Stating the obvious: intravenous magnesium sulphate should be the first parenteral bronchodilator in paediatric asthma exacerbations unresponsive to first-line therapy

Comparison of doses of Nebulized Magnesium sulphate as an adjuvant treatment with salbutamol in children with Status Asthmaticus

Objectives

To compare the response between different doses of nebulized magnesium sulphate along with Salbutamol in children between two to 12 years of age with status asthmaticus.

Methods

This single blinded, randomized clinical trial was carried out at the Department of Pediatrics, Dr. Ziauddin University Hospital, Karachi, Pakistan during October 2021 to September 2022. A total of 104 children aged between 2-12 years, with the diagnosis of asthma having "Pediatric Rapid Assessment Measure (PRAM)" score>4 and with reactive airways were included. Children either received three back-to-back nebulization with salbutamol solution only (n=50) or salbutamol and MgSO4 with three different doses (250mg, 500mg or 750mg) after every 20 minutes for 60 minutes. The PRAM score was used as an assessment tool to clinically score asthma.

Results

In a total of 104 children, 53 (51.0%) were girls. The mean age was 5.25±2.86 years. No statistically significant difference was found in PRAM scores at baseline (p=0.448) and at 20-minutes (p=0.072) but significant differences were observed at 40-minutes (p=0.009), 60-minutes (p=0.011), 120-minutes (p=0.010), 6-hours (=0.034), 12-hours (p=0.018), 18-hours (p=0.033) and at 24-hours (p=0.029). The reduction in PRAM scores from baseline to 24-hours following treatment among Salbutamol, Salbutamol+ MgSo4 250mg, Salbutamol+ MgSo4 500mg and Salbutamol+ MgSo4 750mg group were 6.53±1.09, 7.22±1.09, 6.85±1.43 and 7.57±1.06 respectively (p=0.007).

Conclusion

While children with status asthmaticus managed using salbutamol, with or without nebulized MgSO4, showed improved clinical outcomes, combining salbutamol with higher dosages of nebulized MgSO4 resulted in even greater clinical improvement.Clinical Trial Registry: https://clinicaltrials.gov/ct2/show/NCT04929626.

Magnesium sulphate intravenously reduces tachycardia side-effects of β2-agonists

The review by Erumbalaet al. [1] correctly proposing magnesium sulphate (MgSO₄) as the first intravenous bronchodilator missed vital points of its pharmacological actions. The i.v. drug reduces or eliminates tachycardia and palpitation side-effects of β₂-agonists [2–5]. As well as relaxing smooth muscle of the bronchi, vasculature, gut and uterus, MgSO₄ slows cardiac atrial conduction [6, 7], and was used in the past to revert supraventricular tachycardia and fast atrial fibrillation [8, 9]. There is no evidence to be found for the 20–30 min infusion rate for i.v. MgSO₄ of 40–75 mg.kg⁻¹, and this infusion time will not create a sufficiently high serum level to relax bronchial smooth muscle. In acute-severe and life-threatening asthma i.v. MgSO₄ followed by i.v. β₂-agonist is safe [10]; an infusion time of 5 min for MgSO₄ has evidence for the safety of this speed of injection in obstetric [11] and cardiac literature, albeit in adults.

Intravenous magnesium sulphate allows safer intravenous β₂-agonist delivery in acute-severe and life-threatening asthma attackshttps://bit.ly/3veUpfC

Reply to: Magnesium sulphate intravenously reduces tachycardia side-effects of β2-agonists

We thank W.F.S. Sellers and M.F.M. James for their correspondence in response to our review on the use of intravenous magnesium sulphate in acute asthma in childhood [1] and welcome their comments. Salbutamol induced tachycardia and palpitations are a concern in younger children when treated with large doses of salbutamol [2]. Emphasising the effect that magnesium has on reducing this tachycardia is important. We were aware of the lack of evidence for the 20-min infusion rate but did not mention it in the paper. Recognising that it is safe and may have a greater effect if delivered at a greater speed will be useful for further development of randomised controlled acute asthma in childhood studies. This illustrates how important it is to share experience across specialties.

Intravenous magnesium sulphate reduces β₂-agonist induced tachycardiahttps://bit.ly/3pPnGKl