from a single trial up to 27 trials. The vast majority of comparisons included between one and three trials, involving fewer than 100 participants. The total number of participants included in reviews ranged from 40 to 2630. All studies included children; 16 (24%) included children younger than two years of age. Most of the reviews reported search dates older than four years. We have summarised the published evidence as outlined in Cochrane Reviews. Key findings, in terms of our primary outcomes, are that (1) intravenous magnesium sulfate was the only intervention shown to reduce hospital length of stay (high-certainty evidence); (2) no evidence suggested that any intervention reduced the risk of intensive care admission (low- to very low-certainty evidence); (3) the risk of hospital admission was reduced by the addition of inhaled anticholinergic agents to inhaled beta₂-agonists (moderate-certainty evidence), the use of intravenous magnesium sulfate (high-certainty evidence), and the use of inhaled heliox (low-certainty evidence); (4) the addition of inhaled magnesium sulfate to usual bronchodilator therapy appears to reduce serious adverse events during hospital admission (moderate-certainty evidence); (5) aminophylline increased vomiting compared to placebo (moderate-certainty evidence) and increased nausea and nausea/vomiting compared to intravenous beta₂-agonists (low-certainty evidence); and (6) the addition of anticholinergic therapy to short-acting beta₂-agonists appeared to reduce the risk of nausea (high-certainty evidence) and tremor (moderate-certainty evidence) but not vomiting (low-certainty evidence). We considered 4 of the 13 reviews to be at high risk of bias based on the ROBIS framework. In all cases, this was due to concerns regarding identification and selection of studies. The certainty of evidence varied widely (by review and also by outcome) and ranged from very low to high.

AUTHORS' CONCLUSIONS

This overview provides the most up-to-date evidence on interventions for escalation of therapy for acute exacerbations of asthma in children from Cochrane Reviews of randomised controlled trials. A vast majority of comparisons involved between one and three trials and fewer than 100 participants, making it difficult to assess the balance between benefits and potential harms. Due to the lack of comparative studies between various treatment options, we are unable to make firm practice recommendations. Intravenous magnesium sulfate appears to reduce both hospital length of stay and the risk of hospital admission. Hospital admission is also reduced with the addition of inhaled anticholinergic agents to inhaled beta₂-agonists. However, further research is required to determine which patients are most likely to benefit from these therapies. Due to the relatively rare incidence of acute severe paediatric asthma, multi-centre research will be required to generate high-quality evidence. A number of existing Cochrane Reviews should be updated, and we recommend that a new review be conducted on the use of high-flow nasal oxygen therapy. Important priorities include development of an internationally agreed core outcome set for future trials in acute severe asthma exacerbations and determination of clinically important differences in these outcomes, which can then inform adequately powered future trials.

Endpoints in respiratory diseases

A wide range of outcome measures or endpoints has been used in clinical trials to assess the effects of treatments in paediatric respiratory diseases. This can make it difficult to compare treatment outcomes from different trials and also to understand whether new treatments offer a real clinical benefit for patients. Clinical trials in respiratory diseases evaluate three types of endpoints: subjective, objective and health-related outcomes. The ideal endpoint in a clinical trial needs to be accurate, precise and reliable. Ideally, the endpoint would also be measured with minimal risk and across all ages, easy to perform, and be inexpensive. As for any other disease, endpoints for respiratory diseases must be viewed in the context of the important distinction between clinical endpoints and surrogate endpoints. The association between surrogate endpoints and clinical endpoints must be clearly defined for any disease in order for them to be meaningful as outcome measures. The most common endpoints which are used in paediatric trials in respiratory diseases are discussed. For practical purposes, diseases have been separated into acute (bronchiolitis, acute viral-wheeze, acute asthma and croup) and chronic (asthma and cystic fibrosis). Further development of endpoints will enable clinical trials in children with respiratory diseases with the main objective of improving prognosis and safety.

Influence of ambulatory inhaled treatment with different devices on the duration of acute asthma findings in children

BACKGROUND

Efficacy of bronchodilator treatment in children with asthma depends on the proper use of inhalation devices. The aim of this study was to compare the efficacy of inhaled bronchodilator treatment with a spacer and a nebulizer in children with acute asthma findings.

METHODS

Fifty-eight children with acute asthma findings who received ambulatory inhaled bronchodilator treatment with a nebulizer and 39 with a spacer were enrolled in the study. Duration of asthma, inhaled steroid treatment and the number of exacerbations during the previous year were recorded. Duration of current acute symptoms, exacerbation severity score and duration of respiratory findings after initiation of treatment were also recorded.

RESULTS

Children in both groups were similar in age (76.5 +/- 30.3 months using a nebulizer vs 83.1 +/- 25.1 in spacer group, p = 0.26). Duration after diagnosis of asthma, initiation of inhaled steroid treatment and exacerbation symptoms were similar between groups (p = 0.15, 0.76 and 0.93, respectively). Exacerbation severity score in the nebulizer group was not significantly different from the spacer group (2.6 +/- 0.7 vs 2.8 +/- 0.7 respectively, p = 0.19). Number of exacerbations in the previous year was not different (2.0 +/- 1.2 in the nebulizer group vs 1.6 +/- 0.9 in the spacer group, p = 0.08). Duration of acute asthma findings after initiation of inhaled bronchodilator treatment was similar between the two groups (6.5 +/- 2.9 vs 7.2 +/- 4.6 p = 0.34).

CONCLUSION

Nebulizers and spacers have similar influence on the duration of acute asthma findings in children when used in ambulatory home bronchodilator treatment.

Characteristics of spacer device use by patients with asthma and COPD

OBJECTIVE

Spacer devices (SD) in conjunction with metered dose inhalers (MDI) have been shown to be as effective as saline nebulizers for the delivery of beta-agonists. A preliminary study suggests that SDs are not consistently used. The purpose of this study was to investigate patterns of SD ownership and use to identify potential targets for future educational efforts to increase ownership and use of SD.

METHODS

Cross-sectional convenience sample survey of patients presenting to an academic Emergency Department (ED) with a history of asthma/COPD (chronic obstructive pulmonary disease). Informed consent was obtained. Survey data included demographics, association with a primary care physician (PCP), SD ownership, patterns of use, opinions of efficacy about SD and disease severity assessed by duration of asthma/COPD, prior ED visits, hospitalizations, and history of prior intubation. Patterns of use are described and univariate and multivariate analyses were used to identify factors associated with SD ownership.

RESULTS

Of the 313 patients, 55.9% were female, the mean age was 46.0 years (standard deviation 14.7), 54.3% were white, and 143 patients (45.7%) reported owning a SD. A total of 36.4% reported a prior hospitalization for their condition and 24% reported a history of being intubated. Less than half of patients presenting with asthma or COPD exacerbation that reported owning a SD used it the day of presentation to the ED. Logistic regression identified having a PCP and a history of prior hospitalization for asthma/COPD as factors independently associated with SD ownership (odds ratio [OR] 1.7, 95% confidence interval [CI] 1.1-2.7 and OR 2.2, CI 1.3-3.5, respectively).

CONCLUSION

A majority of patients with asthma/COPD do not own a SD. These data suggest that there is significant opportunity for educational efforts directed at a broad range of asthma/COPD patients in hopes of increasing ownership and use of SD.