Magnesium sulfate potentiates several cardiovascular and metabolic actions of terbutaline

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Herbal Sources of Magnesium as a Promising Multifaceted Intervention for the Management of COVID-19

The coronavirus-disease 2019 (COVID-19) was announced as a global pandemic by the World Health Organization (WHO), and it affected all human groups. Severe COVID-19 is characterized by cytokine storms, which can lead to multiorgan failure and death, although fever and cough are the most typical symptoms of mild COVID-19. Plant-based diets provide a 73% lower risk of moderate-to-severe COVID-19. Additionally, the association between low levels of some micronutrients and the adverse clinical consequences of COVID-19 has been demonstrated. So, nutritional therapy can become part of patient care for the survival of this life-threatening disease (COVID-19) also short-term recovery. Magnesium as an essential micronutrient due to its anti-inflammatory and beneficial effects can effectively prevent COVID-19 pandemic by playing a role in the treatment of comorbidities such as diabetes and cardiovascular disorders as major risk factors for mortality. Sufficient magnesium to stay healthy is provided by a proper daily diet, and there is usually no need to take magnesium supplements. Considering that almost half of the dietary magnesium comes from fruits, vegetables, nuts, and grains, it seems necessary to pay attention to the consumption of edible plants containing sufficient magnesium as part of the diet to prevent severe COVID-19. In this study, we have described the beneficial effects of sufficient magnesium levels to control COVID-19 and the importance of plant-based magnesium-rich diets. Additionally, we have listed some edible magnesium-rich plants.

Magnesium in Aging, Health and Diseases

Several changes of magnesium (Mg) metabolism have been reported with aging, including diminished Mg intake, impaired intestinal Mg absorption and renal Mg wasting. Mild Mg deficits are generally asymptomatic and clinical signs are usually non-specific or absent. Asthenia, sleep disorders, hyperemotionality, and cognitive disorders are common in the elderly with mild Mg deficit, and may be often confused with age-related symptoms. Chronic Mg deficits increase the production of free radicals which have been implicated in the development of several chronic age-related disorders. Numerous human diseases have been associated with Mg deficits, including cardiovascular diseases, hypertension and stroke, cardio-metabolic syndrome and type 2 diabetes mellitus, airways constrictive syndromes and asthma, depression, stress-related conditions and psychiatric disorders, Alzheimer's disease (AD) and other dementia syndromes, muscular diseases (muscle pain, chronic fatigue, and fibromyalgia), bone fragility, and cancer. Dietary Mg and/or Mg consumed in drinking water (generally more bioavailable than Mg contained in food) or in alternative Mg supplements should be taken into consideration in the correction of Mg deficits. Maintaining an optimal Mg balance all through life may help in the prevention of oxidative stress and chronic conditions associated with aging. This needs to be demonstrated by future studies.

Continuous infusions of terbutaline in asthma - a review

BACKGROUND

After the safety issues raised by the Salmeterol Multicenter Asthma Research Trial, concerns persist about the safety of agents that cause prolonged β-adrenoceptor stimulation in asthmatic patients. We therefore decided to revisit and review the use of continuous subcutaneous infusions of terbutaline (CSIT)-a treatment often reserved for those with severe and refractory disease.

RESULTS

Original studies from the 1980s included 26 patients and showed that CSIT was well tolerated with predominately cutaneous side effects despite maintaining very high serum levels of terbutaline. CSIT led to improved outcomes in approximately 75% of patients which included rises in lowest daily peak expiratory flow rate (PEFR), diminution in diurnal variation, reduction in other medication requirements, and subjective opinion of symptoms. Almost all patients demonstrating an improvement had a wide variation in their pretreatment PEFRs. However, in a retrospective follow-up of 42 patients, the only outcome to be significantly improved by CSIT was that of mean hospital admissions (p = .031). CSIT is theorized to stimulate a discrete set of β-receptors not accessible by the inhaled route as further increases in Forced expiratory volume in one second (FEV(1)) occur with concurrent nebulized therapy.

CONCLUSION

Although some findings are encouraging, they are drawn from small observational studies done at a time when the standard management of asthma was quite different from today. No randomized controlled trials exist for the use of CSIT, which remains off-license for the treatment of asthma in the United Kingdom. Clearly, prospective well-powered studies are required to fully ascertain its potential benefits and safety profile-something that is unlikely to occur given that the use of CSIT remains low and appears to be declining.

Magnesium in the treatment of asthma

PURPOSE OF REVIEW

To provide an update of recent research on the role of magnesium in the management of asthma.

RECENT FINDINGS

Further evidence has been published that long-term oral magnesium supplementation does not lead to improved control in adult asthma. In contrast, updated meta-analyses of randomized controlled trials have confirmed the efficacy of both intravenous and inhaled (as an adjuvant to salbutamol nebulizer solution) magnesium therapy in severe asthma. This conclusion is still limited by the paucity of randomized controlled trials, however, with many issues yet to be firmly established, such as the efficacy in different patient subgroups, the dose regimes, and the optimal method of administration. International guidelines currently recommend the use of intravenous magnesium in severe asthma, and there is evidence that this approach is now widely used in emergency departments in North America. This audit also illustrated the emerging unregistered use of nebulized magnesium/salbutamol solution.

SUMMARY

Further investigation of the efficacy and safety of magnesium in severe asthma is now urgently required to determine its role in this clinical situation. The research community must heed the call for more research that is being made by funding agencies dealing with this area.

[Effect of intravenous magnesium sulfate on chronic obstructive pulmonary disease exacerbations requiring hospitalization: a randomized placebo-controlled trial]

OBJECTIVE

Magnesium sulfate has been shown to have a bronchodilating effect in asthma, but this effect has not been clearly established in the context of chronic obstructive pulmonary disease (COPD). For this reason we investigated the possible bronchodilating effect of magnesium sulfate in COPD exacerbations.

PATIENTS AND METHODS

We studied 24 patients with exacerbated COPD who required admission to our hospital's pneumology department. All patients underwent baseline spirometry and were subsequently randomized to groups in a double-blind crossover design. Patients received 1.5 g of magnesium sulfate or placebo in an intravenous solution for 20 minutes. Those who received magnesium sulfate the first day were given placebo the second day, and vice versa. Spirometry was performed 15, 30, and 45 minutes after administration of magnesium sulfate or placebo. Finally, 400 microg of salbutamol were administered using a spacer and a final spirometry was performed 15 minutes later. All patients also received treatment with corticosteroids, intravenous antibiotics, oxygen, and regularly-scheduled bronchodilator therapy (salbutamol and ipratropium bromide every 6 hours).

RESULTS

When we compared absolute increase in milliliters and percentage increase in forced expiratory volume in 1 second (FEV1) obtained with magnesium sulfate application to the increases obtained with placebo after 15, 30, and 45 minutes, no significant differences were found. When we compared absolute and percentage increases in FEV1 after administering salbutamol, we found significantly greater increases after magnesium sulfate administration. The mean (SD) absolute increase in FEV1 was 0.18 [corrected] (0.42) L after magnesium sulfate administration and 0.081 [0.01] L after placebo (P=.004). The percentage increase in FEV1 was 17.11% (3.7%) after magnesium sulfate and 7.06% (1.8%) after placebo (P=.008).

CONCLUSIONS

Intravenous administration of magnesium sulfate has no bronchodilating effect in patients with COPD exacerbations. It does, however, enhance the bronchodilating effect of inhaled ss2-agonists.

Bronchial epilepsy or broncho-pulmonary hyper-excitability as a model of asthma pathogenesis

Over the last 20 years, the prevalence of asthma has nearly doubled in industrialized countries. A similar increase has been predicted for the next two decades. Asthma is major illness in terms of morbidity and suffering, asthma is the leading cause of hospitalizations in children under 15 years of age. According to many top experts, asthma is correctly characterized as a syndrome rather than disease. This lack of definition for asthma makes the search for a cause, prevention and potential cure elusive. Episodic airway obstruction and reversible bronchial hyperresponsiveness to non-specific irritants are the major symptoms of asthma. Airway inflammation is now widely accepted as the key factor underlying the pathogenesis of asthma. However, many patients show no signs of inflammation, yet they still have severe airflow limitation and asthma symptoms. The primary clinical symptoms of asthma are attacks of shortness of breath, wheezing, and coughing resulting from excessive and inappropriate constriction of the airway smooth muscle. Our research suggests a possible epileptic or hyper-excitatory condition of bronchial system in asthma pathogenesis. The paroxysmal, spasmodic character of asthma attacks may be similar to seizures. We propose a unified pathogenetic mechanism of asthma as a syndrome of inducible or genetically predisposed membrane hyper-excitability (bronchial epilepsy).

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

Although it is well known that intravenous administration of MgSO4 as an adjunct to conventional therapy is effective in treating asthma attacks, the effect of nebulized MgSO4 as a vehicle for salbutamol has been less evaluated. The aim of this study was to compare the effects of nebulized salbutamol administrated through either MgSO4 or isotonic saline solution on the 'peak expiratory flow rate' (PEFR), other respiratory and clinical parameters, and hospitalization rate of patients suffering from moderate to severe asthma attacks. Twenty-six patients with asthma attack were enrolled in the study in a randomized single blind fashion. After obtaining initial peak expiratory flow measurements (PEFR) and clinical evaluation, all patients received 1mg/kg corticosteroids and oxygen therapy and then either isotonic MgSO4 (2.5 ml, 6.3%)+salbutamol (2.5 ml) or saline (2.5 ml)+salbutamol (2.5 ml) through a jet nebulizer (group 1 (n=14) vs group 2 (n=12), respectively). The nebulizations were repeated every 20 min for the first hour and every hour for the rest of 4 h. The PEFR measurements and clinical assessment were performed after nebulization at 20th, 60th, 120th, 180th and 240th minutes. Patients were discharged when PEFR reached the target level of 70% of predicted. The baseline PEFRs and clinical parameters were similar between groups 1 and 2 (50.2+/-18.5 vs 44.1+/-13.9, respectively, p>0.05). The mean% increase in PEFR at different measurement levels was similar between the groups. When the treatment response was evaluated within the groups, group 2 showed statistically significant increase in PEFR (% of predicted) 1h earlier than group 1 (60th vs 120th minute, p=0.003 vs p=0.007). The mean duration of achieving target-PEFRs was 105.7+/-72.1 min for group 1 and 118.3+/-96.7 min for group 2 (p>0.05). This study suggested that the additional usage of MgSO4 to nebulized salbutamol has no beneficial effect on the treatment of asthma attacks.

Prolongation of QT interval by terbutaline in healthy subjects

In a double-blind, randomized placebo-controlled crossover study, we characterized how terbutaline prolonged cardiac corrected QT interval (QTc). The study was carried out in six young and healthy male subjects in supine position. Escalating terbutaline doses were administered intravenously at infusion rates of 6 mL/h (10 microg terbutaline/min), 12 mL/h (20 microg terbutaline/min), and 18 mL/h (30 microg terbutaline/min). Terbutaline maximally prolonged QTc intervals on average by 60%, from 358 milliseconds (SD 28) to 456 milliseconds (SD 19). The effect was closely associated with a simultaneous decrease in plasma potassium concentration from 4.0 mmol/L (SD 0.1) to 2.5 mmol/L (SD 0.1). The final phase of slow ventricular repolarization, the interval between the apex and the end of T wave, was proven to be highly sensitive to the hypokalemic terbutaline actions, whereas the earlier repolarization phases were not strongly affected by terbutaline. Estimated by using the classic Nernst equation for membrane potentials, terbutaline-induced hypokalemia hyperpolarized ventricular myocardium from the resting level of -90 mV to -110 mV. The prolongation of QTc interval was related to ventricular hyperpolarization with a Pearson correlation coefficient of 0.91. Terbutaline-induced prolongation of QTc interval in healthy volunteers is in conformity with repolarization studies carried out in isolated canine heart ventricular preparations in which the cardiac ventricular cell membrane potential determines the duration of the final phase of slow ventricular repolarization.

Magnesium sulfate as a vehicle for nebulized salbutamol in acute asthma

PURPOSE

Magnesium sulfate is thought to be an effective bronchodilator when administered intravenously to patients with acute severe asthma, and it can be safely administered via inhalation to patients with stable asthma. Our goal was to determine if isotonic magnesium sulfate could be used as a vehicle for nebulized salbutamol for patients with acute asthma.

METHODS

We enrolled 35 patients with acute asthma in a randomized, double-blind, controlled trial. After measurement of peak expiratory flow, patients received 2.5 mg salbutamol plus either 3 mL normal saline solution (n = 16) or isotonic magnesium sulfate (n = 19) through a jet nebulizer. Peak flow was reassessed 10 and 20 minutes after treatment.

RESULTS

Peak flow at baseline was similar in the two groups. Ten minutes after baseline, the mean (+/- SD) percentage increase in peak flow was greater in the magnesium sulfate-salbutamol group (61% +/- 45%) than in the normal saline-salbutamol group (31% +/- 28%; difference = 30%; 95% confidence interval [CI] for the difference: 3% to 56%; P = 0.03). At 20 minutes, the percentage increase in peak flow was 57% greater in the magnesium sulfate group (95% CI: 4% to 110%, P = 0.04). There was a significant inverse correlation between baseline peak flow (percent of predicted) and the percentage increase in peak flow at 20 minutes in the magnesium sulfate group (r = -0.82, P <0.0001), but not in the saline group (r = -0.12, P = 0.67).

CONCLUSION

In patients with acute asthma, isotonic magnesium sulfate, as a vehicle for nebulized salbutamol, increased the peak flow response to treatment in comparison with salbutamol plus normal saline.

Magnesium deficiency and cardiogenic shock after cardiopulmonary bypass

Magnesium is an important cation that has a key role in cellular processes of energy transfer and utilization involving adenosine triphosphate, and influences cell membrane functions. Its antiarrhythmic properties are well-known and it is widely recognized as an adjunct for the treatment of arrhythmias after myocardial infarction and cardiopulmonary bypass. Magnesium may influence hemodynamic performance through its effects on vascular tone, modulation of intracellular calcium, regulation of catecholamine activity, and its essential role in adenosine triphosphate metabolism. The potential for magnesium deficiency to affect cardiovascular performance may be especially relevant in ischemic states. We report a case of cardiogenic shock developing after cardiopulmonary bypass that was initially unresponsive to therapeutic intervention, but that resolved promptly after magnesium administration. The potential role of magnesium in enhancing hemodynamic performance is discussed, with a review of its cellular metabolic properties and activities.

Magnesium sulfate therapy in certain emergency conditions

Intravenous magnesium has been suggested as a treatment for certain emergency conditions for more than 60 years. It is currently proposed to be beneficial in treating asthma, preeclampsia, eclampsia, myocardial infarction, and cardiac arrhythmias. The use and efficacy of the drug, however, are controversial. This article discusses the current state of magnesium sulfate research and therapy.

Effects of oral albuterol on serum lipids and carbohydrate metabolism in healthy men

beta(2)-Selective adrenergic agonists are used in the management of bronchial asthma and preterm labor. Due to their ability to increase muscle strength and size in animal models, new applications for these agents are also being explored for neuromuscular disorders and in rehabilitation. However, the effects of long-term beta(2)-agonist administration on lipoprotein and carbohydrate metabolism are incompletely understood. This investigation evaluated the effects of a beta(2)-agonist, albuterol, on serum lipids and carbohydrate homeostasis in eight healthy nonsmoking men aged 24 to 61 years. Collection of fasting blood samples was completed in duplicate on separate days at baseline, during 14 days of oral albuterol administration (Proventil Repetabs, 8 mg twice daily; Schering Pharmaceuticals, Kenilworth, NJ) and during a 7-day washout period. Carbohydrate homeostasis was evaluated using the minimal model technique at the end of the baseline and albuterol periods. Fasting glucose and insulin, intravenous glucose tolerance, acute insulin response to intravenous glucose (AIRg), insulin sensitivity (Si), and glucose effectiveness (Sg) were not significantly changed during albuterol administration. Significant alterations (P < or = .02) were observed in total cholesterol ([TC] -9.1% +/- 2.5%), low-density lipoprotein cholesterol ([LDL-C] -15.0% +/- 2.9%), and high-density lipoprotein cholesterol ([HDL-C] +10.4% +/- 3.2%) concentrations, as well as the TC/HDL-C (-17.4% +/- 2.6%) and LDL-C/HDL-C (-22.9% +/- 2.4%) ratios. During washout, TC and LDL-C returned to baseline levels, whereas HDL-C remained elevated by 5.8% +/- 2.4% (P < .05). Thus, albuterol administration was associated with favorable changes in the serum lipid profile without marked impairment of glucose tolerance or its physiologic determinants.

Intravenous magnesium sulfate as an adjunct in the treatment of acute asthma

STUDY OBJECTIVE

This study was conducted to determine whether intravenous magnesium sulfate (MgSO4), when used as part of a standardized treatment protocol, can improve pulmonary function and decrease admission rate in patients presenting to the emergency department with exacerbations of asthma.

DESIGN

In this randomized double-blind placebo-controlled study, patients with acute asthma were treated with inhaled beta-agonists at regular intervals and intravenous (IV) steroids. At 30 min after entry, patients received either 2 g IV MgSO4 or IV placebo. Patients were monitored for up to 4 h with regular measurements of pulmonary function. Patients who were discharged from the emergency department were contacted at 1 day and 7 days for follow-up.

SETTING

Emergency departments of a university-affiliated, voluntary hospital and municipal hospital.

PARTICIPANTS

Asthmatics aged 18 to 65 years during acute exacerbation with FEV1 less than 75% predicted both before and after a single albuterol treatment.

INTERVENTIONS

Patients were given 2 g of MgSO4 or placebo as an adjunct to standardized emergency department procedure for acute asthma.

MEASUREMENTS AND RESULTS

One hundred thirty-five patients were studied. Hospital admission rates were 35.3% for placebo-treated group and 25.4% for the magnesium-treated group (p = 0.21). FEV1 measured at 120 min was 56% predicted for the placebo-treated group and 55% predicted for the magnesium-treated group. (p = 0.92) For subgroup analysis, patients were divided into "severe" (baseline FEV1 < 25% predicted on presentation) or "moderate" (baseline FEV1, 25 to 75% predicted on presentation). For the severe group, admission rates were 78.6% (11/14) for the placebo-treated group and 33.3% (7/21) for the magnesium-treated group (p = 0.009). For the moderate patients, admission rates were 22.4% (11/49) for the placebo-treated group and 22.2% (10/25) for the magnesium-treated group (p = 0.98). There was no significant improvement in FEV1 in the moderate group for magnesium-treated patients. However, in the severe group, there was a significant improvement in FEV1 at 120 min and 240 min (p = 0.014 and 0.026, respectively).

CONCLUSION

Intravenous MgSO4 decreased admission rate and improved FEV1 in patients with acute severe asthma but did not cause significant improvement in patients with moderate asthma.