Intravenous or nebulised magnesium sulphate versus standard therapy for severe acute asthma (3Mg trial): a double-blind, randomised controlled trial

Invasive Respiratory Support in Critical Pediatric Asthma

In the United States and Canada, severe asthma requiring mechanical ventilation has declined over the past decade reflecting a rise in noninvasive therapies. When aggressive noninvasive therapies fail, endotracheal intubation and mechanical ventilation are lifesaving and should be planned for in advance. As speed is important, the most experienced practitioner should intubate and rapid correction of hypercarbia and respiratory acidosis should be avoided. An elevated minute ventilation may cause pulmonary hyperinflation leading to air-leak syndrome and/or hemodynamic instability. Patients with severe air flow obstruction in asthma typically have near-normal respiratory system compliance. Therefore, an increase in plateau pressure (Pplat) usually reflects dynamic hyperinflation. A suggested upper limit for Pplat is 25-30 cm H2O. Intrinsic PEEP (PEEPi) is measured with an expiratory hold and is valuable in that PEEP set on the ventilator can be lower than PEEPi. A reasonable ventilation strategy involving low ventilator rates and PEEP without quick correction of blood gases should be adopted. Alternative modalities to conventional mechanical ventilation are limited and unless very experienced with high-frequency oscillatory ventilation, the risk likely outweighs benefit. Heliox may be beneficial but cannot be delivered by every ventilator and this varies by manufacturer. Inhaled anesthetics are direct bronchodilators and likely beneficial but as no conventional ICU ventilator can deliver them, close cooperation with Anesthesiology is needed. Extracorporeal membrane oxygenation (ECMO) is a rescue therapy that is particularly useful in cases of severe air-leak syndrome. As with mechanical ventilation, ECMO does not reverse the asthma disease process but allows support of the patient until there is improvement with other therapies. Most children who die experience cardiac arrest prior to hospitalization. Otherwise, most mechanically ventilated children survive to hospital discharge but there is a suggestion of additional mortality from asthma in the following decade.

Albumin Versus Balanced Crystalloid for the Early Resuscitation of Sepsis: An Open Parallel-Group Randomized Feasibility Trial- The ABC-Sepsis Trial

OBJECTIVES

International guidelines recommend IV crystalloid as the primary fluid for sepsis resuscitation, with 5% human albumin solution (HAS) as the second line. However, it is unclear which fluid has superior clinical effectiveness. We conducted a trial to assess the feasibility of delivering a randomized controlled trial comparing balanced crystalloid against 5% HAS as sole early resuscitation fluid in patients with sepsis presenting to hospital.

DESIGN

Multicenter, open, parallel-group randomized feasibility trial.

SETTING

Emergency departments (EDs) in 15 U.K. National Health Service (NHS) hospitals.

PATIENTS

Adult patients with sepsis and a National Early Warning Score 2 greater than or equal to five requiring IV fluids withing one hour of randomization.

INTERVENTIONS

IV fluid resuscitation with balanced crystalloid or 5% HAS for the first 6 hours following randomization.

MEASUREMENTS AND MAIN RESULTS

Primary feasibility outcomes were recruitment rate and 30-day mortality. We successfully recruited 301 participants over 12 months. Mean ( sd ) age was 69 years (± 16 yr), and 151 (50%) were male. From 1303 participants screened; 502 participants were potentially eligible and 300 randomized to receive trial intervention with greater than 95% of participants receiving the intervention. The median number of participants per site was 19 (range, 1-63). Thirty-day mortality was 17.9% ( n = 53). Thirty-one participants died (21.1%) within 30 days in the 5% HAS arm, compared with 22 participants (14.8%) in the crystalloid arm (adjusted odds ratio, 1.50; 95% CIs, 0.84-2.83).

CONCLUSIONS

Our results suggest it is feasible to recruit critically ill patients to a fluid resuscitation trial in U.K. EDs using 5% HAS as a primary resuscitation fluid. There was lower mortality in the balanced crystalloid arm. Given these findings, a definitive trial is likely to be deliverable, but the point estimates suggest such a trial would be unlikely to demonstrate a significant benefit from using 5% HAS as a primary resuscitation fluid in sepsis.

The role of magnesium in cardiac arrest

Cardiac arrest is a leading cause of death globally. Only 25.8% of in-hospital and 33.5% of out-of-hospital individuals who achieve spontaneous circulation following cardiac arrest survive to leave the hospital. Respiratory failure and acute coronary syndrome are the two most common etiologies of cardiac arrest. Effort has been made to improve the outcomes of individuals resuscitated from cardiac arrest. Magnesium is an ion that is critical to the function of all cells and organs. It is often overlooked in everyday clinical practice. At present, there have only been a small number of reviews discussing the role of magnesium in cardiac arrest. In this review, for the first time, we provide a comprehensive overview of magnesium research in cardiac arrest focusing on the effects of magnesium on the occurrence and prognosis of cardiac arrest, as well as in the two main diseases causing cardiac arrest, respiratory failure and acute coronary syndrome. The current findings support the view that magnesium disorder is associated with increased risk of cardiac arrest as well as respiratory failure and acute coronary syndrome.

Magnesium Is a Vital Ion in the Body-It Is Time to Consider Its Supplementation on a Routine Basis

The importance of maintaining proper magnesium intake and total body magnesium content in preserving human health remains underappreciated among medical professionals and laymen. This review aimed to show the importance of hypomagnesemia as a modifiable risk factor for developing disease processes. We searched the PubMed database and Google Scholar using the keywords 'magnesium', 'diabetes', 'cardiovascular disease', 'respiratory disease', 'immune system', 'inflammation', 'autoimmune disease', 'neurology', 'psychiatry', 'cognitive function', 'cancer', and 'vascular calcification'. In multiple contexts of the search terms, all reviews, animal experiments, and human observational data indicated that magnesium deficiency can lead to or contribute to developing many disease states. The conclusions of several in-depth reviews support our working hypothesis that magnesium and its supplementation are often undervalued and underutilized. Although much research has confirmed the importance of proper magnesium supply and tissue levels, simple and inexpensive magnesium supplementation has not yet been sufficiently recognized or promoted.

Nebulized medications in the emergency department: A narrative review of nontraditional agents

PURPOSE

This article summarizes emerging nontraditional therapies administered via the nebulization route for use in the emergency department (ED).

SUMMARY

Although traditional routes of medication administration (eg, intravenous) have been the mainstay of administration modalities for decades, these routes may not be appropriate for all patients. Nowhere is this more readily apparent than in the ED setting, where patients with a variety of presentations receive care. One unique route for medication administration that has increasingly gained popularity in the ED is that of aerosolized drug delivery. This route holds promise as direct delivery of medications to the site of action could yield a more rapid and effective therapeutic response while also minimizing systemic adverse effects by utilizing a fraction of the systemic dose. Medication administration via nebulization also provides an alternative that is conducive to rapid, less invasive access, which is advantageous in the emergent setting of the ED. This review is intended to analyze the existing literature regarding this route of administration, including the nuances that can impact drug efficacy, as well as the available literature regarding novel, noncommercial nebulized medication therapy given in the ED.

CONCLUSION

Multiple medications have been investigated for administration via this route, and when implementing any of these therapies several practical considerations must be taken into account, from medication preparation to administration, to ensure optimal efficacy while minimizing adverse effects. The pharmacist is an essential bedside team member in these scenarios to assist with navigating unique and complex nuances of this therapy as they develop.

Asthma and COPD: A Focus on β-Agonists - Past, Present and Future

Asthma has been recognised as a respiratory disorder for millennia and the focus of targeted drug development for the last 120 years. Asthma is one of the most common chronic non-communicable diseases worldwide. Chronic obstructive pulmonary disease (COPD), a leading cause of morbidity and mortality worldwide, is caused by exposure to tobacco smoke and other noxious particles and exerts a substantial economic and social burden. This chapter reviews the development of the treatments of asthma and COPD particularly focussing on the β-agonists, from the isolation of adrenaline, through the development of generations of short- and long-acting β-agonists. It reviews asthma death epidemics, considers the intrinsic efficacy of clinical compounds, and charts the improvement in selectivity and duration of action that has led to our current medications. Important β2-agonist compounds no longer used are considered, including some with additional properties, and how the different pharmacological properties of current β2-agonists underpin their different places in treatment guidelines. Finally, it concludes with a look forward to future developments that could improve the β-agonists still further, including extending their availability to areas of the world with less readily accessible healthcare.

Role of Magnesium in the Intensive Care Unit and Immunomodulation: A Literature Review

Both the role and the importance of magnesium in clinical practice have grown considerably in recent years. Emerging evidence suggests an association between loss of magnesium homeostasis and increased mortality in the critical care setting. The underlying mechanism is still unclear, but an increasing number of in vivo and in vitro studies on magnesium's immunomodulating capabilities may shed some light on the matter. This review aims to discuss the evidence behind magnesium homeostasis in critically ill patients, and its link with intensive care unit mortality via a likely magnesium-induced dysregulation of the immune response. The underlying pathogenetic mechanisms, and their implications for clinical outcomes, are discussed. The available evidence strongly supports the crucial role of magnesium in immune system regulation and inflammatory response. The loss of magnesium homeostasis has been associated with an elevated risk of bacterial infections, exacerbated sepsis progression, and detrimental effects on the cardiac, respiratory, neurological, and renal systems, ultimately leading to increased mortality. However, magnesium supplementation has been shown to be beneficial in these conditions, highlighting the importance of maintaining adequate magnesium levels in the intensive care setting.

Safety and Effectiveness of Magnesium Sulphate for Severe Acute Asthma Management Among Under-five Children: Systematic Review and Meta-analysis

Background

Asthma is the common chronic inflammatory disease affecting children. It is usually associated with airway hyper-responsiveness. Globally, the prevalence of asthma among pediatrics population varies from 10% to 30%. Its symptoms range from chronic cough to life-threatening bronchospasm. At emergency department, all patients with acute severe asthma should initially receive oxygen, nebulized β2-agonists, nebulized anticholinergic agent, and corticosteroids. Though bronchodilators act within minutes, corticosteroids may require hours. Magnesium sulphate (MgSO₄) was first considered for treating asthma about 60 years ago. Several case reports were published on its usefulness in decreasing admission and endotracheal intubation. So far, evidence is conflicting to fully employ MgSO₄ for asthma management in children under five.

Objective

This systematic review was aimed to evaluate the effectiveness and safety of MgSO₄ in the treatment of severe acute asthmatic attacks in children.

Methods

A systematic and comprehensive search of literature was performed to identify controlled clinical trials conducted on IV and nebulized MgSO₄ in pediatric patients with acute asthma.

Results

Data generated from three randomized clinical trials were included in the final analysis. In this analysis, intravenous MgSO₄ did not improve respiratory function (RR=1.09, 95%CI: 0.81-1.45) and not safer than conventional treatment (RR=0.38, 95%CI: 0.08-1.67). Similarly, use of nebulized MgSO₄ showed no significant effect on respiratory function (RR=1.05, 95%CI: 0.68-1.64) and more tolerable (RR=0.31, 95%CI: 0.14-0.68).

Conclusion

Intravenous MgSO₄ may not be superior to conventional treatment in moderate to severe acute asthma among children and neither have significant adverse effects. Similarly, nebulized MgSO₄ showed no significant effect on respiratory function in moderate to severe acute asthma in children under five but it seems a safer alternative.

Salbutamol for analgesia in renal colic: study protocol for a prospective, randomised, placebo-controlled phase II trial (SARC)

BACKGROUND

Renal colic is the pain experienced by a patient when a renal calculus (kidney stone) causes partial or complete obstruction of part of the renal outflow tract. The standard analgesic regimes for renal colic are often ineffective; in some studies, less than half of patients achieve complete pain relief, and a large proportion of patients require rescue analgesia within 4 h. Current analgesic regimes are also associated with significant side effects including nausea, vomiting, drowsiness and respiratory depression. It has been hypothesised that beta adrenoreceptor agonists, such as salbutamol, may reduce the pain of renal colic. They have been shown to impact a number of factors that target the physiological causes of pain in renal colic (ureteric spasm and increased peristalsis, increased pressure at the renal pelvis and prostaglandin release with inflammation). There is biological plausibility and a body of evidence sufficient to suggest that this novel treatment for the pain of renal colic should be taken to a phase II clinical trial. The aim of this trial is to test whether salbutamol is an efficacious analgesic adjunct when added to the standard analgesic regime for patients presenting to the ED with subsequently confirmed renal colic.

METHODS

A phase II, randomised, placebo-controlled trial will be performed in an acute NHS Trust in the East Midlands. Patients presenting to the emergency department with pain requiring IV analgesia and working diagnosis of renal colic will be randomised to receive standard analgesia ± a single intravenous injection of Salbutamol. Secondary study objectives will explore the feasibility of conducting a larger, phase III trial.

DISCUSSION

The trial will provide important information about the efficacy of salbutamol as an analgesic adjunct in renal colic. It will also guide the development of a definitive phase III trial to test the cost and clinical effectiveness of salbutamol as an analgesic adjunct in renal colic. Salbutamol benefits from widespread use across the health service for multiple indications, extensive staff familiarity and a good side effect profile; therefore, its potential use for pain relief may have significant benefits for patient care.

TRIAL REGISTRATION

ISRCTN Registry ISRCTN14552440 . Registered on 22 July 2019.

Omalizumab: An Optimal Choice for Patients with Severe Allergic Asthma

Omalizumab is the first monoclonal antibody that was globally approved as a personalized treatment option for patients with moderate-to-severe allergic asthma. This review summarizes the knowledge of almost two decades of use of omalizumab to answer some important everyday clinical practice questions, concerning its efficacy and safety and its association with other asthma-related and drug-related parameters. Evidence suggests that omalizumab improves asthma control and reduces the incidence and frequency of exacerbations in patients with severe allergic asthma. Omalizumab is also effective in those patients in reducing corticosteroid use and healthcare utilization, while it also seems to improve lung function. Several biomarkers have been recognized in predicting its efficacy in its target group of patients, while the optimal duration for evaluating its efficacy is between 16 and 32 weeks.

Management of Asthma Exacerbations in the Emergency Department

Asthma exacerbations occur across a wide spectrum of chronic severity; they contribute to millions of emergency department (ED) visits in both children and adults every year. Management of asthma exacerbations is an important part of the continuum of asthma care. The best strategy for ED management of an asthma exacerbation is early recognition and intervention, continuous monitoring, appropriate disposition, and, once improved, multifaceted transitional care that optimizes subacute and chronic asthma management after ED discharge. This article concisely reviews ED evaluation, treatment, disposition, and postdischarge care for patients with asthma exacerbations, based on high-quality evidence (eg, systematic reviews from the Cochrane Collaboration) and current international guidelines (eg, the National Asthma Education and Prevention Program Expert Panel Report 3, Global Initiative for Asthma, and Australian guidelines). Special populations (young children, pregnant women, and the elderly) also are addressed. Despite advances in asthma science, there remain many important evidence gaps in managing ED patients with asthma exacerbation. This article summarizes several of these controversial areas and challenges that merit further investigation.

Difficulty Ventilating: A Case Report on Ventilation Considerations of an Intubated Asthmatic Undergoing Air Medical Critical Care Transport

The air medical transport of intubated patients is a high-risk mission that requires preplanning before helicopter launch. This case describes a scenario in which the helicopter emergency medical services (HEMS) team was unable to ventilate a patient because of the mechanical limitations of the transport ventilator. The HEMS mission was ultimately aborted, and the patient had to be transported by a ground crew equipped with a hospital-based ventilator. In addition to the optimal medical management of the patient in status asthmaticus, critical care transport crews must be familiar with the treatment of patients exhibiting extremely high peak airway pressures. Specifically, ventilator manipulations as well as the technical specifications of the transport ventilator may preclude the patient from being transported by the HEMS team. It is imperative that the patient's current ventilator setting be evaluated before the launch of the aircraft to prevent any possible delays in patient care.

Magnesium sulphate for treating acute bronchiolitis in children up to two years of age

BACKGROUND

Acute bronchiolitis is a significant burden on children, their families and healthcare facilities. It mostly affects children younger than two years of age. Treatment involves adequate hydration, humidified oxygen supplementation, and nebulisation of medications, such as salbutamol, epinephrine, and hypertonic saline. The effectiveness of magnesium sulphate for acute bronchiolitis is unclear.

OBJECTIVES

To assess the effects of magnesium sulphate in acute bronchiolitis in children up to two years of age.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, LILACS, CINAHL, and two trials registries to 30 April 2020. We contacted trial authors to identify additional studies. We searched conference proceedings and reference lists of retrieved articles. Unpublished and published studies were eligible for inclusion.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs, comparing magnesium sulphate, alone or with another treatment, with placebo or another treatment, in children up to two years old with acute bronchiolitis. Primary outcomes were time to recovery, mortality, and adverse events. Secondary outcomes were duration of hospital stay, clinical severity score at 0 to 24 hours and 25 to 48 hours after treatment, pulmonary function test, hospital readmission within 30 days, duration of mechanical ventilation, and duration of intensive care unit stay.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We used GRADE methods to assess the certainty of the evidence.

MAIN RESULTS

We included four RCTs (564 children). One study received funding from a hospital and one from a university; two studies did not report funding sources. Comparator interventions differed among all four trials. Studies were conducted in Qatar, Turkey, Iran, and India. We assessed two studies to be at an overall low risk of bias, and two to be at unclear risk of bias, overall. The certainty of the evidence for all outcomes and comparisons was very low except for one: hospital re-admission rate within 30 days of discharge for magnesium sulphate versus placebo. None of the studies measured time to recovery, duration of mechanical ventilation, duration of intensive care unit stay, or pulmonary function. There were no events of mortality or adverse effects for magnesium sulphate compared with placebo (1 RCT, 160 children). The effects of magnesium sulphate on clinical severity are uncertain (at 0 to 24 hours: mean difference (MD) on the Wang score 0.13, 95% confidence interval (CI) -0.28 to 0.54; and at 25 to 48 hours: MD on the Wang score -0.42, 95% CI -0.84 to -0.00). Magnesium sulphate may increase hospital re-admission rate within 30 days of discharge (risk ratio (RR) 3.16, 95% CI 1.20 to 8.27; 158 children; low-certainty evidence). None of our primary outcomes were measured for magnesium sulphate compared with hypertonic saline (1 RCT, 220 children). Effects were uncertain on the duration of hospital stay in days (MD 0.00, 95% CI -0.28 to 0.28), and on clinical severity on the Respiratory Distress Assessment Instrument (RDAI) score at 25 to 48 hours (MD 0.10, 95% CI -0.39 to 0.59). There were no events of mortality or adverse effects for magnesium sulphate, with or without salbutamol, compared with salbutamol (1 RCT, 57 children). Effects on the duration of hospital stay were uncertain (magnesium sulphate: 24 hours (95% CI 25.8 to 47.4), magnesium sulphate + salbutamol: 20 hours (95% CI 15.3 to 39.0), and salbutamol: 24 hours (95% CI 23.4 to 76.9)). None of our primary outcomes were measured for magnesium sulphate + epinephrine compared with no treatment or normal saline + epinephrine (1 RCT,120 children). Effects were uncertain for the duration of hospital stay in hours (MD -0.40, 95% CI -3.94 to 3.14), and for RDAI scores (0 to 24 hours: MD -0.20, 95% CI -1.06 to 0.66; and 25 to 48 hours: MD -0.90, 95% CI -1.75 to -0.05).

AUTHORS' CONCLUSIONS

There is insufficient evidence to establish the efficacy and safety of magnesium sulphate for treating children up to two years of age with acute bronchiolitis. No evidence was available for time to recovery, duration of mechanical ventilation and intensive care unit stay, or pulmonary function. There was no information about adverse events for some comparisons. Well-designed RCTs to assess the effects of magnesium sulphate for children with acute bronchiolitis are needed. Important outcomes, such as time to recovery and adverse events should be measured.

Intravenous and intramuscular therapy in near fatal asthma. A response to Al-Shamrani

The invited review by Al-Shamrani et al. (2020) [1] failed to address the management of a patient having an asthma attack who arrives in the Emergency Department with respiratory failure or in a moribund condition. The only route available for drug therapy in these patients is intravenously (IV) or intramuscularly in a final attempt to reduce bronchoconstriction. This could avoid tracheal intubation and lung ventilation, or make these procedures safer (Sellers, 2013; Williams et al., 1992) [2,3] for the patient if some bronchodilation occurs. Intubation and ventilation prevent coughing but tenacious mucus remains which blocks the bronchi. There are no randomised controlled trials or national asthma guidelines to inform practice at this stage of the disease, especially in under 18 year olds, so case report evidence, experience, common sense, and pharmacological principles must be engaged to save the patient’s life.

Evaluation and management of the critically ill adult asthmatic in the emergency department setting

INTRODUCTION

Asthma is a common reason for presentation to the Emergency Department and is associated with significant morbidity and mortality. While patients may have a relatively benign course, there is a subset of patients who present in a critical state and require emergent management.

OBJECTIVE

This narrative review provides evidence-based recommendations for the assessment and management of patients with severe asthma.

DISCUSSION

It is important to consider a broad differential diagnosis for the cause and potential mimics of asthma exacerbation. Once the diagnosis is determined, the majority of the assessment is based upon the clinical examination. First line therapies for severe exacerbations include inhaled short-acting beta agonists, inhaled anticholinergics, intravenous steroids, and magnesium. Additional therapies for refractory cases include parenteral epinephrine or terbutaline, helium‑oxygen mixture, and consideration of ketamine. Intravenous fluids should be administered, as many of these patients are dehydrated and at risk for hypotension if they receive positive pressure ventilatory support. Noninvasive positive pressure ventilation may prevent the need for endotracheal intubation. If mechanical ventilation is required, it is important to avoid breath stacking by setting a low respiratory rate and allowing permissive hypercapnia. Patients with severe asthma exacerbations will require intensive care unit admission.

CONCLUSIONS

This review provides evidence-based recommendations for the assessment and management of severe asthma with a focus on the emergency clinician.

Hypomagnesemia in critically ill patients

BACKGROUND

Magnesium (Mg) is essential for life and plays a crucial role in several biochemical and physiological processes in the human body. Hypomagnesemia is common in all hospitalized patients, especially in critically ill patients with coexisting electrolyte abnormalities. Hypomagnesemia may cause severe and potential fatal complications if not timely diagnosed and properly treated, and associate with increased mortality.

MAIN BODY

Mg deficiency in critically ill patients is mainly caused by gastrointestinal and/or renal disorders and may lead to secondary hypokalemia and hypocalcemia, and severe neuromuscular and cardiovascular clinical manifestations. Because of the physical distribution of Mg, there are no readily or easy methods to assess Mg status. However, serum Mg and the Mg tolerance test are most widely used. There are limited studies to guide intermittent therapy of Mg deficiency in critically ill patients, but some empirical guidelines exist. Further clinical trials and critical evaluation of empiric Mg replacement strategies is needed.

CONCLUSION

Patients at risk of Mg deficiency, with typical biochemical findings or clinical symptoms of hypomagnesemia, should be considered for treatment even with serum Mg within the normal range.

Inhaled magnesium sulfate in the treatment of acute asthma

BACKGROUND

Asthma exacerbations can be frequent and range in severity from mild to life-threatening. 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, the role of inhaled MgSO₄ is less clear.

OBJECTIVES

To determine the efficacy and safety of inhaled MgSO₄ administered in acute asthma.

SPECIFIC AIMS

to quantify the effects of inhaled MgSO₄ I) in addition to combination treatment with inhaled β₂-agonist and ipratropium bromide; ii) in addition to inhaled β₂-agonist; and iii) in comparison to inhaled β₂-agonist.

SEARCH METHODS

We identified randomised controlled trials (RCTs) from the Cochrane Airways Group register of trials and online trials registries in September 2017. We supplemented these with searches of the reference lists of published studies and by contact with trialists.

SELECTION CRITERIA

RCTs including adults or children with acute asthma were eligible for inclusion in the review. We included studies if patients were treated with nebulised MgSO₄ alone or in combination with β₂-agonist or ipratropium bromide or both, and were compared with the same co-intervention alone or inactive control.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial selection, data extraction and risk of bias. We made efforts to collect missing data from authors. We present results, with their 95% confidence intervals (CIs), as mean differences (MDs) or standardised mean differences (SMDs) for pulmonary function, clinical severity scores and vital signs; and risk ratios (RRs) for hospital admission. We used risk differences (RDs) to analyse adverse events because events were rare.

MAIN RESULTS

Twenty-five trials (43 references) of varying methodological quality were eligible; they included 2907 randomised patients (2777 patients completed). Nine of the 25 included studies involved adults; four included adult and paediatric patients; eight studies enrolled paediatric patients; and in the remaining four studies the age of participants was not stated. The design, definitions, intervention and outcomes were different in all 25 studies; this heterogeneity made direct comparisons difficult. The quality of the evidence presented ranged from high to very low, with most outcomes graded as low or very low. This was largely due to concerns about the methodological quality of the included studies and imprecision in the pooled effect estimates. Inhaled magnesium sulfate in addition to inhaled β₂-agonist and ipratropiumWe included seven studies in this comparison. Although some individual studies reported improvement in lung function indices favouring the intervention group, results were inconsistent overall and the largest study reporting this outcome found no between-group difference at 60 minutes (MD -0.3 % predicted peak expiratory flow rate (PEFR), 95% CI -2.71% to 2.11%). Admissions to hospital at initial presentation may be reduced by the addition of inhaled magnesium sulfate (RR 0.95, 95% CI 0.91 to 1.00; participants = 1308; studies = 4; I² = 52%) but no difference was detected for re-admissions or escalation of care to ITU/HDU. Serious adverse events during admission were rare. There was no difference between groups for all adverse events during admission (RD 0.01, 95% CI -0.03 to 0.05; participants = 1197; studies = 2). Inhaled magnesium sulfate in addition to inhaled β₂-agonistWe included 13 studies in this comparison. Although some individual studies reported improvement in lung function indices favouring the intervention group, none of the pooled results showed a conclusive benefit as measured by FEV1 or PEFR. Pooled results for hospital admission showed a point estimate that favoured the combination of MgSO₄ and β₂-agonist, but the confidence interval includes the possibility of admissions increasing in the intervention group (RR 0.78, 95% CI 0.52 to 1.15; participants = 375; studies = 6; I² = 0%). There were no serious adverse events reported by any of the included studies and no between-group difference for all adverse events (RD -0.01, 95% CI -0.05 to 0.03; participants = 694; studies = 5). Inhaled magnesium sulfate versus inhaled β₂-agonistWe included four studies in this comparison. The evidence for the efficacy of β₂-agonists in acute asthma is well-established and therefore this could be considered a historical comparison. Two studies reported a benefit of β₂-agonist over MgSO₄ alone for PEFR and two studies reported no difference; we did not pool these results. Admissions to hospital were only reported by one small study and events were rare, leading to an uncertain result. No serious adverse events were reported in any of the studies in this comparison; one small study reported mild to moderate adverse events but the result is imprecise.

AUTHORS' CONCLUSIONS

Treatment with nebulised MgSO₄ may result in modest additional benefits for lung function and hospital admission when added to inhaled β₂-agonists and ipratropium bromide, but our confidence in the evidence is low and there remains substantial uncertainty. The recent large, well-designed trials have generally not demonstrated clinically important benefits. Nebulised MgSO₄ does not appear to be associated with an increase in serious adverse events. Individual studies suggest that those with more severe attacks and attacks of shorter duration may experience a greater benefit but further research into subgroups is warranted.Despite including 24 trials in this review update we were unable to pool data for all outcomes of interest and this has limited the strength of the conclusions reached. A core outcomes set for studies in acute asthma is needed. This is particularly important in paediatric studies where measuring lung function at the time of an exacerbation may not be possible. Placebo-controlled trials in patients not responding to standard maximal treatment, including inhaled β₂-agonists and ipratropium bromide and systemic steroids, may help establish if nebulised MgSO₄ has a role in acute asthma. However, the accumulating evidence suggests that a substantial benefit may be unlikely.

Effects of nebulised magnesium sulphate on inflammation and function of the guinea-pig airway

Magnesium sulphate is a potential treatment for acute severe asthma. However, the mechanisms and dose-response relationships are poorly understood. The first objective of this study was to examine whether inhaled magnesium sulphate exerts bronchodilator activity measured as bronchoprotection against histamine-induced bronchoconstriction in conscious guinea-pigs alone and combined with salbutamol. Secondly, we examined whether inhaled magnesium sulphate inhibits airways inflammation and function in models of neutrophilic and eosinophilic lung inflammation induced, respectively, by inhaled lipopolysaccharide or the inhaled antigen, ovalbumin (OVA). Airway function was measured in conscious guinea-pigs as specific airway conductance (sG_aw) by whole-body plethysmography. Anti-inflammatory activity was measured against lung inflammatory cell influx induced by OVA inhalation in OVA-sensitised animals or by lipopolysaccharide (LPS) exposure of non-sensitised animals. Airway function (sG_aw) was measured over 24h after OVA exposure. Airway hyperresponsiveness to inhaled histamine and inflammatory cells in bronchoalveolar lavage fluid were recorded 24h after OVA or LPS challenge. Histamine-induced bronchoconstriction was inhibited by inhaled magnesium sulphate or salbutamol alone and in combination, they produced synergistic bronchoprotection. LPS-induced neutrophil influx was inhibited by 6 days pretreatment with magnesium sulphate. Early and late asthmatic responses in OVA sensitised and challenged animals were attenuated by magnesium sulphate. Lung inflammatory cells were increased by OVA, macrophages being significantly reduced by magnesium sulphate. Nebulised magnesium sulphate protects against histamine-induced bronchoconstriction in conscious guinea-pigs and exerts anti-inflammatory activity against pulmonary inflammation induced by allergen (OVA) or LPS. These properties of magnesium sulphate explain its beneficial actions in acute asthma.

Using re-randomization to increase the recruitment rate in clinical trials - an assessment of three clinical areas

Background

Patient recruitment in clinical trials is often challenging, and as a result, many trials are stopped early due to insufficient recruitment. The re-randomization design allows patients to be re-enrolled and re-randomized for each new treatment episode that they experience. Because it allows multiple enrollments for each patient, this design has been proposed as a way to increase the recruitment rate in clinical trials. However, it is unknown to what extent recruitment could be increased in practice.

Methods

We modelled the expected recruitment rate for parallel-group and re-randomization trials in different settings based on estimates from real trials and datasets. We considered three clinical areas: in vitro fertilization, severe asthma exacerbations, and acute sickle cell pain crises. We compared the two designs in terms of the expected time to complete recruitment, and the sample size recruited over a fixed recruitment period.

Results

Across the different scenarios we considered, we estimated that re-randomization could reduce the expected time to complete recruitment by between 4 and 22 months (relative reductions of 19% and 45%), or increase the sample size recruited over a fixed recruitment period by between 29% and 171%. Re-randomization can increase recruitment most for trials with a short follow-up period, a long trial recruitment duration, and patients with high rates of treatment episodes.

Conclusions

Re-randomization has the potential to increase the recruitment rate in certain settings, and could lead to quicker and more efficient trials in these scenarios.

Lack of efficacy of nebulized magnesium sulfate in treating adult asthma: A meta-analysis of randomized controlled trials

BACKGROUND

Nebulized magnesium sulfate (MgSO₄) has been used to treat asthma, but the efficacy remains controversial. We aimed to comprehensively review the efficacy of nebulized MgSO₄ in treating adult patients with asthma.

METHODS

PubMed, Embase, and Cochrane Library were searched for relevant studies published up to July 18, 2016. Randomized controlled trials (RCTs) were included if adult patients with acute or stable asthma had been treated with nebulized MgSO₄ compared with placebo or another bronchodilator. Standardized mean differences (SMDs), relative risks (RRs) and 95% confidence intervals (CIs) were calculated. Outcomes included pulmonary function, hospital admission and adverse events.

RESULTS

A total of 1386 patients from sixteen trials (1240 acute asthma patients and 146 stable asthma patients) were subjected to meta-analysis. Compared to placebo as normal saline, whether using in acute or stable adult asthma, nebulized MgSO₄ did not significantly improve the respiratory function: SMD 0.39 (95% CI -0.03-0.82, P = 0.07), and 1.48 (95% CI -0.14-3.11, P = 0.07), respectively. Furthermore, nebulized MgSO₄ did not reduce hospital admission in adult patients with acute asthma (RR, 0.72; 95% CI, 0.52-1.00; P = 0.05), although it was not associated with increased adverse events (RR 1.15; 95% CI, 0.88-1.52; P = 0.31).

CONCLUSIONS

Evidence to date suggests that nebulized MgSO₄ has no role in the management of adult patients with acute or stable asthma.

The efficacy of nebulized magnesium sulfate alone and in combination with salbutamol in acute asthma

Objective

Evaluation of the efficacy of nebulized magnesium sulfate (MgSO₄) alone and in combination with salbutamol in acute asthma.

Methods

A double-blind randomized controlled study was conducted in Chest and Emergency Departments. Thirty patients of acute attack of bronchial asthma were randomized into three groups: MgSO₄ nebulization (group A), salbutamol nebulization (group B), and their combination (group C). All patients were monitored before and after nebulization (each 20 minutes) for peak expiratory flow rate (PEFR), respiratory rate (RR), heart rate (HR), blood pressure, pulsus paradoxus, oxygen saturation, clinical examination, and Fischl index.

Results

A highly significant improvement in PEFR, PEFR percentage, and Fischl index and significant decrease in RR and HR was observed in all groups. A similar improvement in PEFR was observed in group A and group B (P=0.389). The difference in peak expiratory flow (PEF) improvement was insignificant between group B and group C (P=0.101), while there was a significant difference between group A and group C (P=0.014) in favor of group C.

Conclusion

Nebulized MgSO₄ alone or combined with salbutamol has a clinically significant bronchodilator effect in acute asthma and leads to clinical improvement, increase in PEFR, reduction in HR, and reduction in RR. The response to nebulized MgSO₄ alone (PEFR improvement 54±35.6 L/min, P=0.001) is comparable (P=0.389) to that of nebulized salbutamol (PEFR improvement 67.0±41.9 L/min, P=0.001) and is significantly less than (P=0.014) that of nebulized combination (PEFR improvement 92.0±26.9 L/min, P=0.000).

Intravenous magnesium sulfate for treating children with acute asthma in the emergency department

BACKGROUND

Acute asthma in children can be life-threatening and must be treated promptly in the emergency setting. Intravenous magnesium sulfate is recommended by various guidelines for cases of acute asthma that have not responded to first-line treatment with bronchodilators and steroids. The treatment has recently been shown to reduce the need for hospital admission for adults compared with placebo, but it is unclear whether it is equally effective for children.

OBJECTIVES

To assess the safety and efficacy of intravenous magnesium sulfate (IV MgSO4) in children treated for acute asthma in the emergency department (ED).

SEARCH METHODS

We identified studies by searching the Cochrane Airways Review Group Specialised Register up to 23 February 2016. We also searched ClinicalTrials.gov and reference lists of other reviews, and we contacted study authors to ask for additional information.

SELECTION CRITERIA

We included randomised controlled trials of children treated in the ED for exacerbations of asthma if they compared any dose of IV MgSO4 with placebo.

DATA COLLECTION AND ANALYSIS

Two review authors screened the results of the search and independently extracted data from studies meeting the inclusion criteria. We resolved disagreements through discussion and contacted study authors in cases of missing data and other uncertainties relating to the studies.We analysed dichotomous data as odds ratios and continuous data as mean differences, both using fixed-effect models. We assessed each study for risk of bias and rated the quality of evidence for each outcome with GRADE and presented the results in a 'Summary of findings' table. There was insufficient evidence to conduct the planned subgroup analyses.

MAIN RESULTS

Five studies (182 children) met the inclusion criteria, and four contributed data to at least one meta-analysis. The included studies were overall at low risk of bias, but our confidence in the evidence was generally low, mainly due to the small sample sizes. Treatment with IV MgSO4 reduced the odds of admission to hospital by 68% (odds ratio (OR) 0.32, 95% confidence interval (CI) 0.14 to 0.74; children = 115; studies = 3; I(2) = 63%). This result was based on data from just three studies including 115 children. Meta-analysis for the secondary outcomes was extremely limited by paucity of data. We performed meta-analysis for the outcome 'return to the emergency department within 48 hours', which showed a very imprecise effect estimate that was not statistically significant (OR 0.40, 95% CI 0.02 to 10.30; children = 85; studies = 2; I(2) = 0%). Side effects and adverse events were not consistently reported and meta-analysis was not possible, however few side effects or adverse events were reported.

AUTHORS' CONCLUSIONS

IV MgSO4 may reduce the need for hospital admission in children presenting to the ED with moderate to severe exacerbations of asthma, but the evidence is extremely limited by the number and size of studies. Few side effects of the treatment were reported, but the data were extremely limited.

Management of Acute Exacerbation of Asthma and Chronic Obstructive Pulmonary Disease in the Emergency Department

Acute asthma and chronic obstructive pulmonary disease (COPD) exacerbations are the most common respiratory diseases requiring emergent medical evaluation and treatment. Asthma and COPD are chronic, debilitating disease processes that have been differentiated traditionally by the presence or absence of reversible airflow obstruction. Asthma and COPD exacerbations impose an enormous economic burden on the US health care budget. In daily clinical practice, it is difficult to differentiate these 2 obstructive processes based on their symptoms, and on their nearly identical acute treatment strategies; major differences are important when discussing anatomic sites involved, long-term prognosis, and the nature of inflammatory markers.

Nebulized magnesium for moderate and severe pediatric asthma: A randomized trial

BACKGROUND

Intravenous magnesium sulfate, a rescue therapy added to bronchodilator and systemic steroid therapy for moderate and severe asthma, is uncommonly administered. We hypothesized that nebulized magnesium would confer benefit without undue risk.

DESIGN AND METHODS

Patients aged 2 to 14 y with moderate and severe asthma (PRAM severity score ≥ 4) admitted to infirmary/observation unit care were randomized double-blind on admission to receive 800 mg nebulized magnesium or normal saline placebo after all received intensive therapy with combined nebulized albuterol-ipratropium and intravenous methylprednisolone. Time to medical readiness for discharge was the primary outcome; sample size was chosen to detect a 15% absolute improvement. Improvement over time in PRAM severity score and other secondary outcomes were compared for the overall group and severe asthma subset.

RESULTS

One hundred and ninety-one magnesium sulfates and 174 placebo patients met criteria for analysis. The groups were similar with mean baseline PRAM scores >7. Blinded active therapy significantly increased blood magnesium level 2 hr post-treatment completion compared to placebo, 0.85 vs 0.82 mmol/L, P = 0.001. There were no important adverse effects. Accelerated failure time analysis showed a non-significantly shortened time to medical readiness for discharge of 14% favoring the magnesium sulfate group, OR = 1.14, 95% CI 0.93 to 1.40, P = 0.20. Mean times until readiness for discharge were 14.7 hr [SD 9.7] versus 15.6 hr [SD 11.3] for the investigational and placebo groups, respectively, P = 0.41.

CONCLUSIONS

Adding nebulized magnesium to combined nebulized bronchodilator and systemic steroid therapy failed to significantly shorten time to discharge of pediatric patients with moderate or severe asthma.

Dysmagnesemia in Hospitalized Patients: Prevalence and Prognostic Importance

OBJECTIVE

To examine the prevalence of serum magnesium (Mg) alterations and outcomes in hospitalized patients.

PATIENTS AND METHODS

All admissions to Mayo Clinic in Rochester, Minnesota, from January 1, 2009, through December 31, 2013 (288,120 patients), were screened. Admission Mg from each unique patient and relevant clinical data were extracted from the institutional electronic database.

RESULTS

After excluding patients aged less than 18 years, those without Mg measurement, and readmission episodes, a total of 65,974 patients were studied. Magnesium levels of 2.1 mg/dL or higher were found in 20,777 patients (31.5%), and levels less than 1.7 mg/dL were noted in 13,320 (20.2%). Hypomagnesemia was common in patients with hematologic/oncological disorders, and hypermagnesemia was common in those with cardiovascular disease. The lowest hospital mortality, assessed by restricted cubic spline and percentage death, occurred in patients with Mg levels between 1.7 and 1.89 mg/dL. An Mg level of less than 1.7 mg/dL was independently associated with an increased risk of hospital mortality after adjusting for all variables except the admission diagnosis; risk for longer hospital stay and being discharged to a care facility were increased in the fully adjusted model. An elevated Mg level of 2.3 mg/dL or higher was a predictor for all adverse outcomes. The magnitude of Mg elevations in patients with levels of 2.3 mg/dL or higher (N=7908) was associated with worse hospital mortality in a dose-response manner. In patients with cardiovascular diseases, Mg levels of 1.5 to 1.69 mg/dL and 2.3 mg/dL or higher both independently predicted poor outcomes including hospital mortality.

CONCLUSION

Dysmagnesemia in hospitalized patients is common, with hypermagnesemia being most prevalent. Compared with hypomagnesemia, hypermagnesemia is a stronger predictor for poor outcomes. Magnesium supplementation for patients without Mg deficiency should be avoided in the absence of randomized controlled trials documenting a benefit.

Advances in acute asthma

PURPOSE OF REVIEW

The purpose of this study is to highlight some of the recent findings related with the management of acute exacerbations in the context of the emergency department setting.

RECENT FINDINGS

β₂-agonist heliox-driven nebulization significantly increased by 17% [95% confidence interval (CI) 5.2-29.4] peak expiratory flow, and decreased the rate of hospital admissions (risk ratio 0.77, 95% CI 0.62-0.98), compared with oxygen-driven nebulization. Other findings indicate that there is no robust evidence to support the use of intravenous or nebulized magnesium sulphate in adults with severe acute asthma, and that levalbuterol was not superior to albuterol regarding efficacy and safety in individuals with acute asthma. Finally, hyperlactatemia developed during the first hours of acute asthma treatment has a high prevalence, is related with the use of β₂-agonists and had no clinical consequences.

SUMMARY

After a comprehensive review of the best quality pieces of literature published in the last year, it is possible to conclude that the goals of acute asthma management remain almost unchanged.

[Current and prospective issues about adult asthma]

The management of asthma treatment is likely to change in coming years, with the development of a more personalized approach. Biological therapies targeting Th2 cytokines (IL-4, IL-5 and IL-13) offer new treatment pathways for patients with severe asthma and high Th2 activity. Bronchial thermoplasty is the only treatment for severe asthma that could provide a long standing effect, but many questions still remain and its use is restricted to clinical research. Weight loss should be a goal during long-term management of obese asthmatics. Involvement of a new inflammatory pathway including IL-1 and IL-17 in a murine model of obesity and asthma may lead to new therapies in this subgroup of asthmatics.

Comparative effectiveness of intravenous and inhaled magnesium in acute asthma

Evaluation of: Goodacre S, Cohen J, Bradburn M et al. Intravenous or nebulised magnesium sulphate versus standard therapy for severe acute asthma (3Mg trial): a double-blind, randomized controlled trial. Lancet Respir. Med. 1, 293-300 (2013). Acute exacerbations of asthma are common. The current recommended treatment approach to managing an acute asthma exacerbation is to administer a short-acting inhaled β2-agonist (SABA). SABAs are rapidly effective but may not provide the bronchodilation needed to restore adequate lung function. Consequently, in severe acute asthma exacerbations, despite a standard approach to treatment including SABAs, hospitalization is common. Magnesium is a bronchodilator that may provide additional benefit to SABAs in managing acute asthma exacerbations. In this article, the comparative effectiveness of inhaled and intravenous magnesium in addition to standard therapy is evaluated in the management of severe acute asthma exacerbations. Although neither inhaled nor intravenous magnesium achieved the protocol-specified benefits, intravenous magnesium was associated with fewer hospitalizations and a trend for greater improvement in the symptom of breathlessness than inhaled magnesium.

The role of magnesium sulfate in acute asthma: does route of administration make a difference?

PURPOSE OF REVIEW

The role of magnesium sulfate (MgSO4) in the treatment of acute asthma is not clear. Four recent systematic reviews suggest a limited role of intravenous (i.v.) and inhaled nebulized treatment. The purpose of this review is to summarize the current literature, focus on two recent large multicenter randomized controlled trials, and discuss future research directions.

RECENT FINDINGS

The Magnesium Nebulized Trial In Children (MAGNETIC) trial has shown little benefit to routine use of nebulized MgSO4 in children with acute asthma, but there may be a benefit in those with severe exacerbations and a shorter duration of symptoms. The 3Mg trial has shown no role for nebulized MgSO4 in adults and, at best a limited role for i.v. MgSO4 in only the most severe exacerbations. This is the only study with direct comparison of nebulized and i.v. MgSO4.

SUMMARY

MgSO4 has a role in severe exacerbations of acute asthma and there is no evidence of benefit outside this clinical situation. Both nebulized and i.v. treatments are well tolerated and inexpensive. In adults, the most effective route of administration is i.v. There are no direct comparison studies in children. Further research should focus on more severe exacerbations.

The rise, fall, and resurgence of immunotherapy in type 1 diabetes

Despite considerable effort to halt or delay destruction of β-cells in autoimmune type 1 diabetes (T1D), success remains elusive. Over the last decade, we have seen a proliferation of knowledge on the pathogenesis of T1D that emerged from studies performed in non-obese diabetic (NOD) mice. However, while results of these preclinical studies appeared to hold great promise and boosted patients' hopes, none of these approaches, once tested in clinical settings, induced remission of autoimmune diabetes in individuals with T1D. The primary obstacles to translation reside in the differences between the human and murine autoimmune responses and in the contribution of many environmental factors associated with the onset of disease. Moreover, inaccurate dosing as well as inappropriate timing and uncertain length of drug exposure have played a central role in the negative outcomes of such therapeutic interventions. In this review, we summarize the most important approaches tested thus far in T1D, beginning with the most successful preclinical studies in NOD mice and ending with the latest disappointing clinical trials in humans. Finally, we highlight recent stem cell-based trials, for which expectations in the scientific community and among individuals with T1D are high.

Inhaled anticholinergics and short-acting beta(2)-agonists versus short-acting beta2-agonists alone for children with acute asthma in hospital

BACKGROUND

Inhaled anticholinergics given in addition to β2-agonists are effective in reducing hospital admissions in children presenting to the emergency department with a moderate to severe asthma exacerbation. It seems logical to assume a similar beneficial effect in children hospitalised for an acute asthma exacerbation.

OBJECTIVES

To assess the efficacy and safety of anticholinergics added to β2-agonists as inhaled or nebulised therapy in children hospitalised for an acute asthma exacerbation. To investigate the characteristics of patients or therapy, if any, that would influence the magnitude of response attributable to the addition of anticholinergics.

SEARCH METHODS

We identified trials from the Cochrane Airways Group Specialised Register of trials (CAGR), which is derived through systematic searches of bibliographic databases including the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CINAHL, AMED and PsycINFO and through handsearching of respiratory journals and meeting abstracts. The search is current to November 2013.

SELECTION CRITERIA

Randomised trials comparing the combination of inhaled or nebulised anticholinergics and short-acting β2-agonists versus short-acting β2-agonists alone in children one to 18 years of age hospitalised for an acute asthma exacerbation were eligible.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the methodological quality of trials and extracted data; disagreement was resolved by consensus or with the input of a third review author, when needed. Primary outcomes were duration of hospital stay and serious adverse events. Secondary outcomes included admission and duration of stay in the intensive care unit (ICU), ventilation assistance, time to short-acting β2-agonists spaced at four hours or longer, supplemental asthma therapy, duration of supplemental oxygen, change from baseline in asthma severity, relapse after discharge, adverse health effects and withdrawals.

MAIN RESULTS

Seven randomised trials were included, four of which reported usable data on 472 children with asthma one to 18 years of age who were admitted to paediatric wards. No trials included patients admitted to the ICU. The anticholinergic used, ipratropium bromide 250 μg, was given every one to eight hours over a period from four hours to the entire length of the hospital stay. Two of four trials (50%) contributing data were deemed of high methodological quality. The addition of anticholinergics to β2-agonists showed no evidence of effect on the duration of hospital admission (mean difference (MD) -0.28 hours, 95% confidence interval (CI) -5.07 to 4.52, 3 studies, 327 participants, moderate quality evidence) and no serious or non-serious adverse events were reported in any included trials. As a result of the similarity of trials, we could not explore the influence of age, admission site, intensity of anticholinergic treatment and co-interventions on primary outcomes. No statistically significant group difference was noted in other secondary outcomes, including the need for supplemental asthma therapy, time to short-acting β2-agonists spaced at four hours or longer, asthma clinical scores, lung function and overall withdrawals for any reason.

AUTHORS' CONCLUSIONS

In children hospitalised for an acute asthma exacerbation, no evidence of benefit for length of hospital stay and other markers of response to therapy was noted when nebulised anticholinergics were added to short-acting β2-agonists. No adverse health effects were reported, yet the small number of trials combined with inadequate reporting prevent firm reassurance regarding the safety of anticholinergics. In the absence of trials conducted in ICUs, no conclusion can be drawn regarding children with impending respiratory failure. These findings support current national and international recommendations indicating that healthcare practitioners should refrain from using anticholinergics in children hospitalised for acute asthma.

Intravenous magnesium sulfate for treating adults with acute asthma in the emergency department

BACKGROUND

Asthma is a chronic respiratory condition characterised by airways inflammation, constriction of airway smooth muscle and structural alteration of the airways that is at least partially reversible. Exacerbations of asthma can be life threatening and place a significant burden on healthcare services. Various guidelines have been published to inform management personnel in the acute setting; several include the use of a single bolus of intravenous magnesium sulfate (IV MgSO4) in cases that do not respond to first-line treatment. However, the effectiveness of this approach remains unclear, particularly in less severe cases.

OBJECTIVES

To assess the safety and efficacy of IV MgSO4 in adults treated for acute asthma in the emergency department.

SEARCH METHODS

We identified trials from the Cochrane Airways Review Group Specialised Register (CAGR) up to 2 May 2014. We also searched www.ClinicalTrials.gov and reference lists of other reviews, and we contacted trial authors to ask for additional information.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of adults treated in the emergency department (ED) for exacerbations of asthma if they compared any dose of IV MgSO4 with placebo.

DATA COLLECTION AND ANALYSIS

All review authors screened titles and abstracts for inclusion, and at least two review authors independently extracted study characteristics, risk of bias and numerical data. Disagreements were resolved by consensus, and we contacted trial investigators to obtain missing information.We analysed dichotomous data as odds ratios using study participants as the unit of analysis, and we analysed continuous data as mean differences or standardised mean differences using fixed-effect models. We rated all outcomes using GRADE and presented results in Summary of findings table 1.We carried out subgroup analyses on the primary outcome for baseline severity of exacerbations and whether or not ipratropium bromide was given as a co-medication. Unpublished data and studies at high risk of bias for blinding were removed from the main analysis in sensitivity analyses.

MAIN RESULTS

Fourteen studies met the inclusion criteria, randomly assigning 2313 people with acute asthma to the comparisons of interest in this review.Most studies were double-blinded trials comparing a single infusion of 1.2 g or 2 g IV MgSO4 over 15 to 30 minutes versus a matching placebo. Eleven were conducted at a single centre, and three were multi-centre trials. Participants in almost all of the studies had already been given at least oxygen, nebulised short-acting beta2-agonists and IV corticosteroids in the ED; in some studies, investigators also administered ipratropium bromide. Ten studies included only adults, and four included both adults and children; these were included because the mean age of participants was over 18 years.Intravenous MgSO4 reduced hospital admissions compared with placebo (odds ratio (OR) 0.75, 95% confidence interval (CI) 0.60 to 0.92; I(2) = 28%, P value 0.18; n = 972; high-quality evidence). In absolute terms, this odds ratio translates into a reduction of seven hospital admissions for every 100 adults treated with IV MgSO4 (95% CI two to 13 fewer). The test for subgroup differences revealed no statistical heterogeneity between the three severity subgroups (I(2) = 0%, P value 0.73) or between the four studies that administered nebulised ipratropium bromide as a co-medication and those that did not (I(2) = 0%, P value 0.82). Sensitivity analyses in which unpublished data and studies at high risk for blinding were removed from the primary analysis did not change conclusions.Within the secondary outcomes, high- and moderate-quality evidence across three spirometric indices suggests some improvement in lung function with IV MgSO4. No difference was found between IV MgSO4and placebo for most of the non-spirometric secondary outcomes, all of which were rated as low or moderate quality (intensive care admissions, ED treatment duration, length of hospital stay, readmission, respiration rate, systolic blood pressure).Adverse events were inconsistently reported and were not meta-analysed. The most commonly cited adverse events in the IV MgSO4 groups were flushing, fatigue, nausea and headache and hypotension (low blood pressure).

AUTHORS' CONCLUSIONS

This review provides evidence that a single infusion of 1.2 g or 2 g IV MgSO4 over 15 to 30 minutes reduces hospital admissions and improves lung function in adults with acute asthma who have not responded sufficiently to oxygen, nebulised short-acting beta2-agonists and IV corticosteroids. Differences in the ways the trials were conducted made it difficult for the review authors to assess whether severity of the exacerbation or additional co-medications altered the treatment effect of IV MgSO4. Limited evidence was found for other measures of benefit and safety.Studies conducted in these populations should clearly define baseline severity parameters and systematically record adverse events. Studies recruiting participants with exacerbations of varying severity should consider subgrouping results on the basis of accepted severity classifications.

Prediction of unsuccessful treatment in patients with severe acute asthma

BACKGROUND

Clinical assessment can be used to identify which patients with acute asthma are at risk of unsuccessful initial treatment.

OBJECTIVE

To determine which elements of clinical assessment predict unsuccessful treatment, defined as needing critical care or any unplanned additional treatment.

METHODS

We analysed data from a large multicentre trial (the 3Mg trial). Adults with severe acute asthma underwent standardised clinical assessment, including peak expiratory flow rate (PEFR), up to 2 h after initiation of treatment. Standard care was provided other than blinded random allocation to trial treatment or placebo. Patients were followed up by record review up to 30 days. Unsuccessful treatment was defined as needing (1) critical care or (2) critical care or any unplanned additional treatment within 7 days of presentation. Logistic regression was used to identify predictors and derive a prediction model for each outcome.

RESULTS

Out of 1084 patients analysed, 81 (7%) received critical care and 157 (14%) received critical care or unplanned additional treatment. Baseline PEFR (p=0.017), baseline heart rate (p<0.001), other serious illness (p=0.019), PEFR change (p=0.015) and heart rate change (p<0.001) predicted need for critical care. Baseline PEFR (p=0.010), baseline heart rate (p<0.001), baseline respiratory rate (p=0.017), other serious illness (p=0.023), PEFR change (p=0.003) and heart rate change (p=0.001) predicted critical care or additional treatment. Models based on these characteristics had c-statistics of 0.77 and 0.69, respectively.

CONCLUSIONS

PEFR, heart rate and other serious illnesses are the best predictors of unsuccessful treatment, but models based on these variables provide modest predictive value.