A randomized clinical trial of magnesium sulphate as a vehicle for nebulized salbutamol in the treatment of moderate to severe asthma attacks

Magnesium sulfate treatment for acute severe asthma in adults-a systematic review and meta-analysis

Introduction

Add-on magnesium sulfate (MgSO4) for refractory asthma exacerbation has been much debated. The aim of this review and meta-analysis is, therefore, to provide an update on the current evidence for the efficacy of MgSO4 in exacerbations of asthma in adults refractory to standard of care treatment.

Methods

A systematic review was performed in accordance with the PRISMA guidelines. The search was performed in the PubMed database (updated April 2023). For the meta-analysis, a random-effects model was applied using the metaphor package for RStudio (RStudio, Inc.).

Results

A total of 17 randomized controlled trials were included. Three of the nine studies addressing treatment with intravenous (IV) MgSO4 found a significant effect on lung function compared to placebo. Of the eight studies investigating hospital admission rate, only two found a significant effect of MgSO4. Six of the nine studies investigating treatment with nebulized MgSO4 compared to placebo found a favorable effect on forced expiratory volume in 1. second (FEV1) and peak expiratory flow rate (PEF). Only two of the five studies investigating the effect on hospital admission rate found an effect of MgSO4. Comparing effect sizes in a meta-analysis revealed a greater effect on PEF in asthma patients treated with nebulized MgSO4 (MD, 23.57; 95% CI, -2.48 to 49.62, p < 0.01) compared to placebo. The analysis of patients treated with i.v. MgSO4 compared to placebo showed no statistically significant difference (MD, 5.49; 95% CI, -18.67 to 29.65, p = 0.10).

Conclusion

Up to two out of three studies revealed an effect of MgSO4 treatment for asthma exacerbation when assessed by FEV1/PEF, but fewer studies were positive for the outcome of hospital admissions.

Indian Guidelines on Nebulization Therapy

Inhalational therapy, today, happens to be the mainstay of treatment in obstructive airway diseases (OADs), such as asthma, chronic obstructive pulmonary disease (COPD), and is also in the present, used in a variety of other pulmonary and even non-pulmonary disorders. Hand-held inhalation devices may often be difficult to use, particularly for children, elderly, debilitated or distressed patients. Nebulization therapy emerges as a good option in these cases besides being useful in the home care, emergency room and critical care settings. With so many advancements taking place in nebulizer technology; availability of a plethora of drug formulations for its use, and the widening scope of this therapy; medical practitioners, respiratory therapists, and other health care personnel face the challenge of choosing appropriate inhalation devices and drug formulations, besides their rational application and use in different clinical situations. Adequate maintenance of nebulizer equipment including their disinfection and storage are the other relevant issues requiring guidance. Injudicious and improper use of nebulizers and their poor maintenance can sometimes lead to serious health hazards, nosocomial infections, transmission of infection, and other adverse outcomes. Thus, it is imperative to have a proper national guideline on nebulization practices to bridge the knowledge gaps amongst various health care personnel involved in this practice. It will also serve as an educational and scientific resource for healthcare professionals, as well as promote future research by identifying neglected and ignored areas in this field. Such comprehensive guidelines on this subject have not been available in the country and the only available proper international guidelines were released in 1997 which have not been updated for a noticeably long period of over two decades, though many changes and advancements have taken place in this technology in the recent past. Much of nebulization practices in the present may not be evidence-based and even some of these, the way they are currently used, may be ineffective or even harmful. Recognizing the knowledge deficit and paucity of guidelines on the usage of nebulizers in various settings such as inpatient, out-patient, emergency room, critical care, and domiciliary use in India in a wide variety of indications to standardize nebulization practices and to address many other related issues; National College of Chest Physicians (India), commissioned a National task force consisting of eminent experts in the field of Pulmonary Medicine from different backgrounds and different parts of the country to review the available evidence from the medical literature on the scientific principles and clinical practices of nebulization therapy and to formulate evidence-based guidelines on it. The guideline is based on all possible literature that could be explored with the best available evidence and incorporating expert opinions. To support the guideline with high-quality evidence, a systematic search of the electronic databases was performed to identify the relevant studies, position papers, consensus reports, and recommendations published. Rating of the level of the quality of evidence and the strength of recommendation was done using the GRADE system. Six topics were identified, each given to one group of experts comprising of advisors, chairpersons, convenor and members, and such six groups (A-F) were formed and the consensus recommendations of each group was included as a section in the guidelines (Sections I to VI). The topics included were: A. Introduction, basic principles and technical aspects of nebulization, types of equipment, their choice, use, and maintenance B. Nebulization therapy in obstructive airway diseases C. Nebulization therapy in the intensive care unit D. Use of various drugs (other than bronchodilators and inhaled corticosteroids) by nebulized route and miscellaneous uses of nebulization therapy E. Domiciliary/Home/Maintenance nebulization therapy; public & health care workers education, and F. Nebulization therapy in COVID-19 pandemic and in patients of other contagious viral respiratory infections (included later considering the crisis created due to COVID-19 pandemic). Various issues in different sections have been discussed in the form of questions, followed by point-wise evidence statements based on the existing knowledge, and recommendations have been formulated.

Comparison of peak expiratory Flow(PEF) and COPD assessment test (CAT) to assess COPD exacerbation requiring hospitalization: A prospective observational study

Background: Acute exacerbation of chronic obstructive pulmonary disease (COPD) resulting in hospitalization is significantly associated with the increased morbidity and mortality, but there is a lack of an effective method to assess it. This study aimed to compare the ability of peak expiratory flow (PEF) and COPD assessment test (CAT) to assess COPD exacerbations requiring hospitalization. Methods : A cohort of 110 patients with moderate to severe COPD was studied over a period of 12 months, and their daily morning PEFs and CAT scores were recorded throughout the study. Results : After 12 months of follow-up, 72 patients experienced 156 COPD exacerbations, 74 (47%) that resulted in hospitalization and 82 (53%) that did not result in hospitalization. Change in CAT score from baseline to exacerbation was significantly related to change in PEF and Spearman’s rho =0.375 (95% CI, 0.227 to 0.506; p < .001). Change in PEF and CAT score from baseline to hospitalized exacerbation was significantly larger than that from baseline to non-hospitalized exacerbation (p < .05). Multivariable analysis indicated that ΔPEF (OR 1.11, 95% CI 1.06–1.16, p < .001) and ΔCAT (OR 1.64 95% CI 1.18–2.27, p = .003) were independently associated with risk of hospitalized exacerbation. ROC analysis indicated that the optimal cutoff value of ΔPEF for identifying hospitalized exacerbation was 49 L/min (27% from baseline), with a sensitivity and specificity of 82.7% and 76.7% (area under the curve [AUC] = 0.872 (95% CI 0.80–0.944, p < .05). The optimal cutoff value of ΔCAT score for identifying hospitalized exacerbation was 10.5 (63% from baseline), with a sensitivity and specificity of 67.3% and 77.4% [AUC]=0.763 (95% CI 0.67–0.857, p < .05). The AUC of ΔPEF and ΔCAT combined for the identification of hospitalized exacerbation was 0.900 (95% CI 0.841–0.959, p < .05), which was larger than that of ΔCAT or ΔPEF. Conclusions: ΔPEF and ΔCAT were independently associated with risk of hospitalized exacerbation. Compared with CAT, PEF was superior to identify hospitalized exacerbation. Identification via PEF and CAT combined is more effective than using PEF or CAT alone. These results help to assess the severity of COPD exacerbation and provide valuable information for clinical decision-making.

The role of magnesium in different inflammatory diseases

Magnesium deficiency (MgD) can cause inflammation in human body. The known mechanisms of inflammation caused by MgD include activation of phagocytic cells, opening of calcium channels, activation of the N-methyl-D-aspartate (NMDA) receptor, and activation of nuclear factor (NF)-κB. In addition, MgD causes systemic stress response through neuroendocrinological pathways. The inflammation caused by MgD can result in pro-atherogenic changes in the metabolism of lipoproteins, endothelial dysfunction, and high blood pressure. Studies suggest that magnesium may play an important role in the pathophysiology of some inflammatory diseases. Several clinical trials and laboratory studies have been done on the functional role of magnesium. In this study, we review some inflammatory diseases, in which the magnesium has a role in their pathophysiology. Among these diseases, diabetes, asthma, preeclampsia, atherosclerosis, heart damage, and rheumatoid arthritis have been highlighted.

Monitoring peak expiratory flow could predict COPD exacerbations: A prospective observational study

BACKGROUND

Exacerbation of chronic obstructive pulmonary disease (ECOPD) is an important event during the course of the disease. It causes a more rapid decline in lung function, which is associated with hospitalization and the risk of death. Therefore, it is essential to discover approaches to early detection and prevention of ECOPD. Peak expiratory flow (PEF) can be safely used instead of spirometry which can assess the severity of COPD as a standard tool. We hypothesized that monitoring PEF could possibly be used to predict the ECOPD.

METHOD

To verify this hypothesis, daily morning PEF was monitored for 6 months in 53 patients with moderate to severe COPD (mean FEV1 31.53%predicted) who were enrolled in Ningbo, China.

RESULT

A total of 69 exacerbations of COPD (63 of gradual onset, six of sudden onset) were recorded in this study. Thirty cases (43.5%) of gradual onset exacerbations needed to be hospitalized, and the mean PEF significantly decreased (vs baseline) during the 5 days that preceded those exacerbations (from 161.9 ± 39.4 L/min to 137.9 ± 36.1 L/min, P < 0.05, statistical power = 0.92). However, this was not the case with non-hospitalized exacerbations (from 175.4 ± 42.5 L/min to 161.5 ± 39.3 L/min, P = 0.172, statistical power = 0.63). The ROC analysis demonstrated that 24 h before hospitalized exacerbation, the optimal cutoff value of ΔPEF for its prediction was 28 L/min (17% from baseline), with a sensitivity and specificity of 76.7% and 72.7%, respectively (area under the curve [AUC] = 0.84, P < 0.05, statistical power = 0.78). While 48 h before hospitalized exacerbation, the optimal cutoff value of ΔPEF for its prediction was 14 L/min (9% from baseline), with a sensitivity and specificity of 86.7% and 66.7%, respectively (AUC = 0.863, P < 0.05, statistical power = 0.87).

CONCLUSIONS

As a rapid, inexpensive method, PEF could be used for the prediction and early detection of hospitalized exacerbation of COPD. This may provide opportunity for early intervention of ECOPD.

Limitations of the results from randomized clinical trials involving intravenous and nebulised magnesium sulphate in adults with severe acute asthma

The role of intravenous (IV) or nebulised magnesium sulphate (MgSO₄) in the treatment of severe acute asthma in adults is unclear. A controversy exists regarding its efficacy. In children MgSO₄ has a more evident clinical effect, but the child population has not been considered in this work. The applicability of the results from randomized clinical trials (RCTs) involving MgSO₄ in adult population is questioned in the optimal treatment of asthma exacerbations. According to the newest guidelines from the Global Initiative for Asthma (GINA), optimal treatment in the emergency department (ED) is based on short-acting beta₂-agonists (SABA), oral or IV corticosteroids (CS), short acting muscarinic antagonists (SAMA) and the controlled oxygen therapy. Further improvements with IV or nebulised MgSO₄ were assessed in a recent large multicentre, double-blind, placebo-controlled randomized 3 Mg trial, which failed to demonstrate clinical benefit. Several other RCTs found some benefit with MgSO₄, although the majority lacked some treatment options that are used in the optimal treatment of asthma exacerbations. Therefore, we reviewed the limitations of RCTs of IV or nebulised MgSO₄ in adults with acute asthma, with the aim to answer in which subpopulation MgSO₄ could be beneficial.

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.

The role of magnesium sulfate in the intensive care unit

Magnesium (Mg) has been developed as a drug with various clinical uses. Mg is a key cation in physiological processes, and the homeostasis of this cation is crucial for the normal function of body organs. Magnesium sulfate (MgSO4) is a mineral pharmaceutical preparation of magnesium that is used as a neuroprotective agent. One rationale for the frequent use of MgSO4 in critical care is the high incidence of hypomagnesaemia in intensive care unit (ICU) patients. Correction of hypomagnesaemia along with the neuroprotective properties of MgSO4 has generated a wide application for MgSO4 in ICU.

The effect of nebulised magnesium sulphate in the management of childhood moderate asthma exacerbations as adjuvant treatment

BACKGROUND

After the bronchodilator effect of magnesium was shown, the use of magnesium in treatment of asthma exacerbations became common. With the results of recent studies, the use of intravenous magnesium in severe asthma exacerbations took its place. We aimed to examine the effects of adding isotonic magnesium sulphate instead of isotonic saline into nebulised salbutamol on the Modified Pulmonary Index Score (MPIS) and the hospitalisation rate in moderate asthma exacerbations.

METHODS

Our study population included 100 children age between 3 and 15 years with asthma admitted to emergency department due to moderate asthma exacerbations. The patients were randomised to placebo or magnesium, with 50 patients in each arm. All patients received 1mg/kg of systemic methylprednisolone at the beginning of treatment and thereafter received either nebulised salbutamol (0.15mg/kg/dose) and 1ml magnesium sulphate (15%)+1.5ml isotonic saline on three occasions at roughly 20min intervals (Magnesium group) or nebulised salbutamol (0.15mg/kg/dose) and 2.5ml isotonic saline mixture on three occasions at roughly 20min intervals (Placebo group). The MPIS of patients on 0th min, 20th min, 40th and 120th min were calculated and compared. The primary outcome was to compare MPIS values at the end of 120th min.

RESULTS

Both groups have similar demographic, allergic characteristics and baseline MPIS scores. When the MPIS scores in the 120th min and admission rates in the 200th min, there was no significant difference between the two groups.

CONCLUSIONS

The use of nebulised magnesium sulphate in moderate asthma exacerbation as adjuvant treatment showed no benefit to standard treatment in our study.

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).

Magnesium nebulization utilization in management of pediatric asthma (MagNUM PA) trial: study protocol for a randomized controlled trial

BACKGROUND

Up to 30 % of children with acute asthma are refractory to initial therapy, and 84 % of this subpopulation needs hospitalization. Finding safe, noninvasive, and effective strategies to treat this high-risk group would substantially decrease hospitalizations, healthcare costs, and the psycho-social burden of the disease. Whereas intravenous magnesium (Mg) is effective in severe refractory asthma, its use is sporadic due to safety concerns, with the main treatment goal being to prevent intensive care unit admission. In contrast, nebulized Mg is noninvasive, allows higher pulmonary drug concentrations, and has a much higher safety potential due to the lower rate of systemic delivery. Previous studies of inhaled Mg show disparate results due to the use of unknown/inefficient delivery methods and other methodological flaws.

METHODS/DESIGN

The study is a randomized double-blind controlled trial in seven Canadian pediatric Emergency Departments (two-center pilot 2011 to 2014, Canada-wide November 2014 to December 2017). The trial will include 816 otherwise healthy children who are 2 to 17 years old, having had at least one previous wheezing episode, have received systemic corticosteroids, and have a Pediatric Respiratory Assessment Measure (PRAM) ≥ 5 points after three salbutamol and ipratropium treatments for a current acute asthma exacerbation. Eligible consenting children will receive three experimental treatments of nebulized salbutamol with either 600 mg of Mg sulfate or placebo 20 min apart, using an Aeroneb Go nebulizer, which has been shown to maximize pulmonary delivery while maintaining safety. The primary outcome is hospitalization within 24 h of the start of the experimental therapy for persistent respiratory distress or supplemental oxygen. Secondary outcomes include all-cause hospitalization within 24 h, PRAM, vital signs, number of bronchodilator treatments by 240 min, and the association between the difference in the primary outcome between the groups, age, gender, baseline PRAM, atopy, and "viral induced wheeze" phenotype (Fig. 1).

DISCUSSION

If effective, inhaled Mg may represent an effective strategy to minimize morbidity in pediatric refractory acute asthma. Unlike previous works, this trial targets nonresponders to optimized initial therapy who are the most likely to benefit from inhaled Mg. Future dissemination of results will include knowledge translation, incorporation into a Cochrane Review, presentation at scientific meetings, and a peer-reviewed publication.

TRIAL REGISTRATION

NCTO1429415 , registered 2 September 2011.

Effect of inhaled magnesium sulfate on bronchial hyperresponsiveness

OBJECTIVES

To determine the response of nebulized magnesium sulfate on the lung function of children with bronchial hyperresponsiveness.

METHODS

Eighty-four children with asthma were divided into three groups randomly: magnesium sulfate (M), albuterol (A), and a combination of magnesium sulfate and albuterol (M + A). All patients were nebulized with acetylcholine, and then treated as designed. Lung function was compared between the three groups.

RESULTS

Forced expiratory volume in first second (FEV1) significantly improved in all the three groups but it was better in (A) and (M + A) compared to (M) at 10 min and 20 min [10 min: 1.26 L ± 0.53 (A) vs. 1.10 L ± 0.27 (M), 1.35 L ± 0.59 (M + A) vs. 1.10 L ± 0.27 (M), p < 0.05; 20 min: 1.32 L ± 0.61 (A) vs. 1.17 L ± 0.30 (M), 1.42 L ± 0.59 (M + A) vs. 1.17 L ± 0.30 (M), p < 0.05]. Variation of FEV1, as absolute value at 10 min or 20 min over post-Ach FEV1 was significantly different in (A) or (M + A) compared to (M).

CONCLUSIONS

Nebulized albuterol and magnesium sulfate + albuterol can more effectively improve FEV1 in children with bronchial hyperresponsiveness than nebulized magnesium sulfate at 10 min and 20 min after inhalation. It is further suggested that addition of magnesium sulfate to albuterol does not result in additional benefit.

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.

Intravenous and nebulized magnesium sulfate for treating acute asthma in adults and children: a systematic review and meta-analysis

OBJECTIVES

This systematic review and meta-analysis was conducted to estimate the effects of intravenous and nebulized magnesium sulfate on treating adults and children with acute asthma.

METHODS

Electronic literature search and the manual search of key respiratory journals were performed up to October 18, 2011. Randomized controlled trials were included if patients had been treated with intravenous or nebulized magnesium sulfate in combination with β2-agonists and were compared with the use of β2-agonists. Standardized mean differences (SMDs) and the relative risks (RRs) were calculated for pulmonary functions and hospital admission respectively.

RESULTS

25 trials (16 intravenous, 9 nebulized) involving 1754 patients were included. In adults intravenous treatment was associated with a significant effect upon respiratory function (SMD, 0.30; 95% confidence interval (CI), 0.05 to 0.55; p = 0.02) but weak evidence of effect upon hospital admission (RR 0.86,95% CI 0.73 to 1.01; p = 0.06) in adults, and in children with significant effects upon both respiratory function (SMD, 1.94; 95% CI, 0.80 to 3.08; p = 0.0008) and hospital admission (RR, 0.70; 95% CI, 0.54 to 0.91; p = 0.008). Nebulized treatment was associated with significant effects upon respiratory function (SMD, 0.23; 95% CI, 0.06 to 0.41; p = 0.009) and hospital admission (RR, 0.63; 95% CI, 0.43 to 0.92; p = 0.02) in adults.

CONCLUSION

The use of intravenous magnesium sulfate, in addition to β2-agonists and systemic steroids, in the treatment of acute asthma appears to produce benefits with respect to improve pulmonary function and reduce the number of hospital admissions for children, and only improve pulmonary function for adults. However, the use of nebulized magnesium sulfate just appears to produce benefits for adults.

Inhaled magnesium sulfate in the treatment of acute asthma

BACKGROUND

Asthma exacerbations can be frequent and range in severity from relatively mild to status asthmaticus. The use of magnesium sulfate (MgSO(4)) is one of numerous treatment options available during acute exacerbations. While the efficacy of intravenous MgSO(4) has been demonstrated, little is known of the role of inhaled MgSO(4).

OBJECTIVES

To determine the efficacy of inhaled MgSO(4) administered in acute asthma on pulmonary functions and admission rates.

SPECIFIC AIMS

To quantify the effects of inhaled MgSO(4) i) in addition to inhaled β(2)-agonist, ii) in comparison to inhaled β(2)-agonist alone or iii) in addition to combination treatment with inhaled β(2) -agonist and ipratropium bromide.

SEARCH METHODS

Randomised controlled trials were identified from the Cochrane Airways Group register of trials in September 2012. These trials were supplemented with trials found in the reference list of published studies, studies found using extensive electronic search techniques, as well as a review of the grey literature and conference proceedings.

SELECTION CRITERIA

Randomised (or pseudo-randomised) controlled trials including adults or children with acute asthma were eligible for inclusion in the review. Studies were included if patients were treated with nebulised MgSO(4) alone or in combination with β(2)-agonist and/or ipratropium bromide and were compared with β(2)-agonist alone or inactive control.

DATA COLLECTION AND ANALYSIS

Trial selection, data extraction and risk of bias were assessed independently by two review authors. Efforts were made to collect missing data from authors. Results are presented as standardised mean differences (SMD) for pulmonary function and risk ratios (RR) for hospital admission; both are displayed with their 95% confidence intervals (CI).

MAIN RESULTS

Sixteen trials (21 references) of unclear and high risk of bias were eligible and included 896 patients who were randomised (838 patients completed). Seven of the 16 included studies involved adults exclusively, three included adults and paediatric patients, four studies enrolled paediatric patients and in the remaining two studies the age of participants was not stated.The design, definitions, intervention and outcomes were different in all 16 studies; this heterogeneity made direct comparisons difficult (see additional tables 1-3).The overall risk of bias among the included studies was variable and this is reflected in the 'Summary of findings' table with most outcomes being judged as only moderate or less.Inhaled magnesium sulfate in addition to inhaled β(2)-agonistThere was no statistically significant improvement in pulmonary function when inhaled MgSO(4) and β(2)-agonist was compared with β(2)-agonist alone (SMD 0.23; 95% CI -0.27 to 0.74; three studies, n = 188); however, there was considerable between study heterogeneity. There was no clear advantage in terms of hospital admissions (RR 0.76 95% CI 0.49, 1.16; four studies, n = 249), and there were no serious adverse events reported.Inhaled magnesium sulfate versus inhaled β(2)-agonistThe results of pulmonary function in three studies that compared inhaled MgSO(4) versus β(2)-agonist were too heterogeneous to combine; however, two of the studies found poorer lung function on MgSO(4). There was no significant difference in terms of hospital admissions in a single small study when MgSO(4) was compared to β(2)-agonist (RR 0.53 95% CI 0.05, 5.31; one study, n = 33), and there were no serious adverse events reported.Inhaled magnesium sulfate in addition to inhaled β(2)-agonist and ipratropiumA further comparison has been included in the 2012 update of this review of MgSO(4) given in addition to inhaled ipratropium and β(2)-agonist therapy (as recommended by the GINA guidelines). However, there is not yet enough data for this outcome to come to any definite conclusions, but both small studies in adults with severe asthma exacerbation found improvements in pulmonary function with additional inhaled MgSO(4).

AUTHORS' CONCLUSIONS

There is currently no good evidence that inhaled MgSO(4) can be used as a substitute for inhaled β(2)-agonists. When used in addition to inhaled β(2)-agonists (with or without inhaled ipratropium), there is currently no overall clear evidence of improved pulmonary function or reduced hospital admissions. However, individual study results from three trials suggest possible improved pulmonary function in those with severe asthma exacerbations (FEV1 less than 50% predicted). Heterogeneity among trials included in this review precludes a more definitive conclusion. Further studies should focus on inhaled MgSO(4) in addition to the current guideline treatment for acute asthma (inhaled β(2) -agonist and ipratropium bromide). As the evidence suggests that the most effective role of nebulised MgSO(4) may be in those with severe acute features and this is where future research should be focused. A set of core outcomes needs to be agreed upon both in adult and paediatric studies to allow improved study comparison in future. 

Magnesium sulfate for acute asthma in adults: a systematic literature review

Magnesium sulfate (MgSO(4)) has been considered as an adjunct therapy for severe and life-threatening asthma exacerbation. The literature search was performed using MEDLINE, EMBASE, Cochrane Library and Google Scholar to summarize the current state of knowledge regarding magnesium therapy in acute exacerbation of adult asthma. A total of 16 trials and 4 meta-analyses were identified. As results, intravenous MgSO(4) was beneficial in severe exacerbation, but evidence for nebulized magnesium was insufficient. However, larger trials are required to draw confirmative conclusions on the efficacy. Regarding the safety concern, the risk of major toxicity appears to be very low at usual doses described in the literature. Additionally, results from 4 surveys were examined on the gaps between knowledge and practice, and on the barrier to the use of MgSO(4) at emergency departments. This literature review summarized the up-to-date evidence on the issues regarding the use of MgSO(4) for acute asthma. We expect more studies to be conducted for evidence making in the Asian-Pacific regions.

Usefulness of inhaled magnesium sulfate in the coadjuvant management of severe asthma crisis in an emergency department

RATIONALE

Treatment of severe asthma may be difficult despite the use of several medications including parenteral corticosteroids. Intravenous magnesium sulfate (MgSO(4)) is one ancillary drug for severe crisis; its inhaled use is controversial.

OBJECTIVES

To evaluate the usefulness of inhaled MgSO(4) compared to placebo in improving lung function, oxygen saturation, and reducing hospital admission as an adjunct to standard treatment in severe asthma crisis.

PATIENTS AND METHODS

We conducted a placebo-controlled, double-blind clinical trial with asthmatic patients >18 years of age with asthmatic crisis and FEV(1)<60% of predicted (%p). All subjects received 125 mg of IV methylprednisolone followed by nebulization with the combination of albuterol (7.5mg) and ipratropium bromide (1.5mg) diluted in 3 ml of isotonic saline solution (as placebo) or 3 ml (333 mg) of MgSO(4). After 90 min, subjects with FEV(1)<60%p or SpO(2)<88% or persistent symptoms were admitted to the emergency department (ED).

RESULTS

We included 30 patients per group who were similar at baseline. The MgSO(4) group showed higher post-bronchodilator (post-BD) FEV(1)%p (69+/-13 vs. 61+/-12, p<0.014) and SpO(2) (92+/-4 vs. 88+/-5%, p<0.006) than the placebo group. Fewer treated patients were admitted to the ED (5 vs. 13) (p<0.047), with relative risk (RR) of 0.26 (95% CI 0.079-0.870).

CONCLUSIONS

Adding inhaled MgSO(4) treatment to standard therapy in severe asthma crisis improves FEV(1)%p and SpO(2) post-BD and reduces the rate of ED admissions.

Intravenous and nebulised magnesium sulphate for acute asthma: systematic review and meta-analysis

OBJECTIVES

To estimate the effect of intravenous and nebulised magnesium sulphate upon hospital admissions and pulmonary function in adults and children with acute asthma.

METHODS

We undertook a systematic review and meta-analysis of randomised and quasi-randomised trials of intravenous or nebulised magnesium sulphate in acute asthma. Trials were identified by searches of the electronic literature, relevant journal websites and conference proceedings, and contact with authors and experts. Data were pooled using random effects meta-analysis of the relative risk (RR) of hospital admission and the standardised mean difference (SMD) in pulmonary function.

RESULTS

24 studies (15 intravenous, 9 nebulised) incorporating 1669 patients were included. Intravenous treatment was associated in adults with weak evidence of an effect upon respiratory function (SMD 0.25, 95% confidence interval (CI) -0.01 to 0.51; p = 0.05), but no significant effect upon hospital admission (RR 0.87, 95% CI 0.70 to 1.08; p = 0.22), and in children with a significant effect upon respiratory function (SMD 1.94, 95% CI 0.80 to 3.08; p<0.001) and hospital admission (RR 0.70, 95% CI 0.54 to 0.90; p = 0.005). Nebulised treatment was associated in adults with weak evidence of an effect upon respiratory function (SMD 0.17, 95% CI -0.02 to 0.36; p = 0.09), and hospital admission (RR 0.68, 95% CI 0.46 to 1.02; p = 0.06), and in children with no significant effect upon respiratory function (SMD -0.26, 95% CI -1.49 to 0.98; p = 0.69) or hospital admission (RR 2.0, 95% CI 0.19 to 20.93; p = 0.56).

CONCLUSION

Intravenous magnesium sulphate appears to be an effective treatment in children. Further trials are needed of intravenous and nebulised magnesium sulphate in adults and nebulised magnesium sulphate in children.

Nebulized magnesium sulfate in the management of acute exacerbations of asthma

OBJECTIVE

To evaluate the efficacy and safety of nebulized magnesium sulfate in the treatment of acute exacerbations of asthma.

DATA SOURCES

MEDLINE, EMBASE, and PubMed (all to October 2005) were searched using the key words magnesium, magnesium sulfate, magnesium compounds, nebulise, nebulize, vaporise, vaporize, nebulizers and vaporizers, aerosols, asthma, exacerbation, bronchial spasm, and bronchospasm.

STUDY SELECTION AND DATA EXTRACTION

Prospective, randomized, controlled trials that evaluated efficacy and safety endpoints of nebulized magnesium sulfate in the management of acute exacerbations of asthma were included. All studies were evaluated independently by both authors. Efficacy outcomes included pulmonary function, clinical disease severity (as defined by each study), and rate of hospitalization. Safety outcomes were as described by each trial.

DATA SYNTHESIS

Six prospective trials met the study criteria. Nebulized magnesium alone failed to demonstrate any benefit compared with beta(2)-agonists alone at improving pulmonary function. In trials in which nebulized magnesium was used as a vehicle for albuterol, there appear to be additional benefits to albuterol therapy in terms of improvements in pulmonary function in a population with mild-to-moderate asthma. The heterogeneous patient populations, study designs, magnesium doses, and the delivery methods preclude the extrapolation of these results to current clinical practice.

CONCLUSIONS

The studies included in this review fail to clarify the role of nebulized magnesium sulfate; therefore, this therapy cannot be recommended at this time. Future studies evaluating the role of nebulized magnesium as an adjunct therapy to beta(2)-agonist, anticholinergic, and corticosteroid therapy are necessary to determine whether a clinically relevant benefit of this intervention exists.