|Year : 2007 | Volume
| Issue : 3 | Page : 225-227
Intravenous magnesium sulfate therapy in severe asthma
Mohd. Al-Ajmi1, P Mandal2
1 MD, Consultant & Chairman of Surgical Disciplines, Department of Anaesthesia & ICU, Armed Forces Hospital, Kuwait (AFHK)
2 MD, Sr. Specialist, Department of Anaesthesia & ICU, Armed Forces Hospital, Kuwait (AFHK), Kuwait
|Date of Acceptance||25-Mar-2007|
|Date of Web Publication||20-Mar-2010|
Department of Anaesthesia & ICU, Armed Forces Hospital, Kuwait (AFHK)
Source of Support: None, Conflict of Interest: None
A 22-year-old female, known asthmatic since seven years, developed severe bronchospasm in the preoperative period. Bronchospasm remained unresponsive to the inhaled beta-agonist plus anticholinergic, IV aminophylline and hydrocortisone but responded quickly with magnesium sulfate® ( PSI, KSA) infusion 1.25gm in 100ml normal saline over 20 minutes and another 1.25 gm over next 30 minutes as the initial infusion showed improvement in her clinical symptoms. Within half an hour of administering the 1st infusion of magnesium sulfate (1.25 gm) the respiratory rate started reducing, rhonchi became less, SpO 2 came upto 92% and remained always above 90%. Encouraged by this result IV magnesium sulfate 2.5 gm in 500 ml normal saline was infused over next 24 hours along with alternate salbutamol and ipratropium nebulization every 6 hourly. With this treatment regimen the patient became asymptomatic within next 24 hours with normal clinical parameters and FEV 1 value. Hence it may be concluded that IV magnesium sulfate can be considered for patients with acute severe asthma who do not respond to standard therapeutic medications.
Keywords: Severe bronchospasm; Bronchodilators; Nebulization beta-agonist, Anticholinergic; IV, Magnesium sulfate.
|How to cite this article:|
Al-Ajmi M, Mandal P. Intravenous magnesium sulfate therapy in severe asthma. Indian J Anaesth 2007;51:225-7
| Introduction|| |
Nebulized beta-agonist in asthmatics is considered to be the 1st choice of bronchodilator therapy ,. But frequently it has met with disappointing results in an increasing number of moderate to severe asthmatic patients who may be characterized as "poor responders" . These type of patients even do not respond to combination therapy with nebulized beta-agonist, anticholinergic, locally acting or intravenously (IV) administered steroids. For them magnesium sulfate administered either IV  or nebulized  as isotonic solution may be of help to achieve rapid bronchodilatation. We present here such a case of severe asthma who was unresponsive to the inhaled beta-agonist plus anticholinergic, IV aminophylline and hydrocortisone but responded quickly with IV magnesium sulfate therapy.
| Case report|| |
A 22-year-old female weighing 55 kg, known asthmatic since last seven years, was admitted to Armed Forces Hospital, Kuwait (AFHK) to undergo cholecystectomy for gall stone disease. She developed suddenly shortness of breath and perspiration following dust storm. She was shifted to ICU for respiratory therapy after the surgical registrar found that she had developed acute bronchospasm. On arrival in the ICU with ordinary oxygen mask she was put into continuous monitoring for SpO 2, EKG, heart rate, respiratory rate and noninvasive blood pressure. She was put into supine head-up position with ventimask oxygen (35%). On examination, she was conscious and oriented, her respiratory rate was more than 30 per minute, she was having tracheal tug and all her accessory muscles of respiration were active. Her chest expansion was very minimal. On auscultation of her chest bilateral extensive rhonchi and fine crepitations were audible. Her forced expiratory volume in one second (FEV 1) was 25% of her predicted value and SpO 2 was between 80-85%. A diagnosis of acute exacerbation of bronchial asthma was made and treatment was initiated. She was initially receiving 35% oxygen by ventimask which was gradually increased to 50%. Salbutamol (500 mg in 5 ml) and ipratropium (500 mg in 2ml) nebulization was provided alternately without any improvement in her clinical symptoms. Intravenous aminophylline 250 mg bolus plus 3mg.kg -1.hour -1 of infusion was started. Hydrocortisone 200mg IV bolus too was tried with limited result in her symptoms and FEV 1 alue (28% of predicted) after 30 minutes of treatment. SpO 2 value improved marginally and maintained between 85-88% only but no improvement in her dyspnoea or rhonchi in the chest.
At this point magnesium sulfate® ( PSI, KSA) 1.25gm in 100ml normal saline was infused over 20 minutes and another 1.25 gm was infused over next 30minutes as the initial infusion showed improvement in her clinical symptoms. Within half an hour of administering the 1st infusion of magnesium sulfate (1.25 gm) the respiratory rate started reducing, rhonchi was less, SpO 2 came upto 92% and remained always above 90%. Her chest movement could be visible and the normal pattern of respiration was resumed plus she could cough out mucoid sputum. Tracheal tug disappeared, FEV 1 value improved to 45%. Encouraged by this result IV magnesium sulfate 2.5 gm in 500 ml normal saline was infused over next 24 hours along with alternate salbutamol and ipratropium nebulization every 6 hourly but aminophylline infusion was discontinued. Abed side X-ray chest was unremarkable at this point. There was continuous improvement in her symptoms, chest findings and FEV 1 values. SpO 2 value came up and remained above 98% after two hours of magnesium sulfate infusion. Her FiO 2 was reduced to 35%. After 24 hours, magnesium sulfate infusion was discontinued but alternate salbutamol and ipratropium nebulization every 6 hourly were continued. During magnesium sulfate infusion no arrhythmia or haemodynamic changes were noticed. Biochemical parameters in the blood were within normal limits including the magnesium level -1 mmol.L -1 (N=0.74-1.03 mmol.L -1 ). She was observed in the ICU for another day and then shifted to ward. At that time her respiratory rate was 12-16/minute, SpO 2 98-100% in room air and FEV 1 was 75% of her predicted value.
| Discussion|| |
When there is need for quick bronchodilatation, ( 2 agonists remained the main stay in the initial management of acute asthma ,,. However, the potential role of other agents in the initial management of acute asthma is still unclear. Aminophylline, many a times, in acute asthma for adults  and children  failed to demonstrate a beneficial result. Steroids appear to reduce inflammation of the bronchial wall and help to avoid hospital admissions . Significant debate exists with respect to the benefit of other agents such as magnesium sulfate in the treatment of acute asthma. Magnesium, a predominantly intracellular cation, is an important cofactor in many enzymatic reactions and is linked to cellular homeostasis . In addition, magnesium has an effect on smooth muscle cells, with hypomagnesemia causing contraction and hypermagnesemia causing relaxation. There is some evidence that when magnesium is infused into asthmatic patients, it produces additional bronchodilatation ,. Because magnesium levels in asthmatics appear to be similar to those in control subjects , the effect may relate to magnesium's competitive antagonism  with calcium. In addition, evidence suggests that magnesium may reduce the neutrophilic burst  associated with the inflammatory response in asthma. Thus, there is reason to believe that magnesium treatment, in the form of IV magnesium sulfate, may be beneficial in the treatment of acute asthma. The same result was achieved in this patient too. Because she did not respond to initial medications and observing her distress, once even we thought to put her into ventilator as there was no BiPAP or CPAP mask available with us.
The dose of initial infusion of magnesium sulfate was selected as conservative, because we used this drug (as bronchodilator) for the first time in this patient. Many authors ,, have used initial loading dose 2 gm over a period of 20 minutes where as we infused almost half the dose at a time. But even with that dose we had achieved our goal as evident in her clinical condition and respiratory parameters plus reduction in the other drug therapy.
Hence moderate dose of magnesium sulfate appears to be safe and beneficial in patients with acute severe asthma unresponsive to conventional therapy.
To conclude, IV magnesium sulfate can be considered for patients with acute severe asthma who do not respond to standard therapeutic medications.
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