A meta-analysis on intravenous magnesium sulphate for treating acute asthma.
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AIM: To evaluate the effectiveness of intravenous magnesium sulphate in the treatment of acute asthmatic attacks in children by meta-analysis. METHODS: A systematic and comprehensive search of the literature was performed to identify controlled clinical trials of magnesium sulphate in paediatric acute asthma which evaluated outcomes of hospitalisation or short term pulmonary function tests or symptom scores. Unpublished data were searched by personal contacts with authors and specialists. Two reviewers independently assessed trial qualities and synthesised data. Heterogeneity among studies was evaluated by the Cochrane Q test. Outcome data were pooled by random or fixed effect models depending on presence or absence of heterogeneity. RESULTS: Five randomised placebo controlled trials involving a total of 182 patients were identified. They compared intravenous magnesium sulphate to placebo in treating paediatric patients with moderate to severe asthmatic attacks in the emergency department, with co-therapies of inhaled beta2 agonists and systemic steroids. The studies were of high quality with results judged to be valid. Four studies showed that magnesium sulphate was effective, while one study found it ineffective. There was no significant heterogeneity in the primary outcome of hospitalisation. In the fixed effect model, magnesium sulphate is effective in preventing hospitalisation (OR 0.290, 95% CI 0.143 to 0.589). The number needed to treat is 4 (95% CI 3 to 8). Secondary outcomes of short term pulmonary function tests and clinical symptom scores also showed significant improvement. CONCLUSION: Intravenous magnesium sulphate probably provides additional benefit in moderate to severe acute asthma in children treated with bronchodilators and steroids. (+info)
Effects of magnesium sulphate and clonidine on propofol consumption, haemodynamics and postoperative recovery.
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BACKGROUND: This placebo-controlled, double-blind study was designed to assess the effects of magnesium sulphate and clonidine on peroperative haemodynamics, propofol consumption and postoperative recovery. METHODS: Sixty ASA I-II patients undergoing spinal surgery were randomized into three groups. Group M received magnesium sulphate 30 mg kg(-1) as a bolus before induction and 10 mg kg(-1) h(-1) by infusion. Group CL received clonidine 3 microg kg(-1) as a bolus before induction and 2 microg kg(-1) h(-1) by infusion during the operation period. The same volume of isotonic solution was administered to the control group (group CT). Anaesthesia was induced with propofol and was maintained with propofol infusion [dose according to the bispectral index (BIS)], fentanyl and cisatracurium. Analysis of variance and the Bonferroni test were used for statistical analysis. RESULTS: Induction of anaesthesia with propofol was rapid in the presence of magnesium sulphate and clonidine. The time for BIS to reach 60 was significantly shorter in group M and group CL (P<0.0001) but postoperative recovery was slower with magnesium sulphate compared with the clonidine and control groups (P<0.0001). There was no statistical difference in heart rate and arterial blood pressure between the groups. Propofol requirements for induction and maintenance of anaesthesia were significantly lower with magnesium and clonidine (P<0.0001). CONCLUSION: Clonidine caused bradycardia and hypotension and magnesium sulphate caused delayed recovery, but can be used as adjuvant agents with careful management. (+info)
Effect of magnesium sulfate administration on blood-brain barrier in a rat model of intraperitoneal sepsis: a randomized controlled experimental study.
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INTRODUCTION: Permeability changes in the blood-brain barrier (BBB) and their possible contribution to brain edema formation have a crucial role in the pathophysiology of septic encephalopathy. Magnesium sulfate has been shown to have a protective effect on BBB integrity in multiple experimental models. In this study we determine whether magnesium sulfate administration could have any protective effects on BBB derangement in a rat model of sepsis. METHODS: This randomized controlled experimental study was performed on adult male Sprague-Dawley rats. Intraperitoneal sepsis was induced by using the infected fibrin-thrombin clot model. To examine the effect of magnesium in septic and sham-operated rats, a dose of 750 micromol/kg magnesium sulfate was given intramuscularly immediately after surgery. Control groups for both infected and sham-operated rats were injected with equal volume of saline. Those rats surviving for 24 hours were anesthetized and decapitated for the investigation of brain tissue specific gravity and BBB integrity by the spectrophotometric assay of Evans blue dye extravasations. Another set of experiments was performed for hemodynamic measurements and plasma magnesium level analysis. Rats were allocated into four parallel groups undergoing identical procedures. RESULTS: Sepsis significantly increased BBB permeability to Evans blue. The dye content of each hemisphere was significantly lower in the magnesium-treated septic rats (left hemisphere, 0.00218 +/- 0.0005; right hemisphere, 0.00199 +/- 0.0007 [all results are means +/- standard deviation]) than in control septic animals (left hemisphere, 0.00466 +/- 0.0002; right hemisphere, 0.00641 +/- 0.0003). In septic animals treated with magnesium sulfate, specific gravity was higher (left hemisphere, 1.0438 +/- 0.0007; right hemisphere, 1.0439 +/- 0.0004) than in the untreated septic animals (left hemisphere, 1.0429 +/- 0.0009; right hemisphere, 1.0424 +/- 0.0012), indicating less edema formation with the administration of magnesium. A significant decrease in plasma magnesium levels was observed 24 hours after the induction of sepsis. The dose of magnesium that we used maintained the baseline plasma magnesium levels in magnesium-treated septic rats. CONCLUSIONS: Magnesium administration attenuated the increased BBB permeability defect and caused a reduction in brain edema formation in our rat model of intraperitoneal sepsis. (+info)
Spectral reflectance and morphologic correlations in eastern Terra Meridiani, Mars.
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The Mars Express Observatoire pour la Mineralogie, l'Eau, les Glaces, et l'Activite (OMEGA) hyperspectral image data covering eastern Terra Meridiani indicate the ubiquitous presence of molecular water in etched terrain materials that disconformably overlie heavily cratered terrains and underlie the hematite-bearing plains explored by the Opportunity rover. Identification of crystalline water in kieserite (MgSO4.H2O) is linked to materials exposed in a valley and plateau to the north of hematite-bearing plains. The mineralogical similarities between the etched terrain deposits examined with OMEGA data and the layered rocks examined by Opportunity imply that the ancient aqueous environments inferred from analyses of the rover data extend over regional scales. (+info)
Magnesium sulphate only slightly reduces the shivering threshold in humans.
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BACKGROUND: Hypothermia may be an effective treatment for stroke or acute myocardial infarction; however, it provokes vigorous shivering, which causes potentially dangerous haemodynamic responses and prevents further hypothermia. Magnesium is an attractive anti-shivering agent because it is used for treatment of postoperative shivering and provides protection against ischaemic injury in animal models. We tested the hypothesis that magnesium reduces the threshold (triggering core temperature) and gain of shivering without substantial sedation or muscle weakness. METHODS: We studied nine healthy male volunteers (18-40 yr) on two randomly assigned treatment days: (1) control and (2) magnesium (80 mg kg(-1) followed by infusion at 2 g h(-1)). Lactated Ringer's solution (4 degrees C) was infused via a central venous catheter over a period of approximately 2 h to decrease tympanic membrane temperature by approximately 1.5 degrees C h(-1). A significant and persistent increase in oxygen consumption identified the threshold. The gain of shivering was determined by the slope of oxygen consumption vs core temperature regression. Sedation was evaluated using a verbal rating score (VRS) from 0 to 10 and bispectral index (BIS) of the EEG. Peripheral muscle strength was evaluated using dynamometry and spirometry. Data were analysed using repeated measures anova; P<0.05 was statistically significant. RESULTS: Magnesium reduced the shivering threshold (36.3 [SD 0.4] degrees C vs 36.6 [0.3] degrees C, P = 0.040). It did not affect the gain of shivering (control, 437 [289] ml min(-1) degrees C(-1); magnesium, 573 [370] ml min(-1) degrees C(-1); P=0.344). The magnesium bolus did not produce significant sedation or appreciably reduce muscle strength. CONCLUSIONS: Magnesium significantly reduced the shivering threshold. However, in view of the modest absolute reduction, this finding is considered to be clinically unimportant for induction of therapeutic hypothermia. (+info)
Eclampsia: still a problem in Bangladesh.
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This descriptive study, conducted at Dhaka Medical College and Hospital, Bangladesh, includes 2956 consecutive eclamptic patients who were admitted between 1998 and 2000 and evaluates their outcomes after treatment with magnesium sulfate. Although magnesium sulfate controls convulsion efficiently, death from eclampsia remains high in our country. Thus, a second purpose of this study was to identify additional factors responsible for death from eclampsia. Among 32,999 obstetric patients admitted to the hospital during the years 1998 to 2000, 2956 were eclamptic, yielding an incidence of 9%. The antepartum/intrapartum and postpartum incidences of eclampsia were 80% and 20%, respectively. Among the patients with eclampsia, 79% had good prognosis without any added complication except convulsion, and 21% had other complications. For the period 1998 to 2000, the rate of maternal death from eclampsia was 8.6%, which was lower than that of the immediate past year (1997) for which the mortality was 16%. Changing the protocol from diazepam to magnesium sulfate for control of convulsion significantly reduced the incidence of death. But reduction of the risk of death was difficult when patients had developed complications. Most of the patients in the group who had complications died (98%); these complications developed as a result of a delayed decision for treatment. Therefore, efforts should be directed at developing awareness to receive treatment at an appropriate time to prevent the development of eclampsia and to reduce the mortality from eclampsia and its complications. (+info)
Magnesium sulfate in aneurysmal subarachnoid hemorrhage: a randomized controlled trial.
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BACKGROUND AND PURPOSE: Magnesium reverses cerebral vasospasm and reduces infarct volume after experimental subarachnoid hemorrhage (SAH) in rats. We aimed to assess whether magnesium reduces the frequency of delayed cerebral ischemia (DCI) in patients with aneurysmal SAH. METHODS: Patients were randomized within 4 days after SAH. Magnesium sulfate therapy consisted of a continuous intravenous dose of 64 mmol/L per day, to be started within 4 days after SAH and continued until 14 days after occlusion of the aneurysm. The primary outcome DCI (defined as the occurrence of a new hypodense lesion on computed tomography compatible with clinical features of DCI) was analyzed according to the "on-treatment" principle. For the secondary outcome measures "poor outcome" (Rankin >3) and "excellent outcome" (Rankin 0), we used the "intention-to-treat" principle. RESULTS: A total of 283 patients were randomized. Magnesium treatment reduced the risk of DCI by 34% (hazard ratio, 0.66; 95% CI, 0.38 to 1.14). After 3 months, the risk reduction for poor outcome was 23% (risk ratio, 0.77; 95% CI, 0.54 to 1.09). At that time, 18 patients in the treatment group and 6 in the placebo group had an excellent outcome (risk ratio, 3.4; 95% CI, 1.3 to 8.9). CONCLUSIONS: This study suggests that magnesium reduces DCI and subsequent poor outcome, but the results are not yet definitive. A next step should be a phase III trial to confirm the beneficial effect of magnesium therapy, with poor outcome as primary outcome. (+info)
Effects of magnesium on atrial fibrillation after cardiac surgery: a meta-analysis.
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OBJECTIVES: To assess the efficacy of the administration of magnesium as a method for the prevention of postoperative atrial fibrillation (AF) and to evaluate its influence on hospital length of stay (LOS) and mortality. METHODS: Literature search and meta-analysis of the randomised control studies published since 1966. RESULTS: 20 randomised trials were identified, enrolling a total of 2490 patients. Study sample size varied between 20 and 400 patients. Magnesium administration decreased the proportion of patients developing postoperative AF from 28% in the control group to 18% in the treatment group (odds ratio 0.54, 95% confidence interval (CI) 0.38 to 0.75). Data on LOS were available from seven trials (1227 patients). Magnesium did not significantly affect LOS (weighted mean difference -0.07 days of stay, 95% CI -0.66 to 0.53). The overall mortality was low (0.7%) and was not affected by magnesium administration (odds ratio 1.22, 95% CI 0.39 to 3.77). CONCLUSION: Magnesium administration is an effective prophylactic measure for the prevention of postoperative AF. It does not significantly alter LOS or in-hospital mortality. (+info)