Which intravenous bronchodilators are being administered to children presenting with acute severe wheeze in the UK and Ireland?

Analysis of guideline recommendations for treatment of asthma exacerbations in children: a Pediatric Emergency Research Networks (PERN) study

RATIONALE

There is significant practice variation in acute paediatric asthma, particularly severe exacerbations. It is unknown whether this is due to differences in clinical guidelines.

OBJECTIVES

To describe and compare the content and quality of clinical guidelines for the management of acute exacerbations of asthma in children between geographic regions.

METHODS

Observational study of guidelines for the management of acute paediatric asthma from institutions across a global collaboration of six regional paediatric emergency research networks.

MEASUREMENTS AND MAIN RESULTS

158 guidelines were identified. Half provided recommendations for at least two age groups, and most guidelines provided treatment recommendations according to asthma severity.There were consistent recommendations for the use of inhaled short-acting beta-agonists and systemic corticosteroids. Inhaled anticholinergic therapy was recommended in most guidelines for severe and critical asthma, but there were inconsistent recommendations for its use in mild and moderate exacerbations. Other inhaled therapies such as helium-oxygen mixture (Heliox) and nebulised magnesium were inconsistently recommended for severe and critical illness.Parenteral bronchodilator therapy and epinephrine were mostly reserved for severe and critical asthma, with intravenous magnesium most recommended. There were regional differences in the use of other parenteral bronchodilators, particularly aminophylline.Guideline quality assessment identified high ratings for clarity of presentation, scope and purpose, but low ratings for stakeholder involvement, rigour of development, applicability and editorial independence.

CONCLUSIONS

Current guidelines for the management of acute paediatric asthma exacerbations have substantial deficits in important quality domains and provide limited and inconsistent guidance for severe exacerbations.

Intravenous magnesium sulfate for asthma exacerbations in children: Systematic review with meta-analysis

BACKGROUND

Asthma is the most prevalent chronic disease in children and constitutes a significant healthcare burden. First-line therapy for acute asthma exacerbations is well established. However, secondary treatments, including intravenous magnesium sulfate (IV-MgSO4), remain variable due to scarcity of data on its efficacy and safety.

OBJECTIVE

To assess the effectiveness and safety of IV-MgSO4 as a second line of treatment in managing children with asthma exacerbations.

METHODS

We searched five databases from inception until April 2023 on randomized clinical trials of IV-MgSO4 in children with acute asthma exacerbations. The primary outcomes were hospitalization rate and length, and change in the severity score. Secondary outcomes included percentage increase in peak expiratory flow rate (PEFR), hospital re-admission rate, need and length for pediatric intensive care unit (PICU) treatment, and adverse effects. Meta-analysis was performed for three outcomes with estimated odds ratios (ORs) or mean differences (MDs) and 95% confidence intervals (CIs).

RESULTS

Eleven studies met the final criteria. In comparison to control, administration of IV-MgSO4 was associated with a reduced hospitalization risk (OR 0.15; 95%CI: 0.03, 0.73) in four studies, and improvement of lung function (MD 26.77% PEFR; 95%CI: 18.41, 54.79) in two studies. There were no significant differences in the length of stay between groups. Due to heterogeneity, a narrative synthesis of other outcomes was performed.

CONCLUSION

The use of IV-MgSO4 demonstrated a reduction in the hospitalization rate and PEFR improvement in children with asthma exacerbations. Adverse effects were rare. Further well-designed studies are needed to better determine the efficacy and safety profile of IV-MgSO4.

Effect of magnesium sulfate on oxygenation and lung mechanics in morbidly obese patients undergoing bariatric surgery: a prospective double-blind randomized clinical trial

BACKGROUND

Respiratory mechanics are often significantly altered in morbidly obese patients and magnesium sulfate (MgSO4) is a promising agent for managing several respiratory disorders. This study aimed to examine the effects of MgSO4 infusions on arterial oxygenation and lung mechanics in patients with morbid obesity undergoing laparoscopic bariatric surgery.

METHODS

Forty patients with morbid obesity aged 21-60 years scheduled for laparoscopic bariatric surgery under general anesthesia were randomly allocated to either the control (normal saline infusion) or MgSO4 group (30 mg/kg lean body weight [LBW] of 10% MgSO4 in 100 ml normal saline intravenously over 30 min as a loading dose, followed by 10 mg/kg LBW/h for 90 min). The primary outcome was intraoperative arterial oxygenation (ΔPaO2/FiO2). Secondary outcomes included intraoperative static and dynamic compliance, dead space, and hemodynamic parameters.

RESULTS

At 90 min intraoperatively, the Δ PaO2/FiO2 ratio and the Δ dynamic lung compliance were statistically significantly higher in the MgSO4 group (mean ± SE: 16.1 ± 1.0, 95% CI [14.1, 18.1] and 8.4 ± 0.5 ml/cmH2O, 95% CI [7.4, 9.4]), respectively), and the Δ dead space (%) was statistically significantly lower in the MgSO4 group (mean ± SE: -8.0 ± 0.3%, 95% CI [-8.6, -7.4]) (P < 0.001). No significant differences in static compliance were observed.

CONCLUSIONS

Although MgSO4 significantly preserved arterial oxygenation and maintained dynamic lung compliance and dead space in patients with morbid obesity, the clinical relevance is minimal. This study failed to adequately reflect the clinical importance of these results.

Acute paediatric asthma treatment in the prehospital setting: a retrospective observational study

OBJECTIVES

To describe the incidence of and patterns of 'escalated care' (care in addition to standard treatment with systemic corticosteroids and inhaled bronchodilators) for children receiving prehospital treatment for asthma.

DESIGN

Retrospective observational study.

SETTING

State-wide ambulance service data (Ambulance Victoria in Victoria, Australia, population 6.5 million) PARTICIPANTS: Children aged 1-17 years and given a final diagnosis of asthma by the treating paramedics and/or treated with inhaled bronchodilators from 1 July 2019 to 30 June 2020.

PRIMARY AND SECONDARY OUTCOME MEASURES

We classified 'escalation of care' as parenteral administration of epinephrine, or provision of respiratory support. We compared clinical, demographic and treatments administered between those receiving and not receiving escalation of care.

RESULTS

Paramedics attended 1572 children with acute exacerbations of asthma during the 1 year study period. Of these, 22 (1.4%) had escalated care, all receiving parenteral epinephrine. Patients with escalated care were more likely to be older, had previously required hospital admission for asthma and had severe respiratory distress at initial assessment.Of 1307 children with respiratory status data available, at arrival to hospital, the respiratory status of children had improved overall (normal/mild respiratory distress at initial assessment 847 (64.8%), normal/mild respiratory distress at hospital arrival 1142 (87.4%), p<0.0001).

CONCLUSIONS

Most children with acute exacerbations of asthma did not receive escalated therapy during their pre-hospital treatment from ambulance paramedics. Most patients were treated with inhaled bronchodilators only and clinically improved by the time they arrived in hospital.

Optimising intravenous salbutamol in children: a phase 2 study

OBJECTIVE

The β2-agonists such as salbutamol are the mainstay of asthma management. Pharmacokinetic-pharmacodynamic (PKPD) models to guide paediatric dosing are lacking. We explored the relationship between salbutamol dose, serum concentration, effectiveness and adverse effects in children by developing a PKPD model.

DESIGN

A prospective cohort study of children admitted to hospital with acute asthma, who received intravenous salbutamol.

SETTING

Children were recruited in two cohorts: the emergency departments of two London hospitals or those retrieved by the Children's Acute Transport Service to three London paediatric intensive care units.

PATIENTS

Patients were eligible if aged 1-15 years, admitted for acute asthma and about to receive or receiving intravenous salbutamol.

INTERVENTIONS

Treatment was according to local policy. Serial salbutamol plasma levels were taken. Effectiveness measurements were recorded using the Paediatric Asthma Severity Score (PASS). Toxicity measurements included lactate, pH, glucose, heart rate, blood pressure and arrhythmias. PKPD modelling was performed with non-linear mixed-effect models.

MAIN OUTCOMES

Fifty-eight children were recruited with 221 salbutamol concentration measurements from 54 children. Median (range) age was 2.9 (1.1-15.2) years, and weight was 13.6 (8-57.3) kg. Ninety-five PASS measurements and 2078 toxicity measurements were obtained.

RESULTS

A two-compartment PK model adequately described the time course of salbutamol-plasma concentrations. An E_MAX (maximum drug effect) concentration-effect relationship described PASS and toxicity measures. PKPD simulations showed an infusion of 0.5 µg/kg/min (maximum 20 µg/min) for 4 hours after bolus achieves >90% maximal bronchodilation for 12 hours.

CONCLUSIONS

A paediatric PKPD model for salbutamol is described. An infusion of 0.5 µg/kg/min after bolus achieves effective bronchodilation. Higher rates are associated with greater tachycardia and hyperglycaemia.

Priorities for child health research across the UK and Ireland

BACKGROUND

The General and Adolescent Paediatric Research Network in the UK and Ireland (GAPRUKI) was established in 2016. The aims of GAPRUKI are to unite general paediatricians around the UK and Ireland, to develop research ideas and protocols, and facilitate delivery of multicentre research.

OBJECTIVES

To undertake a research prioritisation exercise among UK and Ireland general paediatricians.

METHODS

This was a four-phase study using a modified Delphi survey. The first phase asked for suggested research priorities. The second phase developed ideas and ranked them in priority. In the third phase, priorities were refined; and the final stage used the Hanlon Prioritisation Process to agree on the highest priorities.

RESULTS

In phase one, there were 250 questions submitted by 61 GAPRUKI members (66% of the whole membership). For phase two, 92 priorities were scored by 62 members and the mean Likert scale (1-7) scores ranged from 3.13 to 5.77. In a face-to-face meeting (phases three and four), 17 research questions were identified and ultimately 14 priorities were identified and ranked. The four priorities with the highest ranking focused on these three respiratory conditions: asthma, bronchiolitis and acute wheeze. Other priorities were in the diagnosis or management of constipation, urinary tract infection, fever, gastro-oesophageal reflux and also new models of care for scheduled general paediatric clinics.

CONCLUSION

Research priorities for child health in the UK and Ireland have been identified using a robust methodology. The next steps are for studies to be designed and funded to address these priorities.

Treatment patterns and frequency of key outcomes in acute severe asthma in children: a Paediatric Research in Emergency Departments International Collaborative (PREDICT) multicentre cohort study

RATIONALE

Severe acute paediatric asthma may require treatment escalation beyond systemic corticosteroids, inhaled bronchodilators and low-flow oxygen. Current large asthma datasets report parenteral therapy only.

OBJECTIVES

To identify the use and type of escalation of treatment in children presenting to hospital with acute severe asthma.

METHODS

Retrospective cohort study of children with an emergency department diagnosis of asthma or wheeze at 18 Australian and New Zealand hospitals. The main outcomes were use and type of escalation treatment (defined as any of intensive care unit admission, nebulised magnesium, respiratory support or parenteral bronchodilator treatment) and hospital length of stay (LOS).

MEASUREMENTS AND MAIN RESULTS

Of 14 029 children (median age 3 (IQR 1-3) years; 62.9% male), 1020 (7.3%, 95% CI 6.9% to 7.7%) had treatment escalation. Children with treatment escalation had a longer LOS (44.2 hours, IQR 27.3-63.2 hours) than children without escalation 6.7 hours, IQR 3.5-16.3 hours; p<0.001). The most common treatment escalations were respiratory support alone (400; 2.9%, 95% CI 2.6% to 3.1%), parenteral bronchodilator treatment alone (380; 2.7%, 95% CI 2.5% to 3.0%) and both respiratory support and parenteral bronchodilator treatment (209; 1.5%, 95% CI 1.3% to 1.7%). Respiratory support was predominantly nasal high-flow therapy (99.0%). The most common intravenous medication regimens were: magnesium alone (50.4%), magnesium and aminophylline (24.6%) and magnesium and salbutamol (10.0%).

CONCLUSIONS

Overall, 7.3% children with acute severe asthma received some form of escalated treatment, with 4.2% receiving parenteral bronchodilators and 4.3% respiratory support. There is wide variation treatment escalation.

Stating the obvious: intravenous magnesium sulphate should be the first parenteral bronchodilator in paediatric asthma exacerbations unresponsive to first-line therapy

What is the most appropriate second-line intravenous bronchodilator treatment when a child with a severe asthma attack is not responsive to initial inhaled therapy? The second-line treatment options for acute asthma include parenteral β₂-agonists, methylxanthine and magnesium sulphate (MgSO₄). There is a poor evidence-base to inform this decision. This review argues that intravenous MgSO₄ is the obvious treatment of choice for this situation as the initial treatment based on current knowledge.  We describe the mode of action, scope and limitations of MgSO₄, safety profile, economic impact, comparisons of the alternatives, and finally, what the guidelines say.  This review explores the suitability of intravenous MgSO₄ as a pragmatic and safe initial second-line therapy for children unresponsive to initial asthma management.

Treating acute severe asthma attacks in children: using aminophylline

Aminophylline does have a role in treating severe asthma attacks in children with asthma. Clinicians just need to be aware of the toxic side-effects of the drug and manage the drug carefully. https://bit.ly/3o7IJV1.

Question 5: Magnesium Sulphate for Acute Asthma in children

Most children who present to the emergency department with acute asthma, respond well to inhaled β₂-agonists (spacer or nebuliser), oxygen (if required) and systemic steroids. Guidelines across the world agree on this simple, straight forward evidenced based approach. In children with more severe asthma attacks and those who do not respond to initial treatment, the evidence base for the secondary level treatment is less clear. Many regimens exist for the next step. Intravenous Magnesium Sulphate (MgSO₄) is now used frequently in these situations and some centres are starting to use nebulized MgSO₄ as part of the initial maximal inhaled therapy options. This paper examines the role of MgSO₄ in acute asthma in children. It focusses on how MgSO₄ might work, what are the current recommendations for use and then what is the current evidence base to support its use. We have presented the evidence for the use of both nebulized and intravenous MgSO₄. At the end of the paper we have suggested future directions for research in this area. Our aim is to present a synthesis of the current role of MgSO₄ in the management of an acute asthma attack.

Pharmacology and Therapeutics of Bronchodilators Revisited

Bronchodilators remain the cornerstone of the treatment of airway disorders such as asthma and chronic obstructive pulmonary disease (COPD). There is therefore considerable interest in understanding how to optimize the use of our existing classes of bronchodilator and in identifying novel classes of bronchodilator drugs. However, new classes of bronchodilator have proved challenging to develop because many of these have no better efficacy than existing classes of bronchodilator and often have unacceptable safety profiles. Recent research has shown that optimization of bronchodilation occurs when both arms of the autonomic nervous system are affected through antagonism of muscarinic receptors to reduce the influence of parasympathetic innervation of the lung and through stimulation of β ₂-adrenoceptors (β ₂-ARs) on airway smooth muscle with β ₂-AR-selective agonists to mimic the sympathetic influence on the lung. This is currently achieved by use of fixed-dose combinations of inhaled long-acting β ₂-adrenoceptor agonists (LABAs) and long-acting muscarinic acetylcholine receptor antagonists (LAMAs). Due to the distinct mechanisms of action of LAMAs and LABAs, the additive/synergistic effects of using these drug classes together has been extensively investigated. More recently, so-called "triple inhalers" containing fixed-dose combinations of both classes of bronchodilator (dual bronchodilation) and an inhaled corticosteroid in the same inhaler have been developed. Furthermore, a number of so-called "bifunctional drugs" having two different primary pharmacological actions in the same molecule are under development. This review discusses recent advancements in knowledge on bronchodilators and bifunctional drugs for the treatment of asthma and COPD. SIGNIFICANCE STATEMENT: Since our last review in 2012, there has been considerable research to identify novel classes of bronchodilator drugs, to further understand how to optimize the use of the existing classes of bronchodilator, and to better understand the role of bifunctional drugs in the treatment of asthma and chronic obstructive pulmonary disease.

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.

Intravenous Magnesium in Asthma Pharmacotherapy: Variability in Use in the PECARN Registry

OBJECTIVE

To examine the use, efficacy, and safety of intravenous magnesium sulfate (IVMg) in children with asthma whose emergency department (ED) management is recorded in the Pediatric Emergency Care Applied Research Network (PECARN) Registry.

STUDY DESIGN

This multicenter retrospective cohort study analyzed clinical data from 7 EDs from 2012 to 2017. We described use of IVMg in children aged 2-17 years treated for acute asthma and its effect on blood pressure. We also used multivariable analysis to examine factors associated with use of IVMg and its association with return visits within 72 hours.

RESULTS

Across 61 854 asthma visits for children, clinicians administered IVMg in 6497 (10.5%). Median time from triage to IVMg administration was 154 minutes (IQR 84, 244). During 22 495 ED visits resulting in hospitalization after ED treatment, IVMg was administered in 5774 (25.7%) (range by site 15.9%, 50.6%). Patients were discharged home from the ED after 11.1% of IVMg administrations, and hypotension occurred after 6.8%. Variation in IVMg use was not explained by patient characteristics. Revisits did not differ between patients discharged after IVMg and those not receiving IVMg.

CONCLUSIONS

In PECARN Registry EDs, administration of IVMg occurs late in ED treatment, for a minority of the children likely to benefit, with variation between sites, which suggests the current clinical role for IVMg in preventing hospitalization is limited. Discharge after IVMg administration is likely safe. Further research should prospectively assess the efficacy and safety of early IVMg administration.

Acute severe paediatric asthma: study protocol for the development of a core outcome set, a Pediatric Emergency Reserarch Networks (PERN) study

BACKGROUND

Acute severe childhood asthma is an infrequent, but potentially life-threatening emergency condition. There is a wide range of different approaches to this condition, with very little supporting evidence, leading to significant variation in practice. To improve knowledge in this area, there must first be consensus on how to conduct clinical trials, so that valid comparisons can be made between future studies. We have formed an international working group comprising paediatricians and emergency physicians from North America, Europe, Asia, the Middle East, Africa, South America, Central America, Australasia and the United Kingdom.

METHODS/DESIGN

A 5-stage approach will be used: (1) a comprehensive list of outcomes relevant to stakeholders will be compiled through systematic reviews and qualitative interviews with patients, families, and clinicians; (2) Delphi methodology will be applied to reduce the comprehensive list to a core outcome set; (3) we will review current clinical practice guidelines, existing clinical trials, and literature on bedside assessment of asthma severity. We will then identify practice differences in tne clinical assessment of asthma severity, and determine whether further prospective work is needed to achieve agreement on inclusion criteria for clinical trials in acute paediatric asthma in the emergency department (ED) setting; (4) a retrospective chart review in Australia and New Zealand will identify the incidence of serious clinical complications such as intubation, ICU admission, and death in children hospitalized with acute severe asthma. Understanding the incidence of such outcomes will allow us to understand how common (and therefore how feasible) particular outcomes are in asthma in the ED setting; and finally (5) a meeting of the Pediatric Emergency Research Networks (PERN) asthma working group will be held, with invitation of other clinicians interested in acute asthma research, and patients/families. The group will be asked to achieve consensus on a core set of outcomes and to make recommendations for the conduct of clinical trials in acute severe asthma. If this is not possible, the group will agree on a series of prioritized steps to achieve this aim.

DISCUSSION

The development of an international consensus on core outcomes is an important first step towards the development of consensus guidelines and standardised protocols for randomized controlled trials (RCTs) in this population. This will enable us to better interpret and compare future studies, reduce risks of study heterogeneity and outcome reporting bias, and improve the evidence base for the management of this important condition.

Variability of outcome measures in trials of intravenous therapy in acute severe paediatric asthma: a systematic review

OBJECTIVE

To determine the variability of primary and secondary outcomes used in trials of intravenous bronchodilators in children with acute severe paediatric asthma.

METHODS

Systematic search of MEDLINE, EMBASE, Cochrane CENTRAL and the WHO International Clinical Trials Registry Platform for randomised trials in children (less than18 years) with acute severe paediatric asthma comparing intravenous bronchodilator therapy to another treatment. Initial search was performed on 7 January 2016 with an updated search performed on 6 September 2018. Primary and secondary outcomes were collated.

RESULTS

We identified 35 published papers and four registered study protocols. 56 primary outcomes were found, the most common being a clinical asthma score (23/56; 41%). Other identified primary outcomes included bedside tests of respiratory function (11/56; 20%) and measures of length of stay (9/56; 16%). There were a total of 60 different secondary outcomes, the most common were various length of stay measures (24/60; 40%) and adverse events (11/60; 18%).

CONCLUSION

Studies comparing intravenous treatment modalities for children with acute severe paediatric asthma exhibit great variation in the type, number and timing of outcome measures used. There are no patient or family-specific outcomes reported. There is a need to develop international consensus.

TRIAL REGISTRATION NUMBER

CRD42017055331.

Efficacy and side effects of intravenous theophylline in acute asthma: a systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

Theophylline has been used for decades to treat both acute and chronic asthma. Despite its longevity in the practitioner's formulary, no detailed meta-analysis has been performed to determine the conditions, including concomitant medications, under which theophylline should be used for acute exacerbations of asthma. We aimed to quantify the usefulness and side effects of theophylline with or without ethylene diamine (aminophylline) in acute asthma, with particular emphasis on patient subgroups, such as children, adults, and concomitant medications.

METHODS

We searched PubMed, EMBASE, The Cochrane Library, ClinicalTrials.gov, and the WHO Clinical Trials Registry for randomized, controlled clinical trials. We planned a priori subgroup analyses by time post-medication, concomitant medication, control type, and age.

RESULTS

We included 52 study arms from 42 individual trials. Of these, 29 study arms included an active control, such as adrenaline, beta-2 agonists, or leukotriene receptor antagonists, and 23 study arms compared theophylline (with or without ethylene diamine) with placebo or no drug. Theophylline significantly reduced heart rate when compared with active control (p=0.01) and overall duration of stay (p=0.002), but beta-2 agonists were superior to theophylline at improving forced expiratory volume in one second (FEV1) (p=0.002). Theophylline was not significantly different from other drugs in its effects on respiratory rate, forced vital capacity (FVC), peak expiratory flow rate, admission rate, use of rescue medication, oxygen saturation, or symptom score. Closer examination of the data revealed that the medications given in addition to theophylline or control significantly changed the effectiveness of theophylline (subgroup difference: p<0.00001).

CONCLUSION

Given the low cost of theophylline, and its similar efficacy and rate of side effects compared with other drugs, we suggest that theophylline, when given with bronchodilators with or without steroids, is a cost-effective and safe choice for acute asthma exacerbations.

Optimizing the Dosing of Intravenous Theophylline in Acute Severe Asthma in Children

Optimizing the management of children presenting with acute severe asthma is of utmost importance to minimize hospital stays, morbidity, and mortality. Intravenous medications, including theophyllines, are used as second-line treatments for children experiencing a life-threatening exacerbation. For intravenous theophylline (aminophylline), guidelines and formularies recommend a target therapeutic range between 10 and 20 mg/l, with the commonest regimen being a loading dose of 5 mg/kg followed by an infusion calculated by age and weight. This review assesses the evidence underpinning these recommendations, highlighting the shortcomings in our understanding of the association between serum concentrations achieved, dose given, and clinical improvement experienced. To close the knowledge gap and improve outcomes for children presenting with acute severe asthma, we propose a series of research strategies to improve the assessment of illness severity, ascertain the optimal dose to maximize benefit and minimize risk, prospectively collect adverse events, and to better understand the inter-individual variation in responses to treatments.

Quantitation of salbutamol using micro-volume blood sampling - applications to exacerbations of pediatric asthma

OBJECTIVES

A novel gas chromatography-mass spectrometry (GC-MS) method has been developed to quantify salbutamol in micro-volumes (10 µL) of blood. A potential application is paediatric therapeutic dose monitoring (TDM) in acute severe asthma.

METHODS

At presentation, the children receive multiple doses of salbutamol (inhaled, nebulised and occasionally intravenous) but it is difficult to distinguish children who do not respond to treatment because of inadequate concentrations from those with toxicity, as symptoms are similar. A comparison was made between traditional dried blood spots (DBS) and the newly developed technique volumetric absorptive micro-sampling (VAMS), with specific investigation into the effect of drying time on analyte recovery.

RESULTS

For both sampling techniques, the final assay demonstrated good precision and accuracy across the concentration range tested (3-100 ng/mL), including both the normal therapeutic and toxic range. The method was developed to comply with FDA guidelines with precision and accuracy ≤15% for all concentrations, except the limit of quantification (5 ng/mL) where they were ≤20%. VAMS offered advantages in sampling ease and reduced GC-MS interference. The assay was successfully applied to the quantification of blood salbutamol concentrations in three healthy volunteers dosed with 1 mg salbutamol by inhalation.

CONCLUSIONS

This demonstrated its potential for use in paediatric TDM studies, where in the acute situation considerably higher doses of salbutamol will have been administered. This is the first time that a TDM method for salbutamol has been carried out using VAMS and offers all the advantages provided by DBS, whilst eliminating the inherent sampling volume inaccuracies of traditional DBS collection.

Magnesium sulfate infusion for acute asthma in the emergency department

OBJECTIVES

To describe the role of intravenous magnesium sulfate (MgSO₄) as therapy for acute severe asthma in the pediatric emergency department (ED).

SOURCE

Publications were searched in the PubMed and Cochrane databases using the following keywords: magnesium AND asthma AND children AND clinical trial. A total of 53 publications were retrieved using this criteria. References of relevant articles were also screened. The authors included the summary of relevant publications where intravenous magnesium sulfate was studied in children (age <18 years) with acute asthma. The NAEPP and Global Initiative for Asthma expert panel guidelines were also reviewed.

SUMMARY OF THE DATA

There is a large variability in the ED practices on the intravenous administration of MgSO₄ for severe asthma. The pharmacokinetics of MgSO₄ is often not taken into account with a consequent impact in its pharmacodynamics properties. The cumulative evidence points to the effectiveness of intravenous MgSO₄ in preventing hospitalization, if utilized in a timely manner and at an appropriate dosage (50-75mg/kg). For every five children treated in the ED, one hospital admission could be prevented. Another administration modality is a high-dose continuous magnesium sulfate infusion (HDMI) as 50mg/kg/h/4h (200mg/kg/4h). The early utilization of HDMI for non-infectious mediated asthma may be superior to a MgSO₄ bolus in avoiding admissions and expediting discharges from the ED. HDMI appears to be cost-effective if applied early to a selected population. Intravenous MgSO₄ has a similar safety profile than other asthma therapies.

CONCLUSIONS

Treatment with intravenous MgSO₄ reduces the odds of hospital admissions. The use of intravenous MgSO₄ in the emergency room was not associated with significant side effects or harm. The authors emphasize the role of MgSO₄ as an adjunctive therapy, while corticosteroids and beta agonist remain the primary acute therapeutic agents.

PREDICT prioritisation study: establishing the research priorities of paediatric emergency medicine physicians in Australia and New Zealand

BACKGROUND

The Paediatric Research in Emergency Departments International Collaborative (PREDICT) performs multicentre research in Australia and New Zealand. Research priorities are difficult to determine, often relying on individual interests or prior work.

OBJECTIVE

To identify the research priorities of paediatric emergency medicine (PEM) specialists working in Australia and New Zealand.

METHODS

Online surveys were administered in a two-stage, modified Delphi study. Eligible participants were PEM specialists (consultants and senior advanced trainees in PEM from 14 PREDICT sites). Participants submitted up to 3 of their most important research questions (survey 1). Responses were collated and refined, then a shortlist of refined questions was returned to participants for prioritisation (survey 2). A further prioritisation exercise was carried out at a PREDICT meeting using the Hanlon Process of Prioritisation. This determined the priorities of active researchers in PEM including an emphasis on the feasibility of a research question.

RESULTS

One hundred and six of 254 (42%) eligible participants responded to survey 1 and 142/245 (58%) to survey 2. One hundred and sixty-eight (66%) took part in either or both surveys. Two hundred forty-six individual research questions were submitted in survey 1. Survey 2 established a prioritised list of 35 research questions. Priority topics from both the Delphi and Hanlon process included high flow oxygenation in intubation, fluid volume resuscitation in sepsis, imaging in cervical spine injury, intravenous therapy for asthma and vasopressor use in sepsis.

CONCLUSION

This prioritisation process has established a list of research questions, which will inform multicentre PEM research in Australia and New Zealand. It has also emphasised the importance of the translation of new knowledge.

Using pharmacokinetic modelling to improve prescribing practices of intravenous aminophylline in childhood asthma exacerbations

OBJECTIVE

To evaluate physiologically based pharmacokinetic modelling (PBPK) software in paediatric asthma patients using intravenous aminophylline.

METHODS

Prospective clinical audit of children receiving iv aminophylline (July 2014 to June 2016), and in-silico modelling using Simcyp software.

RESULTS

Thirty-eight admissions (25 children) were included. Children with aminophylline levels ≥10 mg/l had equivalent clinical outcomes compared to those <10 mg/L, and adverse effects occurred in 57%. Therapeutic drug monitoring (TDM) data correlated well with PBPK model. PBPK modelling of a 5 mg/kg iv loading dose (≤18yr) shows a mean C_max of 8.99 mg/L (5th-95th centiles 5.5-13.7 mg/L), with 70.3% of subjects <10 mg/L, 29.4% achieving 10-20 mg/L, and 0.1% > 20 mg/L. For an aminophylline infusion (0-12 y) of 1.0  mg/kg/h, the mean steady state infusion concentration was 16.4 mg/L, (5th-95th centiles 5.3-32 mg/L), with 26.8% having a serum concentration >20 mg/L. For 12-18yr receiving 0.5  mg/kg/h infusion, the mean steady state infusion concentration was 9.37 mg/L (5th-95th centiles 3.4-18 mg/L), with 59.8% having a serum concentration <10 mg/L.

CONCLUSION

PBPK software modelling correlates well with clinical data. Current aminophylline iv loading dosage recommendations achieve levels <10 mg/l in 70% of children. Routine TDM may need altering as low risk of toxicity (>20 mg/l).

Aminophylline Dosage In Asthma Exacerbations in Children: A Systematic Review

BACKGROUND

Adequate asthma treatment of childhood exacerbations with IV aminophylline depends on appropriate dosage. Recommendations to aim for a target therapeutic range may be inappropriate as serum concentrations correlate poorly with clinical improvement. This review aims to evaluate the evidence for the optimum dosage strategy of intravenous aminophylline in children suffering an exacerbation of asthma.

METHODS

A systematic review comparing dosage regimens of intravenous aminophylline in children suffering an exacerbation of asthma. Primary outcomes were time until resolution of symptoms, mortality and need for mechanical ventilation. Secondary outcomes were date until discharge criteria are met, actual discharge and adverse effects.

DATA SOURCES

CENTRAL, CINAHL, MEDLINE and Web of Science. Search performed in March 2016.

ELIGIBILITY CRITERIA

Studies using intravenous aminophylline in children with an acute exacerbation of asthma which reported the dosage and clinical outcomes.

FINDINGS

14 RCTs were included. There is a poor relationship between the dosage administered to children and symptom resolution, length of stay or need for mechanical ventilation. This study is limited due to its use of indirect evidence.

CONCLUSION

The currently recommended dosage regimens may not represent the optimum safety and efficacy of intravenous aminophylline. There is a need to develop the evidence base correlating dosage with patient centered clinical outcomes, to improve prescribing practices.

Acute severe asthma

Acute exacerbations of asthma are very common reasons for a presentation to emergency departments. This paper focuses on defining the high-risk group, consideration of the concept of phenotypes of acute asthma, the assessment of severe and life-threatening exacerbations and an emphasis on the management of the more severe end of the exacerbation severity. A number of evidence-based guidelines exist throughout the world and are all slightly different. This reflects the poor evidence base for some of those recommendations. Thus, a large variation of treatment drugs, doses and regimen are used and clearly not standardised. This paper aims to present a summary of the best evidence and discuss some of these controversies. The most important aspect of treating an exacerbation of acute asthma is to review regularly and assess response to treatment. Severe and life-threatening episodes should be treated with early use of intravenous treatment in a stepwise manner following the local guidelines. Non-invasive ventilation and high flow nasal cannulae delivery of oxygen in the emergency department are evolving modalities, but evidence for their use is currently limited.

Survey of physicians' attitudes toward the use of magnesium sulfate for acute asthma exacerbations in Turkey

BACKGROUND

Magnesium sulfate (MgSO4) is considered to be a well-tolerated, inexpensive, and effective medication for severe asthma exacerbations. We surveyed physicians who treat patients with asthma to evaluate the current knowledge and usage of MgSO4.

METHODS

A self-administered questionnaire was e-mailed to members of the Turkish National Society of Allergy and Clinical Immunology and was distributed to participants of its annual congress.

RESULTS

Of the 456 respondents (mean age: 36.53 ± 9.11 years), 42.3% reported to use MgSO4 in asthma exacerbations in their practice, and 48.7% agreed that MgSO4 was included in asthma guidelines. The best known indication was that it was useful only in patients refractory to bronchodilators and systemic corticosteroids (67.7%). The two most common reasons to use MgSO4 were to shorten hospital stay (94.7%), and prevent admission to intensive care unit (80.3%). The respondents mostly used MgSO4 in the treatment of severe or life-threatening exacerbations. Thirty-nine percent believed that MgSO4 had no effect on discharge period, and 29% of them marked minor side effects. The most common reason for not using MgSO4 was inexperience (36.5%). Having an academic affiliation (OR = 3.20, p < 0.001), the number of asthmatic outpatients seen per month (OR = 1.82, p = 0.007), and more recent graduation from medical school (≤1991) (OR = 0.23, p < 0.001) were associated with the use of MgSO4 in the multivariate analysis.

CONCLUSION

Even though the effect of MgSO4 in acute severe asthma is well known, only half of the physicians dealing with asthma patients have used it in their practice. Education and encouragement in this regard are necessary.

Asthma changes at a pediatric intensive care unit after 10 years: Observational study

OBJECTIVES:

To describe the change in the management, and outcome of children with acute severe asthma (ASA) admitted to Pediatric Intensive Care Unit (PICU) at tertiary institute, as compared to previously published report in 2003.

METHODS:

This is a retrospective observational study. All consecutive pediatric ASA patients who were admitted to PICU during the study period were included. The data were extracted from PICU database and medical records. The Cohort in this study (2013 Cohort) was compared with the Cohort of ASA, which was published in 2003 from the same institution (2003 Cohort).

RESULTS:

In comparison to previous 2003 Cohort, current Cohort (2013) revealed higher mean age (5.5 vs. 3.6 years; P ≤ 0.001), higher rate of PICU admission (20.3% vs. 3.6%; P ≤ 0.007), less patients who received maintenance inhaled steroids (43.3% vs. 62.4%; P ≤ 0.03), less patients with pH <7.3 (17.9% vs. 42.9%; P ≤ 0.001). There were more patients in 2013 Cohort who received: Inhaled Ipratropium bromide (97% vs. 68%; P ≤ 0.001), intravenous magnesium sulfate (68.2% vs. none), intravenous salbutamol (13.6% vs. 3.6%; P ≤ 0.015), and noninvasive ventilation (NIV) (35.8% vs. none) while no patients were treated with theophylline (none vs. 62.5%). The median length of stay (LOS) was 2 days while mean LOS was half a day longer in the 2013 Cohort. None of our patients required intubation, and there was no mortality.

CONCLUSION:

We observed slight shift toward older age, considerably increased the rate of PICU admission, increased utilization of Ipratropium bromide, magnesium sulfate, and NIV as important modalities of treatment.

Establishing the research priorities of paediatric emergency medicine clinicians in the UK and Ireland

OBJECTIVE

Paediatric Emergency Research in the UK and Ireland (PERUKI) is a collaborative clinical studies group established in August 2012. It consists of a network of 43 centres from England, Ireland, Northern Ireland, Scotland and Wales, and aims to improve the emergency care of children through the performance of robust collaborative multicentre research within emergency departments. A study was conducted regarding the research priorities of PERUKI, to establish the research agenda for paediatric emergency medicine in the UK and Ireland.

METHODS

A two-stage modified Delphi survey was conducted of PERUKI members via an online survey platform. Stage 1 allowed each member to submit up to 12 individual questions that they identified as priorities for future research. In stage 2, the shortlisted questions were each rated on a seven-point Likert scale of relative importance.

PARTICIPANTS

Members of PERUKI, including clinical specialists, academics, trainees and research nurses.

RESULTS

Stage 1 surveys were submitted by 46/91 PERUKI members (51%). A total of 249 research questions were generated and, following the removal of duplicate questions and shortlisting, 60 questions were carried forward for stage 2 ranking. Stage 2 survey responses were submitted by 58/95 members (61%). For the 60 research questions that were rated, the mean score of 'relative degree of importance' was 4.70 (range 3.36-5.62, SD 0.55). After ranking, the top 10 research priorities included questions on biomarkers for serious bacterial illness, major trauma, intravenous bronchodilators for asthma and decision rules for fever with petechiae, head injury and atraumatic limp.

CONCLUSIONS

Research priorities of PERUKI members have been identified. By sharing these results with clinicians, academics and funding bodies, future research efforts can be focused to the areas of greatest need.